Antibacterial compounds

Abstract: A compound of the formula; wherein R⁰ stands for hydrogen atom, nitrogen-containing heterocyclic group, acyl group or esterified carboxyl group, Z stands for S, S→-O, O or CH₂, R⁴ stands for hydrogen atom, methoxy group or formamido group, R¹³ stands for hyd­ rogen atom, methyl group, hydroxyl group or halogen atom and A stands for an optionally substituted imidazol-1-yl group forming a condensed ring at the 2,3- or 3,4-position or a physiologically or phamaceutically acceptable salt or ester thereof. This compound is novel and has excellent antibacterial activity.

Description: This invention relates to novel antibacterial compounds having excellent antibacterial action, a method of preparing same and a pharmaceutical composition. A variety of cephem compounds having a quaternary ammoniomethyl group at the 3-position and 2-(2-aminothiazol-4-yl)-2-hydroxy(or substituted hydroxy)iminoacetamido group at the 7-position simultaneously or derivatives thereof have so far been synthesized, and patent applications [for instance, Japanese Publication of Unexamined Application (Kokai) Sho-53-34795, Sho-54-9296, Sho-54-135792, Sho-54-154786, Sho-55-149289, Sho-57-56485, Sho-57-192394, Sho-58-159498, etc.] concerning those compounds have been filed. However, most of the compounds, whose quaternary ammoniomethyl group at the 3-position has a nitrogen-containing aromatic heterocyclic ring, are those having a monocyclic pyridinium group with or without a substituent or substituents on the ring thereof, and the compounds of the present invention having an imidazol-1-yl group which forms a condensed ring at the 2,3-position or the 3,4-position have never been disclosed in the specification of any patent application, not to speak of a report of the synthesis thereof. Furthermore EP 0 062 321 discloses cephem compounds and US 4 165 430 discloses cephalosporin compounds. Cephem-type antibiotics have been widely used for the therapy of diseases of human beings and animals caused by pathogenic bacteria. These compounds are especially useful for the therapy of diseases caused by bacteria resistant to penicillin-type antibiotics as well as for the therapy of penicillin-sensitive patients. In these cases, it is desirable to use cephem-type antibiotics showing activity against both gram-positive and gram-negative bacteria. For this reason, extensive studies on cephem-type antibiotics having a wide antibacterial spectrum have been carried out. As a result of research work covering a long period of time, it has been found that introduction of 2-(2-aminothiazol-4-yl)-2-hydroxy (or substituted hydroxy)iminoacetamido group or nitrogen-containing heterocycle-amino group at the 7-position of cephem ring renders the cephem compound active against both gram-positive and gram-negative bacteria, which has led to the exploitation and development of what is called "the third generation cephalosporin". At present, several types of the third generation cephalosporin compounds have already been put on the market. Another characteristic feature of these third generation cephalosporin antibiotics lies in that these substances are active against the so-called cephalosporin-resistant bacteria, which penicillins have also encountered. More specifically, cephem compounds of the present invention showed antibacterial action to such an extent as clinically usable against some of Escherichia coli , some of the bacteria belonging to the genus Citrobacter and most of the bacteria belonging to the genus Proteus that are positive to indole reactions as well as against most of the phathogenic bacteria classified into the genus Enterobacter , Serratia or Pseudomonas . The technical concept of these third generation cephalosporin compounds suggested, among others, that such cephem compounds as well as oxa- or carba-derivatives thereof as having a quaternary ammoniomethyl group, e.g. pyridinium methyl group, at the 3-position and the above-mentioned aminothiazolyloxyiminoacetamides or nitrogen-containing heterocycleamino group at the 7-position simultaneously would have more superior antibacterial action and specifically characteristic antibacterial spectrum, and a variety of the compounds of this category have been synthesized. The present invention relates to a compound of the formula: wherein R⁰ stands for (i) hydrogen atom, (ii) nitrogen-containing 5-8 membered heterocyclic group containing 1-4 hetero atoms selected from nitrogen atom optionally oxidized, oxygen atom and sulfur atom or 3H-indol-2-yl, 3H-indol-3-yl, benzopyranyl, quinolyl, pyrido[2,3-d]pyrimidyl, 1,5-, 1,6-, 1,7-, 1,8-, 2,6- or 2,7-naphthylidyl, thieno[2,3-d]-pyridyl, pyrimidopyrimidyl, pyrazinoquinolyl, or benzopyranyl that is unsubstituted or substituted by one to three of C₁₋₆ alkyl group, c₃₋₁₀ cycloalkyl group, c₆₋₁₀ aryl group, C₇₋₁₂ aralkyl group, hydroxyl group, C₁₋₆ alkoxy group, mercapto group, C₁₋₆ alkylthio group, amino group, mono-C₁₋₆ alkylamino group, di-C₁₋₆ alkylamino group, halogen atom, nitro group, azido group, cyano group, carboxyl group, C₁₋₁₀ alkoxycarbonyl group, C₁₋₆ alkanoyl group, C₁₋₆ alkanoyloxy group, carbamoyl group, mono-C₁₋₆ alkylcarbamoyl group, di-C₁₋₆ alkylcarbamoyl group, carbamoyl group, mono-C₁₋₆ alkylcarbamoyl-oxy group or di-C₁₋₆ alkylcarbamoyloxy group, iii) a group of the formula wherein R¹ stands for an amino group or a protected amino group, R² stands for hydrogen atom, halogen atom, or nitro group n is 0 or 1, and R³ stands for hydrogen atom or C₁₋₆ alkyl group, C₂₋₆ alkenyl group, C₂₋₆ alkynyl group, C₃₋₁₀ cycloalkyl group or c₅₋₆ cycloalkenyl group that is unsubstituted or substituted by one or two of hydroxyl, c₁₋₆ alkyl, C₂₋₆ alkenyl, c₂₋₆ alkynyl, c₃₋₁₀ cycloalkyl, C₅₋₆ cycloalkenyl, c₆₋₁₀ aryl, C₇₋₁₉ aralkyl, 2- or 3-pyrrolyl, 3-, 4- or 5-pyrazolyl, 2-, 4- or 5-imidazolyl, 1,2,3- or 1,2,4-triazolyl, 1H- or 2H-tetrazolyl, 2- or 3-furyl, 2- or 3-thienyl, 2-, 4- or 5-oxazolyl, 3-, 4- or 5-isoxazolyl, 1,2,3-oxadiazol or 5-yl, 1,2,4-oxadiazol-3- or 5-yl, 1,2,5- or 1,3,4-oxadiazolyl, 2- 4,- or 5-thiazolyl, 3-, 4- or 5-isothiazolyl, 1,2,3-thiazidazol-4- or 5-yl, 1,2,4-thiadiazol-3- or 5-yl, 1,2,5- or 1,3,4-thiadiazolyl, 2- or 3-pyrrolidinyl, 2-, 3-or 4-pyridyl, 2-, 3- or 4-pyridyl-N-oxide, 3- or 4-pyridazinyl, 3- or 4-pyridazinyl-N-oxide, 2-, 4- or 5-pyrimidinyl, 2-, 4- or 5-pyrimidinyl-N-oxide, pyrazinyl, 2-, 3- or 4-piperidinyl, piperazinyl, 3H-indol-2- or 3-yl, 2-, 3- 4-pyranyl, 2-, 3- or 4-thiopyranyl, benzopyranyl, quinolyl, pyrido[2,3-d]pyrimidyl, 1,5-, 1,6-, 1,7-, 1,8-, 2,6- or 2,7-naphthylidyl, thieno[2,3-d]pyridyl, pyrimidopyrimidyl, pyrazinoquinolyl, benzopyranyl, C₁₋₆ alkoxy, C₃₋₁₀ cycloalkyloxy, c₆₋₁₀ aryloxy, C₇₋₁₉ aralkyloxy, thiazolyloxy, mercapto, C₁₋₆ alkylthio, c₃₋₁₀ cycloalkylthio, c₆₋₁₀ arylthio, c₇₋₁₉ aralkylthio, thiazolylthio, amino, mono-C₁₋₆ alkylamino, di-C₁₋₆ alkylamino, tri-C₁₋₆ alkylammonium, c₃₋₁₀ cycloalkylamino, C₆₋₁₀ arylamino, c₇₋₁₉ aralkylamino, thiazolylamino, thiadiazolylamino, cyclic amino, azido, nitro, halogen, cyano, carboxyl, c₁₋₁₀ alkoxy-carbonyl, c₆₋₁₀ aryloxy-carbonyl, c₇₋₁₉ aralkyloxy-carbonyl, benzoyl, naphthoyl, phthaloyl, phenylacetyl, c₁₋₆ alkanoyl, C₃₋₅ alkenoyl, benzoyloxy, naphthoyloxy, phenylacetoxy, c₂₋₆ alkanoyloxy, c₃₋₅ alkenoyloxy, carbamoyl, N-methylcarbamoyl, N,N-dimethylcarbamoyl, N-ethylcarbamoyl, N,N-diethylcarbamoyl, N-phenylcarbamoyl, N-acetylcarbamoyl, N-benzoylcarbamoyl, N-(p-methoxy-phenyl)carbamoyl, pyrrolidinocarbonyl, piperidinocarbonyl, piperazinocarbonyl, morpholino-carbonyl, thiocarbamoyl, N-methylthiocarbamoyl, N-phenylthiocarbamoyl, carbamoyloxy, N-methylcarbamoyloxy, N,N-dimethylcarbamoyloxy, N-ethylcarbamoyloxy, N-phenylcarbamoyloxy, phthalimido, c₁₋₆ alkanoylamino, benzamido, naphthoylamido, phthalimido, carboxyamino, c₁₋₁₀ alkoxy-carboxamido, C₆₋₁₀ aryloxy-carboxamido or C₇₋₁₉ aralkyloxy-carboxamido; (iv) α-formamido-α-(2-aminothiazol-4-yl)acetyl or α-formacetamido-α-(2-aminothiazol-4-yl)acetyl or (v) methoxy-carbonyl, ethoxycarbonyl, n-propoxycarbonyl, isopropoxy-carbonyl, n-butoxycarbonyl, tert-butoxycarbonyl, cyclohexyloxycarbonyl, norbornyloxycarbonyl, phenoxycarbonyl, naphthyloxycarbonyl, benzyloxycarbonyl, methoxymethyl-oxycarbonyl, acetylmethyloxycarbonyl, 2-trimethylsilyl-ethoxycarbonyl, 2-methanesulfonylethoxycarbonyl, 2,2,2-trichloroethoxycarbonyl, 2-cyanoethoxycarbonyl, p-methylphenoxycarbonyl, p-methoxyphenoxycarbonyl, p-chlorophenoxycarbonyl, p-methylbenzyloxycarbonyl, p-methoxybenzyloxycarbonyl, p-chlorobenzyloxycarbonyl, p-nitrobenzyloxycarbonyl, benzhydryloxycarbonyl, cyclopropyloxycarbonyl, cyclopentyloxycarbonyl, or cyclohexyloxycarbonyl; Z stands for S, S-O, O or CH₂; R⁴ stands for hydrogen atom, methoxy group or formamido group; R¹³ stands for hydrogen atom, methyl group, hydroxyl group or halogen atom, and A stands for an imidazol-1-yl group which forms a fused ring at the 2,3- or 3,4-position representable by the general formula [A¹] or [A²] wherein B stands for a group forming a 5- to 6-membered aromatic heterocyclic ring which may be fused with another aromatic ring or aromatic hetero-cyclic ring, R¹¹ stands for hydrogen atom or a substituent (or substituents) on the imidazole ring and R¹² stands for hydrogen atom or a substituent (or substituents) on the ring which may be fused with the imidazole ring wherein the heterocyclic ring is 5-8 membered ring containing 1-4 hetero atom selected from nitrogen atom optionally oxidized, oxygen atom and sulfur atom and R¹¹ and R¹² is respectively a substituent or substituents selected from a class consisting of hydroxyl group, hydroxy c₁₋₆ alkyl group, c₁₋₆ alkyl group, C₂₋₆ alkenyl group, C₂₋₆ alkynyl group, C₄₋₆ alkadienyl group, c₃₋₁₀ cycloalkyl group, C₅₋₆ cycloalkenyl group, C₃₋₁₀ cycloalkyl C₁₋₆ alkyl group, C₆₋₁₀ aryl group, C₇₋₁₂ aralkyl group, di-C₆₋₁₀ aryl-methyl group, tri-C₆₋₁₀ arylmethyl group, 2- or 3-pyrrolyl, 3-, 4- or 5-pyrazolyl, 2-, 4- or 5-imidazolyl, 1,2,3- or 1,2,4-triazolyl, 1H- or 2H-tetrazolyl, 2- or 3-furyl, 2- or 3-thienyl, 2-, 4- or 5-oxazolyl, 3-, 4- or 5-isoxazolyl, 1,2,3-oxadiazol-4- or 5-yl, 1,2,4-oxadiazol-3- or 5-yl, 1,2,5-or 1,3,4-oxadiazolyl, 2-, 4- or 5-thiazolyl, 3-, 4- or 5-isothiazolyl, 1,2,3-thiadiazol-4- or 5-yl, 1,2,4-thiadiazol-3- or 5-yl, 1,2,5- or 1,3,4-thiadiazolyl, 2- or 3-pyrrolidinyl, 2-, 3-or 4-pyridyl, 2-, 3- or 4-pyridyl-N-oxide, 3- or 4-pyridazinyl, 3- or 4-pyridazinyl-N-oxide, 2-, 4- or 5-pyrimidinyl, 2-, 4- or 5-pyrimidinyl-N-oxide, pyrazinyl, 2-, 3- or 4-piperidinyl, piperazinyl, 3 H-indol-2- or 3-yl, 2,3- or 4-pyranyl, 2-, 3- or 4-thiopyranyl, benopyranyl, quinolyl, pyrido[2,3-d]pyrimidyl, 1,5-, 1,6-, 1,7-, 1,8-, 2,6- or 2,7-naphthylidyl, thieno[2,3-d]pyridyl, pyrimidopyrimidyl, pyrazinoquinolyl, benzopyranyl, c₁₋₆ alkoxy group, C₁₋₆ alkoxy C₁₋₆ alkyl group, C₃₋₁₀ cycloalkyloxy group, C₆₋₁₀aryloxy group, C₇₋₁₉ aralkyloxy group, mercapto group, mercapto C₁₋₆ alkyl group, sulfo group, sulfo C₁₋₆ alkyl group, C₁₋₆ alkylthio group, C₁₋₆ alkylthio C₁₋₆ alkyl group, C₃₋₁₀ cycloalkylthio group, C₆₋₁₀ arylthio group, C₇₋₁₉ aralkylthio group, amino group, amino C₁₋₆ alkyl group, mono-C₁₋₆ alkylamino group, di-C₁₋₆ alkylamino group, mono-C₁₋₆ alkylamino C₁₋₆ alkyl group, di-C₁₋₆ alkylamino C₁₋₆ alkyl group, C₃₋₁₀ cycloalkylamino group, C₆₋₁₀ arylamino group, C₇₋₁₉ aralkylamino group, cyclic amino group, cyclic amino C₁₋₆ alkyl group, cyclic amino C₁₋₆ alkylamino group, azido group, nitro group, halogen atom, halogeno C₁₋₆ alkyl group, cyano group, cyano C₁₋₆ alkyl group, carboxyl group, carboxy C₁₋₆ alkyl group, C₁₋₁₀ alkoxy-carbonyl group, C₁₋₁₀alkoxy-carbonyl C₁₋₆ alkyl group, C₆₋₁₀ aryloxycarbonyl group, C₇₋₁₉ aralkyloxycarbonyl group, benzoyl, naphthoyl, phthaloyl, phenylacetyl, C₁₋₆ alkanoyl group, C₂₋₆ alkanoyl C₁₋₆ alkyl group, C₃₋₅ alkenoyl group, benzoyloxy, naphthoyloxy, phenylacetoxy, C₂₋₆ alkanoyloxy group, C₂₋₆ alkanoyloxy, C₁₋₆ alkyl group, C₃₋₅ alkenoyloxy group, carbamoyl C₁₋₆ alkyl group, carbamoyl, N-methylcarbamoyl, N,N-dimethylcarbamoyl, N-ethylcarbamoyl, N,N-diethylcarbamoyl, N-phenylcarbamoyl, N-acetylcarbamoyl, N-benzoylcarbamoyl, N-(p-methoxyphenyl)carbamoyl, pyrrolidinocarbonyl, piperidinocarbonyl, piperazinocarbonyl, morpholinocarbonyl, thiocarbamoyl, N-methylthiocarbamoyl, N-phenylthiocarbamoyl, carbamoyloxy, N-methylcarbamoyloxy, N,N-dimethylcarbamoyloxy, N-ethylcarbamoyloxy, N-phenylcarbamoyloxy, carbamoyloxy C₁₋₆ alkyl group, C₁₋₆ alkanoylamino group, benzamido, naphthoylamido, phthalimido, sulfonamido group, carboxyamino group, C₁₋₁₀ alkoxycarboxamido group, C₆₋₁₀ aryloxy-carboxamido group, and C₇₋₁₉ aralkyloxycarboxamido group, or a physiologically or pharmaceutically acceptable salt or ester thereof, a method of preparing them and to pharmaceutical compositions. More specifically, the antibacterial compounds of the present invention are cephem compounds representable by the general formula [I] (Z=S, S→O) as well as oxa-(Z=O) or carba-(Z=CH₂) derivatives thereof. The cephem compounds in the present specification are a group of compounds named on the basis of "cepham" disclosed in "the Journal of the American Chemical Society" Vol. 84 , p. 3400 (1962), and mean, among the cepham compounds, those having a double bond at the the 3,4-position. As stated hereinbefore, it has gradually become apparent that a cephem compound as well as oxa- or carba-derivatives thereof having a quaternary ammoniomethyl group at the 3-position and an aminothiazolyloxyiminoacetamido group or nitrogen-containing heterocycle-amino group at the 7-position simultaneously has further excellent antibacterial activity and specific antibacterial spectrum. A number of compounds having a nitrogen-containing aromatic heterocyclic ring as the quaternary ammoniomethyl group at the 3-position have already been synthesized and corresponding patent applications have been filed. Most of those heterocyclic rings are monocyclic pyridinium groups or those having a substituent on the ring thereof, and compounds of this invention having an imidazol-1-yl group which forms a condensed ring at the 2,3-position or the 3,4-position have not been synthesized at all. The present inventors succeeded in synthesizing the compounds representable by the general formula [I] and having such structural features, and examined the antibacterial activities and antibacterial spectrum, resulting in the findings that the compounds [I] have strong antibacterial action against various bacteria, especially against cephalosporin-resistant bacteria set forth above, and that they show specific antibacterial action against bacteria belonging to the genus Pseudomonas , and completed the present invention. Reference is made as follows to the group names and symbols used in the present specification. Unless otherwise specifically defined, those groups and symbols are of the following meanings respectively. "Alkyl group" is preferably a straight-chain or branched lower alkyl group having 1-6 carbon atoms (hereinafter sometimes mentioned briefly as "C₁₋₆ alkyl group"), which is exemplified by methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl or n-hexyl. "Alkenyl group" is preferably a straight-chain or branched lower alkenyl group having 2-6 carbon atoms (hereinafter sometimes mentioned briefly as "C₂₋₆ alkenyl group"), which is exemplified by vinyl, ally, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, methallyl, or 1,1-dimethylallyl. "Alkynyl group" is preferably a straight-chain or branched lower alkynyl group having 2-6 carbon atoms (hereinafter sometimes mentioned briefly as "C₂₋₆ alkynyl group"), which is exemplified by ethynyl, 1-propynyl or propargyl. "Cycloalkyl group" is preferably a 3-7 membered alicyclic hydrocarbon group having 3-10 carbon atoms (hereinafter sometimes mentioned briefly as "C₃₋₁₀ cycloalkyl group"), which is exemplified by cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, norbornyl or adamantyl. "Cycloalkenyl group" is preferably a 5-6 membered alicyclic hydrocarbon group having double bond (hereinafter sometimes mentioned briefly as "C₅₋₆ cycloalkenyl group"), which is exemplified by cyclopentenyl, cyclopentadienyl, cyclohexenyl or cyclohexadienyl. "Aryl group" is preferably an aromatic hydrocarbon group having 6-10 carbon atoms (hereinafter sometimes mentioned briefly as "C₆₋₁₀ aryl group"), which is exemplified by phenyl, α-naphthyl, β-naphthyl or biphenylyl. "Aralkyl group" is preferably an aromatic substituted alkyl group having 7-12 carbon atoms (hereinafter sometimes mentioned briefly as "C₇₋₁₂ aralkyl group"), which is exemplified by benzyl, 1-phenylethyl, 2-phenylethyl, phenylpropyl or naphthylmethyl. Incidentally, the C₇₋₁₂ aralkyl group, in combination with the di-C₆₋₁₀ aryl-methyl group and tri-C₆₋₁₀ aryl-methyl group, is sometimes stated as "C₇₋₁₉ aralkyl group". "Diarylmethyl group" means methyl group substituted with two C₆₋₁₀ aryl groups mentioned above (hereinafter sometimes mentioned briefly as "di-C₆₋₁₀ aryl-methyl group"), which is exemplified by benzhydryl. "Triarylmethyl group" means methyl group substituted with three C₆₋₁₀ aryl groups mentioned above (hereinafter sometimes mentioned briefly as "tri-C₆₋₁₀ arylmethyl group"), which is exemplified by trityl. The aryl group of "arylmethylene group" is preferably C₆₋₁₀ aryl group mentioned above, hence "arylmethylene group" being hereinafter sometimes called "C₆₋₁₀ arylmethylene group", which is exemplified by benzylidene (C₆H₅CH=). The alkyl group of "alkoxy group" is preferably C₁₋₆ alkyl group mentioned above, hence "alkoxy group" being hereinafter sometimes called "C₁₋₆ alkoxy group", which is exemplified by methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, tert-butoxy, amyloxy or hexyloxy. The cycloalkyl group of "cycloalkyloxy group" is preferably C₃₋₁₀ cycloalkyl group mentioned above, hence "cycloalkyloxy group" being hereinafter sometimes called "C₃₋₁₀ cycloalkyloxy group", which is exemplified by cyclopropyloxy, cyclopentyloxy, cyclohexyloxy or norbornyloxy. The aryl group of "aryloxy group" is preferably C₆₋₁₀ aryl group mentioned above, hence "aryloxy group" being hereinafter sometimes called "C₆₋₁₀ aryloxy group", which is exemplified by phenoxy or naphthyloxy. The aralkyl group of "aralkyloxy group" is preferably C₇₋₁₉ aralkyl group mentioned above, hence "aralkyloxy group" being hereinafter sometimes called "C₇₋₁₉ aralkyloxy group", which is exemplified by benzyloxy, 1-phenylethyloxy, 2-phenylethyloxy, naphthylmethyloxy, benzhydryloxy or trityloxy. The alkyl group of "alkylthio group" is preferably C₁₋₆ alkyl group mentioned above, hence "alkylthio group" being hereinafter sometimes called "C₁₋₆ alkylthio group", which is exemplified by methylthio, ethylthio, n-propylthio or n-butylthio. The alkylthio group of "aminoalkylthio group" is preferably C₁₋₆ alkylthio group mentioned above, hence "aminoalkylthio group" being hereinafter called "amino C₁₋₆ alkylthio group", which is exemplified by aminomethylthio, 2-aminoethylthio or 3-aminopropylthio. The alkenyl group of "alkenylthio group" is preferably C₂₋₆ alkenyl group mentioned above, hence "alkenylthio group" being hereinafter sometimes called "C₂₋₆ alkenylthio group", which is exemplified by vinylthio, allylthio, 1-propenylthio or isopropenylthio. The cycloalkyl group of "cycloalkylthio group" is preferably C₃₋₁₀ cycloalkyl group mentioned above, hence "cycloalkylthio group" being hereinafter sometimes called "C₃₋₁₀ cycloalkylthio group", which is exemplified by cyclopropylthio or cyclohexylthio. The aryl group of "arylthio group" is preferably C₆₋₁₀ aryl group mentioned above, hence "arylthio group" being hereinafter sometimes called "C₆₋₁₀ arylthio group", which is exemplified by phenylthio or naphthylthio. The aralkyl group of "aralkylthio group" is preferably C₇₋₁₉ aralkyl group mentioned above, hence "aralkylthio group" hereinafter sometimes called "C₇₋₁₉ aralkylthio group", which is exemplified by benzylthio, phenylethylthio, benzhydrylthio or tritylthio. The alkyl group of "monoalkylamino group" is preferably C₁₋₆ alkyl group mentioned above, hence "monoalkylamino group" being hereinafter sometimes called "mono-C₁₋₆ alkylamino group", which is exemplified by methylamino, ethylamino, n-propylamino, n-butylamino, tert-butylamino, n-pentylamino or n-hexylamino. The alkyl group of "dialkylamino group" is preferably C₁₋₆ alkyl group mentioned above, hence "dialkylamino group" being hereinafter sometimes called "di-C₁₋₆ alkylamino group", which is exemplified by dimethylamino, diethylamino, methylethylamino, di-(n-propyl)amino or di-(n-butyl)amino. The alkyl group of "trialkylammonium group" is preferably C₁₋₆ alkyl group mentioned above, hence "trialkylammonium group" being hereinafter sometimes called "tri-C₁₋₆ alkylammonium group", which is exemplified by trimethylammonium [(CH₃)₃N ⊕ -] or triethylammonium. The trialkylammonium group is necessarily accompanied a corresponding anion exemplified by halogenide ion (chloride ion, bromide ion, iodide ion, etc.), sulfate ion, nitrate ion, carbonate ion, organic carboxylate ion (e.g. oxalate ion or trifluoroacetate ion), organic sulfonate ion (e.g. methanesulfonate ion or p-toluenesulfonate ion). The organic carboxylate ion and the organic sulfonate ion may sometimes be intramolecular ones. The cycloalkyl group of "cycloalkylamino group" is preferably C₃₋₁₀cycloalkyl group mentioned above, hence "cycloalkylamino group" being hereinafter sometimes called "C₃₋₁₀ cycloalkylamino", which is exemplified by cyclopropylamino, cyclopentylamino or cyclohexylamino. The aryl group of "arylamino group" is preferably C₆₋₁₀ aryl group mentioned above, hence "arylamino group" being hereinafter sometimes called "C₆₋₁₀ arylamino group", which is exemplified by anilino or N-methylanilino. The aralkyl group of "aralkylamino group" is preferably C₇₋₁₉ aralkyl group mentioned above, hence "aralkylamino group" being hereinafter sometimes called "C₇₋₁₉ aralkylamino group", which is exemplified by benzylamino, 1-phenylethylamino, 2-phenylethylamino, benzhydrylamino or tritylamino. "Cyclic amino group" means a group formed by removing one of the hydrogen atoms bonding to the ring-forming nitrogen atom of such a nitrogen-containing heterocyclic ring or that saturated at its double bond as described hereafter, which is exemplified by 1H-tetrazol-1-yl, 1H-pyrrol-1-yl, pyrrolino, pyrrolidino, 1H-imidazol-1-yl, imidazolino, imidazolidino, 1H-pyrazol-1-yl, pyrazolino, pyrazolidino, piperidino, piperazino or morpholino. The alkyl group of "hydroxyalkyl group" is preferably C₁₋₆ alkyl group mentioned above, hence "hydroxyalkyl group" being hereinafter sometimes called "hydroxy C₁₋₆ alkyl group", which is exemplified by hydroxymethyl, 1-hydroxyethyl, 2-hydroxyethyl or 3-hydroxypropyl. The alkyl group of "mercaptoalkyl group" is preferably C₁₋₆ alkyl group mentioned above, hence "mercaptoalkyl group" being hereinafter sometimes called "mercapto C₁₋₆ alkyl group", which is exemplified by mercaptomethyl, 1-mercaptoethyl or 2-mercaptoethyl. The alkoxy group of "alkoxyalkyl group" is preferably C₁₋₆ alkoxy group mentioned above and the alkyl group of "alkoxyalkyl group" is preferably C₁₋₆ alkyl group mentioned above, hence "alkoxyalkyl group" being hereinafter sometimes called "C₁₋₆ alkoxy C₁₋₆ alkyl group", which is exemplified by methoxymethyl, ethoxymethyl or 2-methoxyethyl. The alkylthio group of "alkylthioalkyl group" is preferably C₁₋₆ alkylthio group mentioned above and the alkyl group of "alkylthioalkyl group" is preferably C₁₋₆ alkyl group mentioned above, hence "alkylthioalkyl group" being hereinafter sometimes called "C₁₋₆ alkylthio C₁₋₆ alkyl group", which is exemplified by methylthiomethyl or 2-methylthioethyl. The alkyl group of "aminoalkyl group" is preferably C₁₋₆ alkyl group mentioned above, hence "aminoalkyl group" being hereinafter sometimes called "amino C₁₋₆ alkyl group", which is exemplified by aminomethyl, 2-aminoethyl or 3-aminopropyl. "Monoalkylaminoalkyl group" is preferably "mono-C₁₋₆ alkyl amino C₁₋₆ alkyl group", which is exemplified by methylaminomethyl, ethylaminomethyl, 2-(N-methylamino)ethyl or 3-(N-methylamino)propyl. Dialkylaminoalkyl group is preferably "di-C₁₋₆ alkylamino C₁₋₆ alkyl group", which is exemplified by N,N-dimethylaminomethyl, N,N-diethylaminomethyl, 2-(N,N-dimethylamino)ethyl, 2-(N,N-diethylamino)ethyl or 3-(N,N-diethylamino)propyl. The cyclic amino group of "cyclic aminoalkyl group" is preferably the one mentioned above and the alkyl group of "cyclic aminoalkyl group" is preferably C₁₋₆ amino group mentioned above, hence hereinafter "cyclic aminoalkyl group" being sometimes called "cyclic amino C₁₋₆ alkyl group", which is exemplified by pyrrolidinomethyl, piperidinomethyl, piperazinomethyl, morpholinomethyl or 2-(morpholino)ethyl. The cyclic aminoalkyl group of "cyclic aminoalkylamino group" is preferably cyclic amino C₁₋₆ alkyl group mentioned above, hence hereinafter "cyclic aminoalkylamino group" being sometimes called "cyclic amino C₁₋₆ alkylamino group", which is exemplified by pyrrolidinomethylamino, piperizinomethylamino, piperazinomethylamino or morpholinomethylamino. The alkyl group of "halogenoalkyl group" is preferably C₁₋₆ alkyl group mentioned above, hence hereinafter "halogenoalkyl group" being sometimes called "halogeno C₁₋₆ alkyl group", which is exemplified by fluoromethyl, difluoromethyl, trifluoromethyl, chloromethyl, dichloromethyl, trichloromethyl, 2-fluoroethyl, 2,2-difluoroethyl, 2,2,2-trifluoroethyl, 2-chloroethyl, 2,2-dichloroethyl, 2,2,2-trichloroethyl, 2-bromoethyl or 2-iodoethyl. The alkyl group of "cyanoalkyl group" is preferably C₁₋₆ alkyl group mentioned above, hence hereinafter "cyanoalkyl group" being sometimes called "cyano C₁₋₆ alkyl group", which is exemplified by cyanomethyl or 2-cyanoethyl. The alkyl group of "carboxyalkyl group" is preferably C₁₋₆ alkyl group mentioned above, hence hereinafter "carboxyalkyl group" being called sometimes "carboxy C₁₋₆ alkyl group", which is exemplified by carboxymethyl, 1-carboxyethyl or 2-carboxyethyl. The alkyl group of "sulfoalkyl group" is preferably C₁₋₆ alkyl group mentioned above, hence hereinafter "sulfoalkyl group" being called sometimes "sulfo C₁₋₆ alkyl group", which is exemplified by sulfomethyl or 2-sulfoethyl. The alkanoyl group of "alkanoylalkyl group" is preferably C₂₋₆ alkanoyl group mentioned hereafter and the alkyl group of "alkanoylalkyl group" is preferably C₁₋₆ alkyl group mentioned above, hence hereinafter "alkanoylalkyl group" being sometimes called "C₂₋₆ alkanoyl C₁₋₆ alkyl group", which is exemplified by acetylmethyl, 1-acetylethyl or 2-acetylethyl. The alkanoyloxy group of "alkanoyloxyalkyl group" is preferably C₂₋₆ alkanoyloxy group to be described hereafter and the alkyl group of "alkanoyloxyalkyl group" is preferably C₁₋₆ alkyl group mentioned above, hence hereinafter "alkanoyloxyalkyl group" being sometimes called "C₂₋₆ alkanoyloxy C₁₋₆ alkyl group", which is exemplified by acetoxymethyl, 1-acetoxyethyl or 2-acetoxyethyl. The alkoxycarbonyl group of "alkoxycarbonylalkyl group" is preferably C₁₋₁₀ alkoxy-carbonyl group to be described hereafter and the alkyl group of "alkoxycarbonylalkyl group" is preferably C₁₋₆ alkyl group mentioned above, hence hereinafter "alkoxycarbonylalkyl group" being sometimes called "C₁₋₁₀ alkoxy-carbonyl C₁₋₆ alkyl group", which is exemplified by methoxycarbonylmethyl, ethoxycarbonylmethyl or tert-butoxycarbonylmethyl. The alkyl group of "carbamoylalkyl group" is preferably C₁₋₆ alkyl group, hence hereinafter "carbamoylalkyl group" being sometimes called "carbamoyl C₁₋₆ alkyl group", which is exemplified by carbamoylmethyl. The alkyl group of "carbamoyloxyalkyl group" is preferably C₁₋₆ alkyl group, hence hereinafter "carbamoylalkyl group" being called sometimes "carbamoyloxy C₁₋₆ alkyl group", which is exemplified by carbamoyloxymethyl. "Halogen atom" is exemplified by fluorine, chlorine, bromine or iodine. "Alkanoyl group" is preferably aliphatic acyl group having 1-6 carbon atoms, hereinafter sometimes called simply "C₁₋₆ alkanoyl group", which is exemplified by formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl or pivaloyl. These alkanoyl groups, except formyl, are sometimes called "C₂₋₆ alkanoyl group". "Alkenoyl group" is preferably the one having 3-5 carbon atoms (hereinafter sometimes simply called "C₃₋₅ alkenoyl group"), which is exemplified by acryloyl, crotonoyl or maleoyl. The cycloalkyl group of "cycloalkylcarbonyl group" is preferably C₃₋₁₀ cycloalkyl group mentioned above, hence hereinafter "cycloalkyl carbonyl group" being sometimes called "C₃₋₁₀ cycloalkyl-carbonyl group", which is exemplified by cyclopropylcarbonyl, cyclobutylcarbonyl, cyclopentylcarbonyl, cyclohexylcarbonyl, cycloheptylcarbonyl or adamantylcarbonyl. The cycloalkenyl group of "cycloalkenylcarbonyl group" is preferably C₅₋₆ cycloalkenyl group, hence hereinafter "cycloalkenylcarbonyl group" being called sometimes "C₅₋₆ cycloalkenyl-carbonyl group", which is exemplified by cyclopentenylcarbonyl, cyclopentadienylcarbonyl, cyclohexenylcarbonyl or cyclohexadienylcarbonyl. The aryl group of "arylcarbonyl group" is preferably C₆₋₁₀ aryl group mentioned above, hence hereinafter "arylcarbonyl group" being called sometimes "C₆₋₁₀ arylcarbonyl group", which is exemplified by benzoyl or naphthoyl. The aralkyl group of "aralkylcarbonyl group" is preferably C₇₋₁₉ aralkyl group, hence hereinafter "aralkylcarbonyl group" being sometimes called "C₇₋₁₉ aralkylcarbonyl group", which is exemplified by phenylacetyl, phenylpropionyl, α,α-diphenylacetyl or α,α,α-triphenylacetyl. The alkyl group of "alkoxycarbonyl group" includes, in this specification, C₃₋₁₀ cycloalkyl group mentioned above, besides lower alkyl groups having 1-8 carbon atoms, hence hereinafter "alkoxycarbonyl group" being sometimes called "C₁₋₁₀ alkoxy-carbonyl group", which is exemplified by methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, isopropoxycarbonyl, n-butoxycarbonyl, isobutoxycarbonyl, tert-butoxycarbonyl, cyclopentyloxycarbonyl, cyclohexyloxycarbonyl or norbornyloxycarbonyl. The aryloxy group of "aryloxycarbonyl group" is preferably C₆₋₁₀ aryloxy group mentioned above, hence hereinafter "aryloxycarbonyl group" being sometimes called "C₆₋₁₀ aryloxy-carbonyl group", which is exemplified by phenoxycarbonyl or naphthyloxycarbonyl. The aralkyloxy group of "aralkyloxycarbonyl group" is preferably C₇₋₁₉ aralkyloxy group mentioned above, which is exemplified by benzyloxycarbonyl, benzhydryloxycarbonyl or trityloxycarbonyl. "Substituted oxycarbonyl group" means the above-mentioned C₁₋₁₀ alkoxy-carbonyl group, C₆₋₁₀ aryloxycarbonyl group or C₇₋₁₉ aralkyloxy-carbonyl group. The alkylthio group of "alkylthiocarbonyl group" is preferably C₁₋₆ alkylthio group mentioned above, hence "alkylthiocarbonyl group" being hereinafter called sometimes "C₁₋₆ alkylthio-carbonyl group", which is exemplified by methylthiocarbonyl, ethylthiocarbonyl, n-propylthiocarbonyl or n-butylthiocarbonyl. The alkanoyl group of "alkanoyloxy group" is preferably C₁₋₆ alkanoyl group mentioned above, hence "alkanoyloxy group" being hereinafter called "C₁₋₆ alkanoyloxy group, which is exemplified by formyloxy, acetoxy, propionyloxy, butyryloxy, valeryloxy or pivaloyloxy. These alkanoyloxy groups, except formyloxy, are sometimes called "C₂₋₆ alkanoyloxy group". The alkenoyl group of "alkenoyloxy group" is preferably C₃₋₅ alkenoyl group mentioned above, hence "alkenoyloxy group" being hereinafter called sometimes "C₃₋₅ alkenoyloxy group", which is exemplified by acryloyloxy or crotonoyloxy. The alkyl group of "monoalkylcarbamoyl group" is preferably C₁₋₆ alkyl group mentioned above, hence "monoalkylcarbamoyl group" being hereinafter sometimes called "mono-C₁₋₆ alkylcarbamoyl group", which is exemplified by N-methylcarbamoyl or N-ethylcarbamoyl. The alkyl group of "dialkylcarbamoyl group" is preferably C₁₋₆ alkyl group, hence "dialkylcarbamoyl group" being hereinafter sometimes called "di-C₁₋₆ alkylcarbamoyl group", which is exemplified by N,N-dimethylcarbamoyl or N,N-diethylcarbamoyl. The monoalkylcarbamoyl group of "monoalkylcarbamoyloxy group" is preferably mono-C₁₋₆ alkylcarbamoyl group mentioned above, hence "monoalkylcarbamoyloxy group" being hereinafter sometimes called "mono-C₁₋₆ alkylcarbamoyloxy group", which is exemplified by N-methylcarbamoyloxy or N-ethylcarbamoyloxy. The dialkylcarbamoyl group of "dialkylcarbamoyloxy group" is preferably di-C₁₋₆ alkylcarbamoyl group mentioned above, hence "dialkylcarbamoyloxy group" being hereinafter sometimes called "di-C₁₋₆ alkylcarbamoyloxy group", which is exemplified by N,N-dimethylcarbamoyloxy or N,N-diethylcarbamoyloxy. The alkyl group of "alkylsulfonyl group" is preferably C₁₋₆ alkyl group mentioned above, hence "alkylsulfonyl group" being hereinafter sometimes called "C₁₋₆ alkylsulfonyl group", which is exemplified by methanesulfonyl or ethanesulfonyl. The aryl group of "arylsulfonyl group" is preferably C₆₋₁₀ aryl group mentioned above, hence "arylsulfonyl group" being hereinafter sometimes called "C₆₋₁₀ arylsulfonyl group", which is exemplified by, among others, benzenesulfonyl. The aralkyl group of "aralkylsulfonyl group" is preferably C₇₋₁₉ aralkyl group mentioned above, hence "aralkylsulfonyl group" being hereinafter sometimes called "C₇₋₁₉ aralkylsulfonyl group", which is exemplified by phenylmethanesulfonyl or diphenylmethanesulfonyl. The alkylsulfonyl group of "alkylsulfonyloxy group" is preferably C₁₋₆ alkylsulfonyl group mentioned above, hence "alkylsulfonyloxy group" being hereinafter sometimes called "C₁₋₆ alkylsulfonyloxy group", which is exemplified by methanesulfonyloxy or ethanesulfonyloxy. The arylsulfonyl group of "arylsulfonyloxy group" is preferably C₆₋₁₀ arylsulfonyl group, hence "arylsulfonyloxy group" being hereinafter sometimes called "C₆₋₁₀ arylsulfonyloxy group", which is exemplified by, among others, benzenesulfonyloxy. The aralkylsulfonyl group of "aralkylsulfonyloxy group" is preferably C₇₋₁₉ aralkylsulfonyl group mentioned above, hence "aralkylsulfonyloxy group" being hereinafter sometimes called "C₇₋₁₉ arylsulfonyloxy group", which is exemplified by phenylmethanesulfonyloxy or diphenylmethanesulfonyloxy. "Amino acid residue" means acyl groups formed by removing hydroxyl group of the carboxyl group of conventional amino acids, which is exemplified by glycyl, alanyl, valyl, leucyl, isoleucyl, seryl, threonyl, cysteinyl, cystinyl, methionyl, aspartyl, glutamyl, lysyl, arginyl, phenylglycyl, phenylalanyl, tyrosyl, histidyl, triptophanyl or prolyl. "Nitrogen-containing heterocyclic ring" means 5-8 membered ring containing one to several, preferably 1-4, nitrogen atoms (optionally oxidized), which may contain, besides nitrogen atoms, one to several, preferably 1-2, hetero atoms such as oxygen atom or sulfur atom. "Nitrogen-containing heterocyclic group" means a group formed by removing one hydrogen atom bonding to ring-forming carbon atom of the above nitrogen-containing heterocyclic ring. "Heterocyclic group" means a group formed by removing one hydrogen atom bonding to carbon atom of a heterocyclic ring, which means 5-8 membered ring containing one to several, preferably 1-4, hetero atoms such as nitrogen atom (optionally oxidized), oxygen atom or sulfur atom, or condensed ring thereof, which is exemplified by 2- or 3-pyrrolyl, 3-, 4- or 5-pyrazolyl, 2-, 4- or 5-imidazolyl, 1,2,3- or 1,2,4-triazolyl, 1H- or 2H-tetrazolyl, 2- or 3-furyl, 2- or 3-thienyl, 2-, 4- or 5-oxazolyl, 3-, 4- or 5-isoxazolyl, 1,2,3-oxadiazol-4- or 5-yl, 1,2,4-oxadiazol-3- or 5-yl, 1,2,5- or 1,3,4-oxadiazolyl, 2-, 4- or 5-thiazolyl, 3-, 4- or 5-isothiazolyl, 1,2,3-thiadiazol-4- or 5-yl, 1,2,4-thiadiazol-3- or 5-yl, 1,2,5- or 1,3,4-thiadiazolyl, 2- or 3-pyrrolidinyl, 2-, 3- or 4-pyridyl, 2-, 3- or 4-pyridyl-N-oxide, 3- or 4-pyridazinyl, 3- or 4-pyridazinyl-N-oxide, 2-, 4- or 5-pyrimidinyl, 2-, 4- or 5-pyrimidinyl-N-oxide, pyrazinyl, 2-, 3- or 4-piperidinyl, piperazinyl, 3H-indol-2- or 3-yl, 2-, 3- or 4-pyranyl, 2-, 3- or 4-thiopyranyl, benzopyranyl, quinolyl, pyrido[2,3-d]pyrimidyl, 1,5-, 1,6-, 1,7-, 1,8-, 2,6- or 2,7-naphthylidyl, thieno[2,3-d]pyridyl, pyrimidopyrimidyl, pyrazinoquinolyl, or benzopyranyl. Heterocyclic groups of "heterocycle-oxy group", "heterocycle-thio group", "heterocycle-amino group", "heterocycle-carbonyl group", "heterocycle-acetyl group" and "heterocycle-carboxamido group" are all preferably "heterocyclic group" mentioned above. "Quaternary ammonium group" means a group in which the bonding hand is the unpaired electron located on one of the tertiary nitrogen atoms of the above-mentioned nitrogen-containing heterocyclic ring, and per se quaternarized, necessarily being accompanied to corresponding anion. The quaternary ammonium group is exemplified by oxazolium, thiazolium, isoxazolium, isothiazolium, pyridinium or quinolinium. The anion is exemplified by hydroxide ion, halogenide ion (e.g. chloride ion, bromide ion or iodide ion), sulfate ion, nitrate ion, carbonate ion, organic carboxylate ion (e.g. oxalate ion or trifluoroacetate ion) or organic sulfonate ion (e.g. p-toluenesulfonate ion), the latter two being sometimes intramolecular ones. The groups bearing asterisk * at the right shoulder are "optionally substituted groups". For example, alkyl* group means "optionally substituted alkyl group". The number of substituents is not restricted to one, but depending on the substituents, two to several, preferably 2-3, which may be the same or different. "C₆₋₁₀ aryl* group", "C₇₋₁₂ aralkyl* group", "C₆₋₁₀ aryl*oxy group" and "C₇₋₁₉ aralkyl*oxy group" are preferably "phenyl* group", "benzyl* group", "phenoxy* group" and "benzyl*oxy group", respectively. In the compound [I] of the present invention, the substituent R⁰ stands for hydrogen atom, nitrogen-containing heterocyclic group, acyl group or esterified carboxyl group. Among them, those compounds [I] in which R⁰ is nitrogen-containing heterocyclic group or acyl group have a strong antibacterial action against various bacteria, especially against cephalosporin-resistant bacteria, and they show specific antibacterial action against bacteria belonging to the genus Pseudomonas . On the other hand, compounds [I], wherein R⁰ is hydrogen atom or esterified carboxyl group, are useful intermediates for producing compounds [I] wherein R⁰ is nitrogen-containing heterocyclic group or acyl group. The nitrogen-containing 5-8 membered heterocyclic group containing 1-4 hetero atoms selected from nitrogen atom optionally oxidized, oxygen atom and sulfur atom (hereinafter some times denoted as the symbol R a ) as the substituent R⁰ is "nitrogen-containing heterocyclic group" as mentioned above, which is exemplified by 2-pyrrolyl, 3-pyrrolyl, 3-pyrazolyl, 4-pyrazolyl, 5-pyrazolyl, 2-imidazolyl, 4-imidazolyl, 5-imidazolyl, 1,2,3-triazolyl, 1,2,4-triazolyl, 1H-tetrazolyl, 2H-tetrazolyl, 2-oxazolyl, 4-oxazolyl, 5-oxazolyl, 3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl, 1,2,3-oxadiazol-4-yl, 1,2,3-oxadiazol-5-yl, 1,2,4-oxadiazol 3-yl, 1,2,4-oxadiazol-5-yl, 1,2,5-oxadiazolyl, 1,3,4-oxadiazolyl, 2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 4-isothiazolyl, 4-isothiazolyl, 5-isothiazolyl, 1,2,3-thiadiazol-4-yl, 1,2,3-thiadiazol-5-yl, 1,2,4-thiadiazol-3-yl, 1,2,4-thiadiazol-5-yl, 1,2,5-thiadiazolyl, 1,3,4-thiadiazolyl, 2-pyrrolidinyl, 3-pyrrolidinyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-pyridyl-N-oxide, 3-pyridyl-N-oxide, 4-pyridyl-N-oxide, 3-pyridazinyl, 4-pyridazinyl, 3-pyridazinyl-N-oxide, 4-pyridazinyl-N-oxide, 2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl, 2-pyrimidinyl-N-oxide, 4-pyrimidinyl-N-oxide, 5-pyrimidinyl-N-oxide, pyrazinyl, 2-piperidinyl, 3-piperidinyl, 4-piperidinyl, piperazinyl, especially preferably 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-imidazolyl, 4-imidazolyl or 5-imidazolyl. The above-mentioned nitrogen-containing heterocyclic groups, 3H-indol-2-yl and 3H-indol-3-yl may have one to three substituents on the ring, in the number of two or three which may be the same or diffrent depending on the kinds of the substituents. These substituents are exemplified by alkyl group, cycloalkyl group, aryl group, aralkyl group, hydroxyl group, alkoxy group, mercapto group, alkylthio group, amino group, monoalkylamino group, dialkylamino group, halogen atom, nitro group, azido group, cyano group, carboxyl group, alkoxycarbonyl group, alkanoyl group, alkanoyloxy group, carbamoyl group, monoalkylcarbamoyl group, dialkylcarbamoyl group, carbamoyloxy group, monoalkylcarbamoyloxy group or dialkylcarbamoyloxy group. As the nitrogen-containing heterocyclic group having one or more substituents, especially preferable are 2-imidazolyl group having as substituents the above-mentioned alkyl group, aryl group or halogen atom, or N-substituted pyridinium-4-yl groups having as substituents the above-mentioned alkyl group or aralkyl group on the nitrogen atom of the 4-pyridyl group to thereby quaternarize the nitrogen atom. The substituted 2-imidazolyl group is exemplified by 1-methyl-2-imidazolyl or 4-chloro-2-imidazolyl, and the N-substituted pyridinium-4-yl group is exemplified by N-methylpyridinium-4-yl, N-ethylpyridinium-4-yl, N-benzylpyridinium-4-yl or N-(p-fluorobenzyl)pyridinium-4-yl, respectively. Hence, most preferable acyl group of R⁰ is representable by the formula; wherein R¹ stands for optionally protected amino group and R² stands for hydrogen atom, halogen atom or nitro group. Accordingly, preferable ones of compound [I] having the acyl group R b as the substituent R⁰ are those of the following structure; [each symbol is as defined above]. Detailed description about the substituents R 1, R² and R³ is as follows. R¹ stands for an optionally protected amino group. In the field of synthesis of β-lactam and peptide, protecting groups of amino group have been sufficiently studied, and the method of protection has already been established. In the present invention as well, any of those known amino-protecting groups may suitably be employed. As such amino-protecting groups, there may be mentioned for example C₁₋₆ alkanoyl* group, C₃₋₅ alkenoyl* group, C₆₋₁₀ aryl*carbonyl group, phthaloyl group, heterocycle*carbonyl group, C₁₋₆ alkyl*sulfonyl group, camphorsulfonyl group, C₆₋₁₀ aryl*sulfonyl group, substituted oxycarbonyl group, carbamoyl* group, thiocarbamoyl* group, C₆₋₁₀ aryl*methyl group, di-C₆₋₁₀ aryl*methyl group, tri-C₆₋₁₀ aryl*methyl group, C₆₋₁₀ aryl*methylene group, C₆₋₁₀ aryl*thio group, substituted silyl group or 2-C₁₋₁₀ alkoxy-carbonyl-1-methyl-1-ethenyl group. As "C₁₋₆ alkanoyl* group", there may concretely be mentioned here formyl, acetyl, propionyl, butyryl, valeryl, pivaloyl, succinyl, glutaryl, monochloroacetyl, dichloroacetyl, trichloroacetyl, monobromoacetyl, monofluoroacetyl, difluoroacetyl, trifluoroacetyl, monoiodoacetyl, 3-oxobutyryl, 4-chloro-3-oxobutyryl, phenylacetyl, p-chlorophenylacetyl, phenoxyacetyl or p-chlorophenoxyacetyl. As "C₃₋₅ alkenoyl* group", there may concretely be mentioned here acryloyl, crotonoyl, maleoyl, cinnamoyl, p-chlorocinnamoyl or β-phenylcinnamoyl. As "C₆₋₁₀ aryl*carbonyl group", there may be mentioned, for example, benzoyl, naphthoyl, p-toluoyl, p-tert-butylbenzoyl, p-hydroxybenzoyl, p-methoxybenzoyl, p-tert-butoxybenzoyl, p-chlorobenzoyl or p-nitrobenzoyl. As the heterocycle*carbonyl group, there may be mentioned those as described hereinafter. As "C₁₋₆ alkyl*sulfonyl group", there may be mentioned, for example, methanesulfonyl or ethanesulfonyl. As "C₆₋₁₀ aryl*sulfonyl group", there may be mentioned here benzenesulfonyl, naphthalenesulfonyl, p-toluenesulfonyl, p-tert-butylbenzenesulfonyl, p-methoxybenzenesulfonyl, p-chlorobenzenesulfonyl or p-nitrobenzenesulfonyl, for example. "Substituted oxycarbonyl group" means not only the the above-mentioned one, i.e. C₁₋₁₀ alkoxy-carbonyl group, C₆₋₁₀ aryloxy-carbonyl group or C₇₋₁₉ aralkyloxycarbonyl group, but contains here one having sustituent, and therefore there may be mentioned here methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, isopropoxycarbonyl, n-butoxycarbonyl, tert-butoxycarbonyl, cyclohexyloxycarbonyl, norbornyloxycarbonyl, phenoxycarbonyl, naphthyloxycarbonyl, benzyloxycarbonyl, methoxymethyloxycarbonyl, acetylmethyloxycarbonyl, 2-trimethylsilylethoxycarbonyl, 2-methanesulfonylethoxycarbonyl, 2,2,2-trichloroethoxycarbonyl, 2-cyanoethoxycarbonyl, p-methylphenoxycarbonyl, p-methoxyphenoxycarbonyl, p-chlorophenoxycarbonyl, p-methylbenzyloxycarbonyl, p-methoxybenzyloxycarbonyl, p-chlorobenzyloxycarbonyl, p-nitrobenzyloxycarbonyl, benzhydryloxycarbonyl, cyclopropyloxycarbonyl, cyclopentyloxycarbonyl or cyclohexyloxycarbonyl, for example. "Carbamoyl* group" is exemplified here by carbamoyl, N-methylcarbamoyl, N-ethylcarbamoyl, N,N-dimethylcarbamoyl, N,N-diethylcarbamoyl, N-phenylcarbamoyl, N-acetylcarbamoyl, N-benzoylcarbamoyl or N-(p-methoxyphenyl)carbamoyl. "Carbamoyl*oxy group" is exemplified here by carbamoyloxy, N-methylcarbamoyloxy, N,N-dimethylcarbamoyloxy, N-ethylcarbamoyloxy or N-phenylcarbamoyloxy. "Thiocarbamoyl* group" is exemplified here by thiocarbamoyl, N-methylthiocarbamoyl or N-phenylthiocarbamoyl, for example. "C₆₋₁₀ aryl*methyl group" is exemplified by benzyl, naphthylmethyl, p-methylbenzyl, p-methoxybenzyl, p-chlorobenzyl or p-nitrobenzyl. "Di-C₆₋₁₀ aryl*methyl group" is exemplified by benzhydryl or di-(p-tolyl)methyl. "Tri-C₆₋₁₀ aryl*methyl group" is exemplified by trityl or tri-(p-tolyl)methyl. "C₆₋₁₀ aryl*methylene group" is exemplified by benzylidene, p-methylbenzylidene or p-chlorobenzylidene. "C₆₋₁₀ aryl*thio group" is exemplified by o-nitrophenylthio. "Substituted silyl group" means a silyl group, together with the amino group to be protected, representable by the general formula; R⁶R⁷R⁸SiNH, (R⁶R⁷R⁸Si)₂N or [wherein R⁶, R⁷, R⁸, R⁹, R¹⁰, R 9' and R 10' are the same or different and stand for C₁₋₆ alkyl group or C₆₋₁₀ aryl* group, and Z' stands for C₁₋₃ alkylene group e.g. methylene, ethylene or propylene], which is exemplified by trimethylsilyl, tert-butyldimethylsilyl or -Si(CH₃)₂CH₂CH₂Si(CH₃)₂-. The C₁₋₁₀ alkoxy-carbonyl group of "2-C₁₋₁₀ alkoxycarbonyl-1-methyl-1-ethenyl group" is preferably those as mentioned in the foregoing. Hence, 2-C₁₋₁₀ alkoxycarbonyl-1-methyl-1-ethenyl group is exemplified by 2-methoxycarbonyl-1-methyl-1-ethenyl, 2-ethoxycarbonyl-1-methyl-1-ethenyl, 2-tert-butoxycarbonyl-1-methyl-1-ethenyl, 2-cyclohexyloxycarbonyl-1-methyl-1-ethenyl or 2-norbornyloxycarbonyl-1-methyl-1-ethenyl. The symbol R² stands for hydrogen atom, halogen atom or nitro group. As the halogen atom are mentioned here fluorine, chlorine, bromine, etc., preferably chlorine. The symbol R³ stands for hydrogen atom or C₁₋₆ alkyl group, C₂₋₆ alkenyl group, C₂₋₆ alkynyl group, c₃₋₁₀ cycloalkyl group or c₅₋₆ cycloalkenyl group that is substituted or unsubstituted by one or two substituents. The C₁₋₆ alkyl group is, also here, preferably those described in the foregoing and may be exemplified by methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl or n-hexyl, especially preferably, methyl, ethyl and n-propyl. The C₂₋₆ alkenyl group is, also here, preferably those described in the foregoing and may be exemplified by vinyl, allyl, isopropenyl, methallyl, 1,1-dimethylallyl, 2-butenyl or 3-butenyl. The C₂₋₆ alkynyl group may be exemplified by ethylnyl, 1-propynyl, 2-propynyl or propargyl. The C₃₋₁₀ cycloalkyl group is, also here, preferably the above-mentioned c₃₋₈ cycloalkyl group and may be exemplified by cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or adamantyl. The C₅₋₆ cycloalkenyl group may be exemplified by 2-cyclopentenyl, 3-cyclopentenyl, 2-cyclohexenyl, 3-cyclohexenyl. Substituents of these residues may be exemplified by hydroxyl group, C₁₋₆ alkyl group, C₂₋₆ alkenyl group, C₂₋₆ alkynyl group, c₃₋₁₀ cycoalkyl group, C₅₋₆ cycloalkenyl group, C₆₋₁₀ aryl group, C₇₋₁₉ aralkyl group, heterocyclic group, C₁₋₆ alkoxy group, C₃₋₁₀ cycloalkoxy group, C₆₋₁₀ aryloxy group, C₇₋₁₉ aralkyloxy group, heterocycle-oxy group, mercapto group, C₁₋₆ alkylthio group, C₃₋₁₀ cycloalkylthio group, C₆₋₁₀ arylthio group, c₇₋₁₉ aralkylthio group, heterocyclethio group, amino group, mono-C₁₋₆ alkylamino group, di-C₁₋₆ alkylamino group, tri-C₁₋₆ alkylammonium group, C₃₋₁₀ cycloalkylamino group, C₆₋₁₀ arylamino group, C₇₋₁₉ aralkylamino group, heterocycle-amino group, cyclic amino group, azido group, nitro group, halogen atom, cyano group, carboxyl group, C₁₋₁₀ alkoxycarbonyl group, C₆₋₁₀ aryloxy-carbonyl group, C₇₋₁₉ aralkyloxy-carbonyl group, C₆₋₁₀ aryl-acyl⁺ group, C₁₋₆ alkanoyl group, C₃₋₅ alkenoyl group, C₆₋₁₀ aryl-acyl⁺oxy group, C₂₋₆ alkanoyloxy group, C₃₋₅ alkenoyloxy group, carbamoyl* group, thiocarbamoyl* group, carbamoyl*oxy group, phthalimido group, C₁₋₆ alkanoylamino group, C₆₋₁₀ aryl-acyl⁺amino group, carboxyamino group, C₁₋₁₀ alkoxycarboxamido group, C₆₋₁₀ aryloxy-carboxamido group or C₇₋₁₉ aralkyloxy-carboxamido group. As substituents of these above residues, more specifically stating, the C₁₋₆ alkyl group stands for the above-mentioned groups, i.e. methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, n-pentyl or n-hexyl, the C₂₋₆ alkenyl group stands for the above mentioned groups, i.e. vinyl, allyl, isopropenyl, methallyl, 1,1-dimethylallyl, 2-butenyl or 3-butenyl, the C₂₋₆ alkynyl group stands for the above mentioned groups, i.e. ethynyl, 1-propynyl, 2-propynyl or propargyl, the c₃₋₁₀ cycloalkyl group stands for the above-mentioned groups, i.e. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl or adamantyl, the C₅₋₆ cycloalkenyl group stands for the above-mentioned groups, i.e. cyclopropenyl, 2-cyclopentenyl, 3-cyclopentenyl, 2-cyclohexenyl, 3-cyclohexenyl, cyclopentadienyl or cyclohexadienyl, the C₆₋₁₀ aryl group stands for the above-mentioned groups, i.e. phenyl, naphthyl or biphenylyl, the C₇₋₁₉ aralkyl group stands for the above-mentioned groups, i.e. benzyl, 1-phenylethyl, 2-phenylethyl, phenylpropyl, naphthylmethyl or benzhydryl, the C₁₋₆ alkoxy group stands for the above-mentioned groups, i.e. methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, tert-butoxy, n-pentyloxy or n-hexyloxy, the C₃₋₁₀ cycloalkyloxy group stands for the above-mentioned groups, i.e. cyclopropyloxy or cyclohexyloxy, the C₆₋₁₀ aryloxy group stands for the above-mentioned groups, i.e. phenoxy or naphthyloxy, the C₇₋₁₉ aralkyloxy group stands for the above-mentioned groups, i.e. benzyloxy, 1-phenylethyloxy, 2-phenylethyloxy or benzhydryloxy, the C₁₋₆ alkylthio group stands for the above-mentioned groups, i.e. methylthio, ethylthio, n-propylthio or n-butylthio, the C₃₋₁₀ cycloalkylthio group stands for the above-mentioned groups, i.e. cyclopropylthio or cyclohexylthio, the C₆₋₁₀ arylthio group stands for the above-mentioned groups, i.e. phenylthio or naphthylthio, the C₇₋₁₉ aralkylthio group stands for the above-mentioned groups, i.e. benzylthio, phenylethylthio or benzhydrylthio, the mono-C₁₋₆ alkylamino group stands for the above-mentioned groups, i.e. methylamino, ethylamino, n-propylamino, or n-butylamino, the di-C₁₋₆ alkylamino group stands for the above-mentioned groups, i.e. dimethylamino, diethylamino, methylethylamino, di-(n-propyl)amino or di-(n-butyl)amino, the tri-C₁₋₆ alkylammonium group stands for the above-mentioned groups, i.e. trimethylammonium or triethylammonium, the C₃₋₁₀ cycloalkylamino group stands for the above-mentioned groups, i.e. cyclopropylamino, cyclopentylamino or cyclohexylamino, the C₆₋₁₀ arylamino group stands for the above-mentioned groups, i.e. anilino or N-methylanilino, the C₇₋₁₉ aralkylamino group stands for the above-mentioned groups, i.e. benzylamino, 1-phenylethylamino, 2-phenylethylamino or benzhydrylamino, the cyclic amino group stands for the above-mentioned groups, i.e. pyrrolidino, piperidino, piperazino, morpholino or 1-pyrrolyl, the halogen atom stands for here fluorine, chlorine, bromine or iodine, the C₁₋₁₀ alkoxy-carbonyl group stands for the above-mentioned groups, i.e. methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, isopropoxycarbonyl, n-butoxycarbonyl, isobutoxycarbonyl, tert-butoxycarbonyl, cyclopentyloxycarbonyl, cyclohexyloxycarbonyl or norbornyloxycarbonyl, the C₆₋₁₀ aryloxy-carbonyl group stands for the above-mentioned groups, i.e. phenoxycarbonyl or naphthyloxycarbonyl, the C₇₋₁₉ aralkyloxy-carbonyl group stands for the above-mentioned groups, i.e. benzyloxycarbonyl or benzhydryloxycarbonyl, the C₆₋₁₀ aryl-acyl⁺ group stands for the above-mentioned groups, i.e. benzoyl, naphthoyl, phthaloyl or phenylacetyl, the C₁₋₆ alkanoyl group stands for the above-mentioned groups, i.e. formyl acetyl, propionyl, butyryl, valeryl, pivaloyl, succinyl or glutaryl, the C₃₋₅ alkenoyl group stands for the above-mentioned groups, i.e. acryloyl, crotonoyl or maleoyl, the C₆₋₁₀ aryl-acyl⁺oxy group stands for the above-mentioned groups, i.e. benzoyloxy, naphthoyloxy or phenylacetoxy, the C₂₋₆ alkanoyloxy group stands for the above-mentioned groups, i.e. acetoxy, propionyloxy, butyryloxy, valeryloxy or pivaloyloxy, the C₃₋₅ alkenoyloxy group stands for the above-mentioned groups, i.e. acryloyloxy or crotoncyloxy, the carbamoyl* group stands for the above-mentioned groups, i.e. carbamoyl, N-methylcarbamoyl, N-ethylcarbamoyl, N,N-dimethylcarbamoyl, N-ethylcarbamoyl, N,N-diethylcarbamoyl, N-phenylcarbamoyl, N-acetylcarbamoyl, N-benzoylcarbamoyl, N-(p-methoxyphenyl)carbamoyl and, in addition, pyrrolidinocarbonyl, piperidinocarbonyl, piperazinocarbonyl or morpholinocarbonyl, the thiocarbamoyl* group stands for the above-mentioned groups, i.e. thiocarbamoyl, N-methylthiocarbamoyl or N-phenylthiocarbonyl, the carbamoyl*oxy group stands for the above-mentioned group, i.e. carbamoyloxy, N-methylcarbamoyloxy, N,N-dimethylcarbamoyloxy, N-ethylcarbamoyloxy or N-phenylcarbamoyloxy, "C₁₋₆ alkanoylamino group" stands for e.g. acetamido, propionamido, butyramido, valeramido or pivalamido, "C₆₋₁₀ aryl-acyl+amino group" stands for e.g. benzamido, naphthoylamido or phthalimido, "C₁₋₁₀ alkoxy-carboxamido group" stands for e.g. methoxycarboxamido (CH₃OCONH-), ethoxycarboxamido or tert-butoxycarboxamido, "C₆₋₁₀ aryloxy-carboxamido group" stands for e.g. phenoxycarboxamido (C₆H₅OCONH-), and "C₇₋₁₉ aralkyloxy-carboxamido group" stands for e.g. benzyloxycarboxamido (C₆H₅CH₂OCONH-) or benzhydryoloxycarboxamido. The heterocyclic group, heterocyclic groups of heterocycle-oxy group, heterocycle-thio group and heterocycle-amino group are also here such groups as formed by removing one hydrogen atom bonding to the carbon atom of the heterocyclic ring. Such a heterocyclic ring as above may be exemplified by a 5- to 8-membered ring containing one to several, preferably 1-4, hetero atoms such as oxygen atom or sulfur atom. Such heterocyclic groups may be exemplified also here by those concretely mentioned above, including 2-pyrrolyl, as they are. Hence, "heterocycle-oxy group" is exemplified by thiazolyloxy, and "heterocycle-thio group" is exemplified by thiazolylthio, and "heterocycle-amino group" is exemplified by thiazolylamino or thiadiazolylamino. Preferable substituted hydrocarbon residues are C₁₋₃ alkyl groups (C₁₋₃ alkyl group means methyl, ethyl, n-propyl, isopropyl, etc.) substituted with e.g. hydroxyl group, cycloalkyl group, alkoxy group, alkylthio group, amino group, trialkylammonium group, halogen atom, carboxyl group, alkoxycarbonyl group, carbamoyl group, cyano group, azido group or heterocyclic group, which may concretely be mentioned, among many others, cyclopropylmethyl, methoxymethyl, ethoxymethyl, 1-methoxyethyl, 2-methoxyethyl, 1-ethoxyethyl, 2-hydroxyethyl, methylthiomethyl, 2-aminoethyl, 2-(trimethylammonium)ethyl, 2-(triethylammonium)ethyl, fluoromethyl, difluoromethyl, trifluoromethyl, 2-fluoroethyl, 2,2-difluoroethyl, chloromethyl, 2-chloroethyl, 2,2-dichloroethyl, 2,2,2-trichloroethyl, 2-bromoethyl, 2-iodoethyl, 2,2,2-trifluoroethyl, carboxymethyl, 1-carboxyethyl, 2-carboxyethyl, 2-carboxypropyl, 3-carboxypropyl, 1-carboxybutyl, cyanomethyl, 1-carboxy-1-methylethyl, methoxycarbonylmethyl, ethoxycarbonylmethyl, tert-butoxycarbonylmethyl, 1-methoxycarbonyl-1-methylethyl, 1-ethoxycarbonyl-1-methylethyl, 1-tert-butoxycarbonyl-1-methylethyl, 1-benzyloxycarbonyl-1-methylethyl, 1-pivaloyloxycarbonyl-1-methylethyl, carbamoylmethyl, 2-azidoethyl, 2-(pyrazolyl)ethyl, 2-(imidazolyl)ethyl, 2-(2-oxopyrrolidin-3-yl)ethyl or 2-amino-4-thiazolylmethyl. Most preferable ones among the above-exemplified hydrocarbon residues are straight-chain C₁₋₃ alkyl groups, e.g. methyl, ethyl and n-propyl; straight-chain or branched C₁₋₃ alkyl groups substituted with halogen atom, hydroxyl group, alkoxy group, carboxyl group, alkoxycarbonyl group or cyano group, e.g. 2-fluoroethyl, 2-chloroethyl, 2-hydroxyethyl, 2-methoxyethyl, cyanomethyl, carboxymethyl, tert-butoxycarbonylmethyl, 1-carboxy-1-methylethyl or 1-tert-butoxycarbonyl-1-methylethyl; allyl group and propargyl group. Supposing here that the symbol R 3' should stand for most preferable hydrocarbon residues exemplified above or hydrogen atom, the compounds [I] of this invention having as R⁰ an acyl group of (wherein R 22' stands for the formula) (wherein R¹ stands for an optionally protected amino group and R² stands for hydrogen atom, halogen atom or nitro group)), possess strong antibacterial activity, and, especially against resistant-bacteria, show excellent bactericidal action. Hence, most preferable compounds [I] are those having the following structural formula. [wherein symbols are of the same meaning as defined above]. Preferable examples of the acyl group shown by each symbol is defined above are 2-(2-aminothiazol-4-yl)-2(Z)-(hydroxyimino) acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(methoxyimino)acetyl, 2-(2-chloroacetamidothiazol-4-yl)-2(Z)-(methoxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(ethoxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(n-propoxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(isopropoxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(n-butoxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(n-hexyloxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(cyclopropylmethyloxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(benzyloxyimino)acetyl 2-(2-aminothiazol-4-yl)-2(Z)-(allyloxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(propargyloxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-methoxymethyloxyimino) acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(ethoxymethyloxyimono)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(1-methoxyethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(2-methoxyethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(2-ethoxyethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(1-ethoxyethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(2-hydroxyethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(methylthiomethyloxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(2-aminoethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(fluoromethyloxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(difluoromethyloxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(trifluoromethyloxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(2-fluoroethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(2,2-difluoroethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(chloromethyloxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(2-chloroethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(2,2-dichloroethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(2,2,2-trichloroethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(2-bromoethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(2-iodoethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(2,2,2-trifluoroethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(carboxymethyloxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(1-carboxyethyloxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(2-carboxyethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(1-carboxypropyloxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(3-carboxypropyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(1-carboxybutyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(cyanomethyloxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(1-carboxy-1-methylethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(methoxycarbonylmethyloxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(ethoxy carbonylmethyloxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(tert-butoxycarbonylmethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[1-(tert-butoxycarbonyl)ethoxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(1-methoxycarbonyl-1-methylethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(1-ethoxycarbonyl-1-methylethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(1-tert-butoxycarbonyl-1-methylethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[1-(tert-butoxycarbonyl)propoxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(1-benzyloxycarbonyl-1-methylethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(1-pivaloyloxycarbonyl-1-methylethyl)oxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(carbamoylmethyloxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[1-(1-carbamoyl-1-methyl)ethyloxyimino]acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-[(2-azidoethyloxyimino)acetyl, 2-(2-aminothiazol-4-yl)-2(Z)-(phenoxycarbonyloxyimino)acetyl, 2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-(hydroxyimino)acetyl, 2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-(methoxyimino)acetyl, 2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-(ethoxyimino)acetyl, 2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-(n-propoxyimino)acetyl, 2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-[(2-fluoroethyl)oxyimino]acetyl, 2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-[(2-chloroethyl)oxyimino]acetyl, 2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-(carboxymethyloxyimino)acetyl, 2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-[(tert-butoxycarbonylmethyl)oxyimino]acetyl, 2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-[(1-carboxy-1-methylethyl)oxyimino]acetyl, 2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-[(1-tert-butoxycarbonyl-1-methylethyl)oxyimino]acetyl, 2-(2-amino-5-bromothiazol-4-yl)-2(Z)-(ethoxyimino)acetyl, 2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-(hydroxyimino)acetyl, 2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-(methoxyimino)acetyl, 2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-(ethoxyimino)acetyl, 2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-(ethoxyimino)acetyl, 2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-[(2-fluoroethyl)oxyimino]acetyl, 2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-[(2-chloroethyl)oxyimino]acetyl, 2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-(carboxymethyloxyimino)acetyl, 2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-[(1-carboxy-1-methylethyl)oxyimino]acetyl, 2-(5-amino-1,2,4-thiadiazol-3-yl)-2(Z)-[(1-tert-butoxycarbonyl-1-methylethyl)oxyimino]acetyl, 2-(5-aminoisoxazol-3-yl)-2(Z)-(ethoxyimino)acetyl, 2-(5-amino-1,2,4-oxadiazol-3-yl)-2(Z)-(ethoxyimino)acetyl, 2-(2-imino-3-hydroxythiazolin-4-yl)-2(Z)-(ethoxyimino)acetyl, 2-(2-amino-3-oxidothiazol-4-yl)-2(Z)-(ethoxyimno)acetyl, 2-thienyl-2(Z)-(methoxyimino)acetyl, 2-thienyl-2(Z)-(ethoxyimino)-acetyl, 2-furyl-2(Z)-(methoxyimino)acetyl, 2-furyl-2(Z)-(ethoxyimino)acetyl, 2-(1,3,4-thiadiazolyl)-2(Z)-(ethoxyimino)acetyl, 2-(p-hydroxyphenyl)-2(Z)-(ethoxyimino)acetyl, 2-phenyl-2(Z)-(ethoxyamino)acetyl, 2-phenyl-2(Z)-(hydroxyimino)acetyl, 2-[p-(γ- D-glutamyl-oxy)phenyl]-2(Z)-(hydroxyimino)acetyl or 2-[p-(3-amino-3-carboxypropoxy)phenyl]-2(Z)-(hydroxyimino)acetyl. The C₁₋₆ alkanoyl* group described as one of the acyl groups (R b ) includes, besides the C₁₋₆ alkanoyl group 4-carboxybutyl, 5-amino-5-carboxyvaleryl, 5-oxo-5-carboxyvaleryl, N-[2-(2-amino-4-thiazolyl)-2(Z)-(methoxyimino)acetyl]-D-alanyl, N-[2-(2-amino-4-thiazolyl-2(Z)-(methoxyimino)acetyl]-D-phenylglycyl or 2-(2-amino-4-thiazolyl)-2-[2-(2-amino-4-thiazolyl)-2(Z)-(methoxyimino)acetamido]acetyl. The C₃₋₅ alkenoyl* groups as acyl groups (R b ) other than C₁₋₆ alkanoyl* groups, may be mentioned also here the afore-mentioned acryloyl, crotonoyl, maleoyl, cinnamoyl, p-chlorocinnamoyl or β-phenylcinnamoyl; the C₃₋₁₀ cycloalkyl-carbonyl groups may be mentioned also here the afore-mentioned cyclopropylcarbonyl, cyclobutylcarbonyl, cyclopentylcarbonyl, cyclohexylcarbonyl, cycloheptylcarbonyl or adamantylcarbonyl; C₅₋₆ cycloalkenyl-carbonyl groups may be mentioned also here the afore-mentioned cyclopentenylcarbonyl, cyclopentadienylcarbonyl, cyclohexenylcarbonyl or cyclohexadienylcarbonyl; C₆₋₁₀ aryl*carbonyl group may be mentioned also here benzoyl, naphthoyl, p-toluoyl, p-tert-butylbenzoyl, p-hydroxybenzoyl, p-methoxybenzoyl, p-tert-butoxybenzoyl, p-chlorobenzoyl or p-nitrobenzoyl; and "heterocycle*carbonyl group" is exemplified by 2- or 3-pyrrolylcarbonyl, 3-, 4- or 5-pyrazolylcarbonyl, 2-, 4- or 5-imidazolylcarbonyl, 1,2,3- or 1,2,4-triazolylcarbonyl, 1H- or 2H-tetrazolylcarbonyl, 2-or 3-furylcarbonyl, 2- or 3-thienylcarbonyl, 2-, 4- or 5-oxazolylcarbonyl, 3-, 4- or 5-isoxazolylcarbonyl, 1,2,3-oxadiazol-4- or 5-ylcarbonyl, 1,2,4-oxadiazol-3-or 5-ylcarbonyl, 1,2,5- or 1,3,4-oxadiazolylcarbonyl, 2-, 4- or 5-thiazolylcarbonyl, 2-amino-4-thiazolylcarbonyl, 3-, 4- or 5-isothiazolylcarbonyl, 1,2,3-thiadiazol-4- or 5-ylcarbonyl, 1,2,4-thiadiazol-3- or 5-ylcarbonyl, 5-amino-1,2,4-thiadiazol-3-ylcarbonyl, 1,2,5- or 1,3,4-thiadiazolylcarbonyl, 2- or 3-pyrrolidinylcarbonyl, 2-, 3- or 4-pyridylcarbonyl, 2-, 3- or 4-pyridylcarbonyl-N-oxide, 3- or 4-pyridazinylcarbonyl, 3- or 4-pyridazinylcarbonyl-N-oxide, 2-, 4- or 5-pyrimidinylcarbonyl, 2-, 4- or 5-pyrimidinylcarbonyl-N-oxide, pyrazinylcarbonyl, 2-, 3- or 4-piperidinylcarbonyl, piperazinylcarbonyl, 3H-indol-2- or 3-ylcarbonyl, 2-, 3- or 4-pyranylcarbonyl, 2-, 3- or 4-thiopyranylcarbonyl, benzopyranylcarbonyl, quinolylcarbonyl, pyrido[2,3-d]pyrimidylcarbonyl, 1,5-, 1,6-, 1,7-,1,8-,2,6- or 2,7-naphthylidylcarbonyl, thieno[2,3-b]pyridylcarbonyl, pyrimidopyridylcarbonyl, pyrazinoquinolylcarbonyl, or 3-(2,6-dichlorophenyl)-5-methylisoxazol-4-ylcarbonyl. As the esterified carboxyl groups (hereinafter sometimes denoted as the symbol R c ) included in the substituents R o , the substituted oxycarbonyl groups mentioned above as protective groups of optionally protected amino groups shown by R¹ can be applied also here as they are. Hence, the afore-mentioned methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, isopropoxycarbonyl, n-butoxycarbonyl, tert-butoxycarbonyl, cyclohexyloxycarbonyl, norbornyloxycarbonyl, phenoxycarbonyl, naphthyloxycarbonyl, benzyloxycarbonyl, methoxymethyloxycarbonyl, acetylmethyloxycarbonyl, 2-trimethylsilylethoxycarbonyl, 2-methanesulfonylethoxycarbonyl, 2,2,2-trichloroethoxycarbonyl, 2-cyanoethoxycarbonyl, p-methylphenoxycarbonyl, p-methoxyphenoxycarbonyl, p-chlorophenoxycarbonyl, p-methylbenzyloxycarbonyl, p-methoxybenzyloxycarbonyl, p-chlorobenzyloxycarbonyl, p-nitrobenzyloxycarbonyl, benzhydryloxycarbonyl, cyclopropyloxycarbonyl, cyclopentyloxycarbonyl or cyclohexyloxycarbonyl can be mentioned here also. The substituent R⁴ in the compounds [I] of this invention stands for hydrogen atom, methoxy group or formamido group (HCONH-). The substituent R¹³ in the compounds [I] of this invention stands for hydrogen atom, methyl group, hydroxyl group or halogen atom. The halogen atom means here fluorine, chlorine, bromine or iodine. In the compounds [I] of this invention, the substituent A stands for imidazol-1-yl group which forms a condensed ring at 2,3- or 3,4-position. The condensed ring means the imidazole ring having a 5- to 6-membered aromatic heterocyclic ring condensed therewith, and it may optionally be further condensed with another aromatic ring or aromatic heterocyclic ring. The mark ⊕ attached to the right shoulder of the substituent A means that A has monovalent positive electric charge. The optionally substituted imidazol-1-yl group (A ⊕ ) forming the condensed ring at 2,3- or 3,4-position is shown by the general formula [A¹] or [A²]; wherein B stands for a group forming 5- to 6-membered aromatic heterocyclic ring which may be condensed with another aromatic ring or aromatic heterocyclic ring, R¹¹ stands for hydrogen atom or a substituent (or substituents) on the imidazole ring and R¹² stands for hydrogen atom or a substituent (or substituents) on the ring which is condensed with the imidazole ring. B consists of carbon atom, nitrogen atom, oxygen atom and/or sulfur atom, and, among them, carbon atom combines with one hydrogen atom or one substituent, or forms another condensed ring together with adjacent carbon atom. The A¹ group may be embodied as follows, for example; The A² group may be embodied as follows, for example; Among these groups, especially preferable are imidazo[1,2-a]pyridinium-1-yl imidazo[1,2-b]pyridazinium-1-yl and imidazo[1,5-a]pyridinium-2-yl In the above-mentioned formulae [A¹] and [A²] as well as A¹ groups and A² groups embodied as above, the positive electric charge A ⊕ is applied, for convenience sake, to the nitrogen atom at the 3-position of imidazole, but there may be a case where the said quaternary nitrogen is that of the nitrogen atom at the 1-position. Further, there may be cases where the monovalent positive electric charge is delocalized at the imidazole ring, or even delocalized on the entire condensed ring. Therefore, the above may include or The position which this positive electric charge takes varies with, among others, the state (solid or in solution) of the compound [I], kinds of solvents, pH, temperature or kinds of substituents. Accordingly, the present invention includes all the cases where the positive electric charge is localized at nitrogen atom or is delocalized on the entire condensed ring. The substituents R¹¹ and R¹² on the condensed ring A may be exemplified by hydroxyl group, hydroxy C₁₋₆ alkyl group, C₁₋₆ alkyl group, C₂₋₆ alkenyl group, C₂₋₆ alkynyl group, C₄₋₆ alkadienyl group, C₃₋₁₀ cycloalkyl group, C₅₋₆ cycloalkenyl group, C₃₋₁₀ cycloalkyl C₁₋₆ alkyl group, C₆₋₁₀ aryl group, C₇₋₁₂ aralkyl group, di-C₆₋₁₀ arylmethyl group, tri-C₆₋₁₀ arylmethyl group, heterocyclic group, C₁₋₆ alkoxy group, C₁₋₆ alkoxy C₁₋₆ alkyl group, C₃₋₁₀ cycloalkyloxy group, C₆₋₁₀ aryloxy group, C₇₋₁₉ aralkyloxy group, mercapto group, mercapto C₁₋₆ alkyl group, sulfo group, sulfo C₁₋₆ alkyl group, C₁₋₆ alkylthio group, C₁₋₆ alkylthio C₁₋₆ alkyl group, C₃₋₁₀ cycloalkylthio group, C₆₋₁₀ arylthio group, C₇₋₁₉ aralkylthio group, amino group, amino C₁₋₆ alkyl group, mono-C₁₋₆ alkylamino group, di-C₁₋₆ alkylamino group, mono-C₁₋₆ alkylamino C₁₋₆ alkyl group, di-C₁₋₆ alkylamino C₁₋₆ alkyl group, C₃₋₁₀ cycloalkylamino group, C₆₋₁₀ arylamino group, C₇₋₁₉ aralkylamino group, cyclic amino group, cyclic amino C₁₋₆ alkyl group, cyclic amino C₁₋₆ alkylamino group, azido group, nitro group, halogen atom, halogeno C₁₋₆ alkyl group, cyano group, cyano C₁₋₆ alkyl group, carboxyl group, carboxy C₁₋₆ alkyl group, C₁₋₁₀ alkoxy-carbonyl group, C₁₋₁₀ alkoxy-carbonyl C₁₋₆ alkyl group, C₆₋₁₀ aryloxy-carbonyl group, C₇₋₁₉ aralkyloxy-carbonyl group, C₆₋₁₀ aryl-acyl⁺ group, C₁₋₆ alkanoyl group, C₂₋₆ alkanoyl C₁₋₆ alkyl group, C₃₋₅ alkenoyl group, C₆₋₁₀ arylacyl⁺oxy group, C₂₋₆ alkanoyloxy group, C₂₋₆ alkanoyloxy C₁₋₆ alkyl group, C₃₋₅ alkenoyloxy group, carbamoyl C₁₋₆ alkyl group, carbamoyl* group, thiocarbamoyl* group, carbamoyl*oxy group, carbamoyloxy C₁₋₆ alkyl group, C₁₋₆ alkanoylamino group, C₆₋₁₀ aryl-acyl⁺amino group, sulfonamido group, carboxyamino group, C₁₋₁₀ alkoxy-carboxamido group, C₆₋₁₀ aryloxy-carboxamido group or C₇₋₁₉ aralkyloxy-carboxamido group. Among the above-mentioned substituents, "C₄₋₆ alkadienyl group" is exemplified by 1,3-butadienyl, "C₃₋₁₀ cycloalkyl C₁₋₆ alkyl group" is exemplified by cyclopentylmethyl or cyclohexylmethyl, and halogen atom means here fluorine, chlorine or bromine. All the groups other than the above may be exemplified as in the foregoing. These substituents may occur singly or in plurarity with the same or different ones. And, in A¹, the 5,6-position of imidazole ring may be condensed with alicyclic ring, aromatic ring or heterocyclic ring. As the examples, the following may be counted: In the above, B and R¹² are of the same significance as afore-defined. The above-mentioned R¹¹ and R¹² may be further substituted. In the above compound [I], the mark ⊖ attached to the right shoulder of the carboxyl substituent (-COO) means that the said carboxyl group is carboxylate anion and forms internal salt by making a pair with the positive electric charge on the substituent A. On the other hand, the compound [I] may be physiologically or pharmaceutically acceptable salts or esters. As the physiologically or pharmaceutically acceptable salts, there may be mentioned, among others, inorganic base salts, ammonium salt , organic base salts, inorganic acid addition salts, organic acid addition salts and basic amino acid salts. There may be exemplified an alkali metal (e.g. sodium, potassium, etc.) or an alkaline earth metal (e.g. calcium) as an inorganic base capable of giving the inorganic base salts; procaine, 2-phenylethylbenzylamine, dibenzylethylenediamine, ethanolamine, diethanolamine, tris-hydroxymethylaminomethane, poly-hydroxyalkylamine or N-methylglucosamine as an organic base capable of giving the organic base salts; hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid or phosphoric acid as an inorganic acid capable of giving the inorganic acid addition salts; p-toluenesulfonic acid, methanesulfonic acid, formic acid, trifluoroacetic acid or maleic acid as an organic acid capable of giving the organic acid addition salts; and lysine, arginine, ornithine or histidine as a basic amino acid capable of giving the basic amino acid salts. Among these salts, basic salts (i.e. inorganic base salts, ammonium salt, organic base salts and basic amino acid salts) mean salts derivable in case there is (are) acidic group(s) e.g. carboxyl group, sulfo group etc. on the substituent R o or A of the compound [I], and acid addition salts (i.e. inorganic acid addition salts and organic acid addition salts) mean salts derivable in case there is(are) basic group(s) e.g. amino group, monoalkylamino group, dialkylamino group, cycloalkylamino group, arylamino group, aralkylamino group, cyclic amino group, nitrogen-containing heterocyclic group etc. on the substituent R o or A of the compound [I]. Incidentally, the acid addition salts also includes an intramolecular salt of the compound [I], i.e. a salt having carboxyl(COOH) group at the 4-position and CH₂A ⊕ .M ⊖ group [wherein M ⊖ denotes an anion formed by removal of a proton (H ⊕ ) from inorganic acid or organic acid; such an anion is exemplified by chloride ion, bromide ion, sulfate ion, p-toluenesulfonate ion, methanesulfonate ion, trifluoroacetate ion] at the 3-position, which is formed through addition of one mole of acid to carboxylate(COO ⊖ ) group of the 4-position and CH₂A ⊕ group of the 3-position of the compound [I]. The ester derivatives of the compound [I] mean esters derivable by esterifying the carboxyl group contained in the molecule, which include esters usable as synthetic intermediates and bioavailably unstable non-toxic enters. The esters usable as synthetic intermediates are exemplified by C₁₋₆ alkyl* ester, C₂₋₆ alkenyl ester, C₃₋₁₀ cycloalkyl ester, C₃₋₁₀ cycloalkyl C₁₋₆ alkyl ester, C₆₋₁₀ aryl* ester, C₇₋₁₂ aralkyl* ester, di-C₆₋₁₀ arylmethyl ester, tri-C₆₋₁₀ aryl-methyl ester or substituted silyl ester. There may be exemplified, as "C₁₋₆ alkyl* group"capable of giving C₁₋₆ alkyl* ester, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, benzyloxymethyl, 2-methylsulfonylethyl, 2-trimethylsilylethyl, 2,2,2-trichloroethyl, 2-iodoethyl, acetylmethyl, p-nitrobenzoylmethyl, p-mesylbenzoylmethyl, phthalimidomethyl, succinimidomethyl, benzenesulfonylmethyl, phenylthiomethyl, dimethylaminoethyl, pyridine-1-oxido-2-methyl, methylsulfinylmethyl, or 2-cyano-1,1-dimethylethyl; as C₂₋₆ alkenyl group capable of giving C₂₋₆ alkenyl ester, the afore-mentioned ones, i.e. vinyl, allyl, 1-propenyl, isopropenyl, 1-butenyl, 2-butenyl, 3-butenyl, methallyl, 1,1-dimethylallyl or 3-methyl-3-butenyl; as C₃₋₁₀ cycloalkyl group capable of giving C₃₋₁₀ cycloalkyl ester, the afore-mentioned ones, i.e. cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, norbornyl or adamantyl; as C₃₋₁₀ cycloalkyl C₁₋₆ alkyl group capable of giving C₃₋₁₀ cycloalkyl C₁₋₆ alkyl ester, the afore-mentioned ones, i.e. cyclopropylmethyl, cyclopentylmethyl or cyclohexylmethyl; as "C₆₋₁₀ aryl* group" capable of giving C₆₋₁₀ aryl* ester, phenyl,α-naphthyl, β-naphthyl, biphenylyl, p-nitrophenyl or p-chlorophenyl; as "C₇₋₁₂ aralkyl* group" capable of giving C₇₋₁₂ aralkyl* ester, benzyl, 1-phenylethyl, 2-phenylethyl, phenylpropyl, naphthylmethyl, p-nitrobenzyl, p-methoxybenzyl, 1-indanyl, phenacyl or 3,5-di-tert-butyl-4-hydroxybenzyl; as di-C₆₋₁₀ aryl-methyl group capable of giving di-C₆₋₁₀ aryl-methyl ester, the afore-mentioned ones, i.e. benzhydryl or bis(p-methoxyphenyl)methyl; as tri-C₆₋₁₀ aryl-methyl group capable of giving tri-C₆₋₁₀ aryl-methyl ester, the afore-mentioned ones, i.e. trityl; and as substituted silyl group capable of giving substituted silyl ester, the afore-mentioned ones, i.e. trimethylsilyl, tert-butyldimethylsilyl or -Si(CH₃)₂CH₂CH₂Si(CH₃)₂-. The above esters include ester at the 4-position. Such compound having above ester group at the 4-position forms an intramolecular salt of CH₂A ⊕ .M ⊖ [wherein M ⊖ has the same meaning as defined above] at the 3-position. As the bioavailably unstable and non-toxic esters, those which have been confirmed as employable in the fields of penicillin and cephalosporin can conveniently be employed also in the present invention, which may be exemplified by C₂₋₆ alkanoyloxy C₁₋₆ alkyl ester, 1-(C₁₋₆ alkoxy)C₁₋₆ alkyl ester or 1-(C₁₋₆ alkylthio)C₁₋₆ alkyl ester. The C₂₋₆ alkanoyloxy C₁₋₆ alkyl ester is exemplified by acetoxymethyl ester, 1-acetoxyethyl ester, 1-acetoxybutyl ester, 2-acetoxyethyl ester, propionyloxymethyl ester, pivaloyloxymethyl ester. The 1-(C₁₋₆ alkoxy)C₁₋₆ alkyl ester is exemplified by methoxymethyl ester, ethoxymethyl ester, isopropoxymethyl ester, 1-methoxyethyl ester or 1-ethoxyethyl ester. The 1-(C₁₋₆ alkylthio)C₁₋₆ alkyl ester is exemplified by methylthiomethyl ester or ethylthiomethyl ester. The present invention includes, besides the above-mentioned ester derivatives, physiologically or pharmaceutically acceptable compounds which are convertible in vivo to the compound [I]. The above-mentioned esters usable as synthetic intermediates and bioavailably unstable non-toxic esters include esters at the 4-position. Such esters at the 4-position usually form an intramolecular salt of CH₂A ⊕ .M ⊖ [wherein M ⊖ has the same meaning as defined above] at the 3-position. When a compound [I] has hydroxyl group, the hydroxyl group may be protected. Groups usable for protecting hydroxyl group include those which are usually employed for protecting hydroxyl group in the field of β-lactam and organic chemistry, which may be exemplified by, besides the afore-mentioned C₂₋₆ alkanoyl groups, substituted oxycarbonyl group, tert-butyl group, C₇₋₁₂ aralkyl* group, di-C₆₋₁₀ aryl-methyl group, tri-C₆₋₁₀ aryl-methyl group, 1-(C₁₋₆ alkoxy)C₁₋₆ alkyl group, 1-(C₁₋₆ alkylthio)C₁₋₆ alkyl group and substituted silyl group, acetal residues e.g. 2-tetrahydropyranyl or 4-methoxy-4-tetrahydropyranyl. When a compound [I] additionally has amino group other than those mentioned above, the amino group may also be protected. Groups employable for protecting those amino groups are exemplified also here by those referred to in the protection of the afore-mentioned amino groups. Among the compounds [I] of this invention, one in which the substituent R o is nitrogen-containing heterocyclic group (R a ) or acyl group (R b ) has a broad antibacterial spectrum and can be used for prophylaxis and therapy of various diseases of men and animals caused by pathogenic bacteria, for example, infections of respiratory tract or of urinary passages. Characteristic features of the antibacterial spectrum of the antibacterial compound [I] (R o =R a or R b ) are mentioned as follows: (1) remarkably strong activity against a variety of gram-negative bacteria; (2) strong activity against gram-positive bacteria (e.g. Staphylococcus aureus or Cornyebacterium diphtheriae; (3) remarkably effective to Pseudomonas aeruginosa which are not sensitive to therapy with conventional cephalosporin-type antibiotics; and (4) Strong activity against a variety of β-lactamase-producing gram-negative bacteria (e.g. the genera Escherichia , Enterobacter , Serratia or Proteus ). Especially against bacteria belonging to the genus Pseudomonas , to which aminoglycoside antibiotics such as Amikacin or Gentamicin have been used, the antibacterial compound [I] shows antibacterial activity comparable to these aminoglycosides with remarkably lower toxicity to men and animals, which is counted as one of the great advantages. Besides, the antibacterial compound [I] (R o =R a or R b ) of this invention has the following characteristic features, i.e. excellent stability, high concentration in blood, long duration of effect and remarkably high concentration in tissue. How to make the compound [I] of this invention, its salts or esters will be described in detail as follows. The processes described hereafter are all conventional as reactions per se , and analogous ones thereto can also be applied. Production Method (1): Synthesis of Compound [II] ([I], R⁰ = hydrogen atom) ― For example, 7-amino compound [II] ([I], R⁰ = hydrogen atom) can be synthesized by allowing a compound representable by the general formula; [wherein the symbol R⁵ stands for hydroxyl group, acyloxy group, carbamoyloxy group, substituted carbamoyloxy or halogen atom, and other symbols are of respectively the same meanings as defined above] or a salt or ester thereof to react with an imidazole compound representable by the general formula A' [A' means optionally substituted imidazole forming a condensed ring at 2,3- or 3,4-position] or a salt thereof. The reaction scheme is as follows: [wherein Z, R⁴, R¹³, R⁵ and A are of the same meaning as defined above]. The starting compound [IX] or a salt or ester thereof is a compound which can be easily produced by a conventional method or an analogous one thereto. As salts and esters of the compound [IX] can be also mentioned here the same ones described hereafter as those of the compound [II]. As the acyloxy group representable by the symbol R⁵, the above-mentioned acyl⁺oxy group can be employed also here, especially preferable being acetoxy, chloroacetoxy, propionyloxy, butyryloxy, pivaloyloxy, 3-oxobutyryloxy, 4-chloro-3-oxobutyryloxy, 3-carboxypropionyloxy, 4-carboxybutyryloxy, 3-ethoxycarbamoylpropionyloxy, benzoyloxy, o-carboxybenzoyloxy, o-(ethoxycarbonylcarbamoyl)benzoyloxy and o-(ethoxycarbonylsulfamoyl)benzoyloxy. As the substituted carbamoyloxy group representable by the symbol R⁵, the above-mentioned ones can be employed also here, especially preferable being methylcarbamoyloxy and N,N-dimethylcarbamoyloxy. Halogen atoms representable by the symbol R⁵ are preferably chlorine, bromine and iodine. As to the imidazole compound A' and its salts, detailed description will be given hereafter. Even in case where the amino group at 7-position is protected, the above reaction proceeds likewise. When necessary, the protecting group may be removed after the reaction to thereby give a 7-amino compound [II] ([I], R⁰ = hydrogen atom). Production Method (2): Synthesis of Compound [I a ] (R⁰ = R a ; R a denotes nitrogen-containing heterocyclic group) For example, (2-1): By allowing the 7-amino compound [II] obtained in the preceding section (1) or a salt or ester thereof (description about the salt and ester will be made hereafter) to react with a compound representable by the general formula R a Hal [R a stands for a nitrogen-containing heterocyclic group and Hal stands for a halogen atom e.g. fluorine, chlorine, bromine or iodine] or its salt, a compound [I a ] [R O = R a ) can be synthesized. The reaction scheme is as follows: [wherein the symbol R a stands for nitrogen containing heterocyclic group, and Z, R⁴, R¹³, A and Hal are of the same meaning as defined above]. As the halogen atom (Hal) of the compound R a Hal, use is most often made of fluorine. As salts of the compound R a Hal are exemplified inorganic acid addition salts such as hydrochloride, hydrobromide, sulfate, nitrate or phosphate, or organic acid addition salts such as formate, acetate, trifluoroacetate, methanesulfonate or p-toluenesulfonate. The reaction is generally conducted by mixing a compound R a Hal or its salt with a 7-amino compound [II] or a salt or ester thereof in water or an aqueous solvent at room temperature (about 15-30°C). For preventing hydrolysis of the compound R a Hal prior to its reaction with the 7-amino compound [II], it is necessary to control the pH of the reaction solution. Optimal pH ranges from 6 to 8.5. For the purpose of eliminating from the reaction system hydrogen halogenide formed during the reaction, use may be made of a deacidifying agent, for example, inorganic bases such as sodium carbonate, potassium carbonate, calcium carbonate or sodium hydrogen carbonate; tertiary amines such as triethylamine, tri-(n-propyl)amine, tri-(n-butyl)amine, diisopropylethylamine, cyclohexyldimethylamine, pyridine, lutidine, γ-collidine, N,N-dimethylaniline, N-methylpiperidine, N-methylpyrrolidine or N-methylmorpholine; or alkylene oxides such as propylene oxide or epichlorohydrin. For preventing the pH to shift to alkali side too far, an inorganic acid such as hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid or phosphoric acid may sometimes be employed. When an aquoeus solvent is employed, as the organic solvent to be mixed with water, there may be exemplified by dimethylsulfoxide, sulfolane, or hexamethyl phosphoramide, besides ethers such as dioxane, tetrahydrofuran, diethyl ether, tert-butyl methyl ether or diisopropyl ether, amides such as formamide, N,N-dimethylformamide or N,N-dimethylacetamide and ketones such as acetone, methyl ethyl ketone or methyl isobutyl ketone. Amount of the compound R a Hal is usually 1-3 mol., preferably 1-2 mol., relative to 1 mol. of the 7-amino compound [II]. While the reaction time varies with kinds of 7-amino compound [II] and the compound R a Hal, kinds of the solvent employed and reaction temperatures, it usually ranges from one minute to 48 hours, preferably from 15 minutes to 3 hours. The compound R a Hal and its salt can be easily produced by a conventional method or an analogous one thereto. According to the method mentioned above, compounds having the following general formula can be synthesized, for example. When the compound R a Hal is too much reactive and liable to be hydrolized, the reaction may be conducted in e.g. anhydrous dimethylsulfoxide in the presence of an organic base e.g. anhydrous triethylamine. According to this method, compounds of the following general formula can be synthesized, for example. The above reaction is sometimes conducted in the presence of an organic acid e.g. p-toluenesulfonic acid, methanesulfonic acid, ethanesulfonic acid, acetic acid or butyric acid, or an inorganic acid e.g. hydrochloric acid, sulfuric acid or carbonic acid. In this case also, as the halogen atom (Hal) of R a Hal, fluorine is most frequently employed. The reaction is usually conducted in a solvent such as dimethylformamide, tetrahydrofuran, dioxane, chloroform, methanol, acetonitrile, benzene, acetone or water, or an optional mixture thereof. The reaction temperature ranges from 0°C to 150°C, preferably 20°C to 80°C. The reaction time usually ranges from 30 minutes to 20 hours. According to this method, compounds of the following general formula can be synthesized, for example. (2-2): After allowing the starting compound [IX] employed in the preceding section(1) or a salt or ester thereof to react with the compound R a Hal or a salt thereof, imidazole compound A' [A' is of the same meaning as defined above] is further allowed to react with the reaction product to synthesize a corresponding compound [I a ] (R⁰ = R a ). The reaction is shown by the following scheme: [wherein the symbol R a stands for nitrogen-containing heterocyclic group, and the symbols Z, R⁴, R¹³, R⁵, A and Hal are of the same meaning as defined above]. The starting compound [IX], its salts and esters, and the compound R a Hal and its salts can be exemplified also here by those mentioned in the foregoing. About the imidazole compound A' and its salts, detailed description will be given later. The reactions of Production Method (2-1) and (1) can be applied as they are. Production Method (3): Synthesis of compound [I b ] For example. (R⁰ = R b ; R b denotes acyl group) (3-1): By allowing the 7-amino compound [II] obtained in the section (1) or a salt or ester thereof to react with carboxylic acid representable by the general formula R b OH [wherein R b denotes acyl group or a salt or reactive derivative thereof, a compound [I b ] (R⁰ = R b ) can be synthesized. The reaction is shown by the following scheme: [wherein the symbol R b stands for acyl group, and the symbols Z, R⁴, R¹³, and A are of the same meaning as defined above]. This is a method of subjecting a 7-amino compound [II] to acylation with carboxylic acid R b OH or a salt or reactive derivative thereof. In this method, the carboxylic acid R b OH in the free form, a salt or reactive derivative thereof is used as the acylating agent of the 7-amino group of the 7-amino compound [II]. More concretely, the free acid R b OH or a reactive derivative of the free acid R b OH, such as inorganic salt, organic salt, acid halide, acid azide, acid anhydride, mixed acid anhydride, active amide, active ester or active thioester is used for the acylation. There may be mentioned, among others, as inorganic salts, alkali metal salts (e.g. sodium salt, potassium salt, etc.) or alkaline earth metal salts (e.g. calcium salt, etc.); as organic salts, trimethylamine salt, triethylamine salt, tert,.butyldimethylamine salt, dibenzylmethylamine salt, benzyldimethylamine salt, N,N-dimethylaniline salt, pyridine salt or quinoline salt; as acid halide, acid chloride or acid bromide; as mixed acid anhydride, mono-C₁₋₆ alkyl carbonic acid mixed anhydride (e.g. mixed acid anhydride of the free acid R b OH with, for example, monomethyl carbonic acid, monoethyl carbonic acid, monoisopropyl carbonic acid, monoisobutyl carbonic acid, mono-tert-butyl carbonic acid, monobenzyl carbonic acid, mono(p-nitrobenzyl)carbonic acid, or monoallyl carbonic acid), C₁₋₆ aliphatic carboxylic acid mixed anhydride (e.g. mixed acid anhydride of the free acid R b OH with, for example, acetic acid, trichloroacetic acid, cyanoacetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, isovaleric acid, pivalic acid, trifluoroacetic acid, trichloroacetic acid or acetoacetic acid), C₇₋₁₂ aromatic carboxylic acid mixed anhydride (e.g. mixed acid anhydride of the free acid R b OH with, for example, benzoic acid, p-toluic acid or p-chlorobenzoic acid), organic sulfonic acid mixed anhydride (e.g. mixed acid anhydride of the free acid R b OH with, for example, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid or p-toluenesulfonic acid); as active amide,an amide with a nitrogen-containing heterocyclic compound (e.g. acid amide of the free acid R b OH with, for example, pyrazole, imidazole or benzotriazole, these nitrogen-containing heterocyclic compounds being optionally substituted with afore-mentioned C₁₋₆ alkyl group, C₁₋₆ alkoxy group, halogen atom, oxo group, thioxo group or C₁₋₆ alkylthio group). As the active ester, those which can be used for the same purpose in the fields of β-lactam and peptide synthesis can all be used, which are exemplified by, - besides organic phosphoric acid ester (e.g. diethoxy phosphoric acid ester or diphenoxy phosphoric acid) -, p-nitrophenyl ester, 2,4-dinitrophenyl ester, cyanomethyl ester, pentachlorophenyl ester, N-hydroxysuccinimide ester, N-hydroxyphthalimide ester, 1-hydroxybenzotriazole ester, 6-chloro-1-hydroxybenzotriazole ester, 1-hydroxy-1H-2-pyridone ester. The active thioester can be exemplified by esters with aromatic heterocyclic thiol compounds (e.g. 2-pyridylthiol ester, 2-benzothiazolylthiol ester, these heterocyclic rings being substituted with afore-mentioned C₁₋₆ alkyl group, C₁₋₆ alkoxy group, halogen atom or C₁₋₆ alkylthio group). On the other hand, the 7-amino compound [II] can be used as free, a salt or ester thereof. Salts of the 7-amino compound [II] are exemplified by inorganic base salts, ammonium salt , organic base salts, inorganic acid addition salts or organic acid addition salts. There may be mentioned, as inorganic base salts, alkali metal salts (e.g. sodium salts or potassium salts) and alkaline earth metal salts (e.g. calcium salts); as organic base salts, for example trimethylamine salts, triethylamine salts, tert-butyldimethylamine salts, dibenzylmethylamine salts, benzyldimethylamine salts, N,N-dimethylaniline salts, pyridine salts or quinoline salts; as inorganic acid addition salts, for example hydrochlorides, hydrobromides, sulfates, nitrates or phosphates; and as organic acid addition salts, formates, acetates, trifluoroacetates, methanesulfonates, or p-toluenesulfonates. As the esters of the 7-amino compound [II], esters already referred to as ester derivatives of the compound [I] can also be counted, more concretely, C₁₋₆ alkyl* ester, C₂₋₆ alkenyl ester, C₃₋₁₀ cycloalkyl ester, C₃₋₆ cycloalkyl C₁₋₆ alkyl ester, C₆₋₁₀ aryl*ester, C₇₋₁₂ aralkyl* ester, di-C₆₋₁₀ aryl-methyl ester, tri-C₆₋₁₀ aryl-methyl ester or C₂₋₆ alkancyloxy C₁₋₆ alkyl ester. The starting material R b OH as well as salts and reactive derivatives thereof can be easily prepared by known methods or analogous methods thereto. A reactive derivative of the compound R b OH, after isolation from the reaction mixture, can be allowed to react with a 7-amino compound [II], or as the reaction mixture containing the reactive derivative of the compound R b OH before the isolation, it can be allowed to react with a 7-amino compound [II]. When the carboxylic acid R b OH is used in the state of its free acid or salt, a suitable condensing agent is employed. As the condensing agents, there may be counted N,N'-di-substituted carbodiimides e.g. N,N'-di-cyclohexylcarbodiimide; azolides e.g. N,N'-carbonyldiimidazole or N,N'-thiocarbonyldiimidazole; dehydrating agents e.g. N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline, phosphorus oxychloride or alkoxyacetylene; 2-halogenopyridinium salts e.g. 2-chloropyridinium methyl iodide or 2-fluoropyridinium methyl iodide. The reactions where these condensing agents are employed are considered to proceed via reactive derivatives of the carboxylic acid R b OH. These reactions are generally conducted in a solvent which does not hamper the reaction. As these solvents, there may be exemplified by ethers such as dioxane, tetrahydrofuran, diethyl ether, tert-butyl methyl ether, diisopropyl ether or ethylene glycol dimethyl ether; esters such as ethyl formate, ethyl acetate or n-butyl acetate; halogenated hydrocarbons such as dichloromethane, chloroform, carbon tetrachloride, trichlene or 1,2-dichloroethane; hydrocarbons such as n-hexane, benzene or toluene; amides such as formamide, N,N-dimethylformamide or N,N-dimethylacetamide; ketones such as acetone, methyl ethyl ketone or methyl isobutyl ketone; or nitriles such as acetonitrile or propionitrile, and, besides, dimethyl sulfoxide, sulfolane, hexamethylphosphoramide or water, singly or in combination. The amount of acylating agent (R b OH) is usually 1-5 mol., preferably 1-2 mol., relative to 1 mol. of the 7-amino compound [II]. The reaction is conducted within the temperature range of -80∼80°C, preferably -40∼50°C, most preferably -30∼30°C. The reaction time varies with kinds of the 7-amino compound [II] and carboxylic acid R b OH, kinds of the solvent (mixture ratio as well when mixture solvents are used) and reaction temperatures, but it is usually within the range from one minute to 72 hours, preferably from 15 minutes to three hours. When an acid halide is employed as the acylating agent, the reaction can be conducted in the presence of a deacidifying agent for the purpose of eliminating from the reaction system the hydrogen halogenide to be liberated. The deacidifying agent may be exemplified by inorganic bases such as sodium carbonate, potassium carbonate, calcium carbonate or sodium hydrogen carbonate; tertiary amines such as triethylamine, tri(n-propyl)amine, tri(n-butyl)amine, diisopropylethylamine, cyclohexyldimethylamine, pyridine, lutidine, γ-collidine, N,N-dimethylaniline, N-methylpiperidine, N-methylpyrrolidine or N-methylmorpholine; or alkylene oxides such as propylene oxide or epichlorohydrin. By the method mentioned above, the compound [VII] described in the foregoing can be synthesized. The reaction scheme is as follows: The carboxylic acid [III] can be easily prepared by a known process or a process analogous thereto. (3-2): By allowing a compound representable by the general formula: [wherein R b stands for acyl group, and other symbols are of the same meaning as defined above] or a salt or ester thereof to react with an imidazole compound of the general formula A' [A' is of the same meaning as defined above] or a salt thereof, a compound [I b ] (R⁰ = R b ) can be synthesized, which is shown by the following reaction scheme: [wherein the symbol R b stands for acyl group and the symbols Z, R⁴, R¹³, R⁵ and A are of the same meaning as defined above]. This reaction is substantially the same as that mentioned in the Production Method (1) above, namely, imidazole compound A' or a salt thereof is allowed to react with a compound [X] or a salt or ester thereof to cause nucleophilic substitution to thereby synthesize a compound [I b ] (R⁰ = R b ). In the compound [X], R⁵ stands for, also here, hydroxyl group, acyloxy group, carbamoyloxy group, substituted carbamoyloxy group or halogen atom. The compound [X] can be used in the free state, or salts or esters thereof. The salts and esters of the compound [X] are those mentioned as salts and esters of the 7-amino compound [II] in the above Production Method (3-1). The compound [X], salts and esters thereof can be easily prepared by known methods or analogous ones thereto. On the other hand, the imidazole compound A' stands for an optionally substituted imidazole forming a condensed ring at the 2,3-position or the 3,4-position. The condensed ring means a form of condensation between the imidazole ring and the 5- to 6-membered aromatic heterocyclic ring. Thus-condensed ring may be further condensed with another aromatic ring or aromatic heterocyclic ring. The optionally substituted imidazole (A') forming a condensed ring at the 2,3-position or the 3,4-position may be represented by the general formula [A 1' ] or [A 2' ]; and the A ⊕ group of the end-product [I b ] (R⁰ = R b ) to be synthesized by allowing the compound [X] to react with the compound [A 1' ] stands for the afore-mentioned A¹ group, and the A ⊕ group of the end-product [I b ] (R⁰ = R b ) to be synthesized by allowing the compound [X] to react with the compound [A 2' ], stands for the afore-mentioned A² group. The symbol B in the formulae of condensed imidazole [A 1' ] and [A 2' ] is of the same meaning as that of symbol B in the [A¹] and [A²] groups defined in the above. Hence, the compound [A 1' ] is exemplified by and the compound [A 2' ] is exemplified by The substituents R 11' and R 12' on the imidazole compound A' are those mentioned as the substituents R¹¹ and R¹² of the group A. And, in the compound [A 1' ], the 5,6-position of the imidazole ring may be condensed with an alicyclic ring, aromatic ring or heterocyclic ring, which may be exemplified by In the above, B and R 12' are of the same meaning as defined in the foregoing. The above-mentioned substituents R 11' and R 12' may be further substituted. The imidazole compound A' may be used as salts thereof, which may be exemplified by inorganic acid addition salts e.g. hydrochloride, hydrobromide, sulfate, nitrate or phosphate, or organic acid addition salts e.g. formate, acetate, trifluoroacetate, methanesulfonate or p-toluenesulfonate. The imidazole compound A' and its salt may be synthesized, in general, by known methods described in literature references or by analogous methods thereto. The nucleophilic substitution to the compound [X] with the imidazole compound A' is a per se well known reaction, which is usually conducted in a solvent, for example, ethers, esters, halogenated hydrocarbons, hydrocarbons, amides, ketones, nitriles or water, which are used in the Production Method (3-1). Besides, alcohols such as methanol, ethanol, n-propanol, isopropanol, ethylene glycol or 2-methoxyethanol may be used as well. When the imidazole compound A' is in liquid state, it may be sometimes used in a large excess amount (e.g. 10-200 mol.) relative to the compound [X] to allow it to act as also the solvent. In this case, use of the above-mentioned solvents is unnecessary, or the imidazole A' may be used as a mixture solvent with any of the above-mentioned solvents. (3-2-1): The case where R⁵ stands for acyloxy group, carbamoyloxy group or a substituted carbamoyloxy group - Preferable solvents are water and mixture solvents of water-miscible organic solvents and water. Among the water-miscible organic solvents, preferable ones are exemplified by acetone, methyl ethyl ketone and acetonitrile. The amount of the nucleophilic reagent A' is usually 1-5 moles, preferably 1-3 moles, relative to 1 mole of the compound [X]. The reaction is conducted within a temperature ranging from 10°C to 100°C, preferably from 30°C to 80°C. The reaction time depends on the kinds of the compound [X] and the compound A', kinds of solvents (mixture ratios when mixture solvents are used), or reaction temperature, and ranges usually from 30 minutes to five days, preferably from one hour to five hours. The reaction is advantageously conducted at pH 2-8, preferably near neutral pH, i.e., pH 5-8. The reaction readily proceeds usually in the presence of 2-30 equivalents of an iodide or thiocyanate. These salts are exemplified by sodium iodide, potassium iodide, sodium thiocyanate and potassium thiocyanate. In addition to the above exemplified salts, a surface-active quaternary ammonium salt such as trimethylbenzylammonium bromide, triethylbenzylammonium bromide or triethylbenzylammonium hydroxide may be sometimes used for allowing the reaction to proceed smoothly. (3-2-2): The case where R⁵ stands for hydroxyl group - The reaction is conducted in the presence of an organic phosphorus compound according to the manner described in, for example, Publication of Unexamined Patent Application (Kokai) in Japan, No. Sho 58-43979. The organic phosphorus compound is exemplified by o-phenylene phosphorochloridate, o-phenylene phosphorofluoridate, methyl o-phenylene phosphate, ethyl o-phenylene phosphate, propyl o-phenylene phosphate, isopropyl o-phenylene phosphate, butyl o-phenylene phosphate, isobutyl o-phenylene phosphate, sec.-butyl o-phenylene phosphate, cyclohexyl o-phenylene phosphate, phenyl o-phenylene phosphate, p-chlorophenyl o-phenylene phosphate, p-acetylphenyl o-phenylene phosphate, 2-chloroethyl o-phenylene phosphate, 2,2,2-trichloroethyl o-phenylene phosphate, ethoxycarbonylmethyl o-phenylene phosphate, carbamoylmethyl o-phenylene phosphate, 2-cyanoethyl o-phenylene phosphate, 2-methylsulfonylethyl o-phenylene phosphate, benzyl o-phenylene phosphate, 1,1-dimethyl-2-propenyl o-phenylene phosphate, 2-propenyl o-phenylene phosphate, 3-methyl-2-butenyl o-phenylene phosphate, 2-thienylmethyl o-phenylene phosphate, 2-furfurylmethyl o-phenylene phosphate, bis-o-phenylene pyrophosphate, 2-phenyl-1,3,2-benzodioxaphosphole-2-oxide, 2-(p-chlorophenyl)-1,3,2-benzodioxaphosphole-2-oxide, 2-butyl-1,3,2-benzodioxaphosphole-2-oxide, 2-anilino-1,3,2-benzodioxaphosphole-2-oxide, 2-phenylthio-1,3,2-benzodioxaphosphole-2-oxide, 2-methoxy-5-methyl-1,3,2-benzodioxaphosphole-2-oxide, 2-chloro-5-ethoxycarbonyl-1,3,2-benzodioxaphosphole-2-oxide, 2-methoxy-5-ethoxycarbonyl-1,3,2-benzodioxaphosphole-2-oxide, 5-ethoxycarbonyl-2-phenyl-1,3,2-benzodioxaphosphole-2-oxide, 2,5-dichloro-1,3,2-benzodioxaphosphole-2-oxide, 4-chloro-2-methoxy-1, 3,2-benzodioxaphosphole-2-oxide, 2-methoxy-4-methyl-1,3,2-benzodioxaphosphole-2-oxide, 2,3-naphthalene methyl phosphate,5,6-dimethyl-2-methyoxy-1,3,2-benzodioxaphosphole-2-oxide, 2,2-dihydro-4,5,6,7-tetrachloro-2,2,2-trimethoxy-1,3,2-benzodioxaphosphole, 2,2-dihydro-4,5,6,7-tetrachloro-2,2,2-triphenoxy-1,3,2-benzodioxaphosphole, 2,2-dihydro-2,2-ethylenedioxy-2-methoxy-1,3,2-benzodioxaphosphole, 2,2-dihydro-benzyl-2,2-dimethoxy-1,3,2-benzodioxaphosphole, 2,2-dihydro-4,5-benzo-2,2,2-trimethoxy-1,3,2-benzodioxaphosphole, 2,2-dihydro-2,2,2-triphenoxy-1,3,2,-benzodioxaphosphole, 2,2-dihydro-2,2-(o-phenylenedioxy)-2-phenoxy-1,3,2-benzodioxaphosphole, 2-chloro-2,2,-dihydro-2,2-(o-phenylenedioxy)-1,3,2,-benzodioxaphosphole 2,2-dihydro-2-methoxy-2,2-(o-phenylenedioxy)-1,3,2-benzodioxaphosphole, 2,2-dihydro-2,2,2-trichloro-1,3,2-benzodioxaphosphole, 9,10-phenanthrenedioxytrimethoxyphosphorus, o-phenylen phosphorochloridite, o-phenylene phosphorobromidite, o-phenylene phosphorofluoridite, methyl o-phenylene phoshite, butyl o-phenylene phosphite methoxycarbonylmethyl o-phenylene phosphite, phenyl o-phenylene phosphite,p-chloro (or p-nitro)phenyl o-phenylene phosphite,2-phenyl-1,3,2-benzodioxaphosphole, bis-o-phenylene pyrophosphite, 2-methoxy-5-methyl-1,3,2-benzodioxaphosphole, 5-acetyl-2-phenoxy-1,3,2-benzodioxaphosphole, 9,10-phenanthrene phosphorochloridite, 2-chloro-4-methyl-1,3,2-benzodioxaphosphole,5-ethoxycarbonyl-2-phenyl-1,3,2-benzodioxaphosphole,2-chloro-2-thioxo-1,3,2-benzodioxaphosphole,2-phenoxy-2-oxo-1,3,2-benzodiazaphosphole,2-phenoxy-1,3,2-benzodioxaazaphosphole,2,2-dihydro-2-oxo-2-methoxy-4,5-dimethyl-1,3,2-dioxaphosphole,2,2-dihydro-2-oxo-2-chloro-4,5-dimethyl-1,3,2-dioxaphosphole,2,2-dihydro-2-oxo-2-(1-imidazolyl)-4,5-dimethyl-1,3,2-dioxaphosphole,2,2-dihydro-2,2-ethylenedioxy-2-methoxy-4,5-dimethyl-1,3,2-dioxaphosphole,2,2-dihydro-2,2-dimethoxy-2-phenoxy-4,5-dimethyl-1,3,2-dioxaphosphole,2,2-dihydro-2,2,2-trimethoxy-4,5-dimethyl-1,3,2-dioxaphosphole,2,2-dihydro-2,2,2-triphenoxy-4,5- dimethyl-1,3,2-dioxaphosphole,2,2-dihydro-2,2,2-triethoxy 4,5-diphenyl-1,3,2-dioxaphosphole,2,2-dihydro-2,2,2-trimethoxy-4,5-diphenyl-1,3,2-dioxaphosphole,2,2-dihydro-2-oxo-2-methoxy-4,5-diphenyl-1,3,2-dioxaphosphole,2,2-dihydro-2,2,2-trimethoxy-1,3,2-dioxaphosphole,2,2-dihydro-2,2,2-trimethoxy-4-phenyl-1,3,2-dioxaphosphole,2,2-dihydro-2,2,2,-trimethoxy-4-methyl-1,3,2-dioxaphosphole,2,2-dihydro-2,2,2-trimethoxy-4-methyl-5-phenylcarbamoyl-1,3,2-dioxaphosphole,2,2,4,5,6,7 - hexahydro-2,2,2-trimethoxy-1,3,2-benzodioxaphosphole,2,2'-oxybis(4,5-dimethyl-2,2-dihydro-1,3,2-dioxaphosphole) and 2,2'-oxybis(4,5-dimethyl-2,2-dihydro-1,3,2-dioxaphosphole-2-oxide). For the reaction, any solvent can be employed if only it does not hamper the reaction, and, preferably, the afore-mentioned ethers, esters, halogenated hydrocarbons, hydrocarbons, amides, ketones and nitriles may be used singly or in a mixture thereof. Especially, use of dichloromethane, acetonitrile, formamide, a mixture of formamide and acetonitrile, or a dichloromethane and acetonitrile brings about a preferable result. The amounts of the nucleophilic reagent A' and the organic phosphorus compound are respectively, relative to 1 mole of the compound [X], 1-5 moles and 1-10 moles, more preferably 1-3 moles and 1-6 moles. The reaction is conducted within the temperature range from -80°C to 50°C, preferably from -40°C to 40°C. The reaction time is usually within the range of one minute to 15 hours, preferably five minutes to two hours. To the reaction system may be added an organic base. As the organic base may be exemplified amines such as triethylamine, tri-(n-butyl)amine, di-(n-butyl)amine, diisobutylamine, dicyclohexylamine or 2,6-lutidine. The amount of the base to be added is preferably 1-5 moles relative to 1 mole of the compound [X]. (3-2-3): The case where R⁵ stands for halogen atom - Preferable solvents are the afore-mentioned ethers, esters, halogenated hydrocarbons, hydrocarbons, amides, ketones, nitriles, alcohols and water. The amount of the nucleophilic reagent A' to be used is usually, relative to one mole of the compound [X], 1-5 moles, preferably 1-3 moles. The reaction is conducted within a temperature range of 0-80°C, preferably 20-60°C. The reaction time is usually 30 minutes to 15 hours, preferably 1-5 hours. For accelerating the reaction, the reaction may be conducted in the presence of a dehalogenating agent. As such dehalogenating agents, there may be counted deacidifying agents such as inorganic bases, tertiary amines and alkylene oxides mentioned in the Production Method (3-1), while the nucleophilic reagent A' itself may be allowed to act as the dehalogenating agent also. In this case, the compound A' is used in an amount of two moles or more relative to one mole of the compound [X]. The halogen atom shown by R⁵ is exemplified by chlorine, bromine and iodine, and preferably iodine. The compound [X] wherein R⁵ stands for iodine can be easily produced in accordance with the method described in, for example, Publication of Unexamined Patent Application (Kokai) in Japan, No. Sho 58-57390 or a method analogous thereto. By the method described here, the afore-mentioned compound [VII] or [VIII] for example can be synthesized. The reaction schemes are as follows: The compounds [III] can be easily prepared by a known method or a method analogous thereto. The following compound [XI] including the compounds [VII] can also be prepared by, besides the above-mentioned Production Method (3-1) or (3-2), the Production Method (3-3) to be described later. The compound [VII] can also be prepared by, besides the Production Method (3-1), (3-2) or (3-3), the Production Method (3-4) to be described later. (3-3): The reaction scheme is as follows: [wherein the symbol R 22' stands for an optionally substituted heterocyclic group, and the symbols Z, R⁴, R¹³, A and R³ are of the same meaning as defined above]. This is a method of synthesizing the compound [XI] by allowing a compound representable by the general formula of R 3'' OH or a reactive derivative thereof to react with a hydroxyimino compound [V], which is a well-known etherifying reaction provided that, when R 22' stands for the resultant compounds [XI] are respectively [VII]. R 3'' stands for an optionally substituted hydrocarbon residue which is the same as that referred to in R³. R 3'' OH may be employed as it is or as a reactive derivative thereof. Reactive derivatives of R 3'' OH are representable by the general formula R 3'' Y, having a group to be liberated together with the hydrogen atom of the hydroxyimino compound [V]. The group Y to be liberated together with hydrogen atom may be exemplified by halogen atom, sulfo group or mono-substituted sulfonyloxy group. The halogen atom may be exemplified by chlorine, bromine or iodine. The mono-substituted sulfonyloxy group may be exemplified by C₁₋₆ alkylsulfonyloxy and C₆₋₁₀ arylsulfonyloxy groups e.g. methanesulfonyloxy,ethanesulfonyloxy, benzenesulfonyloxy or p-toluenesulfonyloxy. When a C₁₋₄ alkylether derivative of the compound [V] is intended, there may be used, besides the above-mentioned reaction derivatives, C₁₋₄ diazoalkane such as diazomethane or diazoethane, and di-C₁₋₄ alkyl sulfate such as dimethyl sulfate or diethyl sulfate. The compound [V] can be prepared by the acylation as mentioned above in The Production Method (3-1) or the nucleophilic substitution as mentioned above in the Production Method (3-2). The reaction schemes are as follows, respectively: The starting materials [XII] and [X'] can be easily prepared by a known method or an analogous one thereto. The compound R 3'' OH and the reactive derivative thereof can also be easily prepared by a known method or an analogous one thereto. (3-3-1): The case where R 3'' OH is used - A suitable dehydrating agent is allowed to react with a hydroxyimino compound [V] to synthesize a compound [XI]. The dehydrating agent may be exemplified by phosphorus oxychloride, thionyl chloride, dialkyl azodicarboxylate (usually used in the presence of phosphine) or N,N-dicyclohexylcarbodiimide, and preferably diethyl azodicarboxylate in the presence of triphenyl phosphine. The reaction in which diethyl azodicarboxylate is used in the presence of triphenyl phosphine is usually conducted in an anhydrous solvent such as ethers or hydrocarbons mentioned above. Relative to 1 mole of the compound [V], 1-1.5 mole each of the compound R 3'' OH, ethyl azodicarboxylate and triphenyl phosphine is employed. The reaction requires 1-4 days at a temperature range of 0-50°C. (3-3-2): The case where R 3'' Y is used - The reaction between R 3'' Y and a hydroxyimino compound [V] is a conventional etherification reaction, which is conducted in a solvent. The solvent is exemplified also here by those as mentioned in the Production Method (3-1) above, i.e., ethers, esters, hydrogenated hydrocarbons, hydrocarbons, amides, ketones, nitriles, alcohols, water or a mixture of any of them, preferably a mixture solvent of a water-miscible solvent and water (e.g. aqueous methanol, aqueous ethanol, aqueous acetone and aqueous dimethyl sulfoxide). The reaction may also be allowed to proceed smoothly in the presence of a suitable base. The base may be exemplified by inorganic bases such as alkali metal salts e.g. sodium carbonate, sodium hydrogencarbonate or potassium carbonate, or alkali metal hydroxides e.g. sodium hydroxide or potassium hydroxide. This reaction may be conducted in a buffer solution of pH 7.5-8.5. The mole numbers of a reagent R 3'' Y and the base relative to 1 mole of the starting compound [V] are respectively 1-5 and 1-10, preferably 1-3 and 1-5, respectively. The reaction temperature is in the range from -30°C to 100°C, preferably, 0°C to 80°C. The reaction time ranges from 10 minutes to 15 hours, preferably from 30 minutes to 5 hours. (3-3-3): The case where C₁₋₄ diazoalkane is used - The reaction is usually conducted in a solvent. As the solvent are employed, for example, the afore-mentioned ethers and hydrocarbons. A hydroxyimino compound [V] is dissolved in a solvent, to which is then added a solution of a diazoalkane compound, whereupon the reaction proceeds. The reagent is used, relative to 1 mole of the compound [V], in an amount of 1-10 moles, preferably 1-5 moles. The reaction is conducted at a relatively low temperature range of from -50°C to 20°C, preferably from -30°C to 0°C. The reaction time ranges from 1 minute to 5 hours, preferably 10 minutes to one hour. (3-3-4): The case where di-C₁₋₄ alkylsulfate is used - The reaction is conducted usually in water or a mixture solvent of a water-miscible solvent and water. As the mixture solvent are mentioned those mentioned in the Production Method (3-3-2). This reaction is usually conducted in the presence of an inorganic base, for example, an alkali metal hydroxide such as sodium hydroxide and potassium hydroxide. The reagent is used in an amount of 0.5-10 moles, preferably 1-2 moles, relative to 1 mole of the compound [V]. The reaction temperature ranges from 20°C to 100°C, preferably 50-100°C. The reaction time ranges from 10 minutes to 5 hours, preferably from 30 minutes to 3 hours. (3-4): The reaction scheme is as follows: [wherein the symbols Z, R⁴, R¹³, A, R¹, R² and R³ are of the same meaning as defined above]. This is a method of synthesizing the end product [VII] by allowing a compound [VI] to react with thiourea representable by the general formula R¹C(=S)NH₂ or a derivative thereof. The compound [VI] is employed in its free state or as a salt or ester thereof. X in the compound [VI] stands for a halogen atom e.g. chlorine, bromine or iodine. As salts of the compound [VI] are mentioned those (inorganic base salts, ammonium salt , organic base salts, inorganic acid addition salts or organic acid addition salts, for example) of the 7-amino compound [II] exemplified in the Production Method (3-1). As esters of the compound [VI] as well, are mentioned those of the 7-amino compound [II] exemplified in the Production Method (3-1) (C₁₋₆ alkyl* ester, C₂₋₆ alkenyl ester, C₃₋₁₀ cycloalkyl ester, C₃₋₆ cycloalkyl C₁₋₆ alkyl ester, C₆₋₁₀ aryl* ester, C₇₋₁₂ aralkyl* ester, di-C₆₋₁₀ aryl-methyl ester, tri-C₆₋₁₀ arylmethyl ester and C₂₋₆ alkanoyloxy C₁₋₆ alkyl ester). The starting compound [VI] can be prepared by allowing a compound representable by the general formula: [wherein the symbols are of the same meaning as defined above] or a salt or reactive derivative thereof to react with the afore-mentioned 7-amino compound [II] or a salt or ester thereof according to the manner as described in the Production Method (3-1) above. Compounds representable by the general formula; or reactive derivatives thereof can be easily prepared by a per se conventional process or an analogous one thereto. The reaction between a compound [VI] and R¹C(=S)NH₂ is usually conducted in a solvent. The solvent may be exemplified by ethers such as dioxane, tetrahydrofuran and diethyl ether, alcohols such as methanol, ethanol and n-propanol, or amides such as dimethylformamide and dimethylacetamide. The amount of thiourea or a reactive derivative thereof representable by R¹C(=S)NH₂ is usually, relative to the compound [VI], 1-5 moles, preferably 1-3 moles. The reaction is conducted at temperatures ranging form 0°C to 100°C, preferably 20-60°C. The reaction time usually ranges from 30 minutes to 15 hours, preferably 1-5 hours. When the compounds [I b ] produced by the above-mentioned Production Methods (3-1) to (3-4) have hydroxyimino (or substituted hydroxyimino) group in the substituent R b , e.g. in the case of the compounds [VII] and so on, there may sometimes be the cases where the compounds [I b ] are obtained as a mixture of syn[Z]- and anti[E]-isomers. In the above-mentioned Production Method (3-1)-(3-4), there may sometimes be the cases where the compound [XI] including the compounds [VII] are obtained as a mixture of syn[Z]- and anti[E]-isomers. For isolating the desired syn-isomer from the mixture, a per se known process or analogous ones thereto may be employed. These processes may be exemplified by fractionation by utilizing the differences in, for example, solubilities or crystallizability, isolation by means of chromatography, or isolation utilizing the differences in hydrolysis rates between the respective ester derivatives. Production Method (4): Compound [I] (R⁰ = R c ; R c denotes esterified carboxyl group) - For example, (4-1): By allowing the 7-amino compound [II] ([I], R⁰ = hydrogen atom) obtained by the above Production Method (1) or a salt or ester thereof to react with an oxycarbonylation reagent , a compound [I] (R⁰ = R c ) can be synthesized. The oxycarbonylation reagent is exemplified by substituted oxycarbonyl halide (e.g. chlorine, bromine or iodine as halogen), substituted oxycarbonyl azide, substituted oxycarbonic anhydride, substituted oxycarbonyl sulfide or substituted oxycarbonyl azolide (e.g. imidazole, N-methylimidazole, triazole, 2-thiooxazolidine or 2-oxoxazolidine as azole). The reaction is conducted usually in a solvent, preferably an anhydrous solvent. As such solvents, use is often made of ethers, e.g. dioxane, tetrahydrofuran, diethyl ether, tert-butyl methyl ether, diisopropyl ether or ethylene glycol dimethyl ether, halogenated hydrocarbons e.g. dichloroethane, chloroform, carbon tetrachloride, trichlene or 1,2-dichloroethane, nitriles, e.g. acetonitrile, alcohols e.g. methanol, ethanol, propanol or butanol, hydrocarbons, e.g. n-hexane, benzene or toluene, amides e.g. dimethylformamide, dimethylacetamide or hexamethylphosphorus triamide, or sulfoxides e.g. dimethyl sulfoxide, singly or as a mixture solvent. The amount of the oxycarbonylation reagent is usually, relative to 1 mole of the 7-amino compound [II], 1-5 moles, preferably 1-2 moles. The reaction is conducted within the temperature range of from -80°C to 80°C, preferably from -40°C to 50°C, most preferably from -30°C to 30°C. While the reaction time varies with kinds of the 7-amino compound [II] and the oxycarbonylation reagents, kinds of solvents and reaction temperatures, it ranges from one minute to 48 hours, preferably from ten minutes to two hours. When a substituted oxycarbonyl halide is employed as the oxycarbonylation reagents, the reaction may be conducted in the presence of a deacidifying agent for the purpose of eliminating from the reaction system the hydrogen halogenide to be liberated. The deacidifying agent may be exemplified by inorganic bases such as sodium carbonate, potassium carbonate, calcium carbonate or sodium hydrogencarbonate; tertiary amines such as triethylamine, tri-(n-propyl)amine, tri-(n-butyl)amine, diisopropylethylamine, cyclohexyldimethylamine, pyridine, lutidine, γ-collidine, N,N-dimethylaniline, N-methylpiperidine, N-methylpyrrolidine or N-methylmorpholine; or alkylene oxides such as propylene oxide or epichlorohydrin. (4-2): By allowing the compound [XII] or a salt or ester thereof to react with the imidazole compound A' [A' is of the same meaning as defined above] or a salt thereof, a compound [I c ] (R⁰ = R c ) can also be synthesized. The reaction is shown by the following scheme: [wherein the symbols are of the same meaning as defined above]. This reaction substantially the same as that mentioned in the Production Methods (1) and (3-2). The starting compound [XII], salts and esters thereof can be easily prepared by a method similar to the Production Method (4-1) above, namely, the oxycarbonylation reagent is allowed to react with a compound [IX] or a salt or ester thereof to synthesized the compound [XII]. After the above-mentioned Production Method (1)-(4), when required, removal of protecting groups and purification are conducted to obtain the end product [I] of this invention. Methods of removing protecting groups and purification are described as follows: Process of removing protecting group: As afore-mentioned, in the fields of β-lactam and peptide syntheses, amino-protecting groups have been sufficiently studied, and the method of protecting amino groups has been established. The method of removing the amino-protecting group has also been established, and, in the present invention as well, for removing protecting groups, conventional technique can be used as such. For example, monohalogenoacetyl group (chloroacetyl, bromoacetyl, etc.) can be removed by using thiourea; alkoxycarbonyl group (methoxycarbonyl, ethoxycarbonyl, tert-butoxycarbonyl, etc.) can be removed by using an acid (e.g. hydrochloric acid); aralkyloxycarbonyl group (e.g. benzyloxycarbonyl, p-methylbenzyloxycarbonyl or p-nitrobenzyloxycarbonyl) can be removed by means catalytic reduction; and 2,2,2-trichloroethoxycarbonyl can be removed by using zinc and an acid (e.g. acetic acid). On the other hand, in the case when the compound [I] as the intermediate has been esterified, the ester residue can be removed by a per se known process or an analogous one thereto. For example, 2-methylsulfonylethyl ester can be removed by using an alkali; aralkyl ester (benzyl ester, p-methoxybenzyl ester, p-nitrobenzyl ester, etc.) can be removed by using an acid (e.g. trifluoroacetic acid) or by means of catalytic reduction; 2,2,2-trichloroethyl ester can be removed by using zinc and an acid (e.g. acetic acid); and silyl ester (e.g. trimethylsilyl ester or tert-butyldimethylsilyl ester) can be removed by using only water. Process of purifying the compound [I]: The compound [I] produced in the reaction mixture by any of the processes described in detail in the foregoing Production Methods (1)-(4) and, upon necessity, followed by removal of protecting groups by conducting the above-mentioned process, can be isolated and purified by a known process such as extraction, column-chromatography, precipitation and recrystallization. On the other hand, the compound [I] thus isolated can be converted into then desired physiologically acceptable salts or bioavailably unstable non-toxic esters. Sulfoxide ([I], Z = S→O) of the cephem compound ([I], Z=S) can be prepared by subjecting the compound ([I], Z=S) to a conventional oxidation. Oxidizing agents suitable for oxidation of sulfur atom of the cephem ring are exemplified by oxygen, peracid, hydroperoxide, or hydrogen peroxide, and the peracid may be given by mixing an acid with a peroxide in the reaction system of the oxidation. As such peracids, use is often made of peracetic acid, perbenzoic acid or p-chloroperbenzoic acid. The reaction is usually conducted in a solvent which is exemplified by ethers such as dioxane or tetrahydrofuran; halogenated hydrocarbons such as dichloromethane, chloroform or chlorobenzene; organic acids such as formic acid, acetic acid trifluoroacetic acid; or amides such as dimethylformamide or dimethylacetamide. The reaction temperature ranges from -20°C to 80°C, and preferably a temperature as low as possible, i.e. ranging from -20°C to 20°C. It is generally known that, when the cephem compound ([I], Z=S) is subjected to oxidation, sulfoxide having an S-configuration is produced. The R- and S-sulfoxide can be separated by utilizing the difference in solubility between them or the difference in travelling rate in chromatography. The above-mentioned oxidation to give sulfoxide can be conducted before or after the afore-mentioned Production Methods (1)-(4). The compound [I] including compounds [VII] of this invention can be administered orally or non-orally as injections, capsules, tablets or granules, like known penicillin and cephalosporin preparations. The dosage is 0.5-80 mg/day, preferably 1-20 mg/day in 3-4 doses relative to one kilogram of the body weight of men and animals infected with pathogenic bacteria as set forth above. Carriers of injectable preparations are exemplified by distilled water or physiological saline solution. When used as capsule, powder, granule or tablet, the compound [I] is mixed with conventional pharmaceutically acceptable excipients (e.g. starch, maltose, sucrose, calcium carbonate or calcium phosphate), binders (e.g. starch, gum-arabica, carboxymethylcellulose, hydroxypropylcellulose or crystalline cellulose), lubricants (e.g. magnesium stearate or talc) and disintegrators (e.g. carboxymethyl calcium or talc). The present invention will be further explained by the following Reference Examples and Working Examples, but those Examples are mere examples and not to restrict the present invention in any manner, including variations to such extent as not deviating the scope of this invention. Elution in column-chromatography in the Reference Examples and Working Examples was conducted under observation by means of TLC (Thin-Layer Chromatography), wherein were employed BOF₂₅₄ (manufactured by E. Merck) as TLC plate, the solvent for elution in the column-chromatography as developing solvent, and a UV detector as detecting means. As silica-gel for the column, Kieselgel 60 (230-400 mesh) manufactured by E. Merck was employed. "Cephadex" is a product of Pharmacia Fine Chemicals. XAD-II resin is a product of Rohm & Haas Co. NMR spectrum was determined by XL-100A (100 MHz)-, EM390 (90 MHz)-, EM360 (60 MHz)- or T₆₀(60 MHz)-type spectrometer using tetramethylsilane as internal or external standard, and all the δ values were shown by ppm. The numeral values parenthesized for mixture solvents mean the ratios by volume of each solvent mixed. "%" for solvents means number of grams in 100 ml of each solution. Symbols in the Reference Examples and Working Examples have respectively the meanings as follows: s : singlet d : doublet t : triplet q : quartet Abq : AB type quartet d. d : double doublet m : multiplet br. : broad J : coupling constant Hz : Herz mg : milligram g : gram ml : milliliter ℓ : liter % : percent DMSO : dimethylsulfoxide D₂O : deuterium oxide CDCl₃ : deuterochloroform Reference Example 1 7β-[2-(2-Chloroacetamidothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid In a mixture of 500 ml of tetrahydrofuran and 500 ml of water is suspended 157 g of 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid. To the suspension is added little by little 141 g of sodium hydrogen carbonate with stirring. To the mixture is added 150 g of 2-(2-chloroacetamidothiazol-4-yl)-2(Z)-methoxyiminoacetyl chloride hydrochloride at 5°C, during 20 minutes with stirring, and the mixture was stirred for further one hour. After completion of the reaction, the reaction mixture is adjusted to pH 3.0 with 10% hydrochloric acid, and extracted twice with 1 ℓ each portion of a mixture of ethyl acetate-tetrahydrofuran (1:1). The extract is dried over anhydrous magnesium sulfate, and then the solvent is evaporated off under reduced pressure to leave colorless powder, which is triturated with 200 ml of ethyl acetate and collected by filtration to afford 253 g of the above-identified compound. Elemental analysis for C₂₀H₂₀ClN₅O₉S₂: Calcd. (%): C,41.85; H,3.51; N,12.20 o Found (%): C,41.39; H,3.57; N,11.94 o 1780, 1740, 1700, 1655, 1540, 1410 o NMR spectrum (d₆ - DMSO)δ:2.20(3H.s), 3.45 and 3.68(2H.ABq, J=18Hz).3,65(2H.s), 3.92(3H.s), 4.38(2H.s), 4.79 & 5.09(2H, ABq,J=18Hz), 5.18(1H.d. J=5Hz), 5.85(1H.d.d.J=5Hz & 8Hz), 7.44(1H.s), 9.66(1H,d,J=8Hz), 12.85(1H,br,s) o Reference Example 2 7β-[2-(2-Aminothiazol-4-yl)-2-(Z)-methoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid In 500 ml of a mixture of tetrahydrofuran-water (1:1) is dissolved 150 g of 7β-2-[2-(chloroacetamidothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid. To the solution is added 51 g of sodium N-methyldithiocarbamate, and the mixture is stirred at 20°C for three hours. To the reaction mixture is added 200 ml of ethyl acetate. The organic layer is removed, and the aqueous layer is adjusted to pH 4 with 10% hydrochloric acid to bring about precipitation of an oily substance, which is extracted with one liter of a mixture of tetrahyrofuran-ethyl acetate (1:1). The aqueous layer is further extracted with 200 ml of 1-butanol. The extracts are combined and dried over anhydrous sodium sulfate, and the solvent is evaporated off under reduced pressure. To the residue is added 200 ml of ethyl acetate, and the mixture is stirred. The precipitating crystals are collected by filtration to give 90 g of the above-identified compound. Elemental analysis for C₁₈H₁₉N₅O₈S₂ : Calcd. (%): C,42.19; H,4.30; N,13.55 o Found (%): C,41.94; H,4.11; N,13.59 o 1770, 1710, 1620, 1520 o NMR spectrum (d₆ - DMSO)δ:2.20(3H,s), 3.43 and 3.65 (2H,ABq, J=18Hz), 3.63(2H,s), 3.86(3H,s), 4.78 and 5.06 (2H,ABq,J=13Hz), 5.14(1H,d, J=5Hz), 5.79(1H,d.d,J=5Hz and 8Hz), 6.73(1H,s), 7.17 (2H,br.), 9.56(1H,d,J=8Hz) o Reference Example 3 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid In 100 ml of dimethylformamide is dissolved 23 g of 2-(2-aminothiazol-4-yl)-2(Z)-ethoxyiminoacetic acid. To the solution are added 15 g of 1-hydroxybenzotriazole and 20.6 g of dicyclohexylcarbodiimide, and the mixture is stirred at 20°C for 1.5 hours. The insolubles are filtered off. The filtrate added, under ice-cooling, to a solution of 31 g of 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid and 28 ml of triethylamine in 100 ml of dimethylformamide. The reaction mixture was stirred at 20°C for three hours. To the mixture is added 500 ml of ether, are resulting precipitates are collected by filtration and then dissolved in 100 ml of water. The resulting aqueous solution is adjusted to pH 3.0 with 10% hydrochloric acid and extracted twice with 200 ml each portion of methyl ethyl ketone. The extract is washed with water and dried over anhydrous sodium sulfate. The solvent is evaporated under reduced pressure to leave a solid which is washed with ethyl acetate to give 31 g of the above-identified compound. 1780, 1720, 1660 o NMR spectrum (d₆-DMSO)δ: 1.30 (3H,t,J=7.5Hz), 2.25(3H, s), 3.45-3.65(4H,m), 4.20(2H,q,J=7.5Hz), 4.70 & 5.10(2H,ABq,J =18Hz), 5.25(2H,d,J=5Hz), 5.90(1H,d,d,J=5Hz & 8Hz), 6.90 (1H,s),7.20-7.80(2H,br.), 9.80(1H,d,J=7.5Hz) o Reference Example 4 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-propoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid In 10 ml of dimethylformamide is dissolved 1.7 g of 2-(2-aminothiazol-4-yl)-2(Z)-propoxyiminoacetic acid. To the solution are added 1.5 g of 1-hydroxybenzotriazole and 1.73 g of dicyclohexylcarbodiimide, and the mixture is stirred at 20°C for 1.5 hours. Insoluble precipitate is filtered off and the filtrate is added to a solution of 2.7 g or 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid and 3.2 ml of triethylamine in 10 ml of dimethylformamide. The reaction mixture is stirred at 20°C for three hours, followed by addition of 100 ml of diethyl ether. Precipitated solid substance is collected by filtration and dissolved in 50 ml of water. The resulting aqueous solution is adjusted to pH 3.0 and then extracted three times with 50 ml each of 1-butanol. The combined extract is washed with water and dried over anhydrous magnesium sulfate. The solvent is evaporated under reduced pressure to leave a solid substance, which is washed with ethyl acetate to give 1.7 g of the above-identified compound. 1790, 1750, 1720, 1680, 1640, 1555 o NMR spectrum (d₆-DMSO)δ: 0.91(3H,t,J=7Hz), 1.4-1.85 (2H,m), 2.18(3H,s), 3.45 and 3.70(2H, ABq,J=16Hz), 3.64(2H,s), 4.10(2H,t,J=7Hz), 4.76-5.08(2H,ABq,J=13Hz), 5.04(1H,d,J=4.5Hz), 5.80(1H,d.d,J=4.5Hz & 8Hz), 6.87(1H,s),7.13(2H,br,s), 9.70(1H,d,J=8Hz) o Reference Example 5 7β-[2-(2-Aminothiazol-4-yl)-2(2)-isopropoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid Starting from 2-(2-aminothiazol-4-yl)-2(Z)-isopropoxyiminoacetic acid and 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid, the titled compound is obtained by a procedure similar to that of Reference Example 3. 1780, 1745, 1720, 1670, 1620, 1530. NMR spectrum (d₆-DMSO)δ : 1.18(6H, d, J=6Hz), 2.20(3H,s), 3.46 & 3.66(2H, ABq, J=18Hz), 3.64(2H, s), 4.93 & 5.21(2H, ABq, J=13Hz), 5.03(1H, d, J=4.5Hz), 5.6-5.9(1H, m), 6.69(1H, s), 7.20(2H, br.s), 9.46(1H, d, J=8Hz) o Reference Example 6 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-butoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid Starting from 2-(2-aminothiazol-4-yl)-2(Z)-butoxyiminoacetic acid, the above-identified compound is obtained by a procedure similar to that of Reference Example 3. 1780, 1750, 1720, 1660, 1620 o NMR spectrum (d₆-DMSO)δ: 0.92(3H,t,J=7Hz), 1.1-1.8(4H. m), 2.22(3H,s), 3.44 and 3.65(2H.ABq,J=17Hz), 3.63(2H.s), 4.08 (2H,t,J=7Hz), 4.81 and 5.08(2H,ABq,J=14Hz), 5.14(1H,d, J=4.5 Hz), 5.78(1H,d.d,J=4.5Hz & 8Hz), 6.69(1H.s). 7.12(2H.br.s), 9.48(1H,d,J=8Hz) o Reference Example 7 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-hexyloxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid Starting from 2-(2-aminothiazol-4-yl)-2(Z)-hexyloxyiminoacetic acid, the above-identified compound is obtained by a similar procedure to that of Reference Example 3. NMR spectrum (d₆-DMSO)δ: 0.87 (3H,t), 1.28 (8H.br.s), 2.20 (3H,s), 3.38 and 3.61(2H,ABq,J=18Hz), 3.63(2H.s), 4.06(2H,t,J=7Hz), 4.77 and 5.05 (2H,ABq,J=13Hz), 5.10(1H,d, J=4.5Hz), 5.74(1H,d.d,J=4.5Hz & 8Hz), 6.70(1H,s), 7.14(2H.br.s), 9.48 (1H,d,J=8Hz) o Reference Example 8 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-allyloxyiminoacetamide]-3-(3-oxobutylyloxymethyl)-3-cephem-4-carboxylic acid In 50 ml of dimethylformamide is dissolved 13 g of 2-(2-aminothiazol-4-yl)-2(Z)-allyloxyiminoacetic acid. To the solution are added 8 g of 1-hydroxybenzotriazole and 10.3 g of dicyclohexylcarbodiimide, and the mixture is stirred at 20°C for three hours. Insoluble substance is removed by filtration, and the filtrate is added, under ice-cooling, to 50 ml of dimethylformamide dissolving 16 g of 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid and 10 g of triethylamine. The reaction mixture is stirred at 20°C for three hours, to which is added 500 ml of diethyl ether, followed by removal of the ether layer to leave insoluble substance. The insoluble substance is dissolved in 50 ml of water, and the aqueous solution is adjusted to pH 3.0 to give the titled compound in crude state, which is dissolved in 500 ml of a mixture of ethyl acetate and tetrahydrofuran (1:1), dried over anhydrous magnesium sulfate, treated with activated carbon, followed by removal of the solvent by evaporation under reduced pressure to leave 25 g of the titled compound as amorphous powder. 1780, 1720, 1660, 1620. NMR spectrum (d₆-DMSO)δ : 2.30 (3H, s), 3.45-3.66 (4H,m), 4.64 (2H, d, J=6Hz), 4.80-5.10 (2H, ABq, J=18Hz), 5.23 (2H, d, J=9Hz), 5.26 (2H,d,J=5Hz), 5.90 (1H, d. d, J=5Hz & 9Hz), 5.90-6.20 (1H,m), 6.80 (1H,s), 7.20-8.00 (2H,br.), 9.83 (1H,d,J=9Hz) o Reference Example 9 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(2-hydroxyethoxyimino)acetomido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid Starting from 2-(2-aminothiazol-4-yl)-2(Z)-(2-hydroxyethoxyimino)acetic acid and 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid, the titled compound is obtained by a procedure similar to that of Reference Example 3. 1780, 1750, 1720, 1670, 1630, 1550. NMR spectrum (d₆-DMSO)δ : 2.20 (3H, s), 2.9-3.2 (2H, m), 3.4-3.7 (2H, m), 3.65 (3H, s), 4.32 (2H, t, J=6Hz), 4.95 & 5.12 (2H, ABq, J=13Hz), 5.04 (1H, d, J=4.5Hz), 5.6-5.9 (1H, m), 6.70 (1H, s), 7.20 (2H, br.s), 9.46 (1H, d, J=8Hz) o Reference Example 10 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-cyclopropylmethoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid Starting from 2-(2-aminothiazol-4-yl)-2(Z)-cyclopropylmethoxyiminoacetic acid and 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid, the titled compound is obtained by a procedure similar to that of Reference Example 3. 1760, 1635, 1540, 1400, 1365, 1270, 1150. NMR spectrum (d₆-DMSO)δ : 0.1-0.6 (4H,m), 0.7-1.5 (1H, m), 2.20 (3H, s), 3.42 & 3.66 (2H, ABq, J=18Hz), 3.64 (2H, s), 3.91 (2H, d, J=7Hz), 4.80 & 5.08 (2H, ABq, J=14Hz), 5.15 (1H, d, J=5Hz), 5.78 (1H, d.d, J=5Hz & J=8Hz), 6.70 (1H, s), 7.22 (2H, br.s), 9.52 (1H, d, J=8Hz) o Reference Example 11 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-carbamoylmethoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid a) In 100 ml of dimethylformamide is dissolved 24 g of 2-(2-chloroacetamidothiazol-4-yl)-2(Z)-carbamoylmethoxyiminoacetic acid. To the solution are added 11.4 g of 1-hydroxybenzotriazole and 22 g of dicyclohexylcarbodiimide, and the mixture is stirred at 20°C for two hours. Insoluble substance is filtered off, and then the filtrate is added at 0°C to 70 ml of dimethylformamide dissolving 22 g of 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid and 21 ml of triethylamine. The reaction mixture is stirred at 20°C for one hour, to which are added 500 ml of methyl ethyl ketone, 60 ml of phosphoric acid and one liter of saturated saline solution. The mixture is stirred. The organic layer is taken and washed with water, which is then dried over anhydrous magnesium sulfate. The solvent is evaporated off under reduced pressure. To the residue is added 200 ml of ethyl acetate, and then the precipitating solid material is collected by filtration to yield 19 g of 7β-[2-(2-chloroacetamidothiazol-4-yl)-2(Z)-carbamoylmethoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid. 1770, 1720, 1640, 1530. b) Into 150 ml of water is dissolved 19 g of 7β-[2-(2-chloroacetamidothiazol-4-yl)-2-(Z)-carbamoylmethoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid which is obtained in the above a). To the solution are added 20 g of sodium methyldithiocarbamate and 150 ml of ethylacetate. The mixture is stirred at 20°C for eight hours, to which is added acetic acid to adjust the pH thereof to 4.0. Then, the aqueous layer is taken, concentrated under reduced pressure. The concentrate is lyophilized. The resulting solid material is dissolved in 100 ml of water, which is subjected to extraction with a mixture of 100 ml of tetrahydrofuran and 200 ml of methyl ethyl ketone. The extract is dried over anhydrous magnesium sulfate, followed by removal of the solvent by evaporation under reduced pressure to give 6.0 g of the titled compound. 1780, 1720, 1660. NMR spectrum (d₆-DMSO)δ : 2.10 (3H, s), 3.40 & 3.65 (2H, ABq, J=18Hz), 3.63(2H, s), 4.40 (2H, s), 4.80 & 5.06 (2H, ABq, J=13Hz), 5.16(1H, d, J=5Hz), 5.80 (1H, d.d, J=5Hz & 8Hz), 6.74 (1H, s), 7.05-7.40 (4H, m), 9.60 (1H, d, J=8Hz) o Reference Example 12 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-benzyloxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid Starting from 2-(2-aminothiazol-4-yl)-2(Z)-benzyloxyiminoacetic acid, the above-identified compound is obtained by a similar procedure to that of Reference Example 3. 1770, 1730, 1700, 1640, 1520 o NMR spectrum (d₆-DMSO)δ : 2.21(3H.s), 3.2-3.8(4H.m), 4.82 and 5.12(2H,Abq,J=13Hz), 5.10(1H,d,J=4.5Hz), 5.18(2H.s), 5.84(1H,d.d,J=4.5Hz and 8Hz), 7.22(2H,br.s), 7.38(5H,s), 9.65 (1H,d,J=8Hz) o Reference Example 13 7β-[2-(Aminothiazol-4-yl)-2(Z)-(2-methoxyethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid Starting from 2-(2-aminothiazol-4-yl)-2(Z)-(2-methoxyethoxyimino)acetic acid, the above-identified compound is obtained by a similar procedure to that of Reference Example 3. 1770, 1750, 1670, 1630, 1540 o NMR spectrum (d₆-DMSO)δ: 2.20(3H,s), 3.28(3H,s), 3.4-3.7(4H,m), 4.19(4H,t,J=7Hz), 4.81 and 5.08(2H,ABq,J=13Hz), 5.77(1H,d.d,J=4.5Hz and 8Hz), 6.73(1H,s), 7.13(2H,br.s), 9.51 (1H,d,J=8Hz) o Reference Example 14 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(2-chloroethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid From 2-(2-aminothiazol-4-yl)-2(Z)-(2-chloroethoxyimino)acetic acid and 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid, the above-identified compound is obtained by a similar procedure to that of Reference Example 3. 1770, 1705, 1660, 1630, 1520 o NMR spectrum (d₆-DMSO)δ: 2.20(3H,s), 3.05 and 3.50(2H, ABq,J=18Hz), 3.60(2H.s), 3.73-3.90(2H.m), 4.20-4.50(2H,m), 4.76 and 5.06(2H,Abq,J=14Hz), 5.16(1H,d,J=5Hz), 5.80(1H,d.d, J=5Hz and 8Hz), 6.76(1H,s), 7.20(2H,br.s), 9.60(1H,d,J=8Hz) o Reference Example 15 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(2-fluoroethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid Starting from 2-(2-aminothiazol-4-yl)-2(Z)-(2-fluoroethoxyimino)acetic acid and 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid, the above-identified compound is obtained by a similar procedure to that of Reference Example 3. 1770, 1740, 1680, 1620, 1540 o NMR spectrum (d₆-DMSO)δ: 2.20(3H,s), 3.50-3.70(2H,m), 3.66(2H,s), 4.10-4.30(1H,m), 4.43-4.66(3H,m), 4.80-5.03(2H,m), 5.20(1H,d,J=4.5Hz), 5.86(1H,d.d,J=4.5Hz and 8Hz), 6.80(1H,s), 7.13(2H,br.s), 9.70(1H,d,J=8Hz) o Reference Example 16 2-Methylthioethyl 2-(2-aminothiazol-4-yl)-2(Z)-(1-tert-butoxycarbonylpropoxyimino)acetate A mixture of 10 g of 2-methylthioethyl 2-(2-aminothiazol-4-yl)-2(Z)-hydroxyiminoacetate, 10 g of tertbutyl 2-bromobutyrate and 7 g of anhydrous potassium carbonate in 250 ml of acetone is kept at 60-70°C for 20 hours with stirring. Insolubles are filtered off and the filtrate is concentrated under reduced pressure. The residue is dissolved in ethyl acetate, and the solution is washed with water, then with saturated aqueous sodium chloride and dried over anhydrous magnesium sulfate. The solvent is then evaporated off to give the above-identified compound as a viscous liquid, which, upon standing, solidifies. Yield: 12.6 g. NMR spectrum (CDCl₃)δ : 0.98(3H,t,J=7Hz),1.48(9H,s), 1.65 -2.15(2H,m), 2.18(3H,s), 2.82(2H,t,J=7Hz), 4.1-4.65(3H,m), 6.27(2H,br.s), 6.72(1H,s) o Reference Example 17 2-(2-Aminothiazol-4-yl)-2(Z)-(1-tert-butoxycarbonylpropoxyimino)acetic acid To a mixture of 100 ml of acetone and 25 ml of water are added 10 g of the ester compound obtained in Reference Example 11 and 0.1 g of ammonium molybdate. To the resulting mixture is added 10 ml of 30% hydrogen peroxide, and the mixture is stirred at room temperature overnight. After addition of an aqueous solution of sodium sulfite, the mixture is neutralized and then extracted with 120 ml of ethyl acetate. The organic layer is diluted with 170 ml of acetone and 170 ml of water and the solution is adjusted to pH 10-11 wtih 30% aqueous potassium carbonate and stirred at 30-40°C for 2 hours. After neutralization with 1 N HCl, the organic layer is separated and extracted with 5% aqueous sodium chloride. The aqueous layers are combined, acidified with 1 N HCl and extracted with methyl ethyl ketone. The organic layer is washed with saturated aqueous sodium chloride and dried over anhydrous magnesium sulfate. The solvent is then evaporated off to give 3.2 g of the above-identified compound as crystals. mp 121.5∼124°C o Elemental analysis for C₁₃H₁₉N₃O₅S · 3/2H₂O : Calcd. (%): C,42.14; H,5.64; N,11.15 o Found (%): C,42.37; H,6.02; N,11.40 o Reference Example 18 2-Methylthioethyl 2-(2-aminothiazol-4-yl)-2(Z)-(1-tert-butoxycarbonylbutoxyimino)acetate Starting from 2-methylthioethyl 2-(2-aminothiazol-4-yl)-2(Z)-hydroxyiminoacetate and tert-butyl 2-bromovalerate, the above-identified compound is obtained by a similar procedure to that of Reference Example 16. mp 102∼105°C o Elemental analysis for C₁₇H₂₇N₃O₅S₂: Calcd. (%): C,48.90; H,6.52; N,10.01 o Found (%): C,48.74; H,6.46; N,10.04 o Reference Example 19 2-(2-Aminothiazol-4-yl)-2(Z)-(1-tert-butoxycarbonylbutoxyimino)acetic acid From the ester compound obtained in Reference Example 3, the above-identified compound is obtained by a similar procedure to that of Reference Example 17. mp 138∼139°C o Elemental analysis for C₁₄H₂₁N₃O₅S·3/2H₂O: Calcd. (%): C,45.27; H,6.51; N,11.31 o Found (%): C,45.26; H,6.09; N,11.15 o Reference Example 20 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid In 20 ml of dimethylformamide is dissolved 6.0 g of 2-(2-aminothiazol-4-yl)-2-(Z)-tert-butoxycarbonylmethoxyiminoacetic acid. To the solution are added 3.5 g of 1-hydroxybenzotriazole and 4.4 g of dicyclohexyl carbodiimide, and the mixture is stirred at 20°C for three hours. Insoluble substance is removed by filtration, and the filtrate is added, under ice-cooling, to 20 ml of dimethylformamide dissolving 6.2 g of 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid and 4.0 g of triethylamine. The reaction solution is stirred at 20°C for eight hours. To 200 ml of diethyl ether is added the reaction mixture and the ether layer is removed. The residue is dissolved in 50 ml of water. The aqueous solution is adjusted to pH 4 with 10% hydrochloric acid to cause precipitation of crystals. The crystals are collected by filtration, washed with water then with diethyl ether, followed by drying to give 10 g of the titled compound. 1790, 1730, 1710, 1660, 1530. NMR spectrum (d₆-DMSO)δ : 1.50(9H, s), 2.20(3H, s), 3.40-3.60(4H, m), 4.40(2H, s), 4.80 & 5.10(2H, ABq, J=14Hz), 5.20(1H, d, J=5Hz), 5.80(1H, d. d, J=5Hz & 8Hz), 6.70 (1H, s), 7.20-7.80 (2H, br.), 9.30 (1H, d, J=8Hz) o Reference Example 21 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(1-tert-butoxycarbonylethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid In 20 ml of N,N-dimethyformamide is dissolved 3 g of 2-(2-aminothiazol-4-yl)-2(Z)-(1-tert-butoxycarbonylethoxyimino)acetic acid. To the solution are added 1.5 g of 1-hydroxybenzotriazole and 2.1 g of dicyclohexylcarbodiimide, and the mixture is stirred at room temperature for 1 hour. Insoluble substance is filtered off and the filtrate is added to a suspension of 3.1 g of 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid and 2 g of triethylamine in 20 ml of dimethylformamide. The mixture is stirred at room temperature for 6 hours. Insoluble substance is removed by filtration and 500 ml of diethyl ether is added to the filtrate. The ether layer is removed and the residue is dissolved in water. The mixture is adjusted to pH 3-4 with 1 N HCl and extracted with methyl ethyl ketone. The organic layer is washed with saturated aqueous sodium chloride solution and dried over anhydrous magnesium sulfate. The solvent is then evarorated off under reduced pressure. The residue solidifies on addition of hexane. The powder obtained is collected by filtration to give 3.9 of the above-identified compound. NMR spectrum (d₆-DMSO)δ: 0.88 and 0.95(3H,2t,J=7Hz), 1.42(9H,s), 2.20(3H,s), 3.44 and 3.68(2H,ABq,J=18Hz), 3.64(2H, s), 4.5-4.7(1H,m), 4.80 and 5.11(2H,ABq,J=14Hz), 5.18(1H,d,J= 4.5Hz), 5.84(1H,d.d,J=4.5Hz and 8Hz), 6.77(1H,s),7.18(2H,br.s), 9.40(1H,d,J= 8Hz) o Reference Example 22 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(1-tert-butoxycarbonylpropoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid. Starting from 2-(2-aminothiazol-4-yl)-2(Z)-(1-tert-butoxycarbonylpropoxyimino)acetic acid, the above-identified compound is obtained by a similar procedure to that of Reference Example 21. NMR spectrum (d₆-DMSO)δ: 0.90 and 0.93(3H.2d,J=7Hz), 1.42(9H,s), 1.45-1.9(2H.m), 2.20(3H,s), 3.22 and 3.51(2H.ABq,J =18Hz), 4.3-4.6(1H.m), 4.77 and 5.12(2H,ABq,J=14Hz), 5.16(1H, d,J=4.5Hz), 5.75-5.95(1H.m), 6.77(1H,s), 9.46(1H,d,J=8Hz) o Reference Example 23 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(1-tert-butoxycarbonylbutoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid Starting from 2-(2-aminothiazol-4-yl)-2(Z)-(1-tert-butoxycarbonylbutoxyimino)acetic acid, the above-identified compound is obtained by a similar procedure to that of Reference Example 21. NMR spectrum (d₆-DMSO)δ: 0.91 and 0.92 (total 3H, each t,J=7Hz), 1.43(9H,s), 1.2-1.9(4H,m), 2.20(3H,s), 3.26 and 3.50(2H,ABq,J= 18Hz), 4.4-4.6(1H,m), 4.80 and 5.10(2H,ABq,J=13Hz), 5.18(1H,d, J=4.5Hz), 5.7-5.95(1H,m), 6.78(1H,s), 9.44(1H,d,J=8Hz) o Reference Example 24 3-(3-Oxobutyryloxymethyl)-7β-[2-(2-tritylaminothiazol-4-yl)-2(Z)-(1-methyl-1-tert-butoxycarbonyl)ethoxyiminoacetamido]-3-cephem-4-carboxylic acid. In 20 ml of dimethylformamide is dissolved 12 g of 2-[(2-tritylaminothiazol-4-yl)-2(Z)-(1-methyl-1-tert-butoxycabonyl)ethoxyiminoacetic acid. To the solution are added 3.5 g of 1-hydroxybenzotriazole and 4.4 g of dicyclohexylcarbodiimide, and the mixture is stirred at 20°C for 20 hours. Insoluble substance is removed by filtration, and the filtrate is added, under ice-cooling, to 20 ml of dimethylformamide dissolving 6.2 g of 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid and 4.0 g of triethylamine. The reaction mixture is stirred at 20°C for 24 hours, to which is added 200 ml of a mixture of diethyl ether and petroleum ether (1:1). The ether layer is removed. To the residue is added 50 ml of water, followed by adjusting the pH to 4.0 to cause precipitation of crystalline powder. The powder is collected by filtration and washed with water then with diethyl ehter, followed by drying to give 13 g of the titled compound. 1780, 1730, 1700, 1680, 1530, 1150. NMR spectrum (d₆-DMSO)δ: 1.35(15H, s), 2.25(3H, s), 3.40-3.60(4H, m), 5.80 & 5.10(2H. ABq,J=14Hz), 5.25(1H, d, J=5Hz), 5.80(1H, d. d, J=5Hz & 8Hz), 6.70(1H, s), 7.20-7.80(2H, br·), 7.30(15H, s), 9.30(1H, d, J=8Hz) o Reference Example 25 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(1-tert-butoxycarbonyl-1-methylethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid Starting from 2-(2-aminothiazol-4-yl)-2(Z)-(1-tert-butoxycarbonyl-1-methylethoxyimino)acetic acid, the above-identified compound is obtained by a similar procedure to that of Reference Example 21. 1780, 1720, 1660, 1530 o NMR spectrum (d₆-DMSO)δ: 1.42(15H,s), 2.20(3H,s), 3.4-3.7(4H.m), 4.70 and 5.10(2H.ABq,J=14Hz), 5.19(1H,d.J=4.5Hz), 5.82(1H,d.d,J=4.5Hz and 8Hz), 6.73(1H,s), 7.19(2H,br.s), 9.29 (1H,d,J=8Hz) o Reference Example 26 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(1-carbamoyl-1-methylethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid Starting from 2- (2-aminothiazol-4-yl)-2(Z)-(1-carbamoyl-1-methylethoxyimino)acetic acid, the above-identified compound is obtained by a similar procedure to that of Reference Example 3. 1770, 1730, 1670, 1610, 1540 o NMR spectrum (d₆-DMSO)δ: 1.39 and 1.42 (total 6H, each s), 2.25(3H s), 3.11 and 3.72(2H,ABq,J=18Hz), 3.60(2H,s), 4.80 and 5.12(2H, ABq.J=16Hz), 4.92(1H,d,J=5Hz), 5.60(1H,d.d,J=5Hz and 8Hz), 6.7-7.1(2H,m), 6.70(1H,s), 7.20(2H,br.s), 9.38(1H,d,J= 8Hz) o Reference Example 27 7β-[2-(5-tert-Butoxycarbonylamino-1,2,4-thiadiazol-3-yl)-2(Z)-methoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid To 4 ml of dichloromethane is added 302 mg of 2-(5-tert-butoxycarbonylamino-1,2,4-thiadiazol-3-yl)-2(Z)-methoxyiminoacetic acid, followed by addition of 208 mg of phosphorus pentachloride. The mixture is stirred with ice-cooling for 15 minutes. The solvent is then evaporated off under reduced pressure and hexane is added to the residue. The mixture is evaporated to dryness under reduced pressure and the residue is dissolved in dichloromethane. The resulting solution is added to a solution of 300 mg of 7β-amino-3-(3-oxobutyloxymethyl)-3-cephem-4-carboxylic acid and 0.6 ml of triethylamine in 5 ml of dimethylacetamide, and the mixture is stirred with ice-cooling for 30 minutes. To the reaction mixture is added a solution of 1 g of phosphoric acid in 10 ml of water and the resulting mixture is extracted with methyl ethyl ketone (10 ml). The extract is washed with water and dried over magnesium sulfate. The solvent is then evaporated off under reduced pressure. Ethyl acetate is added to the residue and the solvent is evaporated again to give 390 mg of the above-identified compound. 2980, 2940, 1780, 1715, 1540, 1370, 1245, 1150, 1040, 855 o NMR spectrum (d₆-DMSO)δ: 1.56(9H,s), 2.20(3H,s), 3.43 and 3.70(2H.ABq,J=18Hz), 3.65(2H,s), 4.00(3H,s), 4.80 and 5.12 (2H.ABq.J=12Hz), 5.18(1H.d,J=4.5Hz), 5.88(1H,d.d,J=9Hz and 4.5Hz), 9.63(1H,d,J=9Hz) o Reference Example 28 7β-[2-(5-Amino-1,2,4-thiadiazol-3-yl)-2(Z)-ethoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid In 200 ml of dichloromethane is suspended 11 g of 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid. To the suspension is added 14 g of bistrimethylsilylacetamide and the mixture is stirred at room temperature until complete dissolution and cooled in an ice-water bath. To this solution, 14 g of 2-(5-amino-1, 2,4-thiadiazol-3-yl)-2(Z)-ethoxyiminoacetyl chloride is added and the mixture is stirred for a while, to which 6 g of dimethylacetamide is added. The whole mixture is stirred with ice-cooling for 60 minutes. The dichloromethane is evaporated off and the residue is dissolved in methyl ethyl ketone. The solution is washed with water and dried. The solvent is then evaporated off and diethyl ether is added to the residue to give a fine precipitate, which is collected by filtration, giving 12.5 g of the above-identified compound. 3300, 3000, 1780, 1720, 1620, 1520, 1410, 1260, 1150, 1040 o NMR spectrum (d₆-DMSO)δ: 1.25(3H,t,J=7Hz), 2.18(3H,s), 3.41 and 3.63(2H,ABq,J=18Hz), 3.62(2H,s), 4.18(2H,q,J=7Hz), 4.76 and 5.06(2H.ABq,J=13Hz), 5.14(1H.d,J=4.8Hz), 5.82(1H,d.d, J=8Hz and 4.8Hz), 8.00(2H.br.), 9.48(1H,d.J=8Hz) o Reference Example 29 i) 7β-[2-(5-Chloro-2-chloroacetamidothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid To 50 ml of dichloromethane is added 2.39 g of 2-(5-chloro-2-chloroacetamidothiazol-4-yl)-2(Z)-methoxyiminoacetic acid and, while cooling at -5°C to -8°C, 2.13 g of phosphorus pentachloride is added and the mixture is stirred for 45 minutes. To the reaction mixture is added 150 ml (in 30-ml portions) of hexane, and the dark oily precipitate is separated and washed with hexane to give the corresponding crude chloride. Separately, a solution of 2.06 g of 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid in 15 ml of tetrahydrofuran is added to a solution of 2.06 g of sodium hydrogen carbonate in 15 ml of water, and to the resulting mixture, the chloride obtained above is added while maintaining the inside temperature at 0-3°C. Thereafter, the mixture is stirred at the temperature not exceeding 5°C for 1 hour and then at room temperature for further 1 hour. Fifty ml of methyl ethyl ketone is added to the reaction mixture and the mixture is acidified with concentrated hydrochloric acid. The organic layer is separated and the aqueous layer is extracted with methyl ethyl ketone. The organic layer and the extract are combined and dried over anhydrous sodium sulfate. The solvent is then evaporated off under reduced pressure to give 2.94 g of the above-identified compound as light-orange powder. NMR spectrum (CDCl₃÷d₆-DMSO)δ: 2.23(3H,s), 3.24-3.73(2H,m), 3.50(2H,s), 4.01(3H,s),4.21(2H.s), 4.91 and 5.18(2H, ABq,J=13Hz), 5.05(1H,d,J=4.5Hz), 5.88(1H,d.d,J=4.5Hz & 9Hz). 6.43(2H,br.), 8.79(1H,d,J=9Hz) o ii) 7β-[2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid To a mixture of 13 ml of water and 13 ml of tetrahydrofuran is dissolved 2.94 g of 7β-[2-(5-chloro-2-chloroacetamidothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid. To the mixture is added 1.15 g of sodium N-methyldithiocarbamate in 3 portions with stirring at room temperature for 3 hours. Ethyl acetate is added to the reaction mixture and the ethyl acetate layer is separated and discarded. The aqueous layer is acidified with concentrated hydrochloric acid and extracted with 200 ml of methyl ethyl ketone. The extract is washed with aqueous sodium chloride solution and dried over anhydrous sodium sulfate. The solvent is then evaporated off to give 2.28 g of the above-identified compound. NMR spectrum (d₆-DMSO÷CDCl₃)δ: 2.21(3H,s), 3.3-3,75 (2H,m), 3.57(2H,s), 3.90(2H,s), 4.81 and 5.09(2H,ABq,J=13Hz), 5.07(1H.d, J=5Hz), 5.77(1H,d.d, J=5Hz & 9Hz), 7.10(2H,br.), 9.46(1H,d,J=9Hz). Reference Example 30 Methyl (2-chloroacetamidothiazol-4-yl-3-oxido)-2(Z)-ethoxyiminoacetate To an ice-cooled solution of 18 g of maleic anhydride in 300 ml of methylene chloride is added 42 ml of 30% aqueous hydrogen peroxide, and the mixture is stirred at 0°C for 2 hours. To this solution is added 40 g of methyl (2-chloroacetamidothiazol-4-yl)-2(Z)-ethoxyiminoacetate and the mixture is stirred at room temperature for 16 hours. To the mixture is added 300 ml of 2% aqueous solution of sodium hydrogen carbonate. The organic layer is separated and washed with two 300-ml portions of saturated aqueous sodium chloride and dried over anhydrous magnesium sulfate. The solvent is then evaporated off and the residue is crystallized from 95% ethanol to give 20 g (48% yield) of the above-identified compound. mp 166-168°C o Elemental analysis for C₁₀H₁₂ClN₃O₅S: Calc. (%): C,37.33; H,3.76; N,13.06 o Found (%): C,37.32; H,3.56; N,12.88 o 1740, 1690, 1560, 1430, 1355, 1280, 1200 o NMR spectrum (d₆-DMSO)δ: 1.28(3H,t,J=7Hz), 3.78(3H,s), 4.26(2H,q,J=7Hz), 4.48(2H,s), 5.82(1H,br.s), 7.62(1H,s) o Reference Example 31 2-(2-Chloroacetamidothiazol-4-yl-3-oxido)-2(Z)-ethoxyiminoacetic acid In 131 ml of ethanol is suspended 20 g of methyl 2-(2-chloroacetamidothiazol-4-yl-3-oxido)-2(Z)-ethoxyiminoacetate. To the suspension is added dropwise 11.3 ml of 35% aqueous sodium hydroxide solution while maintaining the inside temperature at 15-20°C by ice-cooling. The mixture is stirred at room temperature for 7 hours and then concentrated. The residue is dissolved in 150 ml of water and with ice-cooling, the solution is adjusted to pH 3 with concentrated hydrochloric acid. Colorless crystalline precipitate separated is collected by filtration, washed with a small amount of cold water and dried to give 15.5 g (81% yield) of the above-identified compound. mp 154-156°C o Elemental analysis for C₉H₁₀ClN₃O₅S : Calcd. (%): C,35.13; H,3.28; N,13.66 o Found (%): C,35.10; H,3.10; N,13.82 o 1720, 1550, 1360, 1290, 1205 o NMR spectrum (d₆-DMSO)δ: 1.26(3H,t,J=7Hz), 4.25(2H,q,J =7Hz), 4.49(2H,s), 7.55(1H,s), 9.19(2H,br.) o Reference Example 32 7β-tert-Butoxycarbonylamino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid To 500 ml of dimethyl sulfoxide is added 200 g of 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid. To this 200 g of di-tert-butyl carbonate is added at room temperature and the mixture is stirred for 16 hours. To the reaction mixture are added 200 g of ice, 2 liters of water and 1 liter of ethyl acetate, and the mixture is stirred. After phase separation, the upper layer is discarded. To the aqueous layer is added 1 liter of ethyl acetate, and 129 g of phosphoric acid is added dropwise thereto while stirring (pH 4). After thorough mixing, the upper layer is separated and the lower layer is extracted with 1 liter of ethyl acetate. The organic layers are combined, washed with two 2-liter portions of ice-water and then with 1 liter of saturated aqueous sodium chloride, dried over anhydrous magnesium sulfate and then concentrated. To the residue is added 100 ml of methylene chloride, and the resulting mixture is concentrated and dried to give 194 g (74% yield) of the above-identified compound as a classy solid. Elemental analysis for C₁₇H₂₂N₂O₈S·1/2H₂O: Calcd. (%): C,48.22; H,5.47; N,6.62 o Found (%): C,48.16; H,5.30; N,6.32 o 1780, 1720, 1520, 1370, 1320 o NMR spectrum (d₆-DMSO)δ: 1.42(9H,s), 2.18(3H,s), 3.41 and 3.62(2H,ABq,J=18Hz), 3.62(2H,s), 4.78 and 5.06(2H,ABq,J= 14Hz), 5.03(1H,d,J=5Hz), 5.45(1H,d.d,J=5Hz and 8Hz), 7.83(1H. d,J=8Hz) o Reference Example 33 7β-Formamido-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid In 60 ml of formic acid is dissolved 3.2 g of 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid and the solution is cooled to 0-5°C. With stirring, 20 ml of acetic anhydride is added dropwise to the solution during 30 minutes. The mixture is stirred at the same temperature for 30 minutes and then at room temperature for 1 hour. The solvent is evaporated off under reduced pressure and the residue is dissolved in methyl ethyl ketone. The solution is washed with water and saturated aqueous sodium chloride solution and dried over anhydrous magnesium sulfate. The solvent is then evaporated off under reduced pressure and a diisopropylether-hexane mixture is added to the residue to bring about solidification. The solid is then collected by filtration to give 3.1 g of the above-identified compound as a light-yellow powder. 3380, 1780, 1720, 1660, 1625, 1510 o NMR spectrum (d₆-DMSO)δ: 2.20(3H,s), 3.45 and 3.68(2H, ABq,J=18Hz), 3.63(2H,s), 4.79 and 5.09(2H,ABq,J=13Hz), 5.11 (1H,d,J=4.5Hz) , 5.79(1H,d.d,J=4.5Hz and 8Hz), 8.15(1H,br.), 9.00(1H,d,J=8Hz). Reference Example 34 2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-[1-(tert-butoxycarbonyl)-1-methylethoxyimino]acetic acid In 50 ml of methanol is dissolved 6.0 g of 2-(2-aminothiazol-4-yl)-2(Z)-[1-(tert-butoxycarbonyl)-1-methylethoxyimino]acetic acid, and 2.4 g of N-chlorosuccinimide is added to the solution with stirring at room temperature. The mixture is stirred at room temperature for 6 hours and the solvent is evaporated off under reduced pressure. The residue is dissolved in ethyl acetate and the solution is washed with water and saturated aqueous sodium chloride solution and dried over anhydrous magnesium sulfate. The solvent is then evaporated off under reduced pressure to give 5.5 g of the above-identified compound as light-yellow crystals. 3325, 3200, 1720, 1635, 1540, 1140 o NMR spectrum (CDCl₃-d₆-DMSO)δ: 1.42(9H,s), 1.46(6H, s), 6.80-7.80(3H,m) o Reference Example 35 2-(2-Amino-5-bromothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetic acid A mixture of 12 g of 2-(2-aminothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetic acid and 9.54 g of N-bromosuccinimide in 100 ml of methanol is stirred at 60°C for 2 hours. The solvent is evaporated off under reduced pressure and the residue is partitioned between 200 ml of tetrahydrofuran and an aqueous phase consisting of 200 ml of saturated aqueous sodium chloride solution and 50 ml of 5% aqueous sodium thiosulfate solution. The organic phase is separated, washed twice with each 100 ml of saturated aqueous sodium chloride solution and dried over anhydrous magnesium sulfate. The solvent is removed and the residue is crystallized from methanol to give 8.48 g (56% yield) of the above-identified compound as colorless crystals. M.p.: 155-160°C (decomposition) Elemental analysis for C₁₁H₁₄BrN₃O₅S: Calcd.(%): C, 34.75; H, 3.71; N, 11.05. Found (%): C, 34.60; H, 3.99; N, 10.76. 1730, 1700, 1605, 1535, 1415, 1370. NMR spectrum (d₆-DMSO)δ: 1.42(9H, s), 4.56(2H, s), 6.6-8.0(2H, br. s). Reference Example 36 2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetic acid Six grams of 2-(2-aminothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetic acid and 3.2 g of N-chlorosuccinimide are reacted in a manner similar to that in Reference Example 35 and the product obtained is solidified by treating hexane to give 6.5 g of the above-identified compound as a powder. 1735, 1630, 1540, 1370, 1300, 1240. NMR spectrum (d₆-DMSO)δ: 1.41(9H, 2), 4.57(2H, s), 6-8 (2H, br. s). Reference Example 37 2-(2-Chloroacetamido-5-bromothiazol-4-yl)-2(Z)-methoxyiminoacetic acid In 30 ml of dimethylacetamide is dissolved 13.9 g of 2-(2-chloroacetamidothiazol-4-yl)-2(Z)-methoxyiminoacetic acid. To this solution, 10.8 g of N-bromosuccinimide is added and the mixture is stirred at room temperature for 6 hours. To the reaction mixture are added 300 ml of water, 100 ml of ethyl acetate, 300 ml of methyl ethyl ketone and 50 ml of 5% aqueous sodium thiosulfate solution and the mixture is shaken. The organic layer is separated, washed with 100 ml of saturated aqueous sodium chloride solution, dried over anhydrous magnesium sulfate, then concentrated. The residue is crystallized from ethyl acetate to give 13.5 g (76% yield) of the above-identified compound. M.p.: 176-180°C (decomposition) Elemental analysis for C₈H₇BrClN₃O₄S: Calcd.(%): C, 26.94; H, 1.98; N, 11.78. Found (%): C, 26.90; H, 2.09; N, 11.52. 1720, 1670, 1535, 1315, 1280, 1260. NMR spectrum (d₆-DMSO)δ: 3.95(3H, s), 4.36(2H, s), 12.90 (1H, br. s). Reference Example 38 2-(2-Chloroacetamido-5-iodothiazol-4-yl)-2(Z)-methoxyiminoacetic acid To a solution of 13.9 g of 2-(2-chloroacetamidothiazol-4-yl)-2(Z)-methoxyiminoacetic acid in 30 ml of dimethylacetamide, 17.0 g of N-iodosuccinimide is added and the mixture is stirred at 60°C for 1 hour. Then, the reaction mixture is processed as in Reference Example 37 to give 19.6 g (97% yield) of the above-identified compound as colorless crystals. M.p.: 190-195°C (decomposition) Elemental analysis for C₈H₇ClIN₃O₄S: Calcd.(%): C, 23.81; H, 1.75; N, 10.41. Found (%): C, 23.60; H, 2.05; N, 10.19. 1720, 1660, 1535, 1310, 1290, 1270. NMR spectrum (d₆-DMSO)δ: 3.96(3H, s), 4.35(2H, s), 12.91 (1H, br. s). Reference Example 39 7β-[2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-[1-(tert-butoxycarbonyl)-1-methylethoxyimino]acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid 2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-[1-(tert-butoxycarbonyl)-1-methylethoxyimino]acetic acid is reacted with 7β-amino-3-(3-oxobutyryloxymethyl)-4-carboxylic acid in the same manner as in Reference Example 3 to give the above-identified compound. 1780, 1720, 1660, 1530, 1140. Reference Example 40 7β-[2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid Six grams of 2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetic acid, 3.8 g of 1-hydroxy-1H-benzotriazole monohydrate and 4.4 g of dicyclohexylcarbodiimide are dissolved in dimethylformamide under ice-cooling. This mixture is stirred at the same temperature for 5 minutes and then at room temperature for 30 minutes further. To the resulting mixture is added a suspension composite of 5.61 g of 7β-amino-3-(3-oxobutyryloxy)methyl-3-cephem-4-carboxylic acid, 7.5 ml of triethylamine and 20 ml of dimethylformamide and the mixture is stirred at room temperature for 16 hours. To the reaction mixture, 500 ml of diethyl ether is added and the upper layer is removed by decantation. To the lower layer, 300 ml of diethyl ether is added and the upper layer is removed again by decantation. The lower layer is mixed with 100 ml of water, 200 ml of ethyl acetate and 200 ml of methyl ethyl ketone, and then adjusted to pH 2.5. Insoluble substance is removed by filtration and the organic layer is separated, washed twice with each 100 ml of saturated aqueous sodium chloride solution and dried over anhydrous magnesium sulfate. The solvent is evaporated under reduced pressure to give 10.1 g (89% yield) of the above-identified compound. 1780, 1740, 1620, 1530, 1445, 1370, 1310. NMR spectrum (d₆-DMSO)δ: 1.44(9H, s), 2.10(3H, s), 3.42 and 3.64(2H, ABq, J=18Hz), 3.64(2H, s), 4.57(2H, s), 4.79 and 5.08(2H, ABq, J=13Hz), 5.14(1H, d, J=5Hz), 5.84(1H, d.d, J=5 and 8Hz), 7-8(2H, br.), 9.41(1H, d, J=8Hz). Reference Example 41 7β-[2-(2-Amino-5-bromothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid 2-(2-Amino-5-bromothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetic acid and 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid are reacted and worked up in a manner similar to that in Reference Example 40 to give the above-identified compound (99% yield). 1780, 1630, 1620, 1530, 1450, 1370, 1310. NMR spectrum (d₆-DMSO)δ: 1.44(9H, s), 2.20(3H, s), 3.42 and 3.65(2H, ABq, J=18Hz), 3.64(2H, s), 4.58(2H, s), 4.79 and 5.09(2H, ABq, J=14Hz), 5.13(1H, d, J=5Hz), 5.85(1H, d. d, J=5 and 8Hz), 9.38 (1H, d, J=8Hz). Reference Example 42 7β-[2-(5-Amino-1,2,4-thiadiazol-3-yl)-2(Z)-(cyanomethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid A mixture of 13 g of 2-(5-amino-1,2,4-thiadiazol-3-yl)acetic acid, 10.7g of selenium dioxide and 200 ml of dioxane is heated in an oil bath kept at 90°C for 40 minutes with stirring. After cooling, dioxane is evaporated off. To the residue is added 150 ml of ethyl acetate and, after filtration, ethyl acetate is evaporated off under reduced pressure. To the residue are added 100 ml of ethanol and then, with stirring, 3.6 g of O-cyanomethylhydroxylamine. The mixture is then stirred at room temperature for 40 minutes and ethanol is evaporated off under reduced pressure. The residue is dissolved in 150 ml of ethyl acetate. The ethyl acetate solution is washed once with water and then shaken with 100 ml of 5% aqueous sodium bicarbonate solution. The aqueous phase is separated, covered with 150 ml of ethyl acetate and acidified with phosphoric acid with efficient stirring. The ethyl acetate layer is separated and dried over anhydrous magnesium sulfate. Ethyl acetate is evaporated off under reduced pressure and the residue is dissolved in 30 ml of dichloromethane. To the resulting solution, is added 2.2 g of phosphorus pentachloride under ice-cooing. After 20 minutes' stirring at the same temperature, dichloromethane is evaporated off. The residue is redissolved in 5 ml of dichloromethane and the solution is added all at once to a solution composite of 3.1 g of 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid, 6 ml of bistrimethylsilylacetamide and 60 ml of dichloromethane and the mixture is stirred under ice-cooling for 30 minutes. Dichloromethane is then evaporated off and the residue is dissolved in 100 ml of ethyl acetate. The resulting solution is washed with water and dried over anhydrous magnesium sulfate and ethyl acetate is then evaporated off under reduced pressure. To the residue is added 10 ml of ice-cooled trifluoroacetic acid and the mixture is stirred at room temperature for 30 minutes. To the reaction mixture is added 50 ml of ethyl acetate and the solvent is then evaporated under reduced pressure. The residue is triturated with ethyl acetate and the insoluble substance is collected by filtration giving 2 g of crude above-identified compound. The filtrate is then concentrated, the residue treated with diethyl ether and insoluble substance is collected by filtration to give 1.4 g of the above-identified compound. 1780, 1700, 1620, 1520, 1400, 1360, 1310, 1140, 1040. NMR spectrum (d₆-DMSO)δ: 2.21(3H, s), 3.44 and 3.68(2H, ABq, J=18Hz), 3.65(2H, s), 4.79 and 5.10(2H, ABq, J=14Hz), 5.11(2H, s), 5.17(1H, d, J=4.8Hz), 5.85 (1H, d. d, J=4.8 and 8Hz), 8.16(2H, br.), 9.74(1H, d, J=8Hz). Reference Example 43 Imidazo[1,2-a]pyridine derivatives and imidazo[1,5-a]pyridine derivatives are synthesized according to known methods, e.g. W. W. Paudler and H. L. Blewitt J. Org. Chem. 30 , 4081 (1965), J. P. Paolini and R. K. Robius J. Org. Chem., 30 , 4085 (1965), J. P. Paolini and K. Robius J. Heterocyclic Chem., 2 , 53 (1965). Synthesis of novel imidazo[1,2-a]pyridine derivatives is described below. 43-1) 6-Carbamoylimidazo[1,2-a]pyridine To 100 ml of ethanol are added 10 g of 6-aminonicotinamide, 11 g of 40% chloroacetaldehyde and 12.5 g of sodium hydrogen carbonate and the mixture is heated under reflux for 4 hours. Ethanol is evaporated off and 100 ml of water is added to the residue. The mixture is adjusted to pH 10 by adding 10% aqueous sodium hydroxide solution and then extracted four times with each 50 ml of a mixture solvent of tetrahydrofuran-ethyl acetate (1:1). The extracts are combined, dried over anhydrous sodium sulfate and concentrated under reduced pressure. The resulting residue is recrystallized from a mixture solvent of methanol-diethyl ether to give 3.5 g of the above-identified compound as colorless needles. M.P.: 202-204°C 3350, 3120, 1670, 1620, 1420, 1320. NMR spectrum (d₆-DMSO-D₂O)δ: 7.65(3H, s), 8.03(1H, s), 9.10(1H, s). 43-2) 5-Methylthioimidazo[1,2-a]pyridine Into 100 ml of dimethylformamide are suspended 5 g of 5-chloroimidazo[1,2-a]pyridine and 5 g of sodium methanethiolate and the mixture is stirred at 20°C for 1 hour. The solvent is evaporated off under reduced pressure and the residue is dissolved in 200 ml of dichloromethane. The mixture is washed with aqueous saturated sodium chloride solution, dried over anhydrous magnesium sulfate and purified by silica-gel column chromatography to give 3 g of the above-identified compound as an oil. NMR spectrum (CDCl₃)δ: 2.55(3H, s), 6.63(1H, d, J=7Hz), 7.07(1H, d. d, J=7Hz and 9Hz), 7.43(1H, d, J=9Hz), 7.61(2H, s). 43-3) 5-Acetamidoimidazo[1,2-a]pyridine acetate To 200 ml of 1 N sodium hydroxide is dissolved 10 g of 5-aminoimidazo[1,2-a]pyridine hydrobromide and the mixture is extracted with 500 ml of dichloromethane. The extract is evaporated to dryness and the residue is suspended into 50 ml of acetic anhydride. The mixture is heated under reflux for 6 hours. The solvent is evaporated off under reduced pressure and then ethyl acetate is added to the residue to give 3.6 g of the above-identified compound as crystals. M.p.: 110-112°C NMR spectrum (CDCl₃)δ: 2.33(6H, s), 6.73(1H, d, J=7Hz), 7.05-7.4(2H, m), 7.6-8.8(3H, m). 43-4) 6-Cyanoimidazo[1,2-a]pyridine A mixture of 2.6 g of 6-carbamoylimidazo[1,2-a]pyridine and 30 ml of phosphorus oxychloride is heated under reflux for 16 hours. The excess phosphorus oxychloride is removed under reduced pressure and the residue is poured onto ice. The mixture is neutralized with sodium carbonate and extracted with ethyl acetate. The organic layer is washed with saturated aqueous sodium chloride solution and dried over anhydrous magnesium sulfate. The solvent is then evaporated off under reduced pressure to give 2.0 g of the above-identified compound as colorless crystals. M.p.: 166-167°C Elemental analysis for C₈H₅N₃: Calcd.(%): C, 67.13; H, 3.52; N, 29.35. Found (%): C, 67.37; H, 3.62; N, 28.99. 43-5) 8-Hydroxyimidazo[1,2-a]pyridine hydrochloride In 80 ml of concentrated hydrochloric acid is dissolved 5 g of 8-benzyloxyimidazo[1,2-a]pyridine, and the solution is stirred at room temperature for 24 hours and then concentrated. After addition of 1-butanol, water is azeotropically removed by distillation, and the residue is crystallized from diethyl ether to give 3.8 g of the above-identified compound. M.p.: 153-156°C 1670, 1580, 1520, 1410, 1320, 1300. NMR spectrum (d₆-DMSO)δ: 7.2-7.4(2H, m), 8.25(1H, d), 8.3-8.5(2H, m). 43-6) 8-Benzyloxyimidazo[1,2-a]pyridine 2-Amino-3-benzyloxypyridine is reacted with bromoacetaldehyde in aqueous tetrahydrofuran in the presence of sodium hydrogen carbonate, whereby the above-identified compound is obtained. M.p.: 97-98°C Elemental analysis for C₁₄H₁₂N₂O: Calcd.(%): C, 74.98; H, 5.39; N, 12.49. Found (%): C, 74.86; H, 5.40; N, 12.37. 1540, 1500, 1330, 1315, 1280, 1115. NMR spectrum (CDCl₃)δ: 5.31(2H, s), 6.3-6.8(2H, m), 7.2-7.8(8H, m). 43-7) 8-Fluoroimidazo[1,2-a]pyridine 2-Amino-3-fluoropyridine (21.1 g) is added to a solution of bromoacetaldehyde prepared from 74 g of bromoacetaldehyde diethylacetal, 18.5 ml of aqueous hydrogen bromide solution and 18.5 ml of water and made to react in the presence of sodium bicarbonate in aqueous ethanolic solution giving 12 g of the above-identified compound, bp. 91-100°C/1-1.5 mmHg, which solidifies at room temperature. NMR spectrum (CDCl₃)δ: 6.53-7.33(2H, m), 7.60-7.70(2H, m), 7.88-8.03(1H, m). Example 1 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate In 40 ml of a 1:1 mixture of acetonitrile and water are dissolved 4 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid, 4 g of imidazo[1,2-a]pyridine and 4 g of potassium iodide, and the mixture is stirred at 70°C for 2 hours. The solvent is evaporated off under reduced pressure and the residue is solidified by addition of 100 ml of acetonitrile. The resulting powder is collected by filtration and subjected to silica gel column chromatography using a mixture of acetonitrile and water (4:1) as an eluent. The eluted fraction is concentrated under reduced pressure and the residue is lyophilized. A solid obtained is dissolved in 5 ml of water and chromatographed on an XAD-2 column using 10% aqueous ethanol as an eluent. The fractions containing the objective compound are combined and concentrated under reduced pressure, and the residue is lyophilized to give 1.0 g of the above-identified compound. Elemental analysis for: C₂₁H₁₉N₇O₅S₂·7/2 H₂O Calcd. (%): C 43.74 ; H,4.54 ; N,17.00. Found (%): C 44.00 ; H,4.29 ; N,17.23. 1765, 1670, 1605, 1520, 1030 o NMR spectrum (d₆-DMSO)δ: 2.95 & 3.44 (2H, ABq, J=18Hz), 3.80(3H, s), 4.99(1H, d, J=4.5Hz), 5.27 & 5.74(2H, ABq, J=14Hz), 5.59(1H, d. d, J=4.5Hz & 8Hz), 6.68(1H, s), 7.16(2H, br. s), 7.4-7.6(1H, m), 7.85-8.15(1H, m), 8.4-8.9(2H, m), 8.9(1H, d, J=7Hz), 9.46(1H, d, J=8Hz) o Example 2 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(imidazo[1,2-a)pyridinium-1-yl)methyl]-3-cephem-4-carboxylate In a 1:1 mixture of acetonitrile and water are dissolved 5.0 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid, 5.0 g of imidazo[1,2-a]pyridine and 5.0 g of potassium iodide, and the mixture is stirred at 70°C for 2 hours. The solvent is evaporated off under reduced pressure,and the residue is dissolved in 20 ml of water and extracted twice with each 20 ml of ethyl acetate. The organic layer is discarded and the aqueous layer is subjected to XAD-2 column chromatography using 20% aqueous ethanol as an eluent. The fractions containing the objective compound are combined and concentrated under reduced pressure, and the residue is lyophilized. A solid obtained is dissolved in 10 ml of water and chromatographed on a column of Cephadex LH-20 using water as an eluent. The fractions containing the objective compound are combined and concentrated under reduced pressure, and the residue is lyophilized to give 0.5 g of the above-identified compound. Elemental analysis for: C₂₂H₂₁N₇O₅S₂·3H₂O Calcd. (%): C, 45.43 ; H, 4.68 ; N, 16.86. Found (%): C, 45.64 ; H, 4.26 ; N, 16.78 o 1770, 1610, 1530, 1200, 1030 o NMR spectrum (d₆-DMSO)δ: 1.19(3H, t, J=7Hz), 3.00 and 3.45(2H, ABq, J=18Hz), 4.06(2H, q, J=7Hz), 5.01(1H, d, J=4.8Hz), 5.28 & 5.48(2H, ABq, J=14Hz), 5.63(1H, d. d, J=4.8Hz & 8Hz), 6.66(1H, s), 7.15(1H, br. s), 7.40-7.64(1H, m), 7.86-8.10(1H, m), 8.36-8.70(3H, m), 8.88-9.00 (1H, d, J=7Hz), 9.42(1H, d, J=8Hz) o Example 3 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-allyloxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate In 40 ml of a 1:1 mixture of acetonitrile and water are dissolved 2.0 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-allyloxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid, 2.0 g of imidazo[1,2-a]pyridine and 2.0 g of potassium iodide, and the mixture is stirred at 70°C for 1.5 hours. The mixture is concentrated under reduced pressure and the residue is solidified by addition of 50 ml of acetonitrile The resulting powder is collected by filtration, dissolved in 10 ml of water and subjected to XAD-2 column chromatography using 10% aqueous ethanol as an eluent. The fractions containing the objective compound are combined and concentrated under reduced pressure, and the residue is lyophilized to give the crude solid compound, This solid is dissolved in 3 ml of water and chromatographed on a silica gel column using acetonitrile-water (4:1) as an eluent. The fractions containing the objective compound are combined and concentrated under reduced pressure, and the residue lyophilized to give 0.25 g of the above-identified compound. Elemental analysis for: C₂₃H₂₁N₇O₅S₂·₃H₂O Calcd. (%): C, 46.53 ; H, 4.59 ; N, 16.52. Found (%) : C, 46.70 ; H, 4.41 ; N, 16.75 o 1770, 1670, 1610, 1530, 1390 o NMR spectrum (d₆-DMSO-D₂O) δ: 3.00 & 3.50 (2H, ABq, J=18Hz), 4.60(2H, d, J=4.5Hz), 5.05(1H, d, J=5Hz), 5.23(2H, d, J=15Hz), 5.40(2H, s), 5.70(1H, d, J=5Hz), 6.80-6.10(1H, m), 6.73(1H, s), 7.50-7.60(1H, m), 7.90-8.10(1H, m), 8.30-8.46(3H, m), 8.83(1H, d, J=6Hz) o Example 4 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-carboxymethoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate monosodium salt a) In 60 ml of a 1:1 mixture of acetonitrile and water are dissolved 3.0 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-tert-butoxycarbonylmethoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid, 3.0 g of imidazo[1,2-a]pyridine and 3.0 g of potassium iodide, and the mixture is stirred at 70°C for 2 hours. The mixture is concentrated under reduced pressure and to the residue is added 20 ml of water. The mixture is extracted twice with each 20 ml of ethyl acetate and the insoluble substance is removed off. The aqueous layer is subjected to XAD-2 column chromatography using 20% aqueous ethanol as an eluent. The fractions containing the objective compound is combined and concentrated under reduced pressure, and the residue is lyophilized to give 0.9 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-tert-butoxycarbonylmethoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate. b) In 4 ml of trifluoroacetic acid is dissolved 0.8 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-tert-butoxycarbonylmethoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate and the mixture is stirred at 20°C for 2 hours. The mixture is concentrated under reduced pressure and the residue is dissolved in 5 ml of water. Then, the mixture is adjusted to pH 8.0 by adding sodium hydrogen carbonate and subjected to XAD-2 column chromatography using water as an eluent. The fractions containing the objective compound are combined and concentrated under reduced pressure, and then the residue is lyophilized to give 0.4 g of the above-identified compound. Elemental analysis for: C₂₂H₁₈N₇O₇S₂Na·4H₂O Calcd. (%): C, 40.56 ; H, 4.02 ; N, 15.05. Found (%): C, 40.39 ; H, 3.75 ; N, 15.22 o 1770, 1660, 1605, 1530 o NMR spectrum (d₆-DMSO-H₂O) δ: 3.03 & 3.45(2H, ABq, J=18Hz), 4.30(2H, s), 5.03(1H, d, J=4.5Hz), 5.33(2H, s), 5.66(1H, d, J=4.5Hz), 6.80(1H, s), 7.46-7.60(1H, m), 7.95-8.10(1H, m), 8.30-8.50 (3H, m), 8.86(1H, d, J=6Hz) o Example 5 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(1-carboxy-1-methylethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate monosodium salt a) In 60 ml of a 1:1 mixture of acetonitrile and water are dissolved 4.0 g of 3-(3-oxobutyryloxymethyl)-7β-[2-(2-tritylaminothiazol-4-yl)-2(Z)-(1-methyl-1-tert-butoxycarbonyl)ethoxyiminoacetamido]-3-cephem-4-carboxylic acid 4.0 g of imidazo[1,2-a]pyridine and 4.0 g of potassium iodide, and the mixture is stirred at 70°C for 2 hours. The mixture is concentrated under reduced pressure and the residue is extracted four times with each 50 ml of a 1:1 mixture of tetrahydrofuran and ethyl acetate. The extracts are combined and dried over anhydrous magnesium sulfate, and the solvent is evaporated off under reduced pressure. The residue is subjected to silica gel column chromatography using a 9:1 mixture of acetonitrile and water as an eluent to give 1.2 g of 3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-7β-[2-(2-tritylaminothiazol-4-yl)-2(Z)-(1-methyl-1-tert-butoxycarbonyl)ethoxyiminoacetamido]-3-cephem-4-carboxylate. b) To 6 ml of trifluoroacetic acid is dissolved 1.2 g of 3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-7β-[2-(2-tritylaminothiazol-4-yl)-2(Z)-(1-methyl-1-tert-butoxycarbonyl)ethoxyiminoacetamido]-3-cephem-4-carboxylate and the mixture is stirred at 20°C for 2 hr. The mixture is concentrated under reduced pressure and the residue is dissolved in 5 ml of water. Then, the mixture is adjusted to pH 8.0 by adding sodium hydrogen carbonate and subjected to XAD-2 column chromatography using 5% aqueous ethanol as an eluent. The fractions containing the objective compound are combined, concentrated under reduced pressure, and then the residue is lyophilized to give 0.3 g of the above-identified compound. Elemental analysis for: C₂₄H₂₂N₇O₇S₂Na·3H₂O Calcd. (%): C, 43.44 ; H, 4.56 ; N, 14.78. Found (%): C, 43.67 ; H, 4.39 ; N, 14.60 o 1765, 1670, 1600, 1530 o NMR spectrum (d₆-DMSO-H₂O) δ: 1.50(6H, s), 3.10 & 3.55(2H, ABq, J=18Hz), 5.06(1H, d, J=5Hz), 5.43(2H, s), 5.75(1H, d, J=5Hz), 6.73(1H, s), 7.45-7.65(1H, m), 7.96-8.15(1H, m), 8.40-8.55 (3H, m), 8.96(1H, d, J=8Hz) o 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(substituted oxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid is reacted with various imidazole compounds in the same manner as described in Example 1 to give the compounds of Examples 6-22, which have the follwoing general formula: Example 6 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyimonoacetamido]-3-[(6-methylimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate. Elemental analysis for: C₂₂H₂₁N₇O₅S₂·11/2 H₂O Calcd. (%): C, 42.17 ; H, 5.15 ; N, 15.65. Found (%): C, 41.86 ; H, 4.21 ; N, 15.46 o 1765, 1610, 1535, 1035 o NMR spectrum (d₆-DMSO)δ: 2.41(3H, s), 2.95 & 3.43(2H, ABq, J=18Hz), 3.78(3H, s), 4.79(1H, d, J=4.5Hz), 5.20 & 5.41(2H, ABq,J=14Hz), 5.54(1H, d. d, J=4.5Hz & 8Hz), 6.68(1H, s), 7.14(2H, br.s), 7.7-7.96(1H, m), 8.2-8.65(3H, m), 8.72(1H, br.s), 9.45(1H, d) o Example 7 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(7-methylimidazo[1,2-a]pyridinium-1-yl) methyl]-3-cephem-4-carboxylate. Elemental analysis for: C₂₂H₂₁N₇O₅S₂·7/2 H₂O Calcd. (%): C, 44.74 ; H, 4.78 ; N, 16.60. Found (%): C, 44.72 ; H, 4.40 ; N, 16.31 o 1770, 1660, 1615, 1535 o NMR spectrum (d₆-DMSO)δ: 2.52(3H, s), 2.98 & 3.44(2H, ABq, J=18Hz), 3.80(3H, s), 5.00(1H, d, J=4.5Hz), 5.20 & 5.37(2H, ABq, J=14Hz), 5.60(1H, d. d, J=4.5Hz & 8Hz), 6.68(1H, s), 7.12(2H, br. s), 8.2-8.5(1H, m), 8.1-8.5(3H, m), 8.80(1H, d, J=7Hz), 9.45(1H, d, J=8Hz) o Example 8 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(6-chloroimidazo[1,2-a]pyridinium-1-yl) methyl]-3-cephem-4-carboxylate Elemental analysis: C₂₁H₁₈N₇O₅S₂Cl·4H₂O Calcd. (%): C, 40.68 ; H, 4.23 ; N, 15.81. Found (%): C, 40.63 ; H, 3.96 ; N, 15.92 o 1765, 1660, 1610, 1520 o NMR spectrum (d₆-DMSO) δ: 2.96 & 3.34(2H, ABq, J=18Hz), 3.69(3H, s), 4.98(1H, d, J=4.5Hz), 5.23 & 5.50(2H, ABq, J=14Hz), 5.60(1H, d. d, J=4.5Hz & 8Hz), 6.67(1H, s), 7.12(2H, br. s), 8.0-8.2(1H, m), 8.34(1H, br. s), 8.58(1H, br. s), 8.78(1H, d, J=10Hz), 9.28(1H, s), 9.45(1H, d, J=8Hz) o Example 9 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(3-chloroimidazo[1,2-a]pyridinium-1-yl) methyl]-3-cephem-4-carboxylate. Elemental analysis for: C₂₁H₁₈N₇O₅S₂Cl·5H₂O Calcd. (%): C, 39.53 ; H, 4.42 ; N, 15.37. Found (%): C, 39.87 ; H, 3.90 ; N, 15.61 o 1770, 1670, 1615, 1525 o NMR spectrum (d₆-DMSO) δ: 3.03 & 3.40(2H, ABq, J=18Hz), 3.80(3H, s), 5.00(1H, d, J=4.5Hz), 5.25 & 5.50(2H, ABq, J=14Hz), 5.60(1H, d. d, J=4.5Hz & 8Hz), 6.68(1H, s), 7.12(2H, br.s), 7.5-7.78(2H, m), 7.95-8.25(1H, m), 8.65-8.95 (2H, m), 9.44(1H, d, J=8Hz) o Example 10 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(6-carbamoylimidazo[1,2-a]pyridinium-1-yl) methyl]-3-cephem-4-carboxylate Elemental analysis for: C₂₂H₂₀N₈O₆S₂·9/2H₂O Calcd. (%): C, 41.44 ; H, 4.58 ; N, 17.57 Found (%): C, 41.65 ; H, 4.36 ; N, 17.66 1770, 1680, 1620, 1520. NMR spectrum (d₆-DMSO-D₂O)δ: 2.90 & 3.43(2H, ABq, J=18Hz), 3.65(3H, s), 4.93(1H, d, J=4.5Hz), 5.30 (2H, br. s), 5.55(1H, d, J=4.5Hz), 6.60(1H, s), 8.15-8.50(4H, m), 9.30(1H, s) o Example 11 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(3-methylimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for : C₂₂H₂₁N₇O₅S₂·13/2H₂O Calcd. (%): C, 40.99 ; H, 5.32 ; N, 15.21 Found (%): C, 40.98 ; H, 5.42 ; N, 14.91 1770, 1660, 1620, 1530. NMR spectrum (d₆-DMSO)δ: 2.57(3H, s), 2.94 & 3.24 (2H, ABq, J=18Hz), 3.84(3H, s), 5.00(1H, d, J=4.5Hz), 5.23 & 5.48(2H, ABq, J=14Hz), 5.60 (1H, d. d, J=4.5Hz & 8Hz), 6.68(1H, s), 7.14(2H, br. s), 7.4-7.7(1H, m), 7.75-8.18(2H, m), 8.28 (1H, s), 8.41-8.85(1H, m), 9.43(1H, d, J=8Hz) o Example 12 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido] -3-[(5,7-dimethylimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for : C₂₃H₂₃N₇O₅S₂·4H₂O Calcd. (%): C, 45.02 ; H, 5.09 ; N, 15.98 Found (%): C, 44.89 ; H, 4.69 ; N, 16.10 1765, 1660, 1605, 1520 NMR spectrum (d₆-DMSO)δ: 2.70(3H, s), 2.71(3H, s), 2.94 & 3.44(2H, ABq, J=18Hz), 3.78(3H, s), 4.98 (1H, d, J=4.5Hz), 5.20 & 5.40(2H, ABq, J=14Hz), 5.60(1H, d. d, J=4.5Hz & 8Hz), 6.67(1H, s), 7.13 (2H, br.s), 7.25(1H, s), 8.12-8.4(2H, m), 8.50 (1H, s), 9.44(1H, d, J=8Hz) Example 13 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido-3-[(5-acetamidoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for : C₂₃H₂₂N₈O₆S₂·5H₂O Calcd. (%): C, 41.81 ; H, 4.88 ; N, 16.96 Found (%): C, 42.10 ; H, 4.63 ; N, 16.46 1765; 1650, 1610, 1520, 1370, 1280, 1170 NMR spectrum (d₆-DMSO)δ: 2.30(3H, s), 3.03 & 3.48 (2H, ABq, J=18Hz), 3.79(3H, s), 5.00(1H, d, J=4.5Hz), 5.36(2H, br.s), 5.62(1H, d. d,J=4.5Hz & 8Hz), 6.68(1H, s), 7.12(2H, br.s), 7.5-8.6(5H, m), 9.48(1H, d, J=8Hz) Example 14 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(6-bromoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for : C₂₁H₁₈N₇O₅S₂Br·2H₂O Calcd. (%): C, 40.13 ; H, 3.53 ; N, 15.60 Found (%): C, 40.30 ; H, 3,74 ; N, 15.29 1765, 1670, 1610, 1520 NMR spectrum (d₆-DMSO)δ: 2.95 & 3.31(2H, ABq, J= 18Hz), 3.79(3H, s), 4.98(1H, d, J=4.5Hz), 5.1-5.5(2H, m), 5.60(1H, d.d, J=4.5Hz & 8Hz), 6.67 (1H, s), 7.12(2H, br. s), 8.04-8.44(2H, m), 8.48-8.81(1H, m), 9.32(1H, s), 9.42(1H, d, J=8Hz) Example 15 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(8-methylimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for : C₂₂H₂₁N₇O₅S₂·7/2H₂O Calcd. (%): C, 44.74 H, 4.78 ; N, 16.60 Found (%): C, 44.48 ; H, 4.43 ; N, 16.85 1780, 1665, 1615, 1540 NMR spectrum (d₆-DMSO)δ: 2.80 (3H, s), 3.11 & 3.49 (2H, ABq, J=18Hz), 3.80(3H, s), 5.01(1H, d, J= 4.5Hz), 5.43(2H, br. s), 5.63(1H, d. d, J=4.5Hz & 8Hz), 6.69(1H, s), 7.15(2H, br. s), 7.37(1H, t, J=7Hz), 7.73(1H, d, J=7Hz), 8.38(1H, d, J=2Hz), 8.58(1H, d, J=2Hz), 8.64-8.97(1H, m), 9.48(1H, d, J=8Hz) Example 16 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(5-methylimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for: C₂₂H₂₁N₇O₅S₂·9/2H₂O Calcd. (%): C, 43.42 ; H, 4.96 ; N, 16.11 Found (%): C, 43.06 ; H, 4.73 ; N, 16.13 1770, 1680, 1605, 1530 NMR spectrum (d₆-DMSO)δ: 2.77(3H, s), 2.94 & 3.44 (2H, ABq, J=18Hz), 3.79(3H, s), 4.99(1H, d, J=4.5Hz), 5.37 & 5.50(2H, ABq, J=14Hz), 5.60(1H, d.d, J=4.5Hz & 8Hz), 6.68(1H, s), 7.15(2H, br. s) 7.25-7.50(1H, m), 7.7-8.1(1H, m), 8.28-8.68(3H, m), 9.45(1H, d, J=8Hz) Example 17 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(5-chloroimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for : C₂₁H₁₈N₇O₅S₂Cℓ·4H₂O Calcd. (%): C, 40.68 ; H, 4.23 ; N, 15.81 Found (%): C, 40.78 ; H, 3.93 ; N, 15.91 1770, 1670, 1610, 1535, 1510 NMR spectrum (d₆-DMSO)δ: 2.97 & 3.40(2H, ABq, J=18Hz), 3.79(3H, s), 4.90(1H, d, J=4.5Hz), 5.37 & 5.54(2H, ABq, J=14Hz), 5.60(1H, d. d, J=4.5Hz & 8Hz), 6.68(1H, s), 7.14(2H, br. s), 7.62-8.18 (2H, m), 8.4-8.86(3H, m), 9.46(1H, d, J=8Hz) Example 18 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(5-methoxyimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for : C₂₂H₂₁N₇O₆S₂·7/2H₂O Calcd. (%): C, 43.56 ; H, 4.65 ; N, 16.16 Found (%): C, 43.63 ; H, 4.57 ; N, 16.22 1765, 1650, 1620, 1530. NMR spectrum (d₆-DMSO)δ: 2.96 & 3.45(2H, ABq, J=18Hz), 3.80(3H, s), 4.25(3H, s), 4.95(1H, d, J=4.5Hz), 5.24&5.44(2H, ABq, J=14Hz), 5.61(1H, d. d, J=4.5Hz & 8Hz), 6.68(1H, s), 6.9-7.3(3H, m), 7.9-8.35(3H, m), 8.4-8.62(1H, m), 9.46(1H, d, J=8Hz) Example 19 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(5-methylthioimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for : C₂₂H₂₁N₇O₅S₃·4H₂O Calcd. (%): C, 41.83 ; H, 4.63 ; N, 15.52 Found (%): C, 41.91 ; H, 4.40 ; N, 15.20 1770, 1660, 1620, 1530 NMR spectrum (d₆-DMSO)δ: 2.83(3H, s), 3.16(2H, ABq, J=18Hz), 3.80(3H, s), 4.99(1H, d, J=4.5Hz), 5.27 & 5.49(2H, ABq, J=14Hz), 5.61(1H, d. d, J=4.5Hz & 8Hz), 6.68(1H, s), 7.14(2H, br. s), 7.32-7.58(1H, m), 7.78-8.12(1H, m), 8.34-8.36 (1H, m), 8.40-8.72(2H, m), 9.46(1H, d, J=8Hz) Example 20 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(3-N,N-dimethylaminomethylimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for : C₂₄H₂₆N₇O₅S₂·4H₂O Calcd. (%): C, 44.85 ; H, 5.33 ; N, 17.43 Found (%): C, 45.04 ; H, 4.81 ; N, 17.68 1770, 1660, 1610, 1520 NMR spectrum (d₆-DMSO)δ: 2.90(3H, s), 2.98(3H, s), 3.84(3H, s), 5.06(2H, bs), 5.19(1H, d, J=4.5Hz), 5.65(1H, d. d, J=4.5Hz) & 8Hz), 6.72(1H, s), 7.16 (2H, br. s), 7.0-7.25(1H, m), 7.27-7.52(1H, m), 7.6-7.72(1H, m), 7.93(1H, s), 8.82-9.00(1H, m), 9.53(1H, d, J=8Hz) Example 21 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(3-carbamoylimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for : C₂₂H₂₀N₈O₆S₂·9/2H₂O Calcd. (%): C, 41.44 ; H, 4,58 ; N, 17.57 Found (%): C, 41.54 ; H, 4.32 ; N, 17.37 1775, 1680, 1620, 1520 NMR spectrum (d₆-DMSO)δ: 3.09 & 3.49(2H, ABq, J=18Hz), 3.80(3H, s), 5.01(1H, d, J=4.5Hz), 5.37 & 5.67(2H, ABq, J=14Hz), 6.69(1H, s), 7.14 (2H, br. s), 7.54-7.76(1H, m), 7.92-8.28(1H, m), 8.78-9.00(1H, m), 9.16(1H, s), 9.46(1H, d, J=8Hz), 9.76(1H, d, J=7Hz) Example 22 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,5-a]pyridinium-2-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for : C₂₁H₁₉N₇O₅S₂·7/2H₂O Calcd. (%): C, 43.74 ; H, 4.54 ; N, 17.00. Found (%): C, 43.79 ; H, 4.30 ; N,16.79 o 1770, 1660, 1615, 1515 o NMR spectrum (d₆-DMSO)δ: 3.15 & 3.56(2H, ABq, J=18Hz), 3.80(3H, s), 5.03(1H, d, J=4.5Hz), 5.11 & 5.54(2H, ABq, J=13Hz), 5.64(1H, d. d, J=4.5Hz & 8Hz), 6.68(1H, s), 6.9-7.4(4H, m), 7.24-7.45(1H, m), 8.53(1H, s), 8.68(1H, d, J=6Hz), 9.43(1H, d, J=8Hz), 10.03(1H, br.s) o Example 23 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(6-chloroimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid is reacted with 6-chloroimidazo[1,2-a]pyridine in the same manner as described in Example 2 to give the above-identified compound Elemental analysis for : C₂₂H₂₀N₇O₅S₂Cl·4H₂O Calcd. (%): C, 41.67 ; H, 4.45 ; N, 15.46. Found (%): C, 41.85 ; H, 4.09 ; N: 15.69 o 1760, 1660, 1615, 1520, 1380 o NMR spectrum (d₆-DMSO) δ: 1.19(3H, t, J=7Hz), 3.00 & 3.37(2H, ABq, J=18Hz), 4.06(2H, q, J=7Hz), 5.01(1H, d, J=4.5Hz), 5.27 & 5.50(2H, ABq, J=14Hz), 5.63(1H, d.d, J=4.5Hz & 8Hz), 6.67(1H, s), 7.16(2H, br. s), 8.00-8.19(1H, m), 8.26-8.44(1H m), 8.25-8.64(1H, m), 8.66-8.86(1H, m), 9.43(1H, d, J=8Hz) o Example 24 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(1-carboxy-1-methylethoxyimino)acetamido]-3-[(6-chloroimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate 3-(3-Oxobutyryloxymethyl)-7β-[2-(2-tritylaminothiazol-4-yl)-2(Z)-(1-methyl-1-tert-butoxycarbonyl)ethoxyiminoacetamido]-3-cephem-4-carboxylic acid is reacted with 6-chloroimidazo[1,2-a]pyridine in the same manner as described in Example 5 to give the above-identified compound Elemental analysis for : C₂₂H₂₀N₇O₅S₂Cl·4H₂O Calcd. (%): C, 41.68 ; H, 4.45 ; N, 15.47. Found (%): C, 41.42 ; H, 4.67 ; N, 15.42 o 1760, 1610, 1520 o NMR spectrum (d₆-DMSO)δ: 1.38(3H, s), 1.42(3H, s), 3.01(2H, ABq, J=18Hz), 4.97(1H, d, J=4.8Hz), 5.20-5.52(2H, m), 5.60-5.79(1H, m), 6.67(1H, s), 7.10(2H, br. s), 7.96-8.16(1H, m), 8.30-8.80(3H, m), 9.32(1H, s), 11.45(1H, d, J=9Hz) o Example 25 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(1-carboxy-1-methylethoxyimino)acetamido]-3-[(6-methylimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate monosodium salt 3-(3-Oxobutyryloxymethyl)-7β-[2-(2-tritylaminothiazol-4-yl)-2(Z)-(1-methyl-1-tert-butoxycarbonyl)ethoxyiminoacetamido]-3-cephem-4-carboxylic acid is reacted with 6-methylimidazo [1,2-a]pyridine in the same manner as described in Example 5 to give the above-identified compound. Elemental analysis for : C₂₅H₂₄N₇O₇S₂Na·4H₂O Calcd. (%): C, 43.29 ; H, 4.65 ; N, 14.13. Found (%): C, 43.76 , H, 4.55 ; N, 13.59 o 1770, 1660, 1600, 1525 o NMR spectrum (d₆-DMSO)δ: 1.43(6H, s), 2.43(3H, s), 4.99(1H, d, J=4.5Hz), 5.33(2H, br. s), 5.66(1H, d. d, J=4.5Hz & 8Hz), 6.70(1H, s), 7.13(2H, br. s), 7.68-8.02(1H, m), 8.06-8.6(3H, m), 8.64-8.88(1H, m), 11.54(1H, d, J=8Hz) o Example 26 In 60 ml of a 1:1 mixture of acetonitrile and water are dissolved 3.0 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-acetoxymethyl-3-cephem-4-carboxylic acid, 3.0 g of imidazo[1,2-a]pyridine and 3.0 g of potassium ioiide, and the mixture is stirred at 70° for 3 hours. The mixture is concentrated under reduced pressure and the residue is triturated with 20 ml of ethyl acetate. The residue is dissolved in 50 ml of water and subjected to XAD-2 column chromatography using 20% aqueous ethanol as an eluent. The fractions containing the objective compound are combined and concentrated under reduced pressure, and the residue is subjected to silica gel column chromatography using a 4:1 mixture of acetonitrile and water. The fractions containing the objective compound are combined and concentrated under reduced pressure, and the residue is lyophilized to give 0.3 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate. This compound is found to be identical with that obtained in Example 1 in view of agreement in IR and NMR spectra. Example 27 Into a mixture of 20 ml of acetonitrile and 20 ml of formamide is suspended 4.1 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-hydroxymethyl-3-cephem-4-carboxylic acid. To the mixture are added, under cooling at -30°C, successively 4.7 g of imidazo[1,2-a]pyridine and 20 ml of a solution (2 mmole/ml) of methyl o-phenylene phosphate in dichloromethane. The mixture is stirred for 2 hours. The solvent is evaporated off under reduced pressure and to the residue is added 20 ml of acetonitrile. The resulting solid is filtered and suspended in 20 ml of water. The mixture is adjusted to pH 8.0 and subjected to XAD-2 column chromatography using 10% aqueous ethanol as an eluent. The fractions containing the objective compound are combined and concentrated under reduced pressure, and the residue is lyophilized to give 3.0 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate. This compound is found to be identical with that obtained in Example 1 as the result of agreement in physical data. Example 28 Into 20 ml of chloroform is suspended 3.0 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-acetoxymethyl-3-cephem-4-carboxylic acid and 4 ml of N-methyl-N-trimethylsilyltrifluoroacetamide is added to the mixture. The resulting mixture is stirred at 20°C until it becomes homogeneous. Then, 3.3 g of trimethylsilyl iodide is added to the mixture and the mixture is stirred at 20°C for 10 minutes. The reaction mixture is concentrated under reduced pressure and 9 ml of acetonitrile is added to the residue. After addition of 0.8 ml of tetrahydrofuran, the mixture is stirred for 40 minutes. To the mixture is added 2 g of imidazo[1,2-a]pyridine and the mixture is stirred at 20°C for 3 hr. The mixture is cooled under ice-cooling and 1 ml of water is added to it. The precipitated solid is filtered and subjected to silica gel column chromatography using a 4:1 mixture of acetonitrile and water as an eluent. The fractions containing the objective compound are combined and concentrated under reduced pressure, and the residue is lyophilized to give 0.3 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate. This compound is found to be identical with that obtained in Example 1 as the result of agreement in physical data. Example 29 a) In 120 ml of a 1:1 mixture of acetonitrile and water are dissolved 6.2 g of 7β-amino-3-(3-oxo-butyryloxymethyl)-3-cephem-4-carboxylic acid, 6.0 g of imidazo[1,2-a]pyridine and 6.0 g of potassium iodide, and the mixture is stirred at 70°C for 1 hour. The solvent is removed under reduced pressure and the residue is triturated three times with each 30 ml of ethyl acetate. After the solid is filtered and dissolved in 30 ml of water, it is subjected to XAD-2 column chromatography using water as an eluent. The fractions containing the objective compound are combined and concentrated under reduced pressure, and the residue is lyophilized to give 1.3 g of 7β-amino-3-[(imidazo[1,2-a]-pyridinium-1-yl)methyl]-3-cephem-4-carboxylate. b) In a solution of 0.94 g 2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetic acid and 0.64 g of 1-hydroxybenzotriazole in 20 ml of dimethylformamide is added 1.0 g of dicyclohexylcarbodiimide, and the mixture is stirred at 20°C for 2 hr. The precipitated insolubles are filtered off and the filtrate is added to 20 ml of dimethylformamide solution of 1.3 g of 7β-amino-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate obtained in the above a), and the mixture is stirred at 20°C for 3 hr. After 200 ml of diethyl ether is added to the mixture, the ether layer is removed off. The residue is dissolved in 20 ml of water and subjected to XAD-II column chromatography using 10% aqueous ethanol as an eluent. The fractions containing the objective compound are combined and concentrated under reduced pressure. The residue is lyophilized to give 0.25 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate. The physical data of this compound is in agreement with those of the compound obtained in Example 1. Example 30 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-propoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate In a 1:1 mixture of acetonitrile and water are added 1,5 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-propoxyiminoacetamido]-3-(3-oxobutyryloxylmethyl)-3-cephem-4-carboxylic acid, 1.5 g of imidazo[1,2-a]pyridine and 1.5 g of potassium iodide, and the mixture is stirred at 70°C for 2 hours. The solvent is evaporated off under reduced pressure and the residue is subjected to silica gel column chromatography using a 4:1 mixture of acetonitrile and water as an eluent. The eluted fractions are combined and concentrated under reduced pressure, and the residue is lyophilized. The resulting solid is dissolved in 5 ml of water and subjected to 20 % aqueous ethanol as an eluent. The fractions containing the objective compound are combined and concentrated under reduced pressure, and the residue is lyophilized to give 0.25 g of the above-identified compound. Elemental analysis for : C₂₃H₂₃N₇O₅S₂·4H₂O Calcd. : C, 45.02 ; H, 5.09 ; N, 15.98. Found : C, 44.95 ; H, 4.66 ; N, 15.80. 1775, 1650, 1610, 1530. NMR spectrum (d₆-DMSO)δ: 0.86(3H, t, J=7Hz), 1.36-1.80(2H, m), 2.97 & 3.37(2H, ABq, J=18Hz), 3.96(2H, t, J=7Hz), 4.99(1H, d, J=5Hz), 5.27 & 5.45 (2H, ABq, J=13Hz), 5.61(1H, d.d, J=5Hz & 8Hz), 6.65(1H, s), 7.13(2H, br.s), 7.35-7.66(1H, m), 7.84-8.14(1H, m), 8.3-8.76(3H, m), 8.8-9.05(1H, m), 9.40(1H, d, J=8Hz) o 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(substituted-oxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid is reacted with various imidazole compounds in the same manner as described in Example 30 to give the following compounds [VII'] (Example 31-41). Example 31 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(2-fluoroethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental Analysis for : C₂₂H₂₀N₇O₅S₂F·4H₂O Calcd. (%) C, 42.78 ; H, 4.57 ; N, 15.87. Found (%) C, 42.57 ; H, 4.27 ; N, 15.71. 1760, 1610, 1525. NMR spectrum (d₆-DMSO)δ: 2.96 & 3.43(2H, ABq, J= 18Hz), 4.0-4.2(1H, m), 4.2-4.5(2H, m), 4.7-5.0(1H, m), 5.00(1H, d, J=5Hz), 5.2-5.6(2H, m), 5.61(1H, d.d, J=4Hz & 8Hz), 6.70(1H, s), 7.16(2H, br.s), 7.4-7.7(2H, m), 7.8-8.2(2H, m), 8.3-8.8(3H, m), 8.97 (1H, d, J=7Hz), 9.50(1H, d, J=8Hz). Example 32 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(2-chloroethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental Analysis for : C₂₂H₂₀N₇O₅S₂Cl·⁵/₂H₂O Calcd. : C, 43.53 ; H, 4.15 ; N, 16.15. Found : C, 43.25 ; H, 4.03 ; N, 15.94. 1760, 1605, 1520. NMR spectrum (d₆-DMSO)δ: 2.98 & 3.43(2H, ABq, J= 18Hz), 3.7-3.9(2H, m), 4.1-4.4(2H, m), 5.00(1H, d, J=5Hz), 5.25 & 5.47(2H, ABq, J=16Hz), 5.62(1H, d.d, J=5Hz & 8Hz), 6.74(1H, s), 7.16(2H, br.s), 7.4-7.6(2H, m), 7.9-8.2(2H, m), 8.3-8.8(3H, m), 8.93(1H, d, J= 7Hz), 9.45(1H, d, J=8Hz). Example 33 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-isopropoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental Analysis for : C₂₃H₂₃N₇O₅S₂·¹¹/₂H₂O Calcd. : C, 43.11 ; H, 5.35 ; N, 15.30. Found : C, 42.81 ; H, 4.86 ; N, 15.00. 1770, 1650, 1610, 1530. NMR spectrum (d₆-DMSO)δ: 1.18(6H, d, J=6Hz), 5.00(1H, d, J=4.5Hz), 5.28 & 5.48(2H, ABq, J=13Hz), 5.46(1H, d.d, J=4.5Hz & 8Hz), 6.64(1H, s), 7.13 (2H, br.s), 7.3-7.6(1H, m), 7.8-8.15(1H, m), 8.28-8.75(3H, m), 8.8-9.15(1H, m), 9.35(1H, d, J=8Hz). Example 34 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(2-hydroxyethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental Analysis for : C₂₂H₂₁N₇O₆S₂·4H₂O Calcd. : C, 42.92 ; H, 4.75 ; N, 15.93. Found : C, 42.86 ; H, 4.54 ; N, 15.70. 1770, 1650, 1610, 1530. NMR spectrum (d₆-DMSO)δ: 2.97 & 3.43(2H, ABq, J= 18Hz), 3.44-3.72(2H, m), 4.02(2H, t, J=6Hz), 4.50 (1H, br.s), 4.98(1H, d, J=4.5Hz), 5.26 & 5.46(2H, ABq, J=13Hz), 5.60(1H, d.d, J=4.5Hz & 8Hz), 6.67(1H, s), 7.15(2H, br.s), 7.36-7.60(1H, m), 7.80-8.12(1H, m), 8.30-8.76(3H, m), 8.84-9.04(1H, m), 9.36(1H, d, J=8Hz) o Example 35 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-cyclopropylmethyloxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental Analysis for: C₂₄H₂₃N₇O₅S₂¹³/₂H₂O Calcd. : C, 42.98; H, 5.41; N, 14.62. Found C, 43.09; H, 5.60; N, 14.74. 1770, 1620, 1530. NMR spectrum (d₆-DMSO)δ: 0.1-0.6(4H, m), 0.7-1.3 (1H, m), 2.95(1H, ABq, J=18Hz), 3.84(2H, d, J=14 Hz), 4.99(1H, d, J=5Hz), 5.28 & 5.46(2H, ABq, J=13 Hz), 5.62(1H, d.d, J=5Hz & 8Hz), 6.64(1H, s), 7.12(2H, br.s), 7.30-7.60(1H, m), 7.86-8.20(1H, m), 8.20-8.80(3H, m), 8.80-9.02(1H, m), 9.40(1H, d, J= 8Hz) o Example 36 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-carbamoylmethyloxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental Analysis for : C₂₂H₂₀N₈O₆S₂·¹¹/₂H₂O Calcd. : C, 40.30 ; H, 4.77 ; N, 17.09. Found : C, 40.54 ; H, 4.15 ; N, 17.09. 1770, 1675, 1610, 1530. NMR spectrum (d₆-DMSO)δ: 3.00 & 3.44(2H, ABq, J= 18Hz), 4.36(2H, s), 5.02(1H, d, J=4.8Hz), 5.28 & 5.47 (2H, ABq, J=14Hz), 5.66(1H, d.d, J=4.8Hz & J=8Hz), 6.78(1H, s), 7.00-7.60(5H, m), 7.86-8.10(1H, m), 8.28-8.70(3H, m), 8.86-9.00(1H, m), 9.70(1H, d, J= 8Hz) o Example 37 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(2,2,2-trifluoroethyloxylmino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl) methyl]-3-cephem-4-carboxylate Elemental Analysis for : C₂₂H₁₈N₇O₅S₂F₃·3H₂O Calcd. (%): C, 41.58 ; H, 3.81 ; N, 15.43. Found (%): C, 41.30 ; H, 3.99 ; N, 15.25. 1770, 1620, 1530, 1380, 1280, 1060. NMR spectrum (D₂O)δ: 3.15 & 3.56(2H, ABq, J=18Hz), 5.20-5.50(3H, m), 5.80(1H, d, J=4.5Hz), 6.93(1H, s), 7.40-7.60(1H, m), 7.90-8.20(4H, m), 8.66(1H, d, J=6Hz) o Example 38 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(imidazo[1,5-a]pyridinium-2-yl)methyl]-3-cephem-4-carboxylate Elemental Analysis for : C₂₂H₂₁N₇O₅S₂·⁹/₂H₂O Calcd. (%): C, 43.42 ; H, 4.97 ; N, 16.11. Found (%): C, 43.72 ; H, 4.47 ; N, 16.00. 1760, 1600, 1520, 1380. NMR spectrum (d₆-DMSO)δ: 1.18(3H, t, J=7Hz), 3.12 & 3.55(2H, ABq, J=18Hz), 4.05(2H, q, J=7Hz), 5.02(1H, d, J=5Hz), 5.07 & 5.53(2H, ABq, J=14Hz), 5.63(1H, d.d, J=5Hz & 8Hz), 6.67(1H, s), 7.0-7.2 (5H, m), 7.8-7.9(1H, m), 8.5-8.8(2H, m), 9.37(1H, d, J=8Hz) o Example 39 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(2-fluoroethoxyimino)acetamido]-3-[(6-chloroimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental Analysis for : C₂₂H₁₉N₇O₅S₂ClF·3H₂O Calcd. (%) : C, 41.68 ; H, 3.98 ; N, 15.47. Found (%) : C, 41.49 ; H, 4.26 ; N, 15.31. 1765, 1670, 1610, 1530. NMR spectrum (d₆-DMSO)δ: 2.95 & 3.20(2H, ABq, J= 18Hz), 4.00-4.25(1H, m), 4.30-4.53(2H, m), 4.65-5.01(2H, m), 5.06(1H, d, J=5Hz), 5.30-5.56(1H, m), 5.66(1H, d.d, J=4.5Hz & 8Hz), 6.73(1H, s), 7.20(2H, br.s), 8.10(1H, d, J=9Hz), 8.30(1H, s), 8.60(1H, s), 8.76(1H, d, J=9Hz), 9.30(1H, s), 9.55(1H, d, J=8Hz) o Example 40 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[2,1-b]thiazoliom-7-yl)methyl]-3-cephem-4-carboxylate Elemental Analysis for : C₁₉H₁₇N₇O₅S₃·3H₂O Calcd. (%) : C, 39.80 ; H, 4.04 ; N, 17.10. Found (%) : C, 39.65 ; H, 3.99 ; N, 16.73. 1770, 1660, 1610, 1530. NMR spectrum (d₆-DMSO)δ: 2.90 & 3.26(2H, ABq, J= 18Hz), 3.76(3H, s), 4.85 & 5.20(2H, ABq, J=13Hz), 5.66(1H, d.d, J=5Hz & 8Hz), 6.15(1H, d, J=5Hz), 6.70(1H, s), 7.20(2H, br.s), 7.80-7.90(2H, m), 9.50 (1H, d, J=8Hz) o Example 41 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(2,6-dimethylimidazo[2,1-b][1,3,4]thiadiazolium-7-yl)methyl]-3-cephem-4-carboxylate Elemental Analysis for : C₂₀H₂₀N₈O₅S₃·⁹/₂H₂O Calcd. (%) : C, 38.15 ; H, 4.64 ; H, 17.80. Found (%) : C, 38.18 ; H, 4.23 ; H, 18.02. 1770, 1670, 1610, 1530. NMR spectrum (d₆-DMSO)δ: 2.52(3H, s), 2.78(3H, s), 3.09 & 3.52(2H, ABq, J=18Hz), 3.84(3H, s), 4.86 & 5.26(2H, ABq, J=5Hz & 8Hz), 6.72(1H, s), 7.16(2H, br.s), 8.39(1H, s), 9.46(1H, d, J=8Hz) o Example 42 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate In 30 ml of a 1:1 mixture of acetonitrile and water are dissolved 2.3 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid, 1.79 g of 6-cyanoimidazo[1,2-a]pyridine and 2.2 g of potassium iodide, and the mixture is stirred at 60-70°C for 1.5 hours. The solvent is then evaporated off under reduced pressure and the residue is solidified by addition of 100 ml of acetonitrile. The resulting powder is collected by filtration and then subjected to silica gel column chromatography. The acetonitrile-water (7:3)-eluated fraction is concentrated under reduced pressure and the residue is lyophilized. A solid obtained is dissolved in 5 ml of water and chromatographed on a column of MCI GEL CHP20P (150-300 meshes; Mitsubishi Chemical Industries, Ltd., Japan) with water-ethanol. The water-ethanol (85:15)-eluated fraction is concentrated under reduced pressure and the residue lyophilized to give 0.27 g of the above-identified compound. Elemental analysis for C₂₂H₁₈N₈O₅S₂·5H₂O : Calcd. (%): C, 42.03; H, 4.49; N, 17.83 o Found (%): C, 42.28; H, 4.12; N, 17.65 o 2250, 1770, 1670, 1610, 1530 o NMR spectrum (d₆-DMSO)δ: 2.97(1/2×2H.ABq,J=18Hz), 3.79(3H,s), 5.00(1H,d,J=4.5Hz), 5.27 & 5.58(2H,ABq,J=14Hz), 5.61(1H,d.d,J=4.5Hz & 8Hz), 6.68(1H,s), 7.14(2H,br.s), 8.25-8.55(2H,m), 8.65-9.00(2H,m), 9.46(1H,d,J=8Hz), 9.67(1H,s) o 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(substituted oxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid is reached with various imidazole compounds in the same manner as described in Example 42 to give the following compounds [VII'] (Examples 43-83). Example 43 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-butoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₄H₂₅N₇O₅S₂·7/2H₂O: Calcd. (%) : C, 46.59; H, 5.21; N, 15.85 o Found (%) : C, 46.87; H, 5.10; N, 15.65 o 1770, 1670, 1610, 1530 o NMR spectrum (d₆-DMSO)δ: 0.84(3H,t,J=7Hz), 1.1-1.8 (4H.m), 2.96 & 3.43(2H,ABq,J=17Hz), 4.00(2H,t,J=7Hz), 4.98 (1H,d,J=4.5Hz), 5.29 & 5.48(2H,ABq,J=14Hz), 5.60(1H,d.d,J=4.5Hz & 8Hz), 6.64(1H.s), 7.11(2H,br.s), 7.4-7.6(1H,m), 7.84 8.1(1H,m), 7.35-7.78(3H,m), 7.88-8.02(1H,m), 9.39(1H,d,J= 8Hz) o Example 44 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-hexyloxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₆H₂₉N₇O₅S₂·5/2H₂O: Calcd. (%): C, 49.67; H, 5.45; N, 15.60 o Found (%): C, 49.53; H, 5.53; N, 15.23 o 1770, 1670, 1610 o NMR spectrum (d₆-DMSO)δ: 0.78(3H,t,J=7Hz), 1.0-1.7 (8H,m), 2.92 & 3.43(2H,ABq,J=18Hz), 3.98(2H,t,J=7Hz), 4.98 (1H,d,J=4.5Hz), 5.25 & 5.44(2H,ABq,J=14Hz), 5.60(1H,d.d,J=4.5Hz & 8Hz), 6.63(1H,s), 7.10(2H,br.s), 7.36-7.60(1H,m), 7.80-8.10(1H,m), 8.30-8.64(2H,m), 8.54-8.76(1H,m), 8.84-9.00 (1H,m), 9.38(1H,d,J=8Hz) o Example 45 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-benzyloxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₇H₂₃N₇O₅S₂·7/2H₂O: Calcd. (%): C, 49.69; H, 4.63; N, 15.02 o Found (%): C, 49.77; H, 4.38; N, 14.92 o 1765, 1680, 1640, 1610, 1515 o NMR spectrum (d₆-DMSO)δ: 2.91(1/2×2H.ABq,J=18Hz), 4.99(1H,d,J=4.5Hz), 5.09(2H,s), 5.26 & 5.48(2H,ABq,J=14Hz), 5.62(1H,d.d,J=4.5Hz & 8Hz), 6.67(1H.s), 7.13(2H,br.s), 7.00-7.66(7H,m), 7.78-8.2(1H.m), 8.30-8.78(2H,m), 8.82-9.04(1H, m), 9.55(1H,d,J=8Hz) o Example 46 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(2-methoxyethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₃H₂₃N₇O₆S₂·7/2H₂O: Calcd. (%) : C, 44.51; H, 4.87; N, 15.80 o Found (%) : C, 44.67; H, 4.75; N, 15.25 o 1775, 1670, 1610, 1530 o NMR spectrum (d₆-DMSO)δ: 3.00 & 3.46(2H,ABq,J=18Hz), 3.24(3H,s), 4.13(4H,t,J=7Hz), 5.03(1H,d,J=4.5Hz), 5.29 and 5.47(2H,ABq,J=13Hz), 5.64(1H,d.d,J=4.5Hz & 8Hz), 6.69(1H, s), 7.15(2H,br.s), 7.38-7.64(1H,m), 7.86-8.12(1H,m), 8.30-8.72(3H.m), 8.82-9.04(1H.m), 9.43(1H,d,J=8Hz) o Example 47 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-propargyloxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₃H₁₉N₇O₅S₂·7/2H₂O: Calcd (%): C, 46.00; H, 4.36; N, 16.33 o Found (%): C, 46.07; H, 4.51; N, 16.18 o 1770, 1665, 1610, 1530 o NMR spectrum (d₆-DMSO)δ: 3.06(1/2×2H.ABq,J=18Hz), 5.00(1H,d,J=4.5Hz), 5.22-5.56(4H,m), 5.64(1H,d.d,J=4.5Hz and 8Hz), 6.74(1H,s), 7.20(2H,br.s), 7.50-7.64(1H,m), 7.86-8.10(1H,m), 8.34-8.60(3H,m), 8.92(1H,d,J=6Hz), 9.58(1H,d, J=7HZ) o Example 48 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-cyclopentyloxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₅H₂₅N₇O₅S₂·4H₂O: Calcd. (%) : C, 33.26; H, 5.20; N, 15.33 o Found (%) : C, 33.49; H, 5.46; N, 15.15 o 1770, 1665 1610, 1530 o NMR spectrum (d₆-DMSO)δ: 1.30-1.90(8H,m), 3.02 and 3.30(2H,ABq,J=18Hz), 4.80(1H,m), 5.06(1H,d,J=4.5Hz), 5.20-5.44(2H,m), 5.60(1H,d.d,J=4.5Hz & 8Hz), 6.68(1H,s), 7.20(2H,br. s), 7.46-7.60(1H,m), 7.85-7.90(1H,m), 8.22-8.70(3H,m), 8.90 (1H,d,J=7Hz), 9.35(1H,d,J=8Hz) o Example 49 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(6-nitroimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₁H₁₈N₈O₇S₂·3H₂O: Calcd. (%): C, 41.18; H, 3.95; N, 18.30 o Found (%): C, 41.50; H, 4.09; N, 17.98 o 1775, 1665, 1620, 1530 o NMR spectrum (d₆-DMSO)δ: 3.02 & 3.50(2H,ABq,J=18Hz), 3.80(3H,s), 5.06(1H,d,J=4.5Hz), 5.30 & 5.50(2H,ABq,J=14Hz), 5.68(1H,d.d,J=4.5Hz & 8Hz), 6.70(1H,s), 7.16(2H,br.s), 7.74-8.0(2H,m), 8.56-8.78(2H,m), 9.48(1H,d,J=8Hz), 9.96(1H,d,J= 2Hz) o Example 50 7β-[2-(2-Aminothiazol-1-yl)-2(Z)-methoxyiminoacetamido]-3-[(8-ethoxycarbonylimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₄H₂₃N₇O₇S₂·2H₂O: Calcd. (%): C, 46.38; H, 4.38; N, 15.78 o Found (%): C, 46.25; H, 4.61; N, 15.54 o 1765, 1710, 1620, 1530 o NMR spectrum (d₆-DMSO)δ: 1.34(3H,t,J=7Hz), 3.00 and 3.45(2H,ABq,J=18Hz), 3.82(3H,s), 4.48(2H,q,J=7Hz), 5.08 (1H,d,J=4.5Hz), 5.20-5.42(2H,m), 5.70(1H,d.d,J=4.5Hz & 8Hz), 6.72(1H,s), 7.10(2H,br.s), 7.80-8.0(1H,m), 8.34-8.60(3H,m), 9.10-9.22(1H,m), 9.52(1H,d,J=8Hz) o Example 51 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(6,8-dichloroimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₁H₁₇N₇O₅S₂Cℓ₂·4H₂O: Calcd. (%): C, 38.54; H, 3.85; N, 14.99 o Found (%): C, 38.77; H, 4.01; N, 14.67 o 1760, 1660, 1610, 1530 o NMR spectrum (d₆-DMSO)δ: 2.94 & 3.46(2H,Abq,J=18Hz), 3.80(3H,s), 5.06(1H,d,J=4.5Hz), 5.20 & 5.45(2H,ABq,J=14Hz), 5.60(1H,d.d,J=4.5Hz & 8Hz), 6.66(1H,s), 7.14(2H,br.s), 7.70 (1H,s), 8.30-8.50(2H,m), 9.26(1H,s), 9.50(1H,d,J=8Hz) o Example 52 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[[3-(morpholinomethyl)imidazo[1,2-a]-pyridinium-1-yl]methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₆H₂₈N₈O₆S₂·11/2H₂O: Calcd. (%): C, 43.88; H, 5.52; N, 15.74 o Found (%): C, 43.50; H, 5.03; N, 15.46 o 1775, 1670, 1610, 1530 o NMR spectrum (d₆-DMSO)δ: 2.3-2.55(4H,m), 3.01 & 3.45 (2H,ABq,J=18Hz), 3.74-4.05(4H,m), 3.80(3H,s), 4.95(1H,d, J=4.5Hz), 5.26 & 5.46(2H,ABq,J=14Hz), 5.60(1H,d.d,J=4.5Hz and 8Hz), 6.69(1H,s), 7.14(2H,br.s), 7.40-7.68(2H,m), 7.92-8.16(1H.m), 8.6-8.78(1H,m), 8.8-8.98(1H,m), 9.44(1H,d,J=8Hz) o Example 53 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[[3-(hydroxyiminomethyl)imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₂H₂₀N₈O₆S₂·4H₂O: Calcd. (%): C, 42.03; H, 4.48; N, 17.83 o Found (%): C, 41.99; H, 4.70; N, 17.54 o 1770, 1690, 1670, 1610, 1520 o NMR spectrum (d₆-DMSO)δ: 3.08 & 3.49(2H,ABq,J=18Hz), 3.79(3H,s), 4.99(1H,d,J=5Hz), 5.2-5.8(3H,m), 6.69(1H,s), 7.15(2H,br.s), 7.51-7.76(2H,m), 8.00-8.25(2H,m), 8.80-9.00(1H,m), 9.17(1H,s), 9.47(1H,d,J=9Hz), 9.75(1H,d,J=7Hz) o Example 54 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(2-ethoxycarbonylimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₄H₂₃N₇O₇S₂·5H₂O: Calcd. (%): C, 40.88; H, 4.92; N, 14.51 o Found (%): C, 41.07; H, 4.56; N, 14.57 o 1770, 1670, 1600, 1530 o NMR spectrum (d₆-DMSO)δ: 1.39(3H,t,J=7Hz), 2.96 & 3.37 (2H,ABq,J=18Hz), 3.78(3H,s), 4.48(2H,q,J=7Hz), 4.99(1H,d,J= 4.5Hz), 5.46-5.85(3H,m), 6.67(1H,s), 7.14(2H,br.s), 7.5-7.75(1H,m), 8.00-8.26(1H,m), 8.8-9.05(1H,m), 9.14(1H,s), 9.2-9.38(1H,m), 9.47(1H,d,J=9Hz) o Example 55 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-propoxyiminoacetamido]-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₄H₂₂N₈O₄S₂·5H₂O: Calcd. (%): C, 44.99; H, 5.03; N, 17.49 o Found (%): C, 45.06; H, 4.71; N, 17.21 o 2250, 1770, 1670, 1610, 1530 o NMR spectrum (d₆-DMSO)δ: 0.86(3H,t,J=7Hz), 1.35-1.80(2H,m), 2.98 & 3.32(2H,ABq,J=18Hz), 3.96(2H,t,J=7Hz), 5.00(1H,d,J=7Hz), 5.25-5.52(2H,ABq,J=14Hz), 5.55-5.75 (1H,m), 6.65(1H,s), 7.12(2H,br.s), 8.20-8.55(2H,m), 8.6-8.75(1H,m), 8.80-9.00(1H.m), 9.40(1H,d,J=8Hz), 9.74(1H,s) o Example 56 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(6-methylimidazo[1,2-b]pyridazinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₁H₂₀N₈O₅S₂·9/2H₂O: Calcd. (%): C, 41.37; H, 4.79; N, 18.38 o Found (%): C, 41.50; H, 4.86; N, 17.91 o 1770, 1670, 1630, 1550 o NMR spectrum (d₆-DMSO)δ: 2.67(3H,s), 3.03 & 3.46(2H, ABq,J=18Hz), 3.79(3H,s), 5.00(1H,d,J=4.5Hz), 5.25 & 5.50 (2H,ABq,J=14Hz), 5.61(1H,d.d,J=4.5Hz), 6.68(1H,s), 7.15 (2H,br.s), 7.87(1H,d,J=10Hz), 8.55-8.74(2H,m), 9.19(1H,d, J=10Hz), 9.47(1H,d,J=8Hz) o Example 57 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(6-chloroimidazo[1,2-b]pyridazinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₀H₁₇N₈O₅S₂Cl·3H₂O: Calcd. (%): C, 39.84; H, 3.84; N, 18.58 o Found (%): C, 39.62; H, 3.69; N, 18.42 o 1780, 1670, 1610, 1530 o NMR spectrum (d₆-DMSO)δ: 2.97 & 3.43(2H,ABq,J=18Hz), 3.77(3H,s), 4.97(1H,d,J=4.5Hz), 5.21 & 5.54(2H,ABq,J=14Hz), 5.60(1H,d.d,J=4.5Hz & 8Hz), 6.66(1H,s), 7.09(2H,br.s), 8.13 (1H,d,J=10Hz), 8.71-8.84(2H,m), (9.34-9.54(2H,m) o Example 58 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(6-methoxyimidazo[1,2-b]pyridazinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₁H₂₀N₈O₈S₂·9/2H₂O: Calcd. (%): C, 40.32; H, 4.67; N, 17.91 o Found (%): C, 40.34; H, 4.71; N, 17.42 o 1775, 1670, 1620, 1510 o NMR spectrum (d₆-DMSO)δ: 2.99 & 3.44(2H,ABq,J=18Hz), 3.80(3H,s), 4.06(3H,s), 5.01(1H,d,J=4.5Hz), 5.21 & 5.49(2H, ABq,J=14Hz), 5.61(1H,d.d,J=4.5Hz & 8Hz), 6.70(1H,s), 7.15 (2H,br.s), 7.62(1H,d,J=10Hz), 8.48-8.66(2H,m), 9.21(1H,d,J=10Hz), 9.48(1H,d,J=8Hz) o Example 59 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(6-methoxyimidazo[1,2-b]pyridazinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₂H₂₂N₈O₆S₂·5H₂O: Calcd. (%): C, 40.73; H, 4.97; N, 17.27 o Found (%): C, 41.00; H, 4.52; N, 17.62 o 1770, 1660, 1620, 1530 o NMR spectrum (d₆-DMSO)δ: 1.19(3H,t,J=6Hz), 2.99 and 3.44(2H,ABq,J=18Hz), 4.05(3H,s), 4.06(2H,q,J=6Hz), 4.99 (1H,d,J=4.5Hz), 5.19 & 5.50(2H,ABq,J=14Hz), 5.62(1H,d.d, J=4.5Hz & 8Hz), 6.65(1H,s), 7.14(2H,br.s), 7.62(1H,d,J=10 Hz), 8.45-8.68(2H,m), 9.24(1H,d,J=10Hz), 9.43(1H,d,J=8Hz) o Example 60 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(2-methylimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis C₂₂H₂₁N₇O₅S₂·4H₂O: Calcd. (%): C, 44.06; H, 3.52; N, 16.35 o Found (%): C, 44.50; H, 3.77; N, 17.01 o 1770, 1660, 1610, 1530 o NMR spectrum (d₆-DMSO)δ: 2.95 & 3.47(2H,ABq,J=18Hz), 3.78(3H,s), 3.80(3H,s), 5.08(1H,d,J=4.5Hz), 5.44(2H,br.s), 5.62(1H,d.d,J=4.5Hz & 8Hz), 6.68(1H,s), 7.15(2H,br.s), 7.55-8.15(5H,m), 9.48(1H,d,J=8Hz) o Example 61 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(2-carbamoylimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₂H₂₀N₈O₈S₂·17/2H₂O: Calcd. (%) : C, 37.23; H, 5.25; N, 15.78 o Found (%) : C, 37.37; H, 5.43; N, 15.29 o 1765, 1750, 1690, 1610, 1530 o NMR spectrum (d₆-DMSO-D₂O)δ: 3.01 & 3.43(2H,Abq,J= 18Hz), 3.80(3H,s), 4.98(1H,d,J=5Hz), 5.20-5.50(2H,m), 5.60 (1H,d), 6.71(1H,s), 7.3-7.7(2H,m), 7.95-8.28(1H,m), 8.68-9.05(2H,m) o Example 62 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(3-ethoxycarbonyl-2-methylimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₅H₂₅N₇O₇S₂·7/2H₂O: Calcd. (%): C, 45.31; H, 4.87; N, 14.80 o Found (%): C, 45.90; H, 4.65; N, 14.73 o 1760, 1710, 1670, 1600 o NMR spectrum (d₆-DMSO)δ: 1.41(3H,t,J=7Hz), 2.88(3H, s), 3.18(1/2×2H,ABq,J=18Hz), 3.78(3H,s), 4.49(2H,q,J=7Hz), 4.95(1H,d,J=4.5Hz), 5.21 & 5.52(2H,ABq,J=14Hz), 5.50-5.78 (1H,m), 6.67(1H,s), 7.15(2H,br.s), 7.58-7.84(1H,m), 8.00-8.30 (1H,m), 9.10-9.30(1H,m), 9.35-9.60(2H,m) o Example 63 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(1-carbamoyl-1-methylethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₄H₂₄N₈O₆S₂·4H₂O: Calcd. (%): C, 43.90; H, 4.91; N, 17.06 o Found (%): C, 43.94; H, 5.03; N, 16.90 o 1780, 1725, 1670, 1610, 1540 o NMR spectrum (d₆-DMSO)δ: 1.36(6H,br.s), 3.02 & 3.42 (2H,ABq,J=15Hz), 5.01(1H,d,J=5Hz), 5.2-5.3(2H,m), 5.68 (1H,d.d,J=5Hz & 8Hz), 6.71(1H,s), 6.7-7.1(2H,m), 7.21(2H, br.s), 7.4-7.6(1H,m), 7.8-8.1(1H,m), 8.3-8.7(3H,m), 8.8-9.0(1H,m), 9.58(1H,d,J=8Hz) o Example 64 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(6-carbamoylimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₃H₂₂N₈O₈S₂·4H₂O: Calcd. (%): C, 42.99; H, 4.70; N, 17.44 o Found (%): C, 43.19; H, 4.41; N, 17.23 o 1770, 1680, 1610, 1535 o NMR spectrum (d₆-DMSO)δ: 1.18(3H,t,J=7Hz), 3.04 and 3.48(2H,ABq,J=16Hz), 4.05(2H,q,J=7Hz), 5.02(1H,d,J=5Hz), 5.30 & 5.52(2H,ABq,J=16Hz), 5.64(1H,d.d,J=5Hz & 8Hz), 6.67 (1H.s), 7.15(2H,br.s), 7.5-8.2(2H,m), 8.2-8.9(4H,m), 9.44 (1H,d,J=8Hz), 9.60(1H,br.s) o Example 65 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₃H₂₀N₈O₅S₂·5H₂O: Calcd. (%): C, 42.99; H, 4.70; N, 17.44 o Found (%): C, 42.82; H, 4.39; N, 16.98 o 2250, 1770, 1610, 1530 o NMR spectrum (d₆-DMSO)δ: 1.18(3H,t,J=7Hz), 2.99 and 3.44(2H,ABq,J=18Hz), 4.05(2H,q,J=7Hz), 5.01(1H,d,J=5Hz), 5.28 & 5.53(2H,ABq,J=14Hz), 5.64(1H,d.d,J=5Hz & 8Hz), 6.66 (1H,s), 7.14(2H,br.s), 8.2-9.0(4H,m), 9.42(1H,d,J=8Hz), 9.77(1H,br.s) o Example 66 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(2-chloroethoxyimino)acetamido]-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₃H₁₉N₈O₅S₂Cl·7/2H₂O: Calcd. (%): C, 42.50; H, 4.03; N, 17.24 o Found (%): C, 42.54; H, 3.93; N, 16.97 o 2250, 1770, 1650, 1610, 1530 o NMR spectrum (d₆-DMSO)δ: 2.99 & 3.47(2H,ABq,J=18Hz), 3.6-3.9(2H,m), 4.1-4.4(2H,m), 5.12 & 5.27(2H,ABq,J=13Hz), 5.64(1H,d.d,J=5Hz & 8Hz), 6.72(1H.s), 7.19(2H,br.s), 8.2-9.0(4H,m), 9.50(1H,d,J=8Hz), 9.78(1H,br.s) o Example 67 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(8-hydroxyimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₁H₁₉N₇O₈S₂·6H₂O: Calcd. (%): C, 39.55; H, 4.90; N, 15.38 o Found (%): C, 39.39; H, 5.22; N, 14.98 o 1760, 1670, 1620, 1530, 1370 o NMR spectrum (d₆-DMSO)δ: 3.13 & 3.49(2H,ABq,J=18Hz), 3.79(1H,s), 5.02(1H,d,J=5Hz), 5.26 & 5.45(2H,ABq,J=13Hz), 5.63(1H,d.d,J=5Hz & 8Hz), 6.70(1H,s), 7.13(2H,br.s), 6.0-8.4(6H,m), 9.46(1H,d,J=8Hz) o Example 68 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(8-benzyloxyimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₈H₂₅N₇O₆S₂·9/2H₂O: Calcd. (%): C, 47.99; H, 4.89; N, 13.99 o Found (%): C, 47.89; H, 4.60; N, 13.99 o 1770, 1670, 1610, 1570, 1520 o NMR spectrum (d₆-DMSO)δ: 2.93 & 3.31(2H,ABq,J=18Hz), 3.80(3H,s), 4.96(1H,d,J=5Hz), 5.18 & 5.44(2H,ABq,J=13Hz), 5.47(2H,s), 5.59(1H,d.d,J=5Hz & 8Hz), 6.70(1H,s), 7.13(2H,br.s), 7.2-7.7(7H,m), 8.17(1H,d,J=2Hz), 8.50(1H,d,J=7Hz), 8.79(1H,d,J=2Hz), 9.43(1H,d,J=8Hz) o Example 69 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]quinolinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₅H₂₁N₇O₅S₂·11/2H₂O: Calcd. (%): C, 45.31; H, 4.87; N, 14.80 o Found (%): C, 45.32; H, 4.64; N, 14.71 o 1770, 1670, 1620, 1550, 1530, 1455 o NMR spectrum (d₆-DMSO)δ: 3.05 & 3.50(2H,ABq,J=18Hz), 3.80(3H,s), 5.00(1H,d,J=5Hz), 5.37 & 5.58(2H,ABq,J=13Hz), 5.60(1H,d.d,J=5Hz & 8Hz), 6.67(1H,s), 7.12(2H,br.s), 7.4-8.8(7H,m), 9.18(1H,m), 9.47(1H,d,J=8Hz) o Example 70 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(3-methylthiazolo[3,2-a]benzimidazolium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₄H₂₁N₇O₅S₃·8H₂O: Calcd. (%): C, 39.61; H, 5.12; N, 13.47 o Found (%): C, 39.56; H, 4.97; N, 13.46 o 1770, 1670, 1625, 1530, 1480, 1440 o NMR spectrum (d₆-DMSO)δ: 2.85(3H.s), 3.11 & 3.50(2H, ABq,J=18Hz), 5.04(1H,d,J=5Hz), 5.29 & 5.53(2H,ABq,J=13Hz), 5.67(1H,d.d,J=5Hz & 8Hz), 6.70(1H,s), 7.12(2H,br.s), 7.62(1H, s), 6.8-7.9(2H,m), 8.0-8.5(2H,m), 9.50(1H,d,J=8Hz) o Example 71 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyrimidinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₀H₁₈N₈O₅S₂·7/2H₂O: Calcd. (%): C, 41.59; H, 4.36; N, 19.40 o Found (%): C, 41.63; H, 4.26; N, 19.13 o 1775, 1670, 1630, 1610, 1540 o NMR spectrum (d₆-DMSO)δ: 3.12 & 3.54(2H,ABq,J=18Hz), 3.79(3H,s), 5.00(1H,d,J=4.5Hz), 5.15 & 5.31(2H,ABq,J=13.5Hz), 5.62(1H,d.d,J=4.5Hz & 8Hz), 6.68(1H,s), 7.14(2H,br.s), 7.6-7.8(1H,m), 8.36(1H,d,J=2.5Hz), 8.89(1H,d,J=2.5Hz), 9.00-9.18(1H,m), 9.30-9.55(1H,m), 9.43(1H,d,J=8Hz) o Example 72 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(6-chloroimidazo[1,2-b]pyridazinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₁H₁₉ClN₈O₅S₂·7/2H₂O: Calcd. (%): C, 40.29; H, 4.19; N, 17.90 o Found (%): C, 40.46; H, 3.94; N, 17.54 o 1780, 1770, 1670, 1610, 1530 o NMR spectrum (d₆-DMSO)δ: 1.19(3H,t,J=7Hz), 3.01 and 3.47(2H,ABq,J=18Hz), 4.06(2H,q,J=7Hz), 5.00(1H,d,J=4.5Hz), 5.26 & 5.56(2H,ABq,J=14Hz), 5.64(1H,d.d,J=4.5Hz & 8Hz), 6.67 (1H,s), 7.14(2H,br.s), 8.17(1H,d,J=10Hz), 8.78-8.90(2H,m), 9.44(1H,d,J=8Hz), 9.48(1H,d,J=10Hz) o Example 73 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(5,7-dimethylimidazo[1,2-c]pyrimidinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₂H₂₂N₈O₅S₂·5H₂O: Calcd. (%): C, 41.77; H, 5.10; N, 17.71 o Found (%): C, 41.87; H, 4.69; N, 17.24 o 1775, 1670, 1615, 1535 o NMR spectrum (d₆-DMSO)δ: 2.60(3H,s), 2.90(3H,s), 3.26 (1/2×2H.ABq,J=18Hz), 3.79(3H,s), 4.97(1H,d,J=4.5Hz), 5.11 and 5.36(2H,ABq,J=14Hz), 5.58(1H,d.d,J=4.5Hz & 8Hz), 6.67 (1H,s), 7.12(2H,br.s), 8.3-8.65(3H,s), 9.43(1H,d,J=8Hz) o Example 74 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(2-fluoroethoxyimino)acetamido]-3-[(imidazo[1,5-a]pyridinium-2-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₂H₂₀N₇O₅S₂F·7/2H₂O: Calcd. (%): C, 43.42; H, 4.47; N, 16.11 o Found (%): C, 43.58; H, 4.29; N, 15.85 o 1770, 1660, 1610, 1535, 1390, 1360 o NMR spectrum (d₆-DMSO)δ: 3.12 & 3.57(2H,ABq,J=18Hz), 4.0-4.2(1H,m), 4.2-4.5(2H,m), 4.7-4.9(1H,m), 5.04(1H,d,J=5 Hz), 5.53 & 5.51(2H,Abq,J=13Hz), 5.64(1H,d.d,J=5Hz & 8Hz), 6.71(1H.s), 6.9-7.2(5H,m), 7.7-8.0(1H.m), 8.4-8.8(2H,m), 9.45(1H,d,J=8Hz) o Example 75 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(3-carboxy-2-methylimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate monosodium salt Elemental analysis for C₂₃H₂₀N₇O₆S₂Na·6H₂O: Calcd. (%): C, 40.29; H, 4.70; N, 14.29 o Found (%): C, 40.66; H, 4.59; N, 13.79 o 1770, 1610, 1535, 1390 o NMR spectrum (d₆-DMSO)δ: 2.86(3H,s), 2.87 & 3.31 (2H,ABq,J=18Hz), 3.78(3H,s), 4.97(1H,d,J=4.5Hz), 5.2-5.48(2H,m), 5.52-5.70(1H,m), 6.67(1H,s), 7.12(2H,br.s), 7.3-7.56(1H,m), 7.76-8.00(1H,m), 8.66-8.89(1H,m), 9.48 (1H,d,J=8Hz), 10.08-10.24(1H,m) o Example 76 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(2-carboxyimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate monosodium salt Elemental analysis for C₂₂H₁₈N₇O₇S₂Na·4H₂O: Calcd. (%): C, 40.56; H, 4.02; N, 15.05 o Found (%): C, 40.59; H, 3.71; N, 14.57 o 1765, 1620, 1520 o NMR spectrum (d₆-DMSO)δ: 3.02 & 3.29(2H,ABq,J=18Hz), 3.80(3H,s), 4.95(1H,d,J=4.5Hz), 5.56(1H,d.d,J=4.5Hz & 8Hz), 6.07 & 6.25(2H,ABq,J=14Hz), 6.67(1H,s), 7.15(2H,br.s), 7.3-7.6(1H,m), 7.72-3.00(1H,m), 8.44(1H,s), 8.78-9.00(2H,m), 9.45(1H,d,J=8Hz) o Example 77 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(3-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₂H₁₈N₈O₅S₂·4H₂O: Calcd. (%): C, 43.27; H, 4.29; N, 18.35 o Found (%): C, 43.63; H, 4.29; N, 18.16 o 2245, 1770, 1660, 1610 o NMR spectrum (d₆-DMSO)δ: 3.02 & 3.47(2H,ABq,J=18Hz), 3.79(3H,s), 4.99(1H,d,J=5Hz), 5.20-5.79(3H,m), 6.68(1H,s), 7.14(2H,br.s), 7.62-7.84(1H,m), 8.10-8.45(1H,m), 8.9-9.14 (2H,m), 9.46(1H,d,J=8Hz), 9.50(1H,s) o Example 78 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(3-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₃H₂₀N₈O₅S₂·3H₂O: Calcd. (%): C, 45.54; H, 4.32; N, 18.47 o Found (%): C, 45.33; H, 4.44; N, 17.76 o 2240, 1770, 1670, 1610, 1530, 1510 o NMR spectrum (d₆-DMSO)δ: 1.19(3H,t,J=7Hz), 3.03 and 3.47(2H,ABq,J=18Hz), 4.05(2H,q,J=7Hz), 5.00(1H,d,J=4.5Hz), 5.32 & 5.59(2H,ABq,J=14Hz), 5.64(1H,d.d,J=4.5Hz & 8Hz), 6.66 (1H,s), 7.14(2H,br.s), 7.64-7.86(1H,m), 8.17-8.40(1H,m), 8.90-9.15(2H,m), 9.43(1H,d,J=8Hz), 9.50(1H,s) o Example 79 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(2-hydroxyethoxyimino)acetamido]-3-[(6-cyanoimidazo[1,2-a]-pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₃H₂₀N₈O₆S₂·4H₂O: Calcd. (%): C, 43.04; H, 4.41; N, 17.49 o Found (%): C, 43.24; H, 3.64; N, 16.86 o 2250, 1765, 1650, 1610 o NMR spectrum (d₆-DMSO)δ: 2.97 & 3.14(2H,ABq,J=18Hz), 3.9-4.2(4H,m), 5.01(1H,d,J=4.5Hz), 5.34(2H,br.s), 5.62 (1H,d.d,J=4.5Hz & 8Hz), 6.68(1H,s), 7.15(2H,br.s), 8.28-8.58(2H,m), 8.6-9.00(2H,m), 9.38(1H,d,J=8Hz), 9.76(1H, br.s) o Example 80 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[[3-(cyanomethyl)imidazo[1,2-a]pyridinium-1-yl]methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₃H₂₀N₈O₅S₂·4H₂O: Calcd. (%): C, 44.23; H, 4.51; N, 17.93 o Found (%): C, 44.16; H, 4.63; N, 17.93 o 2260, 1765, 1650, 1605 o NMR spectrum (d₆-DMSO)δ: 3.01 & 3.45(2H,ABq,J=18Hz), 3.79(3H,s), 4.70(2H,s), 4.99(1H,d,J=4.5Hz), 5.25 & 5.51(2H, ABq,J=14Hz), 5.60(1H,d.d,J=4.5Hz & 8Hz), 6.68(1H,s), 7.15 (2H,br.s), 7.5-7.78(1H,m), 7.95-8.25(1H,m), 8.6-9.0(3H, m), 9.45(1H,d,J=8Hz) o Example 81 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(6-carboxyimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate monosodium salt Elemental analysis for C₂₂H₁₈N₇O₇S₂Na·5H₂O: Calcd. (%): C, 39.46; H, 4.21; N, 14.64 o Found (%): C, 39.39; H, 4.11; N, 14.53 o 3400, 1765, 1665, 1610, 1530, 1390 o NMR spectrum (d₆-DMSO)δ: 2.53(3H,s), 3.12 & 3.58(2H, ABq,J=16Hz), 5.00(1H,d,J=5Hz), 5.1-5.4(2H,m), 5.71(1H,d, d,J=5Hz & 8Hz), 6.57(1H,s), 7.20(2H,br.s), 8.0-8.7(4H,m), 9.25(1H,d,J=8Hz), 9.45(1H,br.s) o Example 82 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(2-fluoroethoxyimino)acetamido]-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₃H₁₉N₈O₅S₂F·7/2H₂O: Calcd. (%): C, 43.60; H, 4.14; N, 17.68 o Found (%): C, 43.42; H, 3.94; N, 17.42 o 3400, 2250, 1760, 1610, 1520 o NMR spectrum (d₆-DMSO)δ: 2.99 & 3.62(2H,Abq,J=17Hz), 4.0-4.2(1H,m), 4.2-4.6(2H,m), 4.7-5.0(1H,m), 5.02(1H,d,J= 5Hz), 5.28 & 5.54(2H,ABq,J=15Hz), 5.64(1H,d.d,J=5Hz & 8Hz), 6.71(1H,s), 7.17(2H,br.s), 8.2-9.0(4H,m), 9.52(1H,d,J=8Hz), 9.77(1H,br.s) o Example 83 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[[6-(trichloromethyl)imidazo[1,2-a]-pyridinium]methyl]-3-cephem-4-carboxylate Elemental analysis for C₂₂H₁₈N₇O₅S₂Cl₃·5H₂O: Calcd. (%): C, 36.65; H, 3.91; N, 13.60 o Found (%): C, 36.52; H, 3.65; N, 13.35 o 3400, 1755, 1605, 1520 o Example 84 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(1-carboxyethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate monosodium salt In 50% aqueous acetonitrile are dissolved 3 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-(1-tert-butoxycarbonylethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid, 3 g of imidazo[1,2-a]pyridine and 3 g of potassium iodide. The solution is stirred at 60-70°C for 2 hours, and, then, subjected to silica gel column chromatography using aqueous acetone as the eluent. Fractions eluated with 80% aqueous acetone are combined and concentrated under reduced pressure and the residue is lyophilized. A powder thus-obtained is dissolved in water and the solution is subjected to chromatography on a MCI GEL CHP20P column using aqueous alcohol as the eluent. Fractions eluated with 30% aqueous alcohol are combined and concentrated under reduced pressure, and the residue is lyophilized to leave 0.2 g of a powder, which is dissolved in 2 ml of trifluoroacetic acid. The solution is stirred at room temperature for 2 hours and the solvent is removed under reduced pressure. To the residue are added water and sodium carbonate. The resulting solution is subjected to MCI GEL CHP20P column chromatography using water and then 5% aqueous ethanol as the eluent. Fractions containing the desired product are combined and concentrated under reduced pressure. Lyophilization of the residue gives 0.14 g of the above-identified compound. Elemental analysis for C₂₃H₂₀N₇O₇S₂Na·6H₂O: Calcd. (%): C, 39.37; H, 4.60; N, 13.97 o Found (%): C, 39.65; H, 4.20; N, 13.30 o 1780, 1670, 1610, 1530 o NMR spectrum (d₆-DMSO)δ: 1.32(3H,d,J=7Hz), 3.01 and 3.38(2H,Abq,J=18Hz), 4.25-4.56(1H,m), 4.96 & 5.00 (total 1H, each d, J=4.5Hz), 5.2-5.5(2H,m), 5.55-5.84(1H,m), 6.72 & 6.78(total 1H,2s),7.12(2H,br.s), 7.36-7.60(1H,m), 7.76-8.10(1H,m), 8.25-8.65(3H,m), 8.85-9.05(1H,m), 11.56 & 11.71 (total 1H, each d,J= 8Hz) o By a procedure similar to that of Example 84, compounds of the following Examples 85-90 of the above general formula [VII'] can be prepared by reacting 7β-[2-(2-aminothiazol-4-yl)-2(Z)-(substituted oxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid with various imidazole compounds. Example 85 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(1-carboxypropoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate monosodium salt Elemental analysis for C₂₄H₂₂N₇O₇S₂Na·9/2H₂O: Calcd. (%): C, 41.86; H, 4.54; N, 14.24 o Found (%): C, 41.67; H, 4.38; N, 14.58 o 1780, 1765, 1670, 1600, 1530 o NMR spectrum (d₆-DMSO)δ: 0.90 & 0.92 (total 3H, each d,J=7Hz), 1.50-1.95(2H,m), 3.02(1/2×2H,ABq,J=18Hz), 4.00-4.34(1H, m),4.96 & 5.00 (total 1H, each d,j=4.5Hz), 5.18-5.75(3H,m), 6.71 & 6.80 (total 1H, each s), 7.11(2H,br,s), 7.35-7.65(1H,m), 7.75-8.15(1 H,m), 8.25-8.76(3H,m), 8.80-9.10(1H,m), 11.6-12.0(1H,m) o Example 86 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(1-carboxybutoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate monosodium salt Elemental analysis for C₂₅H₂₄N₇O₇S₂Na·5H₂O: Calcd. (%): C, 42.19; H, 4.81; N, 13.77 o Found (%): C, 42.15; H, 4.63; N, 13.61 o 1770, 1670, 1610, 1530 o NMR spectrum (d₆-DMSO)δ: 0.74 & 0.82(total 3H, each t,J=7Hz), 1.1-1.9(4H,m), 2.97 & 3.30(2H,ABq,J=18Hz), 4.1-4.42(1H,m), 4.95 & 5.00(total 1H, each d,J=5Hz), 5,39(2H,br.s), 5.6-5.7(1H,m), 6.70 & 6.77(total 1H,each s), 7.11(2H,br.s), 7.35-7.60(1H,m), 7.75-8.06(1H,m), 8.3-8.7(3H,m), 8.86-9.08(1H,m), 11.62-11.90 (1H,m) o Example 87 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(1-carboxy-1-methylethoxyimino)acetamido]-3-[(6-methylimidazo[1,2-b]pyridazinium-1-yl)methyl]-3-cephem-4-carboxylate monosodium salt Elemental analysis for C₂₄H₂₃N₈O₇S₂Na·5H₂O: Calcd. (%): C, 40.45; H, 4.67; N, 15.72 o Found (%): C, 40.46; H, 4.21; N, 15.33 o 1770, 1610, 1530 o NMR spectrum (d₆-DMSO)δ: 1.36(3H,s), 1.41(3H,s), 2.66 (3H,s), 3.04 & 3.22(2H,ABq,J=18Hz), 4.98(1H,d,J=4.5Hz), 5.22-5.50(2H,m), 5.56-5.60(1H,m), 6.67(1H,s), 7.13(2H,br.s), 7.78(1H,d,J=10Hz), 8.5-8.72(2H,m), 9.13(1H,d,J=10Hz), 11.50 (1H,d,J=8Hz) o Example 88 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(1-carboxy-1-methylethoxyimino)acetamido]-3-[(imidazo[1,5-a]pyridinium-2-yl)methyl]-3-cephem-4-carboxylate monosodium salt Elemental analysis for C₂₄H₂₂N₇O₅S₂Na·9/2H₂O: Calcd.(%): C, 41.86; H, 4.54; N, 14.24 o Found (%): C, 42.08; H, 4.26; N, 13.89 o 1780, 1660, 1610, 1520 o NMR spectrum (d₆-DMSO)δ: 1.39(3H,s), 1.42(3H,s), 3.16 & 3.56(2H,ABq,J=18Hz), 5.05(1H,d,J=4.5Hz), 5.15-5.60 (2H,m), 5.65-5.85(1H,m), 6.69(1H,s), 7.13(2H,br.s), 7.8-7.9(2H,m), 8.2-8.5(2H,m), 8.55-8.81(1H,m), 10.04(1H,br.s), 11.92(1H,d,J=8Hz) o Example 89 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(1-carboxy-1-methylethoxyimino)acetamido]-3-[(6-cyanoimidazo[1,2-a]-pyridinium-1-yl)methyl]-3-cephem-4-carboxylate monosodium salt Elemental analysis for C₂₅H₂₁N₈O₇S₂Na·5H₂O: Calcd. (%): C, 41.55; H, 4.32; N, 15.51 o Found (%): C, 41.47; H, 4.16; N, 15.30 o 2250, 1780, 1610, 1530 o NMR spectrum (d₆-DMSO)δ: 1.38(3H,s), 1.42(3H,s), 3.02 & 3.71(2H,ABq,J=18Hz), 4.99(1H,d,J=5Hz), 5.2-5.5(2H, m), 5.68(1H,d.d,J=5Hz & 8Hz), 6.68(1H,s), 7.10(2H,br.s), 8.2-8.8(4H,m), 9.81(1H,br.s), 11.44(1H,d,J=8Hz) o Example 90 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-(1-carboxy-1-methylethoxyimino)acetamido]-3-[(3-cyanoimidazo[1,2-a]-pyridinium-1-yl)methyl]-3-cephem-4-carboxylate monosodium salt Elemental analysis for C₂₅H₂₁N₈O₇S₂Na·5H₂O: Calcd. (%): C, 41.55; H, 4.32; N, 15.50 o Found (%): C, 41.84; H, 4.14; N, 15.39 o 2240, 1765, 1670, 1600, 1530 o NMR spectrum (d₆-DMSO)δ: 1.40(6H,br.s), 3.12 & 3.49 (2H,ABq,J=18Hz), 5.01(1H,d,J=4.5Hz), 5.40(2H,br.s), 5.71 (1H,d,J=4.5Hz), 6.73(1H,s), 7.55-7.90(1H,m), 8.00-8.80 (3H,m), 9.00(1H,s) o Example 91 7β-[2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Starting from 2.0 g of 7β-[2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-(3-oxobutyryloxy methyl)-3-cephem-4-carboxylic acid, 2 g of imidazo[1,2-a]pyridine and 2 g of potassium iodide, 329 mg of the above-identified compound is obtained by a procedure similar to that in Example 42. Elemental analysis for C₂₁H₁₈ClN₇O₅S₂·2H₂O: Calcd. (%): C, 43.19; H, 3.80; N, 16.79 o Found (%): C, 43.16; H, 3.39; N, 15.50 o 3400, 1765, 1665, 1605, 1520, 1450 o NMR spectrum (d₆-DMSO)δ: 2.96 & 3.44(2H,ABq,J=18Hz), 3.80(3H,s), 4.97(1H,d,J=4.5Hz), 5.2-5.5(2H,m), 5.61(1H, d.d,J=4.5Hz & 8Hz), 7.32(2H,br.s), 7.5-9.0(6H,m), 9.44(1H, d,J=8Hz) o Example 92 7β-[2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-(1-carboxy-1-methylethoxyimino)acetamido]-3-[(imidazo[1,2-a]-pyridinium-1-yl)methyl]-3-cephem-4-carboxylate monosodium salt 7β-[2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-(1-tert-butoxycarbonyl-1-methylethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid is reacted with imidazo[1,2-a]pyridine, by a similar procedure to that of Example 84 to give the above-identified compound. Elemental analysis for C₂₄H₂₁N₇O₇S₂ClNa· 4H₂O: Calcd. (%): C, 40.37; H, 4.09; N, 13.73 o Found (%): C, 40.52; H, 3.76; N, 13.55 o 1765, 1600, 1520 o Example 93 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate 1-β-sulfoxide In 10 ml of acetic acid is dissolved 246 mg of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium)methyl]-3-cephem-4-carboxylate and, under cooling at 10-15°C, 86 mg of m-chloroperbenzoic acid is added thereto. The mixture is stirred at the same temperature for 1 hour. The solvent is then evaporated off under reduced pressure and the residue is dissolved in water. The solution is subjected to chromatography on a column of highporous polymer (MCI GEL CHP20P Mitsubishi Chemical Industries, Ltd.) using 15% ethanol as the eluent. The eluate is concentrated and lyophilized to give 140 mg of the above identified compound. Elemental analysis for C₂₂H₂₁N₇O₆S₂·7/2H₂O: Calcd. (%): C, 43.61; H, 4.64; N, 16.18 o Found (%): C, 43.67; H, 4.42; N, 15.98 o 1780, 1670, 1620, 1525, 1450, 1385, 1350, 1280, 1200, 1040, 770 o NMR spectrum (d₆-DMSO)δ: 1.22(3H,t,J=7Hz), 2.10 (2H,q,J=7Hz), 4.86(1H,d,J=5Hz), 5.44(2H,br.s), 5.76(1H, d.d,J=5Hz & 8Hz), 6.80(1H,s), 7.16(2H,br.s), 7.52(1H,t,J= 7Hz), 7.99(1H,t,J=7Hz), 8.3-8.8(3H,t,J=7Hz), 8.96(1H,d, J=6Hz) o Example 94 7β-[2-(2-Aminothiazol-4-yl)-2-formamidoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate i) In 100 ml of formic acid is dissolved 4 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylate and, under ice-cooling, 20 g of zinc powder is added little by little with stirring in the course of 30 minutes. The mixture is stirred at room temperature for 1 hour, and insoluble substance is filtered off. The filtrate contains 7β-[2-amino-2-(2-aminothiazol-4-yl)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid. TLC [acetonitrile-water (4:1); Merck, Silica Gel Art. 5715), Rf 0.37 ii) A mixture of 10 ml of formic acid and 10 ml of acetic anhydride is warmed at 50°C for 40 minutes, and the resulting mixed acid anhydride solution is cooled and added to the ice-cooled solution of 7β-[2-amino-2-(2-aminothiazol-4-yl)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid obtained in the above procedure i). The mixture is stirred for 2 hours, and 50 ml of water is added thereto, followed by concentration. The concentrate is adjusted to pH 5.5 with sodium hydrogen carbonate to give a solution containing 7β-[2-(2-aminothiazol-4-yl)-2-formamidoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid. TLC [acetonitrile-water (4:1), Merck, Silica Gel Art. 5715), Rf 0.76 iii) The solution of 7β-[2-(2-aminothiazol-4-yl)-2-formamidoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid obtained in the above procedure ii) is concentrated. To the residue, 10g of potassium iodide, 5g of imidazo[1,2-a]pyridine, 50 ml of water and 50 ml of acetonitrile are added and the mixture is stirred at 70°C for 2 hours. After cooling to room temperature, 300 ml of ethyl acetate is added to the reaction mixture. The mixture is stirred and then allowed to stand and the upper layer is removed by decantation. This procedure is repeated three times, and the lower layer is subjected to silica gel column chromatography; the column is washed with acetone-water (8:1) and elution is carried out with acetone-water (3:1). Fractions containing the desired product are combined and concentrated, then subjected to chromatography on a column of highporous polymer (MCI GEL CHP20P, Mitsubishi Chemical Industries, Ltd.); the column is washed with water, and elution is carried out with 10 % ethanol. Fractions containing the desired product are concentrated and the concentrate is subjected to chromatography on a Sephadex (LH-20, Pharmacia) column using water as the developing solvent and eluent. Lyophilization of fractions containing the desired product gives the above-identified compound. Elemental analysis for C₂₁H₁₉N₇O₅S₂ . 4H₂O: Calcd. (%): C, 43.07; H, 4.65; N, 16.74 o Found (%): C, 43.26; H, 4.36; N, 16.61 o 1770, 1680, 1615, 1520, 1450 o NMR spectrum (D₂O+CD₃COCD₃)δ: 3.05&3.43, 3.11&3.48(total 2 H, each ABq, J=18Hz), 5.03, 5.07(total 1H, each d, J=5Hz), 5.28(2H, bs), 5.44(1H, s), 5.56, 5.66(total 1H, each d, J=5Hz), 6.62, 6.64(1H, each S), 7.3-7.6(1H,m), 7.8-8.3(4H,m), 8.68(1H,d,J=6Hz). Example 95 7β-[2-Acetamido-2-(2-aminothiazol-4-yl)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate In 20 ml of acetic acid is dissolved 500 mg of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate, and cooled to the inside temperature of 15°C, followed by addition of 3 ml of acetic anhydride. With vigorous stirring, 1 g of zinc powder is added little by little in the course of 30 minutes, maintaining the inside temperature in the range of 15 to 25° C. The mixture is stirred at room temperature for 1 hour and insoluble substance is filtered off. The filtrate is concentrated and the concentrate is subjected to chromatography on a column of highporous polymer (MCI GEL CHP20P), Mitsubishi Chemical Industries, Ltd.); the column is washed with water and elution is carried out with 10% ethanol. Fractions containing the desired product are concentrated and the concentrate is subjected to chromatography on a Sephadex (LH-20, Pharmacia) column using water as the eluent. The eluate is concentrated and lyophilized to give the above-identified compound. Elemental analysis for C₂₂H₂₁N₇O₅S₂ . 4H₂O: Calcd. (%) C, 44.07; H, 4.87; N, 16.35 o Found (%) C, 44.22; H, 4.69; N, 16.49 o 1760, 1660sh, 1605, 1520, 1440 o NMR spectrum (D₂O) δ: 2.08(3H,s), 3.16&3.52, 3.12&3.50 (total 2H, each Abq,J=18Hz), 5.10, 5.13- (total 1H, each d, J=5Hz), 5.30, 5.33 (total 2H, each br.s), 5.39(1H,s), 5.62, 5.71(total 1H, each d,J=5Hz), 6.68 6.70(1H,s), 7.3-7.7(1H,m), 7.8-8.3(4H,m), 8.69(1H,d,J=6Hz). Example 96 7β-tert-Butoxycarbonylamino-3-[(imidazo[1,2-a]-pyridinium-1-yl)-methyl]-3-cephem-4-carboxylate In a mixture of 50 ml of acetonitrile and 50 ml of water are dissolved 20 g of 7β-tert-butoxycarbonylamino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid, 20 g of imidazo[1,2-a]pyridine and 10 g of sodium iodide, and the solution is stirred at 70°C for 2 hours. Thereafter, 200 ml of ethyl acetate is added to the solution. The mixture is stirred and then allowed to stand. The upper layer is removed by decantation. To the lower layer is added 200 ml of ethyl acetate and the same procedure as above is repeated. The lower layer (aqueous layer) is subjected to chromatography using 150 g of silica gel; the column is washed with 1 liter of acetone and then with 1.8 liters of acetone-water (8:1), and then elution is carried out with acetonitrile-water (3:1). Fractions containing the desired product are concentrated and lyophilized to give 8.0 g (41 % Yield) of the above-identified compound. Elemental analysis for C₂₀H₂₂N₄O₅S . 2H₂O : Calcd. (%) C, 51.49; H, 5.62: N, 12.01 o Found (%) C, 51.60; H, 5.84; N, 12.10 o 1765, 1710, 1610, 1525, 1365 o NMR spectrum (d₆ - D M S O) : 1.38(9H.s), 3.03 & 3.44(2H, ABq, J=18Hz), 4.91(1H,d,J=5Hz), 5.31(1H,d,d,J=5Hz & 8Hz), 5.41(2H, br,s), 7.50(1H,t,J=6Hz), 7.77(1H,d,J=8Hz), 8.00(1H,t,J=7Hz), 8.3 - 8.7(3H,m), 9.00(1H,d,J=6Hz) o Example 97 7β-Amino-3-[( imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate trifluoroacetate Under ice-cooling, 2 g of 7β-tert-butoxycarbonylamino-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate is suspended in 20 ml of methylene chloride, and 20 ml of trifluoroacetic acid is added to the suspension. The mixture is stirred for 30 minutes. The solvent is then evaporated off under reduced pressure and, to the residue, 100 ml of ether is added and the mixture is stirred. The resulting precipitate is collected by filtration, washed with two 20-ml portions of ether and 20 ml of n-hexane and dried to give 1.15 g (60% yield) of the above-identified compound as a light-yellow powder. Elemental analysis for C₁₅H₁₄N₄O₃S·CF₃COOH·2H₂O: Calcd. (%): C, 38.14; H, 3.80; N, 11.12 o Found (%): C, 37.74; H, 3.60; N, 10.83 o 1780, 1675, 1525, 1380, 1200 o NMR spectrum (d₆-DMSO)δ: 3.37 & 3.62(2H,ABq,J=18Hz), 5.16(2H,br.s), 5.47(2H,br.s), 5.47(2H,br.s), 7.58(1H,t,J= 6Hz), 7.8-8.6(4H,m), 9.00(1H,d,J=7Hz) o Example 98 7β-[2-(2-Chloroacetamidothiazol-4-yl-3-oxido)-2(Z)-ethoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate To 50 ml of methylene chloride is added 3.08 g of 2-(chloroacetamidothiazol-4-yl-3-oxido)-2(Z)-ethoxyiminoacetic acid. To this, under ice-cooling, 2.08 g of phosphorus pentachloride is added and the mixture is stirred for 15 minutes. To the reaction mixture is added 150 ml of hexane, and the resulting mixture is stirred for 15 minutes further. Crystals separated are collected by filtration and washed with methylene chloride-hexane (1:3) to give the corresponding acid chloride as hydrochloride. Under ice-cooling, 4.0 g of 7β-amino-3-(3-imidazo[1,2-a]pyridinium-1-yl)methyl-3-cephem-4-carboxylate trifluoroacetate is suspended in 30 ml of dimethylformamide. To this suspension, 5.17 g of diisopropylethylamine and then the above acid chloride are added and the mixture is stirred for 30 minutes. To the mixture is added 200 ml of ether, and the resulting precipitate is collected by filtration and dissolved in a mixture of 20 ml of water and 2 g of sodium hydrogen carbonate. The solution is subjected to chromatography on a column of highporous polymer (MCI GEL CHP20P Mitsubishi Chemical Industries, Ltd.); the column is washed with water and elution is carried out 10% ethanol. Lyophilization of fractions containing the desired product gives 2.9 g (47% yield) of the above-identified compound. Elemental analysis for C₂₄H₂₂ClN₇O₇S₂·3H₂O: Calcd. (%): C, 42.76; H, 4.19; N, 14.55 o Found (%): C, 43.05; H, 4.39; N, 14.26 o 1770, 1610, 1525, 1470, 1380, 1350, 1310, 1270, 1200 o NMR spectrum (d₆-DMSO)δ: 1.25(3H,t,J=7Hz), 4.14(2H,q, J=7Hz),4.08 & 4.32(2H,ABq,J=18Hz), 5.00(1H,d,J=5Hz), 5.38(2H, br.s), 5.63(1H,d.d,J=5Hz & 8Hz), 7.18(1H,s), 7.50(1H,t,J=6Hz), 7.88(1H,t,J=7Hz), 8.2-8.7(3H,m), 8.99(1H,d,J=7Hz) o Example 99 7β-[2-(2-Aminothiazol-4-yl-3-oxido)-2(Z)-ethoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate In 20 ml of water are dissolved 2.7 g of 7β-[2-(2-chloroacetamidothiazol-4-yl-3-oxido)-2(Z)-ethoxyiminoacetamido-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate and 1.0 g of soidum N-methyldithiocarbamate, and the solution is stirred at room temperature for 2 hours. To the solution is added 20 ml of ethyl acetate and, after phase separation, the organic layer is discarded. The aqueous layer is washed with two 20-ml portions of ethyl acetate and subjected to chromatography on a column of MCI GEL CHP20P (Mitsubishi Chemical Industries, Ltd.); the column is washed with water, and elution is carried out with 10% ethanol. Fractions containing the desired product are concentrated and the concentrate is subjected to chromatography on a Sephadex (LH-20, Pharmacia) column using water as the developing solvent and eluent. Fractions containing the desired product are concentrated and lyophilized to give 830 mg (35% yield) of the above-identified compound. Elemental analysis for C₂₂H₂₁N₇O₆S₂·3H₂O: Calcd. (%) : C, 44.21; H, 4.55; N, 16.41 o Found (%) : C, 43.98; H, 4.29; N, 16.20 o 1760, 1610, 1525, 1440, 1380, 1350, 1270, 1200 o NMR spectrum (d₆-DMSO)δ: 1.22(3H,t,J=7Hz), 3.02 & 3.41 (2H,ABq,J=18Hz), 4.17(2H,q,J=7Hz), 4.96(1H,d,J=5Hz), 5.39 (2H,br.s), 5.60(1H,d.d,J=5Hz & 8Hz), 7.00(1H,s), 7.50(1H,t, J=6Hz), 8.00(1H,t,J=7Hz), 8.3-8.7(3H,m), 8.97(1H,d,J=7 Hz), 11.63(1H,d,J=8Hz) o NMR(D₂O)δ: 1.35(t,3H,J=7Hz), 3.20 & 3.55(2H,ABq,J=18Hz), 4.33(2H,q,J=7Hz), 5.20(1H,d,J=5Hz), 5.26 & 5.44(2H,ABq,J= 14Hz), 5.85(1H,d,J=5Hz), 7.12(1H,s), 7.42-7.62(1H,m), 7.85-8.20(3H,m), 8.73(1H,d,J=7Hz) o Example 100 7β-Amino-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate 7β-Amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid and imidazo[1,2-a]pyridine, are reacted in a manner similar to that in Example 42 to give the above-identified compound. 1760, 1610, 1535 o NMR spectrum (d₆-DMSO-DCl)δ: 3.35 & 3.64(2H,ABq,J= 18Hz), 4.94-5.55(4H,m), 7.42-7.67(1H,m), 7.80-8.50(4H,m), 8.85-9.05(1H,m) o Example 101 7β-Formamido-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate 7β-Formamido-3-(3-oxobutyryloxy)methyl-3-cephem-4-carboxylic acid and imidazo[1,2-a]pyridine, are reacted in a manner similar to that in Example 42 to give the above-identified compound. Elemental analysis for C₁₆H₁₄N₄O₄S·2H₂O: Calcd. (%): C, 48.73; H, 4.60; N, 14.21 o Found (%): C, 47.02; H, 4.63; N, 13.85 o 1770, 1670, 1600, 1520 o NMR spectrum (d₆-DMSO)δ: 3.01 & 3.46(2H,ABq,J=18Hz), 4.96(1H,d,J=5Hz), 5.30 & 5.48(2H,ABq,J=15Hz), 5.60(1H,d.d, J=5Hz & 8Hz), 7.4-7.66(1H,m), 7.84-8.20(2H,m), 8.34-8.80 (3H,m), 8.85-9.20(2H,m) o Example 102 7β-[2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate A mixture of 3.0 g of 7β-[2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid, 3.0 g of imidazo[1,2-a]pyridine and 3.0 g of sodium iodide in 20 ml of 50% aqueous acetonitrile is stirred at 70°C for 90 minutes. After being cooled to room temperature, the reaction mixture is chromatographed on a silica gel (50 g) column. The column is washed with 0.2 ℓ of acetone and then with 1 ℓ of acetone:water=20:1. And the product is then eluted with acetone:water=3:1. Fractions containing the objective product are concentrated and subjected to chromatography on a column of Sephadex® LH-20 (Pharmacia Inc., Sweden) with water as eluent. Fractions containing the objective product are concentrated and the residue is lyophilized to give the above-identified compound. Elemental analysis for C₂₆H₂₅ClN₇O₇S₂·2H₂O: Calcd.(%): C, 47.96; H, 4.50; N, 15.06. Found (%): C, 47.70; H, 4.88; N, 14.77. 1760, 1670, 1610, 1530, 1440, 1370, 1310. NMR spectrum (d₆-DMSO)δ: 1.38(9H, s), 2.90(1H, ABq x ¹/2, J=18Hz), 4.48(2H, s), 4.97(1H, d, J=5Hz), 5.25 and 5.49(2H, ABq, J=14Hz), 5.58(1H, d.d, J=5Hz and 8Hz), 7.34(2H, br.s), 7.52(1H, t, J=8Hz), 8.00(1H, t, J=8Hz), 8.40(1H, br.s), 8.52(1H, br.s), 8.70(1H, d, J=9Hz), 8.94(1H, d, J=6Hz), 9.27(1H, d, J=8Hz). Example 103 7β-[2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-(carboxymethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate monosodium salt To 10 ml of trifluoroacetic acid is added 0.28 g of 7β-[2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate and the mixture is stirred at room temperature for 1 hour. The reaction mixture is concentrated and the residue is dissolved in a mixture of 2 g of sodium bicarbonate in 15 ml of water and then subjected to column chromatography on a column of MCI GEL CHP20P (150-300 mesh; Mitsubishi Chemical Industries, Ltd., Japan). The column is washed with 0.8 ℓ of water and the product is then eluted with 7.5% ethanol in water. Fractions containing the objective compound are concentrated and the residue is lyophilized to give the above-identified compound. Elemental analysis for C₂₂H₁₇ClN₇NaO₇S₂·3H₂O: Calcd. (%): C, 39.55; H, 3.47; N, 14.68. Found (%): C, 39.26; H, 3.70; N, 14.39. 1760, 1610, 1530, 1400, 1360, 1310. NMR spectrum (d₆-DMSO)δ: 3.02(1H, ABq x ¹/2, J=18Hz), 4.22 (2H, br.s), 4.97(1H, d, J=5Hz), 5.38(2H, br.s), 5.64(1H, d.d, J=5Hz,and 8Hz), 7.35(2H, br.s), 7.49(1H, t, J=7Hz), 7.98(1H, t, J=8Hz), 8.3-8.7(3H, m), 8.96 (1H, d, J=8Hz), 11.85(1H, d, J=8Hz). Example 104 7β-[2-(2-Amino-5-bromothiazol-4-yl)-2(Z)-(carboxymethoxyimino)acetamido]-3-[(imidozo[1,2-a]pyridinium-1-yl)methyl]- 3-cephem-4-carboxylate monosodium salt i) 7β-[2-(2-Amino-5-bromothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid and imidazo[1,2-a]pyridine are reacted in a manner similar to that in Reference Example 40 to give 7β-[2-(2-amino-5-bromothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate. TLC(acetonitrile:water=6:1, Silica gel Art. 5715, Merck) Rf 0.15 ii) 7β-[2-(2-amino-5-bromothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate obtained in i) is treated in a manner similar to that in Example 108 to give the above-identified compound. Elemental analysis for C₂₂H₁₇BrN₇NaO₇S₂·2H₂O: Calcd.(%): C, 38.05; H, 3.05; N, 14.12. Found (%): C, 37.88; H, 3.31; N, 14.00. 1760, 1605, 1530, 1400, 1360, 1310. NMR spectrum (D₂O)δ: 3.06 and 3.55(2H, ABq, J=18Hz), 5.22 (1H, d, J=5Hz), 5.34(2H, br.s), 5.87(1H, d, J=5Hz), 7.49(1H, t, J=6Hz), 8.05(3H, br.s), 8.14(1H, br.s), 8.69(1H, d, J=6Hz). Example 105 7β-[2-(2-Amino-5-bromothiazol-4-yl)-2(Z)-(carboxymethoxyimino)acetamido]-3-[(6-chloroimidazo[1,2-a]pyridinium-1-yl)-methyl]-3-cephem-4-carboxylate monosodium salt i) 7β-[2-(2-Amino-5-bromothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylate and 6-chloroimidazo[1,2-a]pyridine are reacted in a manner similar to that in Reference Example 40 to give 7β-[2-(2-amino-5-bromothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetamido]-3-[(6-chloroimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate. TLC(acetonitrile:water=6:1, Silica gel Art. 5715, Merck) Rf 0.19 ii) 7β-[2-(2-Amino-5-bromothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetamido]-3-[(6-chloroimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate obtained in i) is treated with trifluoroacetic acid in a manner similar to that in Example 108 to give the above-identified compound. Elemental analysis for C₂₂H₁₆BrClN₇NaO₇S₂·2H₂O: Calcd.(%): C, 36.25; H, 2.77; N, 13.45. Found (%): C, 36.01; H, 2.99; N, 13.16. 1760, 1610, 1520, 1400, 1360, 1320. NMR spectrum (d₆-DMSO)δ: 3.02 and 3.39(2H, ABq, J=18Hz), 4.22(2H, br.s). 4.96(1H, d, J=5Hz), 5.37(2H, br.s), 5.64(1H, d.d, J=5Hz and 8Hz), 7.37(2H, br.s), 8.07(1H, d, J=9Hz), 8.36(1H, br.s), 8.52(1H, br.s), 8.64(1H,d, J=10Hz), 9.31(1H, br.s), 11.85(1H, d, J=8Hz). Example 106 7β-[2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-(carboxymethoxyimino)acetamido]-3-[(6-chloroimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate monosodium salt i) Two grams of 7β-[2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-(tert-butoxycarbonylmethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid is dissolved in 20 ml of trifluoroacetic acid. The solution is stirred at room temperature for 1 hour and then evaporated to dryness under reduced pressure to give crude 7β-[2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-(carboxymethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid. TLC(acetonitrile:water=4:1, Silica gel Art. 5715, Merck) Rf 0.62 ii) The whole amount of 7β-[2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-(carboxymethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid, 2.5 g of 6-chloroimidazo[1,2-a]pyridine and 2 g of sodium iodide are mixed in 20 ml of 50% acetonitrile in water and the mixture is heated at 70°C for 90 minutes with stirring, and then cooled to room temperature. Two grams of sodium bicarbonate is added to the reaction mixture and the mixture is chromatographed on a column of silica gel (50 g). The column is washed with 0.3 ℓ of acetone and then with 0.5 ℓ of acetone:water=8:1 and the product is then eluted with acetone:water=5:2. Fractions containing the objective compound are concentrated and the residue is placed on a column of Sephadex® LH-20 (Pharmacia Inc., Sweden) and eluted with water. Fractions containing the objective compound are lyophilized to give the above-identified compound. Elemental analysis for C₂₂H₁₆Cl₂N₇NaO₇S₂.2H₂O Calcd.(%): C, 38.60; H, 2.95; N, 14.33. Found (%): C, 38.40; H, 2.99; N, 14.06. 1770, 1680, 1620, 1520, 1440, 1320. NMR spectrum (d₆-DMSO)δ: 2.04 and 3.40(2H, ABq, J=18Hz), 4.25(2H, br.s), 4.97(1H, d, J=5Hz), 5.40(2H, br.s), 5.66(1H, d.d, J=5Hz and 8Hz), 7.31(2H, br.s), 8.05(1H, d, J=6Hz), 8.40(1H, d, J=3Hz), 8.58(1H, d, J=7Hz), 9.28(1H, br.s), 9.77(1H, d, J=6Hz). Example 107 7β-[2-(2-Amino-5-bromothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate To a solution of 0.40 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate in 4 ml of dimethylformamide, 0.28 g of N-bromosuccinimide is added under ice-cooling and the mixture is stirred at the same temperature for 2 hours. The reaction mixture is stirred with 100 ml of diethyl ether and the upper layer is removed by decantation. To the residue is added 50 ml of diethyl ether. Insoluble substance is collected by filtration, redissolved in a mixture of 2 ml of water and 2 ml of acetonitrile and placed on a silica gel (50 g) column. The column is washed with 200 ml of acetone and 500 ml of a mixture of acetone:water=20:1, successively, and then the product is eluted with acetone:water=3:1. Fractions containnig the objective compound are concentrated and the residue is chromatographed on a column of Sephadex LH-20 (Pharmacia Inc.) with water. The eluent is lyophilized to give the above-identified compound. Elemental analysis for C₂₁H₁₈BrN₇O₅S₂·H₂O: Calcd.(%): C, 41.32; H, 3.30; N, 16.06. Found (%): C, 41.32; H, 3.45; N, 15.79. 1765, 1610, 1530, 1450, 1380, 1350, 1310. NMR spectrum (d₆-DMSO)δ: 2.98 and 3.43(2H, ABq, J=18Hz), 3.80(3H, s), 4.98(1H, d, J=5Hz), 5.27 and 5.48(2H, ABq, J=14Hz), 5.60(1H, d.d, J=5Hz and 8Hz), 7.36(2H, br.s), 7.51(1H, t, J=7Hz), 8.00(1H, t, J=8Hz), 8.40 (1H, br.s), 8.49(1H, br.s), 8.66(1H, d, J=9Hz), 8.94(1H, d, J=6Hz), 9.42(1H, d, J=8Hz). Example 108 7β-[2-(2-Amino-5-iodothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate In 4 ml of dimethylformamide, is dissolved 0.40 g of 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate. To this, 0.45 g of N-iodosuccinimide is added and the mixture is stirred at room temperature for 1 hour. The reaction mixture is then processed in a manner similar to that in Example 113 to give the above-identified compound. Elemental analysis for C₂₁H₁₈IN₇O₅S₂·H₂O: Calcd.(%): C, 38.36; H, 3.07; N, 14.91. Found (%): C, 38.18; H, 3.31; N, 14.70. 1760, 1670, 1610, 1530, 1380, 1360, 1310. NMR spectrum (d₆-DMSO)δ: 2.96 and 3.36(2H, ABq, J=18Hz), 3.82(3H, s), 4.96(1H, d, J=5Hz), 5.26 and 5.47(2H, ABq, J=14Hz), 5.58(1H, d.d, J=5Hz and 8Hz), 7.32(2H, br.s), 7.50(1H, t, J=7Hz), 8.01(1H, t, J=8Hz), 8.39 (1H, br.s), 8.50(1H, br.s), 8.67(1H, d, J=9Hz), 8.93(1H, d, J=6Hz), 9.36(1H, d, J=8Hz). Example 109 2-(2-Chloroacetamido-5-bromothiazol-4-yl)-2(Z)-methoxyiminoacetic acid and 7β-amino-3-(imidazo[1,2-a]-pyridinium-1-yl)methyl-3-cephem-4-carboxylate difluoroacetate are reacted in a manner similar to that in Example 98 and the product obtained is then made to react with sodium N-methyldithiocarbamate in a manner similar to that in Example 99 to give a compound, which shows IR and NMR spectra identical with those of the compound obtained in Example 113. Example 110 2-(2-Chloroacetamido-5-iodothiazol-4-yl)-2(Z)-methoxyiminoacetic acid and 7β-amino-3-(imidazo[1,2-a]pyridinium-1-yl)methyl-3-cephem-4-carboxylate difluoroacetate are reacted in a manner similar to that in Example 98 and the product obtained is then made to react with sodium N-methyldithiocarbamate in a manner similar to that in Example 99 to give a compound, which shows IR and NMR spectra identical with those of the compound obtained in Example 108. Example 111 7β-[2-(2-Chloroacetamidothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate 2-(2-Chloroacetamidothiazol-4-yl)-2(Z)-methoxyiminoacetic acid and 7β-amino-3-(imidazo[1,2-a]pyridinium-1-yl)methyl-3-cephem-4-carboxylate difluoroacetate are reacted in a manner similar to that in Example 98 to give the above-identified compound. Elemental analysis for C₂₃H₂₀ClN₇O₆S₂·2H₂O: Calcd.(%): C, 44.13; H, 3.86; N, 15.66. Found (%): C, 44.00; H, 3.59; N, 15.39. 1760, 1680, 1620, 1530, 1440, 1360. NMR spectrum (D₆-DMSO)δ: 2.99(1H, ABq x ¹/2, J=18Hz), 3.94(3H, s), 4.38(2H, s), 5.02(1H, d, J=5Hz), 5.24 and 5.49(2H, ABq, J=14Hz), 5.60(1H, d.d, J=5Hz and 8Hz), 7.38(1H, s), 7.51(1H, t, J=7Hz), 8.00(1H, t, J=8Hz), 8.3-8.6(2H, m), 8.66(1H, d, J=9Hz), 8.94(1H, d, J=7Hz), 9.56(1H, d, J=8Hz). Example 112 7β-[2-(2-Chloroacetamidothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate is made to react with sodium N-methyldithiocarbamate in a manner similar to that in Example 99 to give 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate, which is found to be identical with that obtained in Example 1. Example 113 7β-tert-Butoxycarbonylamino-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate Two grams of 7β-tert-butoxycarbonylamino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid and 1.0 g of 6-cyanoimidazo[1,2-a]pyridine are reacted in a manner similar to that in Example 96 to give the above-identified compound. Elemental analysis for C₂₁H₂₁N₅O₅S.2H₂O: Calcd.(%): C, 51.32; H, 5.13; N, 14.25. Found (%): C, 51.09; H, 5.01; N, 13.95. 2230, 1760, 1710, 1640, 1610, 1530, 1390, 1365. NMR spectrum (d₆-DMSO)δ: 1.38(9H, s), 2.94 and 3.44(2H, ABq, J=18Hz), 4.90(1H, d, J=5Hz), 5.28 and 5.51 (2H, ABq, J=14Hz), 5.36(1H, d.d, J=5Hz and 8Hz), 7.71(1H, d, J=8Hz), 8.32(1H, d, J=10Hz), 8.50(1H, br.s), 8.69(1H, br.s), 8.88(1H, d, J=10Hz), 9.77(1H, s). Example 114 7β-Amino-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate ditrifluoroacetate In a manner similar to that in Example 97, 0.30 g of 7β-tert-butoxycarbonylamino-3-[(6-cyanoimidazo[1,2-a]-pyridinium-1-yl)methyl]-3-cephem-4-carboxylate is made to react with 5 ml of trifluoroacetic acid to give the above-identified compound. 2230, 1780, 1680, 1645, 1530, 1390. NMR spectrum (d₆-DMSO)δ: 3.28 and 3.56(2H, ABq, J=18Hz), 4.2-5.2(2H, br.), 5.02(1H, d, J=5Hz), 5.10(1H, d, J=5Hz), 5.47(1H, br.s), 8.26-8.60(4H, m), 9.76(1H, s). Example 115 7β-[2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(8-fluoroimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate The compound obtained in Reference Example 29 and 8-fluoroimidazo[1,2-a]pyridine are reacted in a manner similar to that in Example 42 to give the above-identified compound. NMR spectrum (D₂O)δ: 3.30 and 3.60(2H, ABq, J=18Hz), 4.00(3H, s), 5.22(1H, d, J=4.5Hz), 5.31 and 5.67 (2H, ABq, J=15Hz), 5.85(1H, d, J=4.5Hz), 7.32-8.68 (5H, m). Example 116 7β-[2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,5-a]pyridinium-2-yl)methyl]-3-cephem-4-carboxylate The compound obtained in Reference Example 29 and imidazo[1,5-a]pyridine are reacted in a manner similar to that in Example 42 to give the above-identified compound. Elemental analysys for C₂₁H₁₈ClN₇O₅S₂.5/2H₂O: Calcd.(%): C, 42.53; H, 3.91; N, 16.53. Found (%): C, 42.33; H, 3.16; N, 16.82. 3375, 3100, 1768, 1665, 1610, 1535, 1018. NMR spectrum (d₆-DMSO)δ: 3.21(1H, ABqx¹/2, J=17Hz), 3.79 (3H, s), 5.00(1H, d, J=5Hz), 5.10 and 5.53(2H, ABq, J=13Hz), 5.62(1H, d.d, J=4.2Hz and 8.1Hz), 7.00-8.77 (4H, m), 7.35(2H, br.s), 9.42(1H, d, J=8.5Hz), 10.00 (1H, br.s). Example 117 7β-[2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate i) Starting from 2-(5-chloro-2-chloroacetamidothiazol-4-yl)-2(Z)-ethoxyiminoacetic acid, 7β-[2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-(3-oxobutyryloxymethyl-3-cephem-4-carboxylic acid is obtained by a manner similar to that of Reference Example 29. 3300, 1770, 1700, 1620, 1530 NMR spectrum (d₆-DMSO)δ: 1.27(3H, t, J=7Hz), 2.20(3H, s), 3.3-3.8(2H, m), 3.62(2H, s), 4.17(2H, q, J=7Hz), 4.83 and 5.09(2H, ABq, J=12Hz), 5.13(1H, d, J=5Hz), 5.81(1H, d.d, J=5Hz and 8Hz), 6.63(1H, Br.S), 7.24(2H, br. s), 9.50(1H, d. J=8Hz). ii) 7β-[2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid and imidazo[1,2-a]pyridine are reacted in a manner similar to that in Example 42 to give the above-identified compound. Elemental analysis for C₂₂H₂₀ClN₇O₅S₂.2H₂O: Calcd.(%): C, 44.18; H, 4.04; N, 16.39. Found (%): C, 44.04; H, 3.87; N, 16.13. 3400, 1765, 1605, 1520. NMR spectrum (d₆-DMSO)δ: 1.20(3H, t, J=7Hz), 3.00 and 3.43(2H, ABq, J=17Hz), 4.08(2H, q, J=7Hz), 4.99(1H, d, J=5Hz), 5.2-5.6(2H, m), 5.62(1H, d.d, J=5Hz and 8Hz), 7.34(2H, br.s), 7.4-7.6(1H, m), 7.9-8.1(1H, m), 8.4-8.8(3H, m), 8.8-9.0(1H, m), 9.40(1H, d, J=8Hz). Example 118 7β-[2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-(2-chloroethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate i) 2-(2-Chloroacetamidothiazol-4-yl)-2(Z)-(2-chloroethoxyimino)acetic acid and N-chlorosuccinimide are reacted in a manner similar to that in Reference Example 37 to give 2-(2-chloroacetamido-5-chlorothiazol-4-yl)-2(Z)-(2-chloroethoxyimino)acetic acid. 1720, 1650, 1530. ii) 2-(2-Chloroacetamido-5-chlorothiazol-4-yl)-2(Z)-(2-chloroethoxyimino)acetic acid obtained in i) is made to react with 7β-amino-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid in a manner similar to that in Reference Example 29 to give 7β-[2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-(2-chloroethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid. 3300, 1765, 1700, 1615, 1525. iii) 7β-[2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-(2-chloroethoxyimino)acetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid and imidazo[1,2-a]pyridine are reacted in a manner similar to that in Example 42 to give the above-identified compound. Elemental analysis for C₂₃H₁₉Cl₂N₈O₅S₂·3H₂O: Calcd.(%): C, 43.09; H, 3.93; N, 17.48. Found (%): C, 42.89; H, 3.69; N, 17.21. 3400, 1760, 1610, 1520. NMR spectrum (d₆-DMSO)δ: 3.00 and 3.46(2H, ABq, J=18Hz), 3.6-3.9(2H, m), 4.1-4.4(2H, m), 5.00(1H, d, J=5Hz), 5.12 and 5.27(2H, ABq, J=13Hz), 5.60(1H, d.d, J=5Hz and 8Hz), 7.25(2H, br.s), 7.4-7.6(1H, m), 7.9-8.1(1H, m), 8.3-8.7(3H, m), 8.8-9.0(1H, m), 9.38(1H, d, J=8Hz). Example 119 7β-[2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate The compound obtained in Example 117 and 6-cyanoimidazo[1,2-a]pyridine are reacted in a manner similar to that is Example 42 to give the above-identified compound. Elemental analysis for C₂₃H₁₉ClN₈O₅S₂·3H₂O: Calcd.(%): C, 43.09; H, 3.93; N, 17.48. Found (%): C, 43.19; H, 3.69; N, 17.39. 3350, 2250, 1760, 1610, 1520. NMR spectrum (d₆-DMSO)δ: 1.20(3H, t, J=7Hz), 2.99 and 3.46(2H, ABq, J=18Hz), 4.07(2H, q, J=7Hz), 5.00 (1H, d, J=5Hz), 5.30 and 5.53(2H, ABq, J=15Hz), 5.64(1H, d.d, J=5Hz and 8Hz), 7.33(2H, br.s), 8.2-9.0 (4H, m), 9.41(1H, d, J=8Hz), 9.78(1H, br.s). Example 120 7β-[2-(2-Amino-5-chlorothiazol-4-yl)-2(Z)-(1-carboxy-1-methylethoxyimino)acetamido]-3-[(6-cyanoimidazo[1,2-a]-pyridinium-1-yl)methyl]-3-cephem-4-carboxylate monosodium salt The compound obtained in Reference Example 39 and 6-cyanoimidazo[1,2-a]pyridine are reacted in a manner similar to that in Example 84 to give the above-identified compound. Elemental analysis for C₂₅H₂₀ClN₈O₇S₂·7/2H₂O: Calcd.(%): C, 40.99; H, 3.71; N, 15.29. Found (%): C, 41.09; H, 3.62; N, 15.12. 2250, 1760, 1600, 1520, 1400. NMR spectrum (d₆-DMSO)δ: 1.21(6H, br.s), 2.05 and 2.45 (2H, ABq, J=18Hz), 4.98(1H, d, J=5Hz), 5.2-5.7 (2H, m), 5.73(1H, d.d, J=5Hz and 9Hz), 7.30(2H, br.s), 8.2-8.9(4H, m), 9.87(1H, br.s), 11.45(1H, d, J=9Hz). Example 121 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(5-amino-3-carboxy-2-methylimidazo[1,2-a]pyridinium-1-yl)-methyl]-3-cephem-4-carboxylate 7β-[2-(2-Aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-(3-oxobutyryloxymethyl)-3-cephem-4-carboxylic acid and 5-amino-3-carboxy-2-methylimidazo[1,2-a]pyridine are made to react in a manner similar to that in Example 42 to give the above-identified compound. 1760, 1670, 1610, 1530. NMR spectrum (d₆-DMSO-D₂O)δ: 2.34(3H, s), 3.09 and 3.46 (2H, ABq, J=18Hz), 3.80(3H, s), 5.01(1H, d, J=4.5Hz), 5.14-5.70(3H, m), 6.73(1H, s), 7.98-8.4(2H, m), 8.5-8.72(1H, m).

Claims: Claims for the following Contracting States : BE, CH, DE, FR, GB, IT, LI, LU, NL, SE A compound of the formula: wherein R o stands for (i) hydrogen atom, (ii) nitrogen-containing 5-8 membered heterocyclic group containing 1-4 hetero atoms selected from nitrogen atom optionally oxidized, oxygen atom and sulfur atom or 3H-indol-2-yl, 3H-indol-3-yl, benzopyranyl, quinolyl, pyrido[2,3-d]pyrimidyl, 1,5-, 1,6-, 1,7-, 1,8-, 2,6- or 2,7-naphthylidyl, thieno[2,3-d]-pyridyl, pyrimidopyrimidyl, pyrazinoquinolyl, or benzopyranyl that is unsubstituted or substituted by one to three of C₁₋₆ alkyl group, C₃₋₁₀ cycloalkyl group, C₆₋₁₀ aryl group, C₇₋₁₂ aralkyl group, hydroxyl group, C₁₋₆ alkoxy group, mercapto group, C₁₋₆ alkylthio group, amino group, mono-C₁₋₆ alkylamino group, di-C₁₋₆ alkylamino group, halogen atom, nitro group, azido group, cyano group, carboxyl group, C₁₋₁₀ alkoxycarbonyl group, C₁₋₆ alkanoyl group, C₁₋₆ alkanoyloxy group, carbamoyl group, mono-C₁₋₆ alkylcarbamoyl group, di-C₁₋₆ alkylcarbamoyl group, carbamoyl group, mono-C₁₋₆ alkylcarbamoyl-oxy group or di-C₁₋₆ alkylcarbamoyloxy group iii) a group of the formula wherein R¹ stands for an amino group or a protected amino group, R² stands for hydrogen atom, halogen atom, or nitro group n is 0 or 1, and R³ stands for hydrogen atom or C₁₋₆ alkyl group, C₂₋₆ alkenyl group, C₂₋₆ alkynyl group, C₃₋₁₀ cycloalkyl group or C₅₋₆ cycloalkenyl group that is unsubstituted or substituted by one or two of hydroxyl, C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₃₋₁₀ cycloalkyl, C₅₋₆ cycloalkenyl, C₆₋₁₀ aryl, C₇₋₁₉ aralkyl, 2- or 3-pyrrolyl, 3-, 4- or 5-pyrazolyl, 2-, 4- or 5-imidazolyl, 1,2,3- or 1,2,4-triazolyl, 1H- or 2H-tetrazolyl, 2- or 3-furyl, 2- or 3-thienyl, 2-, 4- or 5-oxazolyl, 3-, 4- or 5-isoxazolyl, 1,2,3-oxadiazol or 5-yl, 1,2,4-oxadiazol-3- or 5-yl, 1,2,5- or 1,3,4-oxadiazolyl, 2- 4- or 5-thiazolyl, 3-, 4- or 5-isothiazolyl, 1,2,3-thiazidazol-4- or 5-yl, 1,2,4-thiadiazol-3- or 5-yl, 1,2,5- or 1,3,4-thiadiadazolyl, 2- or 3-pyrrolidinyl, 2-, 3- or 4-pyridyl, 2-, 3- or 4-pyridyl-N-oxide, 3- or 4-pyridazinyl, 3- or 4-pyridazinyl-N-oxide, 2-, 4- or 5-pyrimidinyl, 2-, 4- or 5-pyrimidinyl-N-oxide, pyrazinyl, 2-, 3- or 4-piperidinyl, piperazinyl, 3H-indol-2- or 3-yl, 2-, 3- 4-pyranyl, 2-, 3- or 4-thiopyranyl, benzopyranyl, quinolyl, pyrido[2,3-d]pyrimidyl, 1,5-, 1,6-, 1,7-, 1,8-, 2,6- or 2,7-naphthylidyl, thieno[2,3-d]-pyridyl, pyrimidopyrimidyl, pyrazinoquinolyl, benzopyranyl, C₁₋₆ alkoxy, C₃₋₁₀ cycloalkyloxy, C₆₋₁₀ aryloxy, C₇₋₁₉ aralkyloxy, thiazolyloxy, mercapto, C₁₋₆ alkylthio, C₃₋₁₀ cycloalkylthio, C₆₋₁₀ arylthio, C₇₋₁₉ aralkylthio, thiazolylthio, amino, mono-C₁₋₆ alkylamino, di-C₁₋₆ alkylamino, tri-C₁₋₆ alkylammonium, C₃₋₁₀ cycloalkylamino, C₆₋₁₀ arylamino, C₇₋₁₉ aralkylamino, thiazolylamino, thiadiazolylamino, cyclic amino, azido, nitro, halogen, cyano, carboxyl, C₁₋₁₀ alkoxy-carbonyl, C₆₋₁₀ aryloxycarbonyl, C₇₋₁₉ aralkyloxy-carbonyl, benzoyl, naphthoyl, phthaloyl, phenylacetyl, C₁₋₆ alkanoyl, C₃₋₅ alkenoyl, benzoyloxy, naphthoyloxy, phenylacetoxy, C₂₋₆ alkanoyloxy, C₃₋₅ alkenoyloxy, carbamoyl, N-methylcarbamoyl, N,N-dimethylcarbamoyl, N-ethylcarbamoyl, N,N-diethylcarbamoyl, N-phenylcarbamoyl, N-acetylcarbamoyl, N-benzoylcarbamoyl, N-(p-methoxy-phenyl)carbamoyl, pyrrolidinocarbonyl, piperidinocarbonyl, piperazinocarbonyl, morpholino-carbonyl, thiocarbamoyl, N-methylthiocarbamoyl, N-phenylthiocarbamoyl, carbamoyloxy, N-methylcarbamoyloxy, N,N-dimethylcarbamoyloxy, N-ethylcarbamoyloxy, N-phenylcarbamoyloxy, phthalimido, C₁₋₆ alkanoylamino, benzamido, naphthoylamido, phthalimido, carboxyamino, C₁₋₁₀ alkoxy-carboxamido, C₆₋₁₀ aryloxy-carboxamido or C₇₋₁₉ aralkyloxy-carboxamido; (iv) α-formamido-α-(2-aminothiazol-4-yl)acetyl or α-formacetamido-α(2-aminothiazol-4-yl)acetyl or (v) methoxy-carbonyl, ethoxycarbonyl, n-propoxycarbonyl, isopropoxy-carbonyl, n-butoxycarbonyl, tert-butoxycarbonyl, cyclohexyloxycarbonyl, norbornyloxycarbonyl, phenoxycarbonyl, naphthyloxycarbonyl, benzyloxycarbonyl, methoxymethyl-oxycarbonyl, acetylmethyloxycarbonyl, 2-trimethylsilyl-ethoxycarbonyl, 2-methanesulfonylethoxycarbonyl, 2,2,2-trichloroethoxycarbonyl, 2-cyanoethoxycarbonyl, p-methylphenoxycarbonyl, p-methoxyphenoxycarbonyl, p-chlorophenoxycarbonyl, p-methylbenzyloxycarbonyl, p-methoxybenzyloxycarbonyl, p-chlorobenzyloxycarbonyl, p-nitrobenzyloxycarbonyl, benzhydryloxycarbonyl, cyclopropyloxycarbonyl, cyclopentyloxycarbonyl, or cyclohexyloxycarbonyl; Z stands for S, S-O, O or CH₂; R⁴ stands for hydrogen atom, methoxy group or formamido group; R¹³ stands for hydrogen atom, methyl group, hydroxyl group or halogen atom, and A stands for an imidazol-1-yl group which forms a fused ring at the 2,3- or 3,4-position representable by the general formula [A¹] or [A²] wherein B stands for a group forming a 5- to 6-membered aromatic heterocyclic ring which may be fused with another aromatic ring or aromatic hetero-cyclic ring, R¹¹ stands for hydrogen atom or a substituent (or substituents) on the imidazole ring and R¹² stands for hydrogen atom or a substituent (or substituents) on the ring which may be fused with the imidazole ring wherein the heterocyclic ring is 5-8 membered ring containing 1-4 hetero atom selected from nitrogen atom optionally oxidized, oxygen atom and sulfur atom and R¹¹ and R¹² is respectively a substituent or substituents selected from a class consisting of hydroxyl group, hydroxy C₁₋₆ alkyl group, C₁₋₆ alkyl group, C₂₋₆ alkenyl group, C₂₋₆ alkynyl group, C₄₋₆ alkadienyl group, C₃₋₁₀ cycloalkyl group, C₅₋₆ cycloalkenyl group, C₃₋₁₀ cycloalkyl C₁₋₆ alkyl group, C₆₋₁₀ aryl group, C₇₋₁₂ aralkyl group, di-C₆₋₁₀ aryl-methyl group, tri-C₆₋₁₀ arylmethyl group, 2- or 3-pyrrolyl, 3-, 4- or 5-pyrazolyl, 2-, 4- or 5-imidazolyl, 1,2,3- or 1,2,4-triazolyl, 1H- or 2H-tetrazolyl, 2- or 3-furyl, 2- or 3-thienyl, 2-, 4- or 5-oxazolyl, 3-, 4- or 5-isoxazolyl, 1,2,3-oxadiazol-4- or 5-yl, 1,2,4-oxadiazol-3- or 5-yl, 1,2,5- or 1,3,4-oxadiazolyl, 2-, 4- or 5-thiazolyl, 3-, 4- or 5-isothiazolyl, 1,2,3-thiadiazol-4- or 5-yl, 1,2,4-thiadiazol-3- or 5-yl, 1,2,5- or 1,3,4-thiadiazolyl, 2- or 3-pyrrolidinyl, 2-, 3- or 4-pyridyl, 2-, 3-or 4-pyridyl-N-oxide 3- or 4-pyridazinyl, 3- or 4-pyridazinyl-N-oxide, 2-, 4- or 5-pyrimidinyl, 2-, 4- or 5-pyrimidinyl-N-oxide, pyrazinyl, 2-, 3- or 4-piperidinyl, piperazinyl, 3 H-indol-2- or 3-yl, 2,3- or 4-pyranyl, 2-, 3- or 4-thiopyranyl, benzopyranyl, quinolyl, pyrido[2,3-d]pyrimidyl, 1,5-, 1,6-, 1,7-, 1,8-, 2,6- or 2,7-naphthylidyl, thieno[2,3-d]-pyridyl, pyrimidopyrimidyl, pyrazinoquinolyl, benzopyranyl, C₁₋₆ alkoxy group, C₁₋₆ alkoxy C₁₋₆ alkyl group, C₃₋₁₀ cycloalkyloxy group, C₆₋₁₀aryloxy group, C₇₋₁₉ aralkyloxy group, mercapto group, mercapto C₁₋₆ alkyl group, sulfo group, sulfo C₁₋₆ alkyl group, C₁₋₆ alkylthio group, C₁₋₆ alkylthio C 1.6 alkyl group, C₃₋₁₀ cycloalkylthio group, C₆₋₁₀ arylthio group, C₇₋₁₉ aralkylthio group, amino group, amino C₁₋₆ alkyl group, mono-C₁₋₆ alkylamino group, di-C₁₋₆ alkylamino group, mono-C₁₋₆ alkylamino C₁₋₆ alkyl group, di-C₁₋₆ alkylamino C₁₋₆ alkyl group, C 3.10 cycloalkylamino group, C₆₋₁₀ arylamino group, C₇₋₁₉ aralkylamino group, cyclic amino group, cyclic amino C₁₋₆ alkyl group, cyclic amino C₁₋₆ alkylamino group, azido group, nitro group, halogen atom, halogeno C₁₋₆ alkyl group, cyano group, cyano C₁₋₆ alkyl group, carboxyl group, carboxy C₁₋₆ alkyl group, C₁₋₁₀ alkoxy-carbonyl group, C 1.19 alkoxy-carbonyl, C₁₋₆ alkyl group, C₆₋₁₀ aryloxycarbonyl group, C₇₋₁₉ aralkyloxycarbonyl group, benzoyl, naphthoyl, phthaloyl, phenylacetyl, C₁₋₆ alkanoyl group, C₂₋₆ alkanoyl C₁₋₆ alkyl group, C₃₋₅ alkenoyl group, benzoyloxy, naphthoyloxy, phenylacetoxy, C₂₋₆ alkanoyloxy group, C₂₋₆ alkanoyloxy, C₁₋₆ alkyl group, C₃₋₅ alkenoyloxy group, carbamoyl C₁₋₆ alkyl group, carbamoyl, N-methylcarbamoyl, N,N-dimethylcarbamoyl, N-ethylcarbamoyl, N,N-diethylcarbamoyl, N-phenylcarbamoyl, N-acetylcarbamoyl, N-benzoylcarbamoyl, N-(p-methoxyphenyl)carbamoyl, pyrrolidinocarbonyl, piperidinocarbonyl, piperazinocarbonyl, morpholinocarbonyl, thiocarbamoyl, N-methylthiocarbamoyl, N-phenylthiocarbamoyl, carbamoyloxy, N-methylcarbamoyloxy, N,N-dimethylcarbamoyloxy, N-ethylcarbamoyloxy, N-phenylcarbamoyloxy, carbamoyloxy C₁₋₆ alkyl group, C₁₋₆ alkanoylamino group, benzamido, naphthoylamido, phthalimido, sulfonamido group, carboxyamino group, C₁₋₁₀ alkoxycarboxamido group, C₆₋₁₀ aryloxy-carboxamido group, and C₇₋₁₉ aralkyloxycarboxamido group, or a physiologically or pharmaceutically acceptable salt or ester thereof. A compound according to claim 1, wherein R⁰ is a group of the formula: wherein R² and R³ are as defined in claim 1. A compound according to claim 2, wherein R³ is hydrogen atom or C₁₋₃ alkyl group that is unsubstituted or substituted by halogen atom, hydroxyl group, C₁₋₆ alkoxy group, carboxyl group, C₁₋₆ alkoxy-carbonyl group, or cyano group and the configuration of OR³ is syn. A compound according to claim 1, wherein the imidazol-1-yl group which forms a fused ring at the 2,3- or 3,4-position is a group of the formula. C compound according to claim 1, wherein the imidazol-1-yl group forming a fused ring at the 2,3- or 3,4-position is imidazol[1,2-a]pyridinium-1-yl or imidazo[1,5-a]pyridinium-2-yl group. A compound according to claim 1 wherein Z is S. A compound according to claim 1 wherein R⁴ is hydrogen atom. A compound according to claim 1 wherein R¹³ is hydrogen atom. A compound according to claim 1 selected from 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-(1-carboxy-1-methylethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-(2-fluoroethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-(2-chloroethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-(2-hydroxyethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(6-chloroimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(6-chloroimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-(1-carboxy-1-methylethoxyimino)acetamido]-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-(2-fluoroethoxyimino)acetamido]-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-(2-chloroethoxyimino)acetamido]-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-amino thiazol-4-yl)-2-(Z)-methoxyiminoacetamido]-3-[(3-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,5-a]pyridinium-2-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-carboxymethoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,5-a]pyridinium-2-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl-3-oxido)-2(Z)-ethoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2-formamidoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate. A method for producing a compound of the formula; with Z, R⁴, R¹³ and A as defined in claim 1, which comprises allowing a compound of the formula; wherein R⁵ stands for hydroxyl group, acyloxy group, carbamoyloxy group, substituted carbamoyloxy group or halogen atom and other symbols are of the same meaning as defined above or a salt or ester thereof to react with an optionally substituted imidazole forming a fused ring at the 2,3- or 3,4-position or a salt thereof. A method for producing a compound of the formula; wherein R a stands for nitrogen-containing heterocyclic group, Z, R⁴, R¹³ and A are as defined in claim 1, which comprises (1) allowing a compound of the formula; wherein the symbols are of the same meaning as defined above or a salt or ester thereof to react with a compound of the general formula R a Hal wherein R a stands for a nitrogen-containing heterocyclic group and Hal stands for a halogen atom or a salt thereof, or (2) allowing a compound of the formula; wherein R⁵ is as defined in claim 10, or a salt or ester thereof to react with an optionally substituted imidazole forming a fused ring at the 2,3- or 3,4-position or a salt thereof. A method for producing a compound of the formula; wherein R b stands for acyl group, with the proviso that the case where R b stands for a group of the formula: wherein R¹ is an amino group which may be protected, R³ is hydrogen atom or an optionally substituted hydrocarbon residue is excluded, Z, R⁴, R¹³ and A are defined as in claim 1, which comprises (1) allowing a compound of the formula; wherein the symbols are of the same meaning as defined above or a salt or ester thereof to react with carboxylic acid of the general formula R b OH wherein R b stands for acyl group or a salt or reactive derivative thereof, or (2) allowing a compound of the formula; wherein R⁵ is as defined in claim 10, or a salt or ester thereof to react with an optionally substituted imidazole forming a fused ring at the 2,3- or 3,4-position or a salt thereof. A method for producing a compound of the formula; wherein R 22' stands for an optionally substituted heterocyclic group, with the proviso that the case where R 22' stands for a group of the formula: wherein R¹ is an amino group which may be protected, is excluded, R 3'' stands for optionally substituted hydrocarbon residue, Z, R⁴, R¹³ and A are defined as in claim 1 which comprises allowing a compound of the formula; wherein the symbols are of the same meaning as defined above or a salt or ester thereof to react with a compound of the general formula R 3'' OH wherein R 3'' stands for optionally substituted hydrocarbon residue or a reactive derivative thereof. A method for producing a compound of the formula: wherein R¹ stands for optionally protected amino group, R² stands for hydrogen atom, halogen atom or nitro group, R³ stands for hydrogen atom or optionally substituted hydrocarbon residue, Z, R⁴, R¹³ and A are defined as in claim 1, which comprises allowing a compound of the formula; wherein X stands for halogen atom and other symbols are of the same meaning as defined above or a salt or ester thereof to react with a compound of the general formula R¹C(=S)NH₂ wherein R¹ stands for optionally protected amino group. A method for producing a compound of the formula; wherein R C stands for esterified carboxyl group, Z, R⁴, R¹³ and A are defined as in claim 1 which comprises (1) allowing a compound of the formula; wherein the symbols are of the same meaning as defined above or a salt or ester thereof to react with an oxycarbonylation reagent, or (2) allowing a compound of the formula; wherein R⁵ is defined as in claim 10, or a salt or ester thereof to react with an optionally substituted imidazole forming a fused ring at the 2,3- or 3,4-position or a salt thereof. A pharmaceutical composition containing at least one of the compounds of the formula; wherein R⁰ stands for hydrogen atom, nitrogen-containing heterocyclic group, acyl group or esterified carboxyl group, with the proviso that the case where R° stands for a group of the formula: wherein R¹ is an amino group which may be protected, R³ is hydrogen atom or an optionally substituted hydrocarbon residue is excluded, Z, R⁴, R¹³ and A are defined as in claim 1. Claims for the following Contracting State : AT A method for producing a compound of the formula: wherein R⁰ stands for (i) hydrogen atom, (ii) nitrogen-containing 5-8 membered heterocyclic group containing 1-4 hetero atoms selected from nitrogen atom optionally oxidized, oxygen atom and sulfur atom or 3H-indol-2-yl or 3H-indol-3-yl, benzo-pyranyl, quinolyl, pyrido[2,3-d]pyrimidyl, 1,5-, 1,6-, 1,7-, 1,8-, 2,6- or 2,7-naphthylidyl, thieno[2,3-d]-pyridyl, pyrimidopyrimidyl, pyrazinoquinolyl, or benzopyranyl that is unsubstituted or substituted by one to three of C₁₋₆ alkyl group, C₃₋₁₀ cycloalkyl group, C₆₋₁₀ aryl group, C₇₋₁₂ aralkyl group, hydroxyl group, C₁₋₆alkoxy group, mercapto group, C₁₋₆alkylthio group, amino group, mono-C₁₋₆ alkylamino group, di-C₁₋₆ alkylamino group, halogen atom, nitro group, azido group, cyano group, carboxyl group, C₁₋₁₀ alkoxycarbonyl group, C₁₋₆ alkanoyl group, C 1.6 alkanoyloxy group, carbamoyl group, mono-C₁₋₆ alkylcarbamoyl group, or di-C₁₋₆ alkylcarbamoyloxy group; iii) a group of the formula wherein R¹ stands for an amino group or a protected amino group, R² stands for hydrogen atom, halogen atom, or nitro group n is 0 or 1, and R³ stands for hydrogen atom or C₁₋₆ alkyl group, C₂₋₆ alkenyl group, C₂₋₆ alkynyl group, C₃₋₁₀ cycloalkyl group or C₅₋₆ cycloalkenyl group that is unsubstituted or substituted by one or two of hydroxyl, C₁₋₆ alkyl, C₂₋₆ alkenyl, C₂₋₆ alkynyl, C₃₋₁₀ cycloalkyl, C₅₋₆ cycloalkenyl, C₆₋₁₀ aryl, C₇₋₁₉ aralkyl, 2- or 3-pyrrolyl, 3-, 4- or 5-pyrazolyl, 2-, 4- or 5-imidazolyl, 1,2,3- or 1,2,4-triazolyl, 1H- or 2H-tetrazolyl, 2- or 3-furyl, 2- or 3-thienyl, 2-, 4- or 5-oxazolyl, 3-, 4- or 5-isoxazolyl, 1,2,3-oxadiazol or 5-yl, 1,2,4-oxadiazol-3- or 5-yl, 1,2,5- or 1,3,4-oxadiazolyl, 2- 4,- or 5-thiazolyl, 3-, 4- or 5-isothiazolyl, 1,2,3-thiazidazol-4- or 5-yl, 1,2,4-thiadiazol-3- or 5-yl, 1,2,5- or 1,3,4-thiadiazolyl, 2- or 3-pyrrolidinyl, 2-, 3-or 4-pyridyl, 2-, 3- or 4-pyridyl-N-oxide, 3- or 4-pyridazinyl, 3- or 4-pyrdazinyl-N-oxide, 2-, 4- or 5-pyrimidinyl, 2-, 4- or 5-pyrimidinyl-N-oxide, pyrazinyl, 2-, 3- or 4-piperidinyl, piperazinyl, 3H-indol-2- or 3-yl, 2-, 3- 4-pyranyl, 2-, 3- or 4-thiopyranyl, benzopyranyl, quinolyl, pyrido[2,3-d]pyrimidyl, 1,5-, 1,6-, 1,7-, 1,8-, 2,6- or 2,7-naphthylidyl, thieno[2,3-d]-pyridyl, pyrimidopyrimidyl, pyrazinoquinolyl, benzopyranyl, C₁₋₆ alxoxy, C₃₋₁₀ cycloalkyloxy, C₆₋₁₀ aryloxy, C₇₋₁₉ aralkyloxy, thiazolyloxy, mercapto, C₁₋₆ alkylthio, C₃₋₁₀ cycloalkylthio, C₆₋₁₀ arylthio, C₇₋₁₉ aralkylthio, thiazolylthio, amino, monoC₁₋₆ alkylamino, di-C₁₋₆ alkylamino, tri-C₁₋₆ alkylammonium, C₃₋₁₀ cycloalkylamino, C₆₋₁₀ arylamino, C₇₋₁₉ aralkylamino, thiazolylamino, thiadiazolylamino, cyclic amino, azido, nitro, halogen, cyano, carboxyl, C₁₋₁₀ alkoxy-carbonyl, C₆₋₁₀ aryloxy-carbonyl, C₇₋₁₉ aralkyloxy-carbonyl, benzoyl, naphthoyl, phthaloyl, phenylacetyl, C₁₋₆ alkanoyl, C₃₋₅ alkenoyl, benzoyloxy, naphthoyloxy, phenylacetoxy, C₂₋₆ alkanoyloxy, C₃₋₅ alkenoyloxy, carbamoyl, N-methylcarbamoyl, N,N-dimethylcarbamoyl, N-ethylcarbamoyl, N,N-diethylcarbamoyl, N-phenylcarbamoyl, N-acetylcarbamoyl, N-benzoylcarbamoyl, N-(p-methoxy-phenyl)carbamoyl, pyrrolidinocarbonyl, piperidinocarbonyl, piperazinocarbonyl, morpholino-carbonyl, thiocarbamoyl, N-methylthiocarbamoyl, N-phenylthiocarbamoyl, carbamoyloxy, N-methylcarbamoyloxy, N,N-dimethylcarbamoyloxy, N-ethylcarbamoyloxy, N-phenylcarbamoyloxy, phthalimido, C₁₋₆ alkanoylamino, benzamido, naphthoylamido, phthalimido, carboxyamino, C₁₋₁₀ alkoxy-carboxamido, C₆₋₁₀ aryloxy-carboxamido or C₇₋₁₉ aralkyloxy-carboxamido; (iv) α-formamido-α-(2-aminothiazol-4-yl)acetyl or α-formacetamido-α-(2-aminothiazol-4-yl)acetyl or (v) methoxy-carbonyl, ethoxycarbonyl, n-propoxycarbonyl, isopropoxy-carbonyl, n-butoxycarbonyl, tert-butoxycarbonyl, cyclohexyloxycarbonyl, norbornyloxycarbonyl, phenoxycarbonyl, naphthyloxycarbonyl, benzyloxycarbonyl, methoxymethyl-oxycarbonyl, acetylmethyloxycarbonyl, 2-trimethylsilyl-ethoxycarbonyl, 2-methanesulfonylethoxycarbonyl, 2,2,2-trichloroethoxycarbonyl, 2-cyanoethoxycarbonyl, p-methylphenoxycarbonyl, p-methoxyphenoxycarbonyl, p-chlorophenoxycarbonyl, p-methylbenzyloxycarbonyl, p-methoxybenzyloxycarbonyl, p-chlorobenzyloxycarbonyl, p-nitro-benzyloxycarbonyl, benzhydryloxycarbonyl, cyclopropyloxycarbonyl, cyclopentyloxycarbonyl, or cyclohexyloxycarbonyl; Z stands for S, S-O, O or CH₂; R⁴ stands for hydrogen atom, methoxy group or formamido group; R¹³ stands for hydrogen atom, methyl group, hydroxyl group or halogen atom, and A stands for an imidazol-1-yl group which forms a fused ring at the 2,3- or 3,4-position representable by the general formula [A¹] or [A²] wherein B stands for a group forming a 5- to 6-membered aromatic heterocyclic ring which may be fused with another aromatic ring or aromatic hetero-cyclic ring, R¹¹ stands for hydrogen atom or a substituent (or substituents) on the imidazole ring and R¹² stands for hydrogen atom or a substituent (or substituents) on the ring which may be fused with the imidazole ring wherein the heterocyclic ring is 5-8 membered ring containing 1-4 hetero atom selected from nitrogen atom optionally oxidized, oxygen atom and sulfur atom and R¹¹ and R¹² is respectively a substituent or substituents selected from a class consisting of hydroxyl group, hydroxy C₁₋₆ alkyl group, C₁₋₆ alkyl group, C₂₋₆ alkenyl group, C₂₋₆ alkynyl group, C₄₋₆ alkadienyl group, C₃₋₁₀ cycloalkyl group, C₅₋₆ cycloalkenyl group, C₃₋₁₀ cycloalkyl C₁₋₆ alkyl group, C₆₋₁₀ aryl group, C₇₋₁₂ aralkyl group, di-C₆₋₁₀ aryl-methyl group, tri-C₆₋₁₀ arylmethyl group, 2- or 3-pyrrolyl, 3-, 4- or 5-pyrazolyl, 2-, 4- or 5-imidazolyl, 1,2,3- or 1,2,4-triazolyl, 1H- or 2H-tetrazolyl, 2- or 3-furyl, 2- or 3-thienyl, 2-, 4- or 5-oxazolyl, 3-, 4- or 5-isoxazolyl, 1,2,3-oxadiazol-4- or 5-yl, 1,2,4-oxadiazol-3- or 5-yl, 1,2,5- or 1,3,4-oxadiazolyl, 2-, 4- or 5-thiazolyl, 3-, 4- or 5-isothiazolyl, 1,2,3-thiadiazol-4- or 5-yl, 1,2,4-thiadiazol-3- or 5-yl, 1,2,5- or 1,3,4-thiadiazolyl, 2- or 3-pyrrolidinyl, 2-, 3- or 4-pyridyl, 2-, 3- or 4-pyridyl-N-oxide, 3- or 4-pyridazinyl, 3- or 4-pyridazinyl-N-oxide, 2-, 4- or 5-pyrimidinyl, 2-, 4- or 5-pyrimidinyl-N-oxide, pyrazinyl, 2-, 3- or 4-piperidinyl, piperazinyl, 3 H-indol-2- or 3-yl, 2,3- or 4-pyranyl, 2-, 3- or 4-thiopyranyl, benopyranyl, quinolyl, pyrido[2,3-d]pyrimidyl, 1,5-, 1,6-, 1,7-, 1,8-, 2,6- or 2,7-naphthylidyl, thieno[2,3-d]-pyridyl, pyrimidopyrimidyl, pyrazinoquinolyl, benzopyranyl, C₁₋₆ alkoxy group, C₁₋₆ alkoxy C₁₋₆ alkyl group, C₃₋₁₀ cycloalkyloxy group, C₆₋₁₀aryloxy group, C₇₋₁₉ aralkyloxy group, mercapto group, mercapto C₁₋₆ alkyl group, sulfo group, sulfo C₁₋₆ alkyl group, C₁₋₆ alkylthio group, C₁₋₆ alkylthio C₁₋₆ alkyl group, C₃₋₁₀ cycloalkylthio group, C₆₋₁₀ arylthio group, C₇₋₁₉ aralkylthio group, amino group, amino C₁₋₆ alkyl group, mono-C₁₋₆ alkylamino group, di-C₁₋₆ alkylamino group, mono-C₁₋₆ alkylamino C₁₋₆ alkyl group, di-C₁₋₆ alkylamino C₁₋₆ alkyl group, C₃₋₁₀ cyloalkylamino group, C₆₋₁₀ arylamino group, C₇₋₁₉ aralkylamino group, cyclic amino group, cyclic amino C₁₋₆ alkyl group, cyclic amino C₁₋₆ alkylamino group, azido group, nitro group, halogen atom, halogeno C₁₋₆ alkyl group, cyano group, cyano C₁₋₆ alkyl group, carboxyl group, carboxy C₁₋₆ alkyl group, C₁₋₁₀ alkoxy-carbonyl group, C₁₋₁₀alkoxy-carbonyl C₁₋₆ alkyl group, C₆₋₁₀ aryloxycarbonyl group, C₇₋₁₉ aralkyloxycarbonyl group, benzoyl, naphthoyl, phthaloyl, phenylacetyl, C₁₋₆ alkanoyl group, C₂₋₆ alkanoyl C₁₋₆ alkyl group, C₃₋₅ alkenoyl group, benzoyloxy, naphthoyloxy, phenylacetoxy, C₂₋₆ alkanoyloxy group, C₂₋₆ alkanoyloxy, C₁₋₆ alkyl group, C₃₋₅ alkenoyloxy group, carbamoyl C₁₋₆ alkyl group, carbamoyl, N-methylcarbamoyl, N,N-dimethylcarbamoyl, N-ethylcarbamoyl, N,N-diethylcarbamoyl, N-phenylcarbamoyl, N-acetylcarbamoyl, N-benzoylcarbamoyl, N-(p-methoxyphenyl)carbamoyl, pyrrolidinocarbonyl, piperidinocarbonyl, piperazinocarbonyl, morpholinocarbonyl, thiocarbamoyl, N-methylthiocarbamoyl, N-phenylthiocarbamoyl, carbamoyloxy, N-methylcarbamoyloxy, N,N-dimethylcarbamoyloxy, N-ethylcarbamoyloxy, N-phenylcarbamoyloxy, carbamoyloxy C₁₋₆ alkyl group, C₁₋₆ alkanoylamino group, benzamido, naphthoylamido, phthalimido, sulfonamido group, carboxyamino group, C₁₋₁₀ alkoxycarboxamido group, C₆₋₁₀ aryloxy-carboxamido group, and C₇₋₁₉ aralkyloxycarboxamido group, or a physiologically or pharmaceutically acceptable salt or ester thereof, which comprises allowing a compound of the formula; wherein R⁵ stands for hydroxyl group, acyloxy group, carbamoyloxy group, substituted carbamoyloxy group or halogen atom and other symbols are of the same meaning as defined above or a salt or ester thereof to react with an optionally substituted imidazole forming a fused ring at the 2,3- or 3,4-position or a salt thereof. A process according to claim 1, wherein R⁰ is a group of the formula: wherein R² and R³ are as defined in claim 1. A process according to claim 2, wherein R³ is hydrogen atom or C₁₋₃ alkyl group that is unsubstituted or substituted by halogen atom, hydroxyl group, C₁₋₆ alkoxy group, carboxyl group, C₁₋₆ alkoxy-carbonyl group, or cyano group and the configuration of OR³ is syn. A process according to claim 1, wherein the imidazol-1-yl group which forms a fused ring at the 2,3- or 3,4-position is a group of the formula A process according to claim 1, wherein the imidazol-1-yl group forming a fused ring at the 2,3- or 3,4-position is imidazol[1,2-a]pyridinium-1-yl or imidazo[1,5-a]pyridinium-2-yl group. A process according to claim 1 wherein Z is S. A process according to claim 1 wherein R⁴ is hydrogen atom. A process according to claim 1 Wherein R¹³ is hydrogen atom. A process according to claim 1 wherein the compound prepared is selected from 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-(1-carboxy-1-methylethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-(2-fluoroethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-(2-chloroethoxyimino)acetamido]-3-[ (imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-(2-hydroxyethoxyimino)acetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(6-chloroimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(6-chloroimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-ethoxyiminoacetamido]-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-(1-carboxy-1-methylethoxyimino)acetamido]-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-(2-fluoroethoxyimino)acetamido]-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-(2-chloroethoxyimino)acetamido]-3-[(6-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-amino thiazol-4-yl)-2-(Z)-methoxyiminoacetamido]-3-[(3-cyanoimidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,5-a]pyridinium-2-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-methoxyiminoacetamidol-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-carboxymetboxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-amino-5-chlorothiazol-4-yl)-2(Z)-methoxyiminoacetamido]-3-[(imidazo[1,5-a]pyridinium-2-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl-3-oxido)-2(Z)-ethoxyiminoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate; 7β-[2-(2-aminothiazol-4-yl)-2-formamidoacetamido]-3-[(imidazo[1,2-a]pyridinium-1-yl)methyl]-3-cephem-4-carboxylate. A method for producing a compound of the formula: wherein R a stands for nitrogen-containing heterocyclic group, Z, R⁴, R¹³ and A are as defined in claim 1, which comprises (1) allowing a compound of the formula: (2) allowing a compound of the formula: wherein R⁵ is as defined in claim 10, or a salt or ester thereof to react with an optionally substituted imidazole forming a fused ring at the 2,3- or 3,4-position or a salt thereof. A method for producing a compound of the formula: wherein R b stands for acyl group, with the proviso that the case where R b stands for a group of the formula: wherein R¹ is an amino group which may be protected, R³ is hydrogen atom or an optionally substituted hydrocarbon residue is excluded, Z, R⁴, R¹³ and A are defined as in claim 1, which comprises (1) allowing a compound of the formula: wherein the symbols are of the same meaning as defined above or a salt or ester thereof to react with carboxylic acid of the general formula R b OH wherein R b stands for acyl group or a salt or reactive derivative thereof, or (2) allowing a compound of the formula; wherein R⁵ is as defined in claim 1 or a salt or ester thereof to react with an optionally substituted imidazole forming a fused rang at the 2,3- or 3,4-position or a salt thereof. A method for producing a compound of the formula: wherein R 22' stands for an optionally substituted heterocyclic group, with the proviso that the case where R 22' stands for a group of the formula: wherein R¹ is an amino group which may be protected, is excluded, R 3'' stands for optionally substituted hydrocarbon residue, Z, R⁴, R¹³ and A are defined as in claim 1, which comprises allowing a compound of the formula: wherein the symbols are of the same meaning as defined above or a salt or ester thereof to react with a compound of the general formula R 3'' OH wherein R 3'' stands for optionally substituted hydrocarbon residue or a reactive derivative thereof. A method for producing a compound of the formula: wherein R¹ stands for optionally protected amino group, R² stands for hydrogen atom, halogen atom or nitro group, R³ stands for hydrogen atom or optionally substituted hydrocarbon residue, Z, R⁴, R¹³ and A are defined as in claim 1, which comprises allowing a compound of the formula: wherein X stands for halogen atom and other symbols are of the same meaning as defined above or a salt or ester thereof to react with a compound of the general formula R¹C(=S)NH₂ wherein R¹ stands for optionally protected amino group. A method for producing a compound of the formula: wherein R C stands for esterified carboxyl group, Z, R⁴, R¹³ and A are defined as in claim 1 which comprises (1) allowing a compound of the formula; wherein the symbols are of the same meaning as defined above or a salt or ester thereof to react with an oxycarbonylation reagent, or (2) allowing a compound of the formula: wherein R⁵ is defined as in claim 1 or a salt or ester thereof to react with an optionally substituted imidazole forming a fused ring at the 2,3- or 3,4-position or a salt thereof. A process for preparing a pharmaceutical composition containing at least one of the compounds of the formula; wherein R⁰ stands for hydrogen atom, nitrogen-containing heterocyclic group, acyl group or esterified carboxyl group, with the proviso that the case where R⁰ stands for a group of the formula: wherein R¹ is an amino group which may be protected, R³ is hydrogen atom or an optionally substituted hydrocarbon residue is excluded, Z, R⁴,R¹³ and A are defined as in claim 1, which comprises combining at least one of the above mentioned compound with a pharmaceutical carrier or diluent.

Inventors: FUJINO, MASAHIKO, KONDO, MASAHIRO, MIYAKE, AKIO
Applicants: TAKEDA CHEMICAL INDUSTRIES, LTD.
Application year: 1985
Main classification: C07D501
IPC codes: A61K31, C07D501, C07D463, C07D277, C07D285, C07D519, A61P31, C07D505, C07D487, C07D471