CEPHEM COMPOUNDS, PROCESSES FOR PREPARATION THEREOF AND PHARMACEUTICAL COMPOSITIONS CONTAINING THEM

Abstract: A compound of the formula: wherein R 2 / b is carboxy or a protected carboxy group, and a salt thereof, processes for its preparation and pharmaceutic­ al compositions containing them in association with a pharmaceutically acceptable carrier or excipient.

Description: Cephalosporins are known to possess good antibiotic activity. GB-A-2 056 975 discloses substituted alkyloxime derivatives of 7-(2-amino-4-thiazolyl)acetamido-ceph-3-em-4-carboxylic acid. The present invention relates to new cephem compounds and pharmaceutically acceptable salts thereof. More particularly, it relates to new cephem compounds and pharmaceutically acceptable salts thereof, which have antimicrobial activities and to processes for preparation thereof, to pharmaceutical composition comprising the same, and to a method of using the same therapeutically in the treatment of infectious diseases in human being and animals. Accordingly, it is one object of the present invention to provide new cephem compounds and pharmaceutically acceptable salts thereof, which are active against a number of pathogenic microorganisms. Another object of the present invention is to provide processes for the preparation of new cephem compounds and pharmaceutically acceptable salts thereof. A further object of the present invention is to provide pharmaceutical composition comprising, as active ingredients, said new cephem compounds and pharmaceutically acceptable salts thereof. Still further object of the present invention is to provide a method for the manufacture of a medicament for the treatment of infectious diseases caused by pathogenic bacteria in human being and animals. According to a first aspect the present invention relates to a new cephem compound which can be represented by the following general formula (I). wherein R¹ is amino or a protected amino group, R² is carboxy, -COO ⊖ or a protected carboxy group, R³ is thiadiazolylthiomethyl (more preferably 1,3,4-thiadiazolylthiomethyl, 1,2,4-thiadiazolylthiomethyl, 1,2,5-thiadiazolylthiomethyl or 1,2,3-thiadiazolylthiomethyl), thiadiazolylthiomethyl substituted with C₁-C₆- alkyl (more preferably 1,2,4-thiadiazolylthiomethyl substituted with C₁-C₆- alkyl, or 1,3,4-thiadiazolylthiomethyl substituted with C₁-C₆ alkyl), thiazolylthiomethyl substituted with hydroxy and carboxy (more preferably 1,2-thiazolylthiomethyl substituted with hydroxy and carboxy), tetrazolylthiomethyl substituted with C₁-C₆- alkyl, tetrazolylthiomethyl substituted with di(C₁-C₆)alkylamino(C₁-C₆)alkyl, tetrazolylthiomethyl substituted with hydroxy(C₁-C₆)alkyl, dihydrotriazinylthiomethyl substituted with oxo, hydroxy and C₁-C₆-alkyl (more preferably 4,5-dihydro-1,2,4-triazinylthiomethyl substituted with oxo, hydroxy and C₁-C₆- alkyl, or 2,5-dihydro-1,2,4-triazinylthiomethyl substituted with oxo, hydroxy and C₁-C₆-alkyl), tetrazolopyridazinylthiomethyl (more preferably tetrazolo[1,5-b]pyridazinylthiomethyl), halomethyl, cyanovinylthiomethyl, carbamoyloxymethyl, pyridiniomethyl substituted with two C₁-C₆- alkyl groups, pyridiniomethyl substituted with hydroxy( C₁-C₆)alkyl, pyridiniomethyl substituted with C₁-C₆- alkyl, pyridiniomethyl substituted with C₁-C₆- alkoxy, pyridiniomethyl substituted with C₁-C₆- alkylthio, pyridiniomethyl substituted with C₁-C₆- alkanesulfonyl, vinyl, hydrogen, pyridiniothiomethyl having C₁-C₆- alkyl, pyridylthiovinyl, pyridiniothiovinyl having C₁-C₆- alkyl, pyrrolidiniomethyl having C₁-C₆- alkyl, hydroxymethyl, tetrahydropyridylmethyl or tetrahydroisoquinolylmethyl, halomethyl, cyanovinylthiomethyl, carbamoyloxymethyl, pyridiniomethyl substituted with 1 to 3 substituent(s) selected from the group consisting of C₁-C₆-alkyl, C₁-C₆-alkylthio, C₁-C₆-alkoxy, hydroxy(C₁-C₆)alkyl and C₁-C₆- alkanesulfonyl, vinyl, hydrogen, pyridiniothiomethyl having C₁-C₆- alkyl, pyridylthiovinyl, pyridiniothiovinyl having C₁-C₆-alkyl, pyrrolidiniomethyl having C₁-C₆-alkyl, hydroxymethyl, tetrahydropyridylmethyl or tetrahydroisoquinolylmethyl, z is -S- or X is an acid residue, n is 0 or 1, X¹ ia halogen and X² is halogen. According a second second aspect of the present invention, the object compounds (I) can be prepared by the following processes. wherein R¹, R², R³, Z, X, n, X¹ and X² are each as defined above, R 1 / a is a protected amino group, Y is an acid residue, R⁴ is pyridine substituted with 1 to 3 substituent(s) selected from the group consisting of C₁-C₆-alkyl, C₁-C₆-alkylthio, C₁-C₆-alkoxy, hydroxy(C₁-C₆)alkyl and C₁-C₆-alkanesulfonyl, pyrrolidine having C₁-C₆-alkyl, tetrahydropyridine, tetrahydroisoquinoline, or a compound of the formula: H-S-R⁵·(X ⊖ ) n wherein X and n are each as defined above, and R⁵ is heterocyclic group which may be substituted with suitable substituent(s), cyanovinyl or pyridinio having C₁-C₆- alkyl, R 4 / a is pyridinio substituted with 1 to 3 substituent(s) selected from the group consisting of C₁-C₆-alkyl, C₁-C₆- alkylthio, C₁-C₆-alkoxy, hydroxy(C₁-C₆ )alkyl and C₁-C₆-alkanesulfonyl, pyrrolidinio having C₁-C₆-alkyl, tetrahydropyridyl, tetrahydroisoquinolyl, or a group of the formula: -S-R⁵ wherein R⁵ is as defined above, W is Y as defined above or X as defined above, R 2 / b is carboxy or a protected carboxy group, A is -CH₂- or -CH=CH-, and R⁶ is C₁-C₆-alkyl. Some of the starting compounds (II) are novel and can be prepared by the following Process (A). wherein R 2 / b and Y are each as defined above, R 4 / b is 1,2,5-thiadiazole-3-thiol or 1,2,4-thiadiazole-5-thiol, and R 4 / c is (1,2,5-thiadiazol-3-yl)thio group or (1,2,4-thiadiazol-5-yl)thio group. The reaction conditions of Process A can be referred to the ones of Preparations 4 and 5. Regarding the compounds (I), (Ia), (Ib), (Ic), (Id), (Ie), (If), (Ig), (Ih) and (III), it is to be understood that said compounds include syn isomer, anti isomer and a mixture thereof. For example, with regard to the object compound (I), syn isomer means one geometrical isomer having the partial structure represented by the following formula: (wherein R¹, X¹ and X² are each as defined above) and anti isomer means the other geometrical isomer having the partial structure represented by the following formula: (wherein R¹, X¹ and X² are each as defined above.) Suitable pharmaceutically acceptable salts of the object compounds (I) are conventional non-toxic salts and include a metal salt such as an alkali metal salt (e.g. sodium salt, and potassium salt) and an alkaline earth metal salt (e.g. calcium salt, and magnesium salt,), an ammonium salt, an organic base salt (e.g. trimethylamine salt, triethylamine salt, pyridine salt, picoline salt, dicyclohexylamine salt, and N,N'-dibenzylethylenediamine salt), an organic acid salt (e.g. acetate, maleate, tartrate, methanesulfonate, benzenesulfonate, formate, and toluenesulfonate), an inorganic acid salt (e.g. hydrochloride, hydrobromide, sulfate, and phosphate) , a salt with an amino acid (e.g. arginine, aspartic acid, and glutamic acid). In the above and subsequent descriptions of the present specification, suitable examples and illustrations of the various definitions which the present invention include within the scope thereof are explained in detail as follows. The term "C₁-C₆ " is intended to mean 1 to 6 carbon atoms. Suitable "protected amino" may include an acylamino or an amino group substituted by a conventional protecting group such as ar(C₁-C₆ )alkyl which may have at least one suitable substituent(s), (e.g. benzyl,and trityl). Suitable acyl moiety in the term "acylamino" may include aliphatic acyl group and acyl group containing an aromatic or heterocyclic ring. And, suitable examples of the said acyl may be C₁-C₆-alkanoyl (e.g. formyl, acetyl, propionyl, butyryl, isobutyryl, valeryl, isovaleryl, oxalyl, succinyl, and pivaloyl); C₁-C₆-alkoxycarbonyl (e.g. methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl, 1-cyclopropyl-ethoxycarbonyl, isopropoxycarbonyl, butoxycarbonyl, tert-butoxycarbonyl, pentyloxycarbonyl, and hexyloxycarbonyl); C₁-C₆-alkanesulfonyl (e.g. mesyl, ethanesulfonyl, propanesulfonyl, isopropanesulfonyl ,and butanesulfonyl); arenesulfonyl (e.g. benzenesulfonyl,and tosyl); aroyl (e.g. benzoyl, toluoyl, xyloxy, naphthoyl, phthalpyl, and indancarbonyl); ar( C₁-C₆)alkanoyl (e.g. phenylacetyl,and phenylpropionyl); ar( C₁-C₆)alkoxycarbonyl (e.g. benzyloxycarbonyl, phenethyloxycarbonyl). The acyl moiety as stated above may have at least one suitable substituent(s) such as halogen (chlorine, bromine, fluorine and iodine), Suitable "protected carboxy" may include an esterified carboxy and suitable examples of the ester moiety in said esterified carboxy may be the ones such as C₁-C₆-alkyl ester (e.g. methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, isobutyl ester, tert-butyl ester, pentyl ester, hexyl ester, and 1-cyclopropylethyl ester which may have at least one suitable substituent(s), for example, C₁-C₆-alkanoyloxy(C₁-C₆)alkyl ester (e.g. acetoxymethyl ester, propionyloxymethyl ester, butyryloxymethyl ester, valeryloxymethyl ester, pivaloyloxymethyl ester, 2-acetoxyethyl ester, 2-propionyloxyethyl ester, and hexanoyloxymethyl ester), C₁-C₆- alkanesulfonyl(C₁-C₆)alkyl ester (e.g. 2-mesylethyl ester) or mono(or di or tri)halo(C₁-C₆ )alkyl ester (e.g. 2-iodoethyl ester, and 2,2,2-trichloroethyl ester); C₁-C₆- alkenyl ester (e.g. vinyl ester, and allyl ester); C₁-C₆- alkynyl ester (e.g. ethynyl ester, and propynyl ester); ar(C₁-C₆)alkyl ester which may have at least one suitable substituent(s) (e.g. benzyl ester, 4-methoxybenzyl ester, 4-nitrobenzyl ester, phenethyl ester, trityl ester, benzhydryl ester, bis(methoxyphenyl)methyl ester, 3,4-dimethoxybenzyl ester, and 4-hydroxy-3,5-di-tert-butylbenzyl ester); aryl ester which may have at least one suitable substituent(s) (e.g. phenyl ester, 4-chlorophenyl ester, tolyl ester, tert-butylphenyl ester, xylyl ester, mesityl ester, and cumenyl ester). Suitable heterocyclic group and heterocyclic moiety means saturated or unsaturated, monocyclic or polycyclic heterocyclic group containing at least one hetero-atom such as an oxygen, sulfur, and nitrogen atom. And, especially preferably heterocyclic group may be heterocyclic group such as unsaturated 3 to 8-membered heteromonocyclic group containing 1 to 4 nitrogen atom(s), for example, pyrrolyl, pyrrolinyl, imidazolyl, pyrazolyl, pyridyl, and its N-oxide, pyrimidyl, pyrazinyl, pyridazinyl, triazolyl (e.g., 4H-1,2,4-triazolyl, 1H-1,2,3-triazolyl, and 2H-1,2,3-triazolyl), tetrazolyl (e.g., 1H-tetrazolyl,and 2H-tetrazolyl), dihydrotriazinyl (e.g., 4,5-dihydro-1,2,4-triazinyl,and 2,5-dihydro-1,2,4-triazinyl); saturated 3 to 8-membered heteromonocyclic group containing 1 to 4 nitrogen atom(s), for example, pyrrolidinyl, imidazolidinyl, piperidino, and piperazinyl; unsaturated condensed heterocyclic group containing 1 to 5 nitrogen atom(s), for example, indolyl, isoindolyl, indolizynyl, benzimidazolyl, quinolyl, isoquinolyl, indazolyl, benzotriazolyl, tetrazolopyridyl, tetrazolopyridazinyl (e.g., tetrazolo[1,5-b]pyridazinyl,), dihydrotriazolopyridazinyl,; unsaturated 3 to 8-membered heteromonocyclic group containing 1 to 2 oxygen atom(s) and 1 to 3 nitrogen atom(s), for example, oxazolyl, isoxazolyl, oxadiazolyl, (e.g., 1,2,4-oxadiazolyl, and 1,3,4-oxadiazolyl, 1,2,5-oxadiazolyl),; saturated 3 to 8-membered heteromonocyclic group containing 1 to 2 oxygen atom(s) and 1 to 3 nitrogen atom(s), for example, morpholinyl; unsaturated condensed heterocyclic group containing 1 to 2 oxygen atom(s) and 1 to 3 nitrogen atom(s), for example, benzoxazolyl, and benzoxadiazolyl; unsaturated 3 to 8-membered heteromonocyclic group containing 1 to 2 sulfur atom(s) and 1 to 3 nitrogen atom(s), for example, 1,3-thiazolyl, 1,2-thiazolyl, thiazolinyl, thiadiazolyl (e.g., 1,2,4-thiadiazolyl, 1,3,4-thiadiazolyl, 1,2,5-thiadiazolyl, and 1,2,3-thiadiazolyl); saturated 3 to 8-membered heteromonocyclic group containing 1 to 2 sulfur atom(s) and 1 to 3 nitrogen atom(s), for example, thiazolidinyl; unsaturated 3 to 8-membered heteromonocyclic group containing a sulfur atom, for example, thienyl; unsaturated condensed heterocyclic group containing 1 to 2 sulfur atom(s) and 1 to 3 nitrogen atom(s), for example, benzothiazolyl, and benzothiadiazolyl; wherein said heterocyclic group may be substituted with 1 to 3 suitable substituent(s) such as lower alkyl (e.g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl, pentyl, cyclopentyl, hexyl, and cyclohexyl); lower alkylthio (e.g., methylthio, ethylthio,and propylthio, ); lower alkenyl (e.g., vinyl, allyl, and butenyl); lower alkenylthio (e.g., vinylthio, allylthio, and butenylthio); hydroxy; aryl (e.g., phenyl, and tolyl); halogen (e.g., chlorine, bromine, iodine or fluorine); amino; di(C₁-C₆ )alkylamino(C₁-C₆)alkyl (e.g., dimethylaminomethyl, dimethylaminoethyl, dimethylaminopropyl, diethylaminopropyl, and diethylaminobutyl); carboxy(C₁-C₆)alkyl (e.g., carboxymethyl, carboxyethyl, and carboxypropyl); esterified carboxy(C₁-C₆)alkyl wherein the esterified carboxy moiety is exemplified above; amino(C₁-C₆)alkyl (e.g., aminomethyl, aminoethyl, aminopropyl, 1-aminomethylethyl, aminobutyl, and aminohexyl,), protected amino(C₁-C₆)alkyl wherein the protected amino and C₁-C₆- alkyl moieties are each as exemplified above, preferably lower alkoxycarbonylamino(C₁-C₆)alkyl (e.g., methoxycarbonylaminomethyl, ethoxycarbonylaminomethyl, t-butoxycarbonylaminomethyl, t-butoxycarbonylaminoethyl,and t-butoxycarbonylaminopropyl) or C₁-C₆- alkanoylamino(C₁-C₆ )alkyl (e.g., acetylaminomethyl, acetylaminoethyl, acetylaminopropyl,and 1-acetylaminomethylethyl); carboxy; oxo; esterified carboxy as exemplified above, preferably C₁-C₆-alkoxycarbonyl; C₁-C₆- alkoxy(C₁-C₆)alkyl (e.g., methoxymethyl, methoxyethyl, methoxypropyl, ethoxymethyl, and ethoxyethyl ); hydroxy(C₁-C₆ )alkyl (e.g., hydroxymethyl, hydroxyethyl, hydroxypropyl,and hydroxybutyl); C₁-C₆- alkylthio(C₁-C₆)alkyl (e.g., methylthiomethyl, methylthioethyl, methylthiopropyl, and ethylthiomethyl); sulfo(C₁-C₆ )alkyl (e.g., sulfomethyl, sulfoethyl, sulfopropyl, and sulfobutyl); C₁-C₆-alkanesulfonyl (e.g., mesyl, ethanesulfonyl, propanesulfonyl, and butanesulfonyl); acyl(C₁-C₆)alkyl wherein the acyl and C₁-C₆-alkyl moieties are each as exemplified above, preferably C₁-C₆ alkanesulfonyl(C₁-C₆)alkyl (e.g., mesylmethyl, mesylethyl, and ethanesulfonylmethyl); acylamino(C₁-C₆)alkyl wherein the acyl and C₁-C₆- alkyl moieties are each as exemplified above, preferably C₁-C₆-alkanesulfonylamino(C₁-C₆)alkyl (e.g. mesylaminomethyl, mesylaminoethyl, mesylaminopropyl, and ethanesulfonylaminomethyl); carboxy(C₁-C₆ )alkylthio (e.g., carboxymethylthio, and carboxyethylthio, ); morpholino(C₁-C₆)alkyl (e.g., morpholinomethyl, morpholinoethyl, and morpholinopropyl, ); piperidino(C₁-C₆)alkyl (e.g., piperidinomethyl, piperidinoethyl, and piperidinopropyl); piperazinyl(C₁-C₆)alkyl which may be substituted with C₁-C₆-alkyl (e.g., 4-methyl-1-piperazinylpropyl Suitable halomethyl may include chloromethyl, bromomethyl, fluoromethyl and iodomethyl. Suitable " C₁-C₆-alkyl" may include methyl, ethyl, propyl, isopropyl, butyl, isobutyl, t-butyl, pentyl, t-pentyl, and hexyl. Suitable "C₁-C₆-alkylthio" may include methylthio, ethylthio, propylthio, butylthio, pentylthio, and hexylthio. Suitable "C₁-C₆-alkoxy" may include methoxy, ethoxy, propoxy, isopropoxy, butoxy, t-butoxy, pentyloxy, and hexyloxy. Suitable "hydroxy(C₁-C₆)alkyl" may include hydroxymethyl, 1(or 2)-hydroxyethyl, 1(or 2 or 3)-hydroxypropyl, 1(or 2 or 3 or 4)-hydroxybutyl, 1(or 2 or 3 or 4 or 5)-hydroxypentyl, and 1(or 2 or 3 or 4 or 5 or 6)-hydroxyhexyl. Suitable " C₁-C₆-alkanesulfonyl" may include mesyl, ethanesulfonyl, pronanesulfonyl, butanesulfonyl, pentanesulfonyl, and hexanesulfonyl. Suitable "halogen" may include chlorine, bromine, fluorine and iodine, and preferred one is fluorine. Suitable "acid residue" may include acyloxy, halogen (e.g., fluorine, chlorine, bromine or iodine), wherein acyl moiety in the term "acyloxy" can be referred to the ones as exemplified above. Preferred embodiments of the object compounds (I) are as follows. Preferred embodiment of R¹ is amino or ar(C₁-C₆)alkylamino (more preferably triphenyl(C₁-C₆)alkylamino, most preferably tritylamino, R² is carboxy, -COO ⊖ or esterified carboxy (more preferably ar-(C₁-C₆)alkoxycarbonyl, most preferably benzhydryloxycarbonyl), Z is -S- or X is an acid residue (more preferably halogen, or mono(or di or tri)halo(C₁-C₆)alkanoyloxy, n is 0 or 1, X¹ is halogen (more preferably fluorine) and X² is halogen (more preferably fluorine). The processes for preparing the object compounds of the present invention are explained in detail in the following. Process 1 : The object compound (I) or a salt thereof can be prepared by reacting the compound (II) or its reactive derivative at the amino group or a salt thereof with the compound (III) or its reactive derivative at the carboxy group or a salt thereof. Suitable reactive derivative at the amino group of the compound (II) may include Schiff's base type imino or its tautomeric enamine type isomer formed by the reaction of the compound (II) with a carbonyl compound such as aldehyde, ketone or the like; a silyl derivative formed by the reaction of the compound (II) with a silyl compound such as N,O-bis(trimethylsilyl)acetamide, or N-trimethylsilylacetamide; a derivative formed by the reaction of the compound (II) with phosphorus trichloride or phosgene,. Suitable salts of the compounds (II) and (III) can be referred to the ones as exemplified for the compound (I). Suitable reactive derivative at the carboxy group of the compound (III) may include an acid halide, an acid anhydride, an activated amide, and an activated ester,. The suitable example may be an acid chloride, an acid azide; a mixed acid anhydride with an acid such as substituted phosphoric acid (e.g. dialkylphosphoric acid, phenylphosphoric acid, diphenylphosphoric acid, dibenzylphosphoric acid, and halogenated phosphoric acid), dialkylphosphorous acid, sulfurous acid, thiosulfuric acid, alkanesulfonic acid (e.g. methanesulfonic acid, and ethanesulfonic acid, ), sulfuric acid, alkylcarbonic acid, aliphatic carboxylic acid (e.g. pivalic acid, pentanoic acid, isopentanoic acid, 2-ethylbutyric acid or trichloroacetic acid,) or aromatic carboxylic acid (e.g. benzoic acid); a symmetrical acid anhydride; an activated amide with imidazole, 4-substituted imidazole, dimethylpyrazole, triazole or tetrazole; or an activated ester (e.g. cyanomethyl ester, methoxymethyl ester, dimethyliminomethyl [(CH₃)₂N ⁺=CH-] ester, vinyl ester, propargyl ester, p-nitrophenyl ester, 2,4-dinitrophenyl ester, trichlorophenyl ester, pentachlorophenyl ester, mesylphenyl ester, phenylazophenyl ester, phenyl thioester, p-nitrophenyl thioester, p-cresyl thioester, carboxymethyl thioester, pyranyl ester, pyridyl ester, piperidyl ester, and 8-quinolyl thioester), or an ester with a N-hydroxy compound (e.g. N,N-dimethylhydroxylamine, 1-hydroxy-2-(1H)-pyridone, N-hydroxysuccinimide, N-hydroxyphthalimide and 1-hydroxy-6-chloro-1H-benzotriazole, etc.),. These reactive derivatives can optionally be selected from them according to the kind of the compound (III) to be used. The reaction is usually carried out in a conventional solvent such as water, acetone, dioxane, acetonitrile, chloroform, methylene chloride, ethylene chloride, tetrahydrofuran, ethyl acetate, N,N-dimethylformamide, pyridine or any other organic solvents which do not adversely influence the reaction. These conventional solvents may also be used in a mixture with water. When the compound (III) is used in free acid form or its salt form in the reaction, the reaction is preferably carried out in the presence of a conventional condensing agent such as N,N'-dicyclohexylcarbodiimide; N-cyclohexyl-N'-morpholinoethylcarbodiimide; N-cyclohexyl-N'-(4-diethylaminocyclohexyl)carbodiimide; N,N'-diethylcarbodiimide, N,N'-diisopropylcarbodiimide; N-ethyl-N'-(3-dimethylaminopropyl)carbodiimide; N,N-carbonylbis-(2-methylimidazole); pentamethyleneketene-N-cyclohexylimine; diphenylketene-N-cyclohexylimine; ethoxyacetylene; 1-alkoxy-1-chloroethylene; trialkyl phosphite; ethyl polyphosphate; isopropyl polyphosphate; phosphorus oxychloride (phosphoryl chloride); phosphorus trichloride; thionyl chloride; oxalyl chloride; triphenylphosphine; 2-ethyl-7-hydroxybenzisoxazolium salt; 2-ethyl-5-(m-sulfophenyl)isoxazolium hydroxide intra-molecular salt; 1-(p-chlorobenzenesulfonyloxy)-6-chloro-1H-benzotriazole; so-called Vilsmeier reagent prepared by the reaction of N,N-dimethylformamide with thionyl chloride, phosgene, and phosphorus oxychloride. The reaction may also be carried out in the presence of an inorganic or organic base such as an alkali metal bicarbonate, tri(lower)alkylamine, pyridine, N-(lower)alkylmorphorine,or N,N-di(lower)alkylbenzylamine,. The reaction temperature is not critical, and the reaction is usually carried out under cooling or at ambient temperature. Process 2 The object compound (Ib) or a salt thereof can be prepared by subjecting the compound (Ia) or a salt thereof to elimination reaction of the amino protective group. Suitable salts of the compounds (Ia) and (Ib) can be referred to the ones as exemplified for the compound (I). The elimination reaction is carried out in accordance with a conventional method such as hydrolysis; reduction; a method treating the compound (Ia) wherein protected amino of R 1 / a is acylamino with iminohalogenating agent, iminoetherifying agent and then, if necessary, hydrolyzing the resultant. The hydrolysis may include a method using an acid or base or hydrazine. These methods may be selected depending on the kind of the protective groups to be eliminated. Among these methods, hydrolysis using an acid is one of the most common and preferable method for eliminating the protective groups such as substituted or unsubstituted alkoxycarbonyl, for example, tert-pentyloxycarbonyl, C₁-C₆- alyanoyl (e.g. formyl, acetyl), cycloalkoxycarbonyl, substituted or unsubstituted aralkoxycarbonyl, aralkyl (e.g. trityl), substituted phenylthio, substituted aralkylidene, substituted alkylidene, or substituted cycloalkylidene. Suitable acid includes an organic or inorganic acid such as formic acid, trifluoroacetic acid, benzenesulfonic acid, p-toluenesulfonic acid, and hydrochloric acid, and the most suitable acid is an acid which can easily be removed from the reaction mixture by a conventional manner such as distillation under reduced pressure, for example, formic acid, trifluoroacetic acid, and hydrochloric acid. The acids can be selected according to the kind of the protective group to be eliminated. When the elimination reaction is conducted with an acid, it can be carried out in the presence or absence of a solvent. Suitable solvent includes water, methylene chloride, alcohol (e.g., methanol, and ethanol) tetrahydrofuran or any other organic solvents which do not adversely influence the reaction, or a mixture thereof. The elimination reaction using trifluoroacetic acid may be carried out in the presence of anisole. The hydrolysis using hydrazine is commonly applied for eliminating a phthaloyl, succinyl type amino-protective group. The elimination using base is used for eliminating an acyl group such as trifluoroacetyl. Suitable base may include an inorganic base and an organic base. The reductive elimination is generally applied for eliminating the protective group, for example, haloalkoxycarbonyl (e.g. trichloroethoxycarbonyl,), substituted or unsubstituted aralkoxycarbonyl (e.g. benzyloxycarbonyl), 2-pyridylmethoxycarbonyl. Suitable reduction may include, for example, reduction with an alkali metal borohydride (e.g. sodium borohydride,), reduction with a combination of a metal (e.g. tin, zinc, iron,) or the said metal together with a metal salt compound (e.g. chromous chloride, and chromous acetate) and an organic or inorganic acid (e.g. acetic acid, propionic acid, and hydrochloric acid) ; and catalytic reduction. Suitable catalyst includes a conventional one, for example, Raney nickel, platinum oxide, and palladium on carbon. Among the protective groups, the acyl group can generally be eliminated by hydrolysis. Especially, halogen substituted-alkoxycarbonyl and 8-quinolyloxycarbonyl groups are usually eliminated by treating with a heavy metal such as copper, or zinc. Among the protective groups, the acyl group can also be eliminated by treating with an iminohalogenating agent (e.g. phosphorus oxychloride) and an iminoetherifying agent such as lower alkanol (e.g. methanol, and ethanol) , if necessary, followed by hydrolysis. The reaction temperature is not critical and may suitably be selected in accordance with the kind of the amino protective group and the elimination method as mentioned above, and the reaction is usually carried out under a mild condition such as under cooling or at slightly elevated temperature. The present invention includes, within its scope, the case that the protected carboxy group for R² is transformed into the free carboxy group in the course of the elimination reaction as mentioned above or in the post-treatment of the reaction mixture or reaction product. Process 3 The object compound (Id) or a salt thereof can be prepared by reacting the compound (Ic) or a salt thereof with the compound (IV) or a salt thereof. Suitable salt of the compound (Ic) can be referred to the ones as exemplified for the compound (I). Suitable salt of the compound (IV) may include a metal salt such as an alkali metal salt (e.g., sodium salt, and potassium salt, and silver salt. The present reaction may be carried out in a solvent such as water, phosphate buffer, acetone, chloroform, nitrobenzene, methylene chloride, ethylene chloride, acetonitrile, N,N-dimethylformamide, methanol, ethanol, ether, tetrahydrofuran, dimethylsulfoxide, or any other organic solvent which does not adversely affect the reaction, preferably in ones having strong polarities. Among the solvents, hydrophilic solvents may be used in a mixture with water. The reaction is preferably carried out in around neutral medium. When the compound (IV) is used in a free form, the reaction is preferably conducted in the presence of a base, for example, inorganic base such as alkali metal hydroxide. alkali metal carbonate, alkali metal bicarbonate, and organic base such as trialkylamine,. The reaction temperature is not critical, and the reaction is usually carried out under cooling, at ambient temperature, under warming or under heating. Process 4 The object compound (If) or a salt thereof can be prepared by reacting the compound (Ie) or a salt thereof with the compound (V). Suitable salts of the compounds (Ie) and (If) can be referred to the ones as exemplified for the compound (I). The reaction is usually carried out in a solvent such as water, acetone, tetrahydrofuran, ethanol, ether, N,N-dimethylformamide or any other solvent which does not adversely influence the reaction. The reaction temperature is not critical and the reaction is usually carried out under cooling to heating. Process 5 The object compound (Ih) or a salt thereof can be prepared by oxidizing the compound (Ig) or a salt thereof. Suitable salts of the compounds (Ig) and (Ih) can be referred to the ones as exemplified for the compound (I). The oxidizing agent to be used in this reaction may include an inorganic peracid or a salt thereof (e.g. periodic acid, persulfuric acid, or sodium or potassium salt thereof, an organic peracid or a salt thereof (e.g. perbenzoic acid, m-chloroperbenzoic acid, performic acid, peracetic acid, chloroperacetic acid, trifluoroperacetic acid, or sodium or potassium salt thereof), ozone, hydrogen peroxide, urea-hydrogen peroxide, or any other conventional oxidizing agent which can oxidize a thio group to a sulfinyl group. The present oxidation reaction is usually carried out in a conventional solvent which does not adversely influence the reaction such as water, acetic acid, chloroform, methylene chloride, acetone, methanol, ethyl acetate, ethanol or a mixture thereof. The reaction temperature is not critical and the reaction is preferably carried out from under cooling to at ambient temperature. Process 6 The object compound (Ig) or a salt thereof can be prepared by reducing the compound (Ih) or a salt thereof. The present reduction can be carried out by a conventional method which is applied for the transformation of into -S-, for example, by using phosphorus trichloride, a combination of stannous chloride and acetyl chloride, a combination of an alkali metal iodide (e.g. sodium iodide) and trihaloacetic anhydride (e.g. trifluoroacetic anhydride,),. The present reduction is usually carried out in a solvent such as acetone, dioxane, acetonitrile, N,N-dimethylformamide, benzene, hexane, chloroform, methylene chloride, ethylene chloride, tetrahydrofuran, ethyl acetate, or any other solvent which does not adversely affect the reaction. The reaction temperature is not critical and the reaction is usually carried out under cooling or at ambient temperature. The object compound (I) and pharmaceutically acceptable salt thereof of the present invention are novel compounds which exhibit high antibacterial activity and inhibit the growth of a wide variety of pathogenic microorganisms including Gram-positive and Gram-negative bacteria and are useful as anti-microbial agents. For therapeutic purpose, the compounds according to the present invention can be used in the form of pharmaceutical preparation which contain said compounds, as an active ingredient, in admixture with a pharmaceutically acceptable carrier such as an organic or inorganic solid or liquid excipient suitable for oral, parenteral or external administration. The pharmaceutical preparations may be capsules, tablets, dragees, ointments or suppositories, solutions, and suspension, emulsions. If desired, there may be included in the above preparations auxiliary substances, stabilizing agents, wetting or emulsifying agents, buffers and other commonly used additives. While the dosage of the compounds will vary depending upon the age and condition of the patient, an average single dose of about 10 mg, 50 mg, 100 mg, 250 mg, 500 mg and 1000 mg of the compounds according to the present invention was proved to be effective for treating infectious diseases caused by pathogenic bacteria. In general, amounts between 1 mg/body and about 6,000 mg/body or even more may be administered per day. In order to illustrate the usefulness of the object compound, anti-microbial activities of the representative compounds of the present invention are shown below. [1] Test Compound : (1) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) [hereinafter referred to as Test Compound (1)] (2) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) [hereinafter referred to as Test Compound (2)] (3) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) [hereinafter referred to as Test Compound (3)] [2] Test Method : In vitro antibacterial activity was determined by the two-fold agar-plate dilution method as described below. One loopful of an overnight culture of each test strain in Trypticase-soy broth (10⁸ viable cells per ml) was streaked on heart infusion agar (HI-agar) containing graded concentrations of representative test compound, and the minimal inhibitory concentration (MIC) was expressed in terms of µg/ml after incubation at 37°C for 20 hours. [3] Test Results : The following Preparations and Examples are given for the purpose of illustrating the present invention. Preparation 1 To an ice-cooled solution of propiolamide (1 g) in tetrahydrofuran (10 ml) and water (10 ml) was added a mixture of triphenylmethanethiol (4.2 g), tetrahydrofuran (10 ml) and 1N aqueous solution (1 ml) of sodium hydroxide at 0-5°C. The mixture was stirred for 30 minutes at 0-10°C. To the reaction mixture was added water (40 ml)and the mixture was cooled. The resultant precipitates were collected by filtration to give (Z)-3-tritylthioacrylamide (4.2 g). IR (Nujol) : 3380, 3180, 1640, 1570 cm⁻¹ Preparation 2 To an ice-cooled suspension of (Z)-3-tritylthioacrylamide (3.9 g) in N,N-dimethylformamide (40 ml) was added phosphorus pentachloride (3.65 g) and the mixture was stirred for 30 minutes at 20°C. The reaction mixture was poured into ice-water and extracted with ethyl acetate. The separated organic layer was washed with brine, dried over magnesium sulfate and evaporated in vacuo to give (Z)-3-tritylthioacrylonitrile (2.85 g). IR (Nujol) : 2200 cm⁻¹ NMR (DMSO-d₆, δ) : 5.65 (1H, d, J=10Hz), 6.88 (1H, d, J=10Hz), 7-7.67 (15H, m) Preparation 3 To a solution of (Z)-3-tritylthioacrylonitrile (3.5 g) in a mixture of tetrahydrofuran (14 ml), methanol (21 ml) and pyridine (0.9 ml) was dropwise added a solution of silver nitrate (2.26 mg) in a mixture of methanol (55 ml) and water (5.5 ml) at ambient temperature. The reaction mixture was stirred at 40°C in dark. The precipitate was collected, washed with methanol and dried over phosphorus pentoxide to give [(Z)-2-cyanovinylthio]silver (2.46 g). IR (Nujol) : 2200, 1530 cm⁻¹ Preparation 4 7-Aminocephalosporanic acid (0.272 g) was added to the solution of potassium 1,2,5-thiadiazole-3-thiolate (0.136 g) in trifluoroacetic acid (5 ml) and the mixture was stirred for a few minutes until the solution turned clear, and then, boron trifluoride etherate (0.434 g) was added thereto and the mixture was stirred for 12 hours at room temperature. The reaction mixture was evaporated under reduced pressure and the residue was adjusted to pH 3.0 with 2% aqueous solution of ammonium hydroxide. The precipitates were collected by filtration, washed with cool water, acetone and diethyl ether and dried to give 7-amino-3-(1,2,5-thiadiazol-3-yl)thiomethyl-3-cephem-4-carboxylic acid (0.210 g). IR (Nujol) : 3150, 1800, 1620, 1530 cm⁻¹ NMR (CF₃COOH, δ) : 3.87 (2H, s), 4.41, 4.93 (2H, ABq, J=14Hz), 5.33 (2H, m), 8.57 (1H, s) Preparation 5 7-Aminocephalosporanic acid (21.2 g) was added to the solution of potassium 1,2,4-thiadiazole-5-thiolate (10.6 g) in trifluoroacetic acid (370 ml) and the mixture was stirred for a few minutes until the solution turned clear, and then, boron trifluoride etherate (33.8 g) was added thereto and the mixture was stirred for 7 hours at room temperature. The reaction mixture was evaporated under reduced pressure and the residue was adjusted to pH 3.0 with 3% aqueous soltuion of ammonium hydroxide. The precipitates were collected by filtration, washed with acetone and diethyl ether and dried to give a crude object compound (28.5 g). The crude object compound (25.0 g) was suspended in concentrated hydrochloric acid (230 ml), and the mixture was stirred for 30 minutes at room temperature. After insoluble material was removed by filtration, the solution was adjusted to pH 3.0 with 28% aqueous solution of ammonium hydroxide under ice-cooling. The resulting precipitates were collected by filtration, washed with cool water, acetone and diisopropyl ether and dried to give 7-amino-3-(1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (15.8 g). IR (Nujol) : 3150, 1790, 1610, 1530 cm⁻¹ NMR (CF₃COOH, δ) : 3.87 (2H, s), 4.63, 4.97 (2H, ABq, J=14Hz), 5.43 (2H, m), 8.93 (1H, s) Example 1 To a solution of 2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetic acid (syn isomer) (0.8 g) and diisopropylethylamine (0.43 g) in N,N-dimethylformamide (20 ml) was added mesyl chloride (0.38 g) at -20°C and the mixture was stirred at the same temperature for 30 minutes to give an activated acid solution. To a solution of 7-amino-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (0.57 g) and N-trimethylsilylacetamide (1.8 g) in tetrahydrofuran (20 ml) was added the activated acid solution obtained above all at once at -10°C. After being stirred at the same temperature for an hour, the mixture was poured into water and adjusted to pH 2.5 with an aqueous solution of sodium bicarbonate. The precipitates were collected by filtration and washed with water to give 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) (1.1 g). IR (Nujol) : 3250, 1780, 1680, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.52, 3.79 (2H, ABq, J=18Hz), 4.25, 4.58 (2H, ABq, J=14Hz), 5.12 (1H, d, J=5Hz), 5.67 (1H, dd, J=5Hz, 8Hz), 6.94 (1H, s), 7.03 (1H, t, J=72Hz), 7.10-7.50 (15H, m), 8.89 (1H, broad s), 9.50 (1H, s), 9.80 (1H, d, J=8Hz) Example 2 A mixture of 2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetic acid (syn isomer) (2.4 g) and diisopropylethylamine (1.29 g) in N,N-dimethylformamide (35 ml) was cooled to -30°C and mesyl chloride (1.15 g) was added dropwise thereto. The mixture was stirred at -20 to -30°C for 30 minutes to give an activated acid solution. On the other hand, a mixture of benzhydryl 7-amino-3-chloromethyl-3-cephem-4-carboxylate (2.18 g) and N-trimethylsilylacetamide (5.25 g) in methylene chloride (20 ml) was stirred to be a clear solution for 30 minutes at room temperature and then cooled to -20°C. To this solution was added the activated acid solution obtained above in one portion. The mixture was stirred for 30 minutes at -15 to -10°C, poured into water and extracted with ethyl acetate. The extract was washed with water three times, dried over magnesium sulfate and evaporated under reduced pressure. The residue was triturated in diisopropyl ether to give benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-chloromethyl-3-cephem-4-carboxylate (syn isomer) (4.64 g). IR (Nujol) : 1780, 1720, 1670, 1590, 1520 cm⁻¹ Example 3 To a solution of 2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetic acid (syn isomer) (1.3 g) and diisopropylethylamine (0.7 g) in N,N-dimethylformamide (20 ml) was added mesyl chloride (0.62 g) at -20°C. The mixture was stirred at the same temperature for 30 minutes and added dropwise to a solution of 7-amino-3-(1,2,3-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (0.9 g) and sodium bicarbonate (0.46 g) in a mixture of tetrahydrofuran (15 ml) and water (15 ml) at 0 to 5°C while keeping the pH value at 7.5 to 8.0 with 5% aqueous solution of sodium bicarbonate. The solution was stirred for 30 minutes at 0 to 5°C, adjusted to pH 7.5 and poured into water (300 ml). The resultant precipitates were collected by filtration, washed with water and dried to give 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,3-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) (1.78 g). IR (Nujol) : 3200, 1780, 1680, 1520 cm⁻¹ NMR (DMSO-d₆, δ) : 3.60 (2H, broad s), 4.23 (2H, broad s), 5.13 (1H, d, J=5Hz), 5.65 (1H, dd, J=5Hz, 8Hz), 6.92 (1H, s), 7.00 (1H, t, J=72Hz), 7.00-7.50 (15H, m), 8.80 (1H, s), 8.80 (1H, broad s), 9.78 (1H, d, J=8Hz) Example 4 The following compounds were obtained according to similar manners to those of Examples 1 to 3. (1) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1770, 1670, 1530 cm⁻¹ (2) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-methyl-5-oxo-6-hydroxy-4,5-dihydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 1780, 1705, 1670, 1580, 1520 cm⁻¹ (3) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-methyl-5-oxo-6-hydroxy-4,5-dihydro- 1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 1770, 1690, 1680, 1580, 1520 cm⁻¹ (4) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,3-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1670, 1620, 1530 cm⁻¹ (5) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 1780, 1670, 1620, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.10-3.63 (2H, m), 5.05 (1H, d, J=5Hz), 5.10-5.63 (2H, m), 5.75 (1H, dd, J=5Hz, 8Hz), 6.87 (1H, s), 6.97 (1H, t, J=72Hz), 7.00-7.50 (15H, m), 7.63-8.50 (2H, m), 8.83 (1H, broad s), 9.08 (2H, broad s) (6) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3150, 1770, 1670, 1610, 1530 cm⁻¹ (7) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[1-(2-hydroxyethyl)-1H-tetrazol-5-yl]thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3230, 1780, 1680, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.53, 3.90 (2H, ABq, J=18Hz), 3.74 (2H, t, J=5Hz), 4.20, 4.45 (2H, ABq, J=14Hz), 4.25 (2H, t, J=5Hz), 5.08 (1H, d, J=5Hz), 5.66 (1H, dd, J=5Hz, 8Hz), 6.93 (1H, s), 7.02 (1H, t, J=72Hz), 7.10-7.47 (15H, m), 8.90 (1H, broad s), 9.80 (1H, d, J=8Hz) (8) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[1-(2-hydroxyethyl)-1H-tetrazol-5-yl]thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1770, 1670, 1620, 1530 cm⁻¹ (9 ) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1780, 1650, 1590, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.50-3.90 (2H, m), 4.30, 4.67 (2H, ABq, J=14Hz), 5.13 (1H, d, J=5Hz), 5.77 (1H, dd, J=5Hz, 8Hz), 6.90 (1H, s), 7.05 (1H, t, J=72Hz), 7.00-7.57 (15H, m), 8.63 (1H, s), 8.85 (1H, broad s), 9.80 (1H, d, J=8Hz) (10) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1670, 1620, 1530 cm⁻¹ (11) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[1-{2-(N,N-dimethylamino)ethyl}-1H-tetrazol-5-yl]thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1660, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 2.68 (3H, s), 2.83 (3H, s), 3.08 (2H, t, J=6Hz), 3.43, 3.78 (2H, ABq, J=18Hz), 4.53 (2H, t, J=6Hz), 5.08 (1H, d, J=5Hz), 5.63 (1H, dd, J=5Hz, 8Hz), 6.95 (1H, s), 7.03 (1H, t, J=72Hz), 7.10-7.50 (15H, m), 8.90 (1H, broad s), 9.83 (1H, d, J=8Hz) (12) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[1-{2-(N,N-dimethylamino)ethyl}- 1H-tetrazol-5-yl]thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1670, 1610, 1530 cm⁻¹ (13) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(Z)-2-cyanovinylthiomethyl]-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3250, 2210, 1780, 1720, 1680, 1520, 1490 cm⁻¹ (14) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(Z)-2-cyanovinylthiomethyl]-3-cephem-4-carboxylic acid (syn isomer) mp : 145 to 150°C (dec.) IR (Nujol) : 3260, 2210, 1770, 1675, 1620, 1560, 1530 cm⁻¹ (15) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(2-methyl-5-oxo-6-hydroxy-2,5-dihydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 125 to 130°C (dec.) IR (Nujol) : 3200, 1780, 1655, 1590, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.60 (3H, s), 3.70 (2H, broad s), 4.10, 4.42 (2H, ABq, J=14Hz), 5.15 (1H, d, J=5Hz), 5.80 (1H, dd, J=5Hz, 8Hz), 6.97 (1H, s), 7.10 (1H, t, J=72Hz), 7.15-7.50 (15H, m), 8.93 (1H, broad s), 9.83 (1H, d, J=8Hz) (16) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(2-methyl-5-oxo-6-hydroxy-2,5-dihydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 165 to 170°C (dec.) IR (Nujol) : 3300, 3200, 1780, 1680, 1640, 1530 cm⁻¹ (17) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-carbamoyloxymethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 125 to 130°C (dec.) IR (Nujol) : 3450, 3350, 3260, 3200, 1770, 1720, 1680, 1650, 1600, 1530 cm⁻¹ (18) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-carbamoyloxymethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 125 to 130°C (dec.) IR (Nujol) : 3200, 1775, 1710, 1670, 1590, 1520 cm⁻¹ NMR (DMSO-d₆, δ) : 3.57 (2H, broad s), 4.67, 4.90 (2H, ABq, J=14Hz), 5.18 (1H, d, J=5Hz), 5.77 (1H, dd, J=5Hz, 8Hz), 6.20-6.50 (2H), 6.97 (1H, s), 7.07 (1H, t, J=72Hz), 7.20-7.50 (15H, m), 8.93 (1H, broad s), 9.83 (1H, d, J=8Hz) (19) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(tetrazolo[1,5-b]pyridazin-6-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 170 to 175°C (dec.) IR (Nujol) : 3400, 3260, 3200, 1770, 1680, 1660, 1620, 1535 cm⁻¹ (20) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(tetrazolo[1,5-b]pyridazin-6-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 130 to 135°C (dec.) IR (Nujol) : 3200, 1785, 1680, 1595, 1575, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.75 (2H, broad s), 4.28, 4.63 (2H, ABq, J=14Hz), 5.20 (1H, d, J=5Hz), 5.83 (1H, dd, J=5Hz, 8Hz), 7.03 (1H, s), 7.17 (1H, t, J=72Hz), 7.20-7.50 (15H, m), 7.78 (1H, d, J=9Hz), 8.63 (1H, d, J=9Hz), 9.93 (1H, d, J=8Hz) (21) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1H-tetrazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 145 to 150°C (dec.) IR (Nujol) : 3300, 1770, 1670, 1620, 1530 cm⁻¹ (22) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1H-tetrazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 115 to 120°C (dec.) IR (Nujol) : 3200, 1770, 1660, 1585, 1560, 1515 cm⁻¹ NMR (DMSO-d₆, δ) : 3.68 (2H, broad s), 3.92 (3H, s), 4.30 (2H, broad s), 5.12 (1H, d, J=5Hz), 5.75 (1H, dd, J=5Hz, 8Hz), 7.0 (1H, s), 7.10 (1H, t, J=72Hz), 7.20-7.50 (15H, m), 8.70 (1H, broad s), 9.85 (1H, d, J=8Hz) (23) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-vinyl-3-cephem-4-carboxylic acid (syn isomer) mp : 105 to 110°C (dec.) IR (Nujol) : 3200, 1770, 1680, 1650, 1585, 1565, 1520 cm⁻¹ NMR (DMSO-d₆, δ) : 3.67 (2H, broad s), 5.20 (1H, d, J=5Hz), 5.33 (1H, d, J=11Hz), 5.58 (1H, d, J=17Hz), 5.85 (1H, dd, J=5Hz, 8Hz), 7.00 (1H, dd, J=17Hz, 11Hz), 7.00 (1H, s), 7.10 (1H, t, J=72Hz), 7.20-7.50 (15H, m), 9.93 (1H, d, J=8Hz) (24) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-vinyl-3-cephem-4-carboxylic acid (syn isomer) mp : 190 to 195°C (dec.) IR (Nujol) : 3420, 3320, 3250, 1770, 1670, 1615, 1530 cm⁻¹ (25) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,5-thiadiazol-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3200, 1775, 1680, 1520 cm⁻¹ NMR (DMSO-d₆, δ) : 3.67 (2H, broad s), 4.23, 4.60 (2H, ABq, J=14Hz), 5.17 (1H, d, J=5Hz), 5.73 (1H, dd, J=5Hz, 8Hz), 7.0 (1H, s), 7.15 (1H, t, J=72Hz), 7.20-7.50 (15H, m), 8.73 (1H, s), 8.93 (1H, broad s), 9.83 (1H, d, J=8Hz) (26) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,5-thiadiazol-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 120 to 125°C (dec.) IR (Nujol) : 3300, 3180, 1770, 1670, 1620, 1530 cm⁻¹ Example 5 Water (2.7 ml) was added to a stirred solution of 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) (0.9 g) in formic acid (9 ml) at 7°C under ice-cooling and the mixture was stirred at the same temperature for 4 hours. The reaction mixture was poured into a mixture of water (150 ml) and ethyl acetate (50 ml) and adjusted to pH 2.5 with an aqueous solution of sodium bicarbonate. The separated organic layer was washed with water, dried over magnesium sulfate and evaporated in vacuo to give 7-[2-(2-aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) (0.4 g). IR (Nujol) : 3300, 1770, 1670, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.50, 3.82 (2H, ABq, J=18Hz), 4.15, 4.57 (2H, ABq, J=14Hz), 5.15 (1H, d, J=5Hz), 5.76 (1H, dd, J=5Hz, 8Hz), 6.96 (1H, s), 7.07 (1H, t, J=72Hz), 7.27 (2H, broad s), 9.51 (1H, s), 9.87 (1H, d, J=8Hz) Example 6 The following compounds were obtained according to a similar manner to that of Example 5. (1) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-methyl-5-oxo-6-hydroxy-4,5-dihydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 1770, 1690, 1680, 1580, 1520 cm⁻¹ (2) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,3-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1670, 1620, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.52, 3.77 (2H, ABq, J=18Hz), 4.24 (2H, broad s), 5.20 (1H, d, J=5Hz), 5.77 (1H, dd, J=5Hz, 8Hz), 6.97 (1H, s), 7.10 (1H, t, J=72Hz), 7.28 (2H, broad s), 8.85 (1H, s), 9.90 (1H, d, J=8Hz) (3) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3150, 1770, 1670, 1610, 1530 cm⁻¹ NMR (D₂O, δ) : 2.53 (3H, s), 3.15, 3.63 (2H, ABq, J=18Hz), 5.27 (1H, d, J=5Hz), 5.30, 5.52 (2H, ABq, J=14Hz), 5.85 (1H, d, J=5Hz), 6.87 (1H, t, J=72Hz), 7.16 (1H, s), 7.90 (1H, dd, J=6Hz, 8Hz), 8.35 (1H, d, J=6Hz), 8.72 (1H, d, J=6Hz), 8.75 (1H, broad s) (4) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[1-(2-hydroxyethyl)-1H-tetrazol-5-yl]thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1770, 1670, 1620, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.20-4.10 (2H, m), 3.55, 3.88 (2H, ABq, J=18Hz), 4.10-4.67 (2H, m), 5.15 (1H, dd, J=5Hz), 5.78 (1H, dd, J=5Hz, 8Hz), 7.0 (1H, s), 7.10 (1H, t, J=72Hz), 9.92 (1H, d, J=8Hz) (5) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1670, 1620, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.53, 3.80 (2H, ABq, J=18Hz), 4.28, 4.62 (2H, ABq, J=14Hz), 5.15 (1H, d, J=5Hz), 5.78 (1H, dd, J=5Hz, 8Hz), 6.97 (1H, s), 7.07 (1H, t, J=72Hz), 7.28 (2H, broad s), 8.68 (1H, s), 9.87 (1H, d, J=8Hz) (6) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[1-{2-(N,N-dimethylamino)ethyl}-1H-tetrazol-5-yl]thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1670, 1610, 1530 cm⁻¹ NMR (D₂O-NaHCO₃, δ) : 2.70 (6H, s), 3.43 (2H, t, J=6Hz), 3.45, 3.72 (2H, ABq, J=18Hz), 4.08, 4.27 (2H, ABq, J=14Hz), 4.68 (2H, t, J=6Hz), 5.19 (1H, d, J=5Hz), 5.76 (1H, dd, J=5Hz, 8Hz), 6.90 (1H, t, J=72Hz), 7.23 (1H, s) (7) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(Z)-2-cyanovinylthiomethyl]-3-cephem-4-carboxylic acid (syn isomer) mp : 145 to 150°C (dec.) IR (Nujol) : 3260, 2210, 1770, 1675, 1620, 1560, 1530 cm⁻¹ (8) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(2-methyl-5-oxo-6-hydroxy-2,5-dihydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 165 to 170°C (dec.) IR (Nujol) : 3300, 3200, 1780, 1680, 1640, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.60 (3H, s), 3.65 (2H, broad s), 4.10, 4.38 (2H, ABq, J=14Hz), 5.16 (1H, d, J=5Hz), 5.80 (1H, dd, J=5Hz, 8Hz), 6.97 (1H, s), 7.08 (1H, t, J=72Hz), 7.29 (2H, broad s), 9.89 (1H, d, J=8Hz) (9) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-carbamoyloxymethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 125 to 130°C (dec.) IR (Nujol) : 3450, 3350, 3260, 3200, 1770, 1720, 1680, 1650, 1600, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.53 (2H, broad s), 4.63, 4.86 (2H, ABq, J=14Hz), 5.18 (1H, d, J=5Hz), 5.79 (1H, dd, J=5Hz, 8Hz), 6.56 (2H, broad s), 7.0 (1H, s), 7.10 (1H, t, J=72Hz), 7.30 (2H, broad s), 9.86 (1H, d, J=8Hz) (10) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(tetrazolo[1,5-b]pyridazin-6-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 170 to 175°C (dec.) IR (Nujol) : 3400, 3260, 3200, 1770, 1680, 1660, 1620, 1535 cm⁻¹ NMR (DMSO-d₆, δ) : 3.63, 3.76 (2H, ABq, J=18Hz), 4.20, 4.58 (2H, ABq, J=14Hz), 5.15 (1H, d, J=5Hz), 5.78 (1H, dd, J=5Hz, 8Hz), 6.96 (1H, s), 7.06 (1H, t, J=72Hz), 7.29 (2H, broad s) 7.73 (1H, d, J=9Hz), 8.55 (1H, d, J=9Hz), 9.88 (1H, d, J=8Hz) (11) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1H-tetrazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 145 to 150°C (dec.) IR (Nujol) : 3300, 1770, 1670, 1620, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.60, 3.73 (2H, ABq, J=18Hz), 3.90 (3H, s), 4.20, 4.35 (2H, ABq, J=14Hz), 5.13 (1H, d, J=5Hz), 5.76 (1H, dd, J=5Hz, 8Hz), 6.96 (1H, s), 7.06 (1H, t, J=72Hz), 7.26 (2H, broad s), 9.88 (1H, d, J=8Hz) (12) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-vinyl-3-cephem-4-carboxylic acid (syn isomer) mp : 190 to 195°C (dec.) IR (Nujol) : 3420, 3320, 3250, 1770, 1670, 1615, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.56, 3.81 (2H, ABq, J=18Hz), 5.20 (1H, d, J=5Hz), 5.30 (1H, d, J=11Hz), 5.58 (1H, d, J=17Hz), 5.75 (1H, dd, J=5Hz, 8Hz), 6.98 (1H, s), 7.0 (1H, dd, J=11Hz, 17Hz), 7.08 (1H, t, J=72Hz), 7.30 (2H, broad s), 9.90 (1H, d, J=8Hz) (13) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,5-thiadiazol-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 120 to 125°C (dec.) IR (Nujol) : 3300, 3180, 1770, 1670, 1620, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.53, 3.75 (2H, ABq, J=18Hz), 4.18, 4.55 (2H, ABq, J=14Hz), 5.14 (1H, d, J=5Hz), 5.75 (1H, dd, J=5Hz, 8Hz), 6.96 (1H, s), 7.08 (1H, t, J=72Hz), 7.30 (2H, broad s), 8.73 (1H, s), 9.86 (1H, d, J=8Hz) Example 7 To a mixture of benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-methyl-5-oxo-6-hydroxy-4,5-dihydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylate (syn isomer) (1.20 g) and anisole (2.5 ml) in methylene chloride (2.5 ml) was added trifluoroacetic acid (5 ml) under ice-cooling. After being stirred for 30 minutes, the mixture was poured into diisopropyl ether (50 ml). The resultant mixture was adjusted to pH 7 with an aqueous solution of sodium bicarbonate. The separated aqueous layer was washed with ethyl acetate, acidified with 6N hydrochloric acid and extracted with a mixture of tetrahydrofuran and ethyl acetate. The extract was washed with a saturated aqueous solution of sodium chloride, dried and evaporated under reduced pressure. The residue was triturated in diethyl ether and collected by filtration to give 7-[2-(2-aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-methyl-5-oxo-6-hydroxy-4,5-dihydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) (600 mg). mp : 195 to 200°C (dec.) IR (Nujol) : 1770, 1690, 1680, 1580, 1520 cm⁻¹ NMR (DMSO-d₆, δ) : 3.29 (3H, s), 3.53, 3.77 (2H, ABq, J=18Hz), 3.99, 4.19 (2H, ABq, J=13Hz), 5.15 (1H, d, J=5Hz), 5.78 (1H, dd, J=5Hz, 8Hz), 6.98 (1H, s), 7.09 (1H, t, J=72Hz), 7.31 (2H, s), 9.90 (1H, d, J=8Hz), 12.41 (1H, s) Example 8 The following compounds were obtained according to a similar manner to that of Example 7. (1) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1770, 1670, 1530 cm⁻¹ (2) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,3-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1670, 1620, 1530 cm⁻¹ (3) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3150, 1770, 1670, 1610, 1530 cm⁻¹ (4) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[1-(2-hydroxyethyl)-1H-tetrazol-5-yl]thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1770, 1670, 1620, 1530 cm⁻¹ (5) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1670, 1620, 1530 cm⁻¹ (6) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[1-{2-(N,N-dimethylamino)ethyl}-1H-tetrazol-5-yl]thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1670, 1610, 1530 cm⁻¹ (7) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(Z)-2-cyanovinylthiomethyl]-3-cephem-4-carboxylic acid (syn isomer) mp : 145 to 150°C (dec.) IR (Nujol) : 3260, 2210, 1770, 1675, 1620, 1560, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.53, 3.63 (2H, ABq, J=18Hz), 3.82, 4.18 (2H, ABq, J=14Hz), 5.20 (1H, d, J=5Hz), 5.70 (1H, d, J=11Hz), 5.78 (1H, dd, J=5Hz, 8Hz), 6.98 (1H, s), 7.08 (1H, t, J=72Hz), 7.29 (2H, broad s), 7.73 (1H, d, J=11Hz), 9.88 (1H, d, J=8Hz) (8) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(2-methyl-5-oxo-6-hydroxy-2,5-dihydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 165 to 170°C (dec.) IR (Nujol) : 3300, 3200, 1780, 1680, 1640, 1530 cm⁻¹ (9 ) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-carbamoyloxymethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 125 to 130°C (dec.) IR (Nujol) : 3450, 3350, 3260, 3200, 1770, 1720, 1680, 1650, 1600, 1530 cm⁻¹ (10) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(tetrazolo[1,5-b]pyridazin-6-yl) thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 170 to 175°C (dec.) IR (Nujol) : 3400, 3260, 3200, 1770, 1680, 1660, 1620, 1535 cm⁻¹ (11) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1H-tetrazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 145 to 150°C (dec.) IR (Nujol) : 3300, 1770, 1670, 1620, 1530 cm⁻¹ (12) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-vinyl-3-cephem-4-carboxylic acid (syn isomer) mp : 190 to 195°C (dec.) IR (Nujol) : 3420, 3320, 3250, 1770, 1670, 1615, 1530 cm⁻¹ (13) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,5-thiadiazol-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 120 to 125°C (dec.) IR (Nujol) : 3300, 3180, 1770, 1670, 1620, 1530 cm⁻¹ Example 9 To a mixture of benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-chloromethyl-3-cephem-4-carboxylate (syn isomer) (1.5 g) and sodium iodide (769 mg) in N,N-dimethylformamide was added 3-mercapto-4-methyl-5-oxo-6-hydroxy-4,5-dihydro-1,2,4-triazine (816 mg). After being stirred for 45 minutes at room temperature, the reaction mixture was poured into water. The resulting precipitates were collected by filtration and dissolved in ethyl acetate. The solution was washed with water, an aqueous solution of sodium bicarbonate and a saturated aqueous solution of sodium chloride successively, dried and evaporated under reduced pressure. The residue was triturated in diisopropyl ether and collected by filtration to give benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-methyl-5-oxo-6-hydroxy-4,5-dihydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylate (syn isomer) (1.25 g). IR (Nujol) : 1780, 1705, 1670, 1580, 1520 cm⁻¹ NMR (DMSO-d₆, δ) : 3.29 (3H, s), 3.68 (2H, m), 3.90, 4.14 (2H, ABq, J=14Hz), 5.18 (1H, d, J=5Hz), 5.75 (1H, dd, J=5Hz, 8Hz), 6.97 (1H, s), 7.03 (1H, t, J=72Hz), 7.30 (25H, m), 9.84 (1H, d, J=8Hz), 12.38 (1H, s) Example 10 To a mixture of [(Z)-2-cyanovinylthio]silver (492 mg) and acetonitrile (10 ml) was added sodium iodide (2.3 g) under stirring at 10°C. The mixture was stirred for 15 minutes at the same temperature and cooled to 5°C, and then a solution of benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-chloromethyl-3-cephem-4-carboxylate (syn isomer) (1.5 g) in acetonitrile (15 ml) was added thereto. The mixture was stirred for 30 minutes at 5°C and the solvent was evaporated to give a residue. To the residue was added a mixture of ethyl acetate (50 ml) and water (30 ml). The insoluble material was filtered off and the filtrate was allowed to stand. The separated organic layer was washed with water and an aqueous solution of sodium chloride successively, and dried over magnesium sulfate. The solvent was evaporated to give a residue. The residue was triturated in diisopropyl ether and collected by filtration to give benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(Z)-2-cyanovinylthiomethyl]-3-cephem-4-carboxylate (syn isomer) (1.40 g). mp : 105 to 110°C (dec.) IR (Nujol) : 3250, 2210, 1780, 1720, 1680, 1520, 1490 cm⁻¹ NMR (DMSO-d₆, δ) : 3.63 (2H, broad s), 3.97 (2H, broad s), 5.25 (1H, d, J=5Hz), 5.63 (1H, d, J=11Hz), 5.78 (1H, dd, J=5Hz, 8Hz), 6.93 (1H, s), 7.0 (1H, s), 7.10 (1H, t, J=72Hz), 7.15-7.60 (15H + 10H + 1H), 8.90 (1H, broad s), 9.87 (1H, d, J=8Hz) Example 11 The following compounds were obtained according to similar manners to those of Examples 9 and 10. (1) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1780, 1680, 1530 cm⁻¹ (2) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,3-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3200, 1780, 1680, 1520 cm⁻¹ (3) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1770, 1670, 1530 cm⁻¹ (4) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-methyl-5-oxo-6-hydroxy-4,5-dihydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 1770, 1690, 1680, 1580, 1520 cm⁻¹ (5) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,3-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1670, 1620, 1530 cm⁻¹ (6) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[1-(2-hydroxyethyl)-1H-tetrazol-5-yl]thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3230, 1780, 1680, 1530 cm⁻¹ (7) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[1-(2-hydroxyethyl)-1H-tetrazol-5-yl]thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1770, 1670, 1620, 1530 cm⁻¹ (8) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1780, 1650, 1590, 1530 cm⁻¹ (9) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1670, 1620, 1530 cm⁻¹ (10) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[1-{2-(N,N-dimethylamino)ethyl}-1H-tetrazol-5-yl]thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1660, 1530 cm⁻¹ (11) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido)-3-[1-{2-(N,N-dimethylamino)ethyl}-1H-tetrazol-5-yl]thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1670, 1610, 1530 cm⁻¹ (12) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(2-methyl-5-oxo-6-hydroxy-2,5-dihydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 125 to 130°C (dec.) IR (Nujol) : 3200, 1780, 1655, 1590, 1530 cm⁻¹ (13) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(2-methyl-5-oxo-6-hydroxy-2,5-dihydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 165 to 170°C (dec.) IR (Nujol) : 3300, 3200, 1780, 1680, 1640, 1530 cm⁻¹ (14) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(tetrazolo[1,5-b]pyridazin-6-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 170 to 175°C (dec.) IR (Nujol) : 3400, 3260, 3200, 1770, 1680, 1660, 1620, 1535 cm⁻¹ (15) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(tetrazolo[1,5-b]pyridazin-6-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 130 to 135°C (dec.) IR (Nujol) : 3200, 1785, 1680, 1595, 1575 1530 cm⁻¹ (16) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1H-tetrazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 145 to 150°C (dec.) IR (Nujol) : 3300, 1770, 1670, 1620, 1530 cm⁻¹ (17) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1H-tetrazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 115 to 120°C (dec.) IR (Nujol) : 3200, 1770, 1660, 1585, 1560, 1515 cm⁻¹ (18) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,5-thiadiazol-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3200, 1775, 1680, 1520 cm⁻¹ (19) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,5-thiadiazol-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 120 to 125°C (dec.) IR (Nujol) : 3300, 3180, 1770, 1670, 1620, 1530 cm⁻¹ (20) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(Z)-2-cyanovinylthiomethyl]-3-cephem-4-carboxylic acid (syn isomer) mp : 145 to 150°C (dec.) IR (Nujol) : 3260, 2210, 1770, 1675, 1620, 1560, 1530 cm⁻¹ (21) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 1780, 1670, 1620, 1530 cm⁻¹ (22) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3150, 1770, 1670, 1610, 1530 cm⁻¹ Example 12 To a solution of N,N-dimethylformamide (438 mg) in ethyl acetate (5 ml) was added phosphorus oxychloride (0.92 g) at 0°C and the mixture was stirred for 30 minutes at the same temperature to give a Vilsmeier reagent. To the Vilsmeier reagent was added a mixture of 2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetic acid (syn isomer) (2.39 g) and ethyl acetate (15 ml) at 0°C and the mixture was stirred for 30 minutes at the same temperature to give an activated acid solution. On the other hand, a mixture of 7-amino-3-(1-methyl-4-pyridiniothiomethyl)-3-cephem-4-carboxylate (2.36 g), N-trimethylsilylacetamide (13 g) and tetrahydrofuran (30 ml) was stirred for one hour at 30°C, cooled to -20°C and added all at once to the above obtained activated acid solution at -20°C, and the mixture was stirred for one hour at -20 to -10°C. The reaction mixture was poured into a mixture of ethyl acetate (60 ml) and water (60 ml), the organic layer was separated and the aqueous layer was extracted with ethyl acetate. The organic layer was combined and washed with an aqueous solution of sodium chloride, dried over magnesium sulfate and evaporated. The residue was triturated with diisopropyl ether to give 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-4-pyridiniothiomethyl)-3-cephem-4-carboxylate (syn isomer) (2.64 g). Example 13 To a solution of 2-(2-aminothiazol-4-yl)-2-difluoromethoxyiminoacetic acid (syn isomer) (948 mg) in N,N-dimethylformamide (20 ml) were added diisopropylethylamine (1.04 g) and mesyl chloride (920 mg) at -50°C, and the mixture was stirred for 30 minutes at the same temperature. On the other hand, a mixture of 7-amino-3-hydroxymethyl-3-cephem-4-carboxylic acid (1.0 g), N-trimethylsilylacetamide (16 g) and tetrahydrofuran (32 ml) was stirred for one hour at room temperature, cooled to -45°C and added all at once to the above obtained activated acid solution, and the mixture was stirred for 2 hours at -40 to -30°C. The reaction mixture was poured into a solution of sodium bicarbonate (1.68 g) in water (100 ml) and the mixture was washed with ethyl acetate (50 ml). The aqueous solution was adjusted to pH 3-4 with 10% hydrogen chloride, salted out and extracted twice with a mixture of tetrahydrofuran (50 ml) and ethyl acetate (50 ml). The extract was washed three times with an aqueous solution of sodium chloride and dried over magnesium sulfate. To the extract was added a solution of sodium 2-ethylhexanoate (0.66 g) in ether (25 ml) and the resulting precipitates were collected by filtration to give sodium 7-[2-(2-aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-hydroxymethyl-3-cephem-4-carboxylate (syn isomer) (0.73 g). IR (Nujol) : 3300, 1750, 1665, 1600, 1525 cm⁻¹ NMR (D₂O, δ) : 3.50, 3.60 (2H, ABq, J=18Hz), 4.27 (2H, s), 5.20 (1H, d, J=5Hz), 5.78 (1H, d, J=5Hz), 6.90 (1H, t, J=71Hz), 7.22 (1H, s) Example 14 The following compounds were obtained according to similar manners to those of Example 1 to 3, 12 and 13. (1) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3250, 1790, 1725, 1690, 1600, 1530 cm⁻¹ (2) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1,2,4-thiadiazol-5-yl) thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 135-140°C (dec.) IR (Nujol) : 3300, 3200, 1775, 1670, 1620, 1530 cm⁻¹ (3) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-carboxy-3-hydroxy-1,2-thiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3200, 1780, 1710, 1670, 1650, 1590, 1525 cm⁻¹ (4) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-carboxy-3-hydroxy-1,2-thiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 180-185°C (dec.) IR (Nujol) : 3300, 1760, 1660, 1600, 1530 cm⁻¹ (5) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(5-methyl-1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3200, 1780, 1680, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 2.67 (3H, s), 3.60 (2H, m), 4.17, 4.58 (2H, ABq, J=14Hz), 5.15 (1H, d, J=5Hz), 5.70 (1H, dd, J=5Hz, 8Hz), 6.98 (1H, s), 7.07 (1H, t, J=72Hz), 7.10-7.67 (15H, m), 8.92 (1H, broad s), 9.85 (1H, d, J=8Hz) (6) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(5-methyl-1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1680, 1610, 1530 cm⁻¹ (7) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3200, 1780, 1720 (s), 1680, 1630, 1590, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.60 (2H, m), 5.12 (1H, d, J=5Hz), 5.83 (1H, dd, J=5Hz, 8Hz), 7.00 (1H, s), 7.10 (1H, t, J=72Hz), 8.92 (1H, broad s), 9.87 (1H, d, J=8Hz) (8) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-cephem-4-carboxylic acid (syn isomer) NMR (DMSO-d₆, δ) : 3.62 (2H, m), 5.12 (1H, d, J=5Hz), 5.85 (1H, dd, J=5Hz, 8Hz), 6.47 (1H, t, J=2Hz), 6.98 (1H, s), 7.09 (1H, t, J=72Hz), 7.30 (2H, broad s), 9.90 (1H, d, J=8Hz) (9) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-ethyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 1780, 1680, 1630, 1590, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 1.17 (3H, t, J=7Hz), 3.55 (2H, ABq, J=7Hz), 3.25-3.72 (2H, m), 5.20 (1H, d, J=5Hz), 5.42, 5.58 (2H, ABq, J=14Hz), 5.67 (1H, dd, J=5Hz, 8Hz), 6.95 (1H, s), 7.05 (1H, t, J=72Hz), 7.00-7.67 (15H, m), 8.53 (1H, d, J=8Hz), 8.93 (1H, broad s), 8.83-9.17 (2H, m), 9.85 (1H, d, J=8Hz) (10) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-ethyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3270, 1770, 1670, 1610, 1530 cm⁻¹ (11) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-methoxy-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3150, 1770, 1670, 1635, 1610, 1560, 1515 cm⁻¹ (12) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-mesyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3160, 1770, 1670, 1610, 1530 cm⁻¹ (13) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-mesyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) NMR (DMSO-d₆, δ) : 3.23, 3.66 (2H, ABq, J=18Hz), 3.45 (3H, s), 5.26 (1H, d, J=5Hz), 5.45, 5.70 (2H, ABq, J=14Hz), 5.80 (1H, d, J=5Hz), 6.88 (1H, t, J=71Hz), 7.16 (1H, s), 8.58 (2H, d, J=6Hz), 9.35 (2H, d, J=6Hz) (14) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methylthio-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3200, 1770, 1660, 1610, 1530 cm⁻¹ (15) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-4-pyridiniothiomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 1765, 1670, 1630, 1600, 1535 cm⁻¹ (16) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(E)-2-(3-pyridylthio)vinyl]-3-cephem-4-carboxylate (syn isomer) NMR (DMSO-d₆, δ) : 3.67-4.0 (2H, m), 5.25 (1H, d, J=5Hz), 5.77 (1H, dd, J=5Hz, 8Hz), 6.53 (1H, d, J=16Hz), 6.90-7.70 (4H + 25H), 7.70-9.0 (4H, m), 9.90 (1H, d, J=8Hz) (17) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(E)-2-(1-methyl-3-pyridiniothio)vinyl]-3-cephem-4-carboxylate iodide (syn isomer) NMR (DMSO-d₆, δ) : 3.70, 4.0 (2H, ABq, J=18Hz), 4.30 (3H, s), 5.27 (1H, d, J=5Hz), 5.80 (1H, dd, J=5Hz, 8Hz), 6.47 (1H, d, J=16Hz), 6.90-7.60 (4H + 25H), 7.90-9.10 (4H, m), 9.92 (1H, d, J=8Hz) (18) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(E)-2-(1-methyl-3-pyridiniothio)vinyl]-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3170, 1760, 1665, 1600, 1530, 1490 cm⁻¹ (19) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-3-pyridiniothiomethyl)-3-cephem-4-carboxylate iodide (syn isomer) NMR (DMSO-d₆, δ) : 3.40-3.90 (2H, m), 3.90-4.40 (2H, m), 4.20 (3H, s), 5.25 (1H, d, J=5Hz), 5.90 (1H, dd, J=5Hz, 8Hz), 6.70-7.60 (3H + 25H), 7.70-8.0 (1H, m), 8.20-8.50 (1H, m), 8.60-8.83 (1H, m), 8.97 (1H, s), 9.83 (1H, d, J=8Hz) (20) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-3-pyridiniothiomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3180, 1760, 1670, 1600, 1530 cm⁻¹ (21) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-chloromethyl-3-cephem-4-carboxylate-1-oxide (syn isomer) NMR (DMSO-d₆, δ) : 3.30, 3.73 (2H, ABq, J=18Hz), 4.45 (2H, broad s), 5.27 (1H, d, J=5Hz), 5.78 (1H, dd, J=5Hz, 8Hz), 6.90-7.60 (3H + 25H), 8.90 (1H, broad s), 9.88 (1H, d, J=8Hz) (22) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-iodomethyl-3-cephem-4-carboxylate-1-oxide (syn isomer) NMR (DMSO-d₆, δ) : 3.0-4.0 (2H, m), 4.40 (2H, broad s), 5.05 (1H, d, J=5Hz), 5.80 (1H, d, J=5Hz, 8Hz), 6.70-7.80 (3H + 25H), 8.85 (1H, broad s), 9.53 (1H, d, J=8Hz) (23) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1-pyrrolidiniomethyl)-3-cephem-4-carboxylate-1-oxide iodide (syn isomer) NMR (DMSO-d₆, δ) : 1.73-2.20 (4H, m), 2.80 (3H, s), 3.10-3.50 (4H, m), 3.90-4.60 (2H), 5.13 (1H, d, J=5Hz), 5.90 (1H, dd, J=5Hz, 8Hz), 7.0-7.70 (10H + 15H + 2H), 8.83 (1H, s), 9.67 (1H, d, J=8Hz) (24) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1-pyrrolidiniomethyl)-3-cephem-4-carboxylate trifluoroacetate (syn isomer) NMR (DMSO-d₆, δ) : 1.70-2.20 (4H), 2.70 (3H, s), 3.0-4.0 (2H + 4H), 4.10, 4.50 (2H), 5.33 (1H, d, J=5Hz), 5.87 (1H, dd, J=5Hz, 8Hz), 7.0-7.70 (10H + 15H + 2H), 8.93 (1H, s), 9.90 (1H, d, J=8Hz) (25) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1-pyrrolidiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3180, 1770, 1670, 1610, 1535 cm⁻¹ Example 15 A mixture of 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-4-pyridiniothiomethyl)-3-cephem-4-carboxylate (syn isomer) (2.58 g), formic acid (25 ml) and water (7.5 ml) was stirred for 3.0 hours at 0°C and evaporated. The residue was triturated with acetone and dissolved in water (200 ml). The mixture was adjusted to pH 3.0 with an aqueous solution of sodium bicarbonate and the precipitates were filtered off. The aqueous layer was subjected to column chromatography on macroporus non-ionic adsorption resin "Diaion HP-20", and the elution was carried out with 30% aqueous solution of methanol. The fractions containing the object compound were collected, concentrated in vacuo and lyophilized to give 7-[2-(2-aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-4-pyridiniothiomethyl)-3-cephem-4-carboxylate (syn isomer) (270 mg). IR (Nujol) : 3300, 1765, 1670, 1630, 1600, 1535 cm⁻¹ NMR (D₂O + DMSO-d₆, δ) : 3.43, 3.70 (2H, ABq, J=15Hz), 4.16 (3H, s), 4.16, 4.42 (2H, ABq, J=14Hz), 5.13 (1H, d, J=5Hz), 5.73 (1H, d, J=5Hz), 6.91 (1H, t, J=71Hz), 7.16 (1H, s), 7.78 (2H, d, J=7Hz), 8.35 (2H, d, J=7Hz) Example 16 The following compounds were obtained according to similar manners to those of Examples 5 and 15. (1) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 135-140°C (dec.) IR (Nujol) : 3300, 3200, 1775, 1670, 1620, 1530 cm⁻¹ (2) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-carboxy-3-hydroxy-1,2-thiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 180-185°C (dec.) IR (Nujol) : 3300, 1760, 1660, 1600, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.67 (2H, broad s), 4.20 (2H, broad s), 5.22 (1H, d, J=5Hz), 5.80 (1H, dd, J=5Hz, 8Hz), 7.0 (1H, s), 7.10 (1H, t, J=72Hz), 9.90 (1H, d, J=8Hz) (3) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(5-methyl-1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1680, 1610, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 2.68 (3H, s), 3.55, 3.80 (2H, ABq, J=18Hz), 4.20, 4.53 (2H, ABq, J=14Hz), 5.17 (1H, d, J=5Hz), 5.77 (1H, dd, J=5Hz, 8Hz), 6.99 (1H, s), 7.08 (1H, t, J=72Hz), 7.23 (2H, broad s), 9.90 (1H, d, J=8Hz) (4) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-cephem-4-carboxylic acid (syn isomer) NMR (DMSO-d₆, δ) : 3.62 (2H, m), 5.12 (1H, d, J=5Hz), 5.85 (1H, dd, J=5Hz, 8Hz), 6.47 (1H, t, J=2Hz), 6.98 (1H, s), 7.09 (1H, t, J=72Hz), 7.30 (2H, broad s), 9.90 (1H, d, J=8Hz) (5) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-ethyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3270, 1770, 1670, 1610, 1530 cm⁻¹ NMR (D₂O + NaHCO₃, δ) : 1.27 (3H, t, J=7Hz), 2.87 (2H, q, J=7Hz), 3.15, 3.63 (2H, ABq, J=18Hz), 5.24 (1H, d, J=7Hz), 5.27, 5.52 (2H, ABq, J=14Hz), 5.87 (1H, d, J=5Hz), 6.87 (1H, t, J=72Hz), 7.15 (1H, s), 7.93 (1H, dd, J=6Hz, 8Hz), 8.40 (1H, d, J=8Hz), 8.73 (1H, d, J=6Hz), 8.77 (1H, s) (6) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-methoxy-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3150, 1770, 1670, 1635, 1610, 1560, 1515 cm⁻¹ (7) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-mesyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3160, 1770, 1670, 1610, 1530 cm⁻¹ (8) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-mesyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) NMR (DMSO-d₆, δ) : 3.23, 3.66 (2H, ABq, J=18Hz), 3.45 (3H, s), 5.26 (1H, d, J=5Hz), 5.45, 5.70 (2H, ABq, J=14Hz), 5.80 (1H, d, J=5Hz), 6.88 (1H, t, J=71Hz), 7.16 (1H, s), 8.58 (2H, d, J=6Hz), 9.35 (2H, d, J=6Hz) (9 ) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methylthio-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3200, 1770, 1660, 1610, 1530 cm⁻¹ (10) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(E)-2-(1-methyl-3-pyridiniothio)vinyl]-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3170, 1760, 1665, 1600, 1530, 1490 cm⁻¹ (11) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-3-pyridiniothiomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3180, 1760, 1670, 1600, 1530 cm⁻¹ (12) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyimino-acetamido]-3-(1-methyl-1-pyrrolidiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3180, 1770, 1670, 1610, 1535 cm⁻¹ (13) Sodium 7-[2-(2-aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-hydroxymethyl-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 1750, 1665, 1600, 1525 cm⁻¹ Example 17 A solution of benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1-pyrrolidiniomethyl)-3-cephem-4-carboxylate trifluoroacetate (syn isomer) (1.25 g) in methylene chloride (4 ml) was stirred at 0-5°C, and anisole (2.6 ml) and trifluoroacetic acid (5.2 ml) were added thereto. The mixture was stirred for one hour at 0 - 5°C. To the reaction mixture was added diisopropyl ether, and the resultant precipitates were collected by filtration, washed with diisopropyl ether and dissolved in water (400 ml). The solution was subjected to column chromatography on macroporus non-ionic adsorption resin "Diaion HP-20" and the elution was carried out with 30% aqueous solution of methanol. The fractions containing the object compound were collected, concentrated in vacuo and lyophilized to give 7-[2-(2-aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1-pyrrolidiniomethyl)-3-cephem-4-carboxylate (syn isomer) (450 mg). IR (Nujol) : 3300, 3180, 1770, 1670, 1610, 1535 cm⁻¹ NMR (D₂O, δ) : 2.0-2.40 (4H), 2.96 (3H, s), 3.30-3.70 (4H), 3.43, 3.90 (2H, ABq, J=18Hz), 3.95, 4.72 (2H, ABq, J=14Hz), 5.33 (1H, d, J=5Hz), 5.85 (1H, dd, J=5Hz, 8Hz), 6.89 (1H, t, J=7Hz), 7.20 (1H, s) Example 18 A solution of benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(E)-2-(1-methyl- 3-pyridiniothio)vinyl]-3-cephem-4-carboxylate iodide (syn isomer) (1.9 g), tetrahydrofuran (60 ml) and water (4 ml) was subjected to column chromatography on Amberlite IRA-400 (CF₃COO ⊖ form) [Trademark, prepared by Rohm & Hass Co.] and the elution was carried out with a solution of water and tetrahydrofuran (1:15). The fractions containing the object compound were collected and evaporated. The residue was triturated with diisopropyl ether to give benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(E)-2-(1-methyl-3-pyridiniothio)vinyl]-3-cephem-4-carboxylate trifluoroacetate (syn isomer) (1.65 g). This compound was treated according to a similar manner to that of Example 17 to give 7-[2-(2-aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(E)-2-(1-methyl-3-pyridiniothio)vinyl]-3-cephem-4-carboxylate (syn isomer). IR (Nujol) : 3300, 3170, 1760, 1665, 1600, 1530, 1490 cm⁻¹ NMR (DMSO-d₆ + D₂O, δ) : 3.69 (2H, broad s), 4.30 (3H, s), 5.20 (1H, d, J=5Hz), 5.71 (1H, d, J=5Hz), 6.58 (1H, d, J=16Hz), 6.94 (1H, t, J=71Hz), 7.13 (1H, d, J=16Hz), 7.15 (1H, s), 7.76-8.0 (1H, m), 8.26-8.46 (1H, m), 8.46-8.63 (1H, m), 8.69 (1H, s) Example 19 The following compounds were obtained according to similar manners to those of Examples 7 and 17. (1) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 135-140°C (dec.) IR (Nujol) : 3300, 3200, 1775, 1670, 1620, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 2.53 (3H, s), 3.55, 3.76 (2H, ABq, J=18Hz), 4.25, 4.62 (2H, ABq, J=14Hz), 5.16 (1H, d, J=5Hz), 5.80 (1H, dd, J=5Hz, 8Hz), 7.0 (1H, s), 7.10 (1H, t, J=72Hz), 7.30 (2H, broad s), 9.88 (1H, d, J=8Hz) (2) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-carboxy-3-hydroxy-1,2-thiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 180-185°C (dec.) IR (Nujol) : 3300, 1760, 1660, 1600, 1530 cm⁻¹ (3) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(5-methyl-1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1680, 1610, 1530 cm⁻¹ (4) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-cephem-4-carboxylic acid (syn isomer) NMR (DMSO-d₆, δ) : 3.62 (2H, m), 5.12 (1H, d, J=5Hz), 5.85 (1H, dd, J=5Hz, 8Hz), 6.47 (1H, t, J=2Hz), 6.98 (1H, s), 7.09 (1H, t, J=72Hz), 7.30 (2H, broad s), 9.90 (1H, d, J=8Hz) (5) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-ethyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3270, 1770, 1670, 1610, 1530 cm⁻¹ (6) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-methoxy-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3150, 1770, 1670, 1635, 1610, 1560, 1515 cm⁻¹ (7) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-mesyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3160, 1770, 1670, 1610, 1530 cm⁻¹ (8) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-mesyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) NMR (DMSO-d₆, δ) : 3.23, 3.66 (2H, ABq, J=18Hz), 3.45 (3H, s), 5.26 (1H, d, J=5Hz), 5.45, 7.50 (2H, ABq, J=14Hz), 5.80 (1H, d, J=5Hz), 6.88 (1H, t, J=71Hz), 7.16 (1H, s), 8.58 (2H, d, J=6Hz), 9.35 (2H, d, J=6Hz) ( 9) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methylthio-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3200, 1770, 1660, 1610, 1530 cm⁻¹ (10) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-4-pyridiniothiomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 1765, 1670, 1630, 1600, 1535 cm⁻¹ (11) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-3-pyridiniothiomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3180, 1760, 1670, 1600, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 2.95-3.60 (2H), 4.18, 4.40 (2H, ABq, J=14Hz), 4.26 (3H, s), 4.96 (1H, d, J=5Hz), 5.50 (1H, dd, J=5Hz, 8Hz), 6.93 (1H, s), 7.03 (1H, t, J=71Hz), 7.28 (2H, broad s), 7.70-7.96 (1H, m), 8.36-8.73 (2H, m), 9.67 (1H, d, J=8Hz), 9.70 (1H, s) (12) Sodium 7-[2-(2-aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-hydroxymethyl-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 1750, 1665, 1600, 1525 cm⁻¹ Example 20 A mixture of 7-[2-(2-aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-acetoxymethyl-3-cephem-4-carboxylic acid (syn isomer) (3.0 g), 4-methoxypyridine (4.0 g), sodium iodide (8.0 g), acetonitrile (4.0 ml) and water (1.0 ml) was heated for 2.0 hours at 65 to 68°C, and then water (100 ml) was added thereto. The mixture was adjusted to pH 3.0 with 1N-hydrogen chloride and the resultant precipitates were filtered off. The aqueous layer was subjected to column chromatography on macroporus non-ionic adsorption resin "Diaion HP-20" and the elution was carried out with 30% aqueous methanol. The fractions containing the object compound were collected, concentrated in vacuo and lyophilized to give 7-[2-(2-aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-methoxy-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) (0.43 g). IR (Nujol) : 3300, 3150, 1770, 1670, 1635, 1610, 1560, 1515 cm⁻¹ NMR (D₂O, δ) : 3.62, 3.20 (2H, ABq, J=18Hz), 4.10 (3H, s), 5.26 (1H, d, J=5Hz), 5.35, 5.13 (2H, ABq, J=14Hz), 5.82 (1H, d, J=5Hz), 6.88 (1H, t, J=71Hz), 7.13 (1H, s), 7.42 (2H, d, J=7Hz), 8.65 (2H, d, J=7Hz) Example 21 A solution of benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-iodomethyl-3-cephem-4-carboxylate-1-oxide (syn isomer) (1.97 g) and N-methylpyrrolidine (204 mg) in tetrahydrofuran (10 ml) was stirred for 40 minutes at 0-5°C and then diisopropyl ether was added thereto. The resultant precipitates were collected by filtration, washed with diisopropyl ether and air-dried to give benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1-pyrrolidiniomethyl)-3-cephem-4-carboxylate-1-oxide iodide (syn isomer) (2.12 g). NMR (DMSO-d₆, δ) : 1.73-2.20 (4H, m), 2.80 (3H, s), 3.10-3.50 (4H, m), 3.90-4.60 (2H), 5.13 (1H, d, J=5Hz), 5.90 (1H, dd, J=5Hz, 8Hz), 7.0-7.70 (10H + 15H + 2H), 8.83 (1H, s), 9.67 (1H, d, J=8Hz) Example 22 The following compounds were obtained according to similar manners to those of Example 9, 10, 20 and 21. (1) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3250, 1790, 1725, 1690, 1600, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 2.50 (3H, s), 3.70 (2H, broad s), 4.25, 4.45 (2H, ABq, J=14Hz), 5.20 (1H, d, J=5Hz), 5.75 (1H, dd, J=5Hz, 8Hz), 6.97 (1H, s), 7.03 (1H, t, J=72Hz), 7.10-7.70 (10H + 15H), 8.90 (1H, s), 9.83 (1H, d, J=8Hz) (2) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 135-140°C (dec.) IR (Nujol) : 3300, 3200, 1775, 1670, 1620, 1530 cm⁻¹ (3) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-carboxy-3-hydroxy-1,2-thiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3200, 1780, 1710, 1670, 1650, 1590, 1525 cm⁻¹ (4) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-carboxy-3-hydroxy-1,2-thiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 180-185°C (dec.) IR (Nujol) : 3300, 1760, 1660, 1600, 1530 cm⁻¹ (5) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(5-methyl-1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3200, 1780, 1680, 1530 cm⁻¹ (6) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(5-methyl-1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1680, 1610, 1530 cm⁻¹ (7) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-ethyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 1780, 1680, 1630, 1590, 1530 cm⁻¹ (8) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-ethyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3270, 1770, 1670, 1610, 1530 cm⁻¹ ( 9) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-mesyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3160, 1770, 1670, 1610, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 3.43 (3H, s), 3.25, 3.69 (2H, ABq, J=18Hz), 5.25 (1H, d, J=5Hz), 5.39, 5.70 (2H, ABq, J=14Hz), 5.83 (1H, d, J=5Hz), 6.89 (1H, t, J=71Hz), 7.16 (1H, s), 8.20-8.45 (1H, m), 9.0-9.15 (1H, m), 9.20-9.40 (1H, m) (10) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-mesyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) NMR (DMSO-d₆, δ) : 3.23, 3.66 (2H, ABq, J=18Hz), 3.45 (3H, s), 5.26 (1H, d, J=5Hz), 5.45, 5.70 (2H, ABq, J=14Hz), 5.80 (1H, d, J=5Hz), 6.88 (1H, t, J=71Hz), 7.16 (1H, s), 8.58 (2H, d, J=6Hz), 9.35 (2H, d, J=6Hz) (11) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methylthio-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3200, 1770, 1660, 1610, 1530 cm⁻¹ NMR (D₂O + DMSO-d₆, δ) : 2.60 (3H, s), 3.16, 3.60 (2H, ABq, J=18Hz), 5.16, 5.50 (2H, ABq, J=14Hz), 5.25 (1H, d, J=5Hz), 5.80 (1H, d, J=5Hz), 6.86 (1H, t, J=71Hz), 7.13 (1H, s), 7.70-8.0 (1H, m), 8.16-8.40 (1H, m), 8.50-8.70 (1H, m), 8.80 (1H, s) (12) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-4-pyridiniothiomethyl)-3-cephem-4-carboxylate (syn isomer) (13) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido] ―3-(1-methyl-4-pyridiniothiomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 1765, 1670, 1630, 1600, 1535 cm⁻¹ (14) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-3-pyridiniothiomethyl)-3-cephem-4-carboxylate iodide (syn isomer) NMR (DMSO-d₆, δ) : 3.40-3.90 (2H, m), 3.90-4.40 (2H, m), 4.20 (3H, s), 5.25 (1H, d, J=5Hz), 5.90 (1H, dd, J=5Hz, 8Hz), 6.70-7.60 (3H + 25H), 7.70-8.0 (1H, m), 8.20-8.50 (1H, m), 8.60-8.83 (1H, m), 8.97 (1H, s), 9.83 (1H, d, J=8Hz) (15) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-3-pyridiniothiomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3180, 1760, 1670, 1600, 1530 cm⁻¹ (16) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1-pyrrolidiniomethyl)-3-cephem-4-carboxylate trifluoroacetate (syn isomer) NMR (DMSO-d₆, δ) : 1.70-2.20 (4H), 2.70 (3H, s), 3.0-4.0 (2H + 4H), 4.10, 4.50 (2H), 5.33 (1H, d, J=5Hz), 5.87 (1H, dd, J=5Hz, 8Hz), 7.0-7.70 (10H + 15H + 2H), 8.93 (1H, s), 9.90 (1H, d, J=8Hz) (17) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1-pyrrolidiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3180, 1770, 1670, 1610, 1535 cm⁻¹ Example 23 A solution of benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(E)-2-(3-pyridylthio)vinyl]-3-cephem-4-carboxylate (syn isomer) (1.74 g), N,N-dimethylformamide (17 ml) and methyl iodide (2.56 g) was stirred for 6.0 hours at room temperature and poured into diisopropyl ether (170 ml). The resultant precipitates were collected by filtration and washed with diisopropyl ether to give benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(E)-2-(1-methyl-3-pyridiniothio)vinyl]-3-cephem-4-carboxylate iodide (syn isomer) (1.98 g). NMR (DMSO-d₆, δ) : 3.70, 4.0 (2H, ABq, J=18Hz), 4.30 (3H, s), 5.27 (1H, d, J=5Hz), 5.80 (1H, dd, J=5Hz, 8Hz), 6.47 (1H, d, J=16Hz), 6.90-7.60 (4H + 25H), 7.90-9.10 (4H, m), 9.92 (1H, d, J=8Hz) Example 24 The following compound was obtained according to a similar manner to that of Example 23. Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-3-pyridiniothiomethyl)-3-cephem-4-carboxylate iodide (syn isomer) NMR (DMSO-d₆, δ) : 3.40-3.90 (2H, m), 3.90-4.40 (2H, m), 4.20 (3H, s), 5.25 (1H, d, J=5Hz), 5.90 (1H, dd, J=5Hz, 8Hz), 6.70-7.60 (3H + 25H), 7.70-8.0 (1H, m), 8.20-8.50 (1H, m), 8.60-8.83 (1H, m), 8.97 (1H, s), 9.83 (1H, d, J=8Hz) Example 25 A mixture of benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-chloromethyl-3-cephem-4-carboxylate (syn isomer) (35 g), m-chloroperbensoic acid (8.64 g) and ethyl acetate (300 ml) was stirred for 30 minutes at 0 to 5°C and then, water (300 ml), sodium bisulfite and sodium bicarbonate were added thereto. The organic layer was separated, washed with an aqueous solution of sodium chloride, dried over magnesium sulfate and evaporated. The residue was triturated with diisopropyl ether to give benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-chloromethyl-3-cephem-4-carboxylate-1-oxide (syn isomer) (29.93 g). NMR (DMSO-d₆, δ) : 3.30, 3.73 (2H, ABq, J=18Hz), 4.45 (2H, broad s), 5.27 (1H, d, J=5Hz), 5.78 (1H, dd, J=5Hz, 8Hz), 6.90-7.60 (3H + 25H), 8.90 (1H, broad s), 9.88 (1H, d, J=8Hz) Example 26 The following compounds were obtained according to a similar manner to that of Example 25. (1) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-iodomethyl-3-cephem-4-carboxylate-1-oxide (syn isomer) NMR (DMSO-d₆, δ) : 3.0-4.0 (2H, m), 4.40 (2H, broad s), 5.05 (1H, d, J=5Hz), 5.80 (1H, d, J=5Hz, 8Hz), 6.70-7.80 (3H + 25H), 8.85 (1H, broad s), 9.53 (1H, d, J=8Hz) (2) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1-pyrrolidiniomethyl)-3-cephem-4-carboxylate-1-oxide iodide (syn isomer) NMR (DMSO-d₆, δ) : 1.73-2.20 (4H, m), 2.80 (3H, s), 3.10-3.50 (4H, m), 3.90-4.60 (2H), 5.13 (1H, d, J=5Hz), 5.90 (1H, dd, J=5Hz, 8Hz), 7.0-7.70 (10H + 15H + 2H), 8.83 (1H, s), 9.67 (1H, d, J=8Hz) Example 27 A mixture of benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-chloromethyl-3-cephem-4-carboxylate-1-oxide (syn isomer) (29 g), sodium iodide (14.6 g) and acetone (300 ml) was stirred for 2.0 hours at 0-5°C and evaporated. To the residue were added ethyl acetate (400 ml) and water (300 ml), and the organic layer was separated, dried and evaporated. The residue was subjected to column chromatography on silica gel (600 g) and the elution was carried out with a mixture of chloroform and ethyl acetate (15:1). The fractions containing the object compound were combined and evaporated. The residue was triturated with diisopropyl ether to give benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-iodomethyl-3-cephem-4-carboxylate-1-oxide (syn isomer) (13.57 g). NMR (DMSO-d₆, δ) : 3.0-4.0 (2H, m), 4.40 (2H, broad s), 5.05 (1H, d, J=5Hz), 5.80 (1H, d, J=5Hz, 8Hz), 6.70-7.80 (3H + 25H), 8.85 (1H, broad s), 9.53 (1H, d, J=8Hz) Example 28 A mixture of benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1-pyrrolidiniomethyl)-3-cephem-4-carboxylate-1-oxide iodide (syn isomer) (1.45 g) and acetonitrile (14 ml) was stirred under cooling in an ice-bath, and N,N-dimethylaniline (490 mg) and phosphorus trichloride (555 mg) were added thereto. The mixture was stirred for one hour under cooling in an ice-bath, and then diisopropyl ether was added to the reaction mixture. The separated oil was triturated with diisopropyl ether to give benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1-pyrrolidiniomethyl)-3-cephem-4-carboxylate iodide. This compound was dissolved in a solution of tetrahydrofuran (54 ml) and water (3.6 ml). The solution was subjected to column chromatography on Amberlite IRA-400 (CF₃COO ⊖ form) and the elution was carried out with a solution of water and tetrahydrofuran (1:15). The fractions containing the object compound were collected and evaporated. The residue was triturated with diisopropyl ether to give benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1-pyrrolidiniomethyl)-3-cephem-4-carboxylate trifluoroacetate (syn isomer) (1.30 g). NMR (DMSO-d₆, δ) : 1.70-2.20 (4H), 2.70 (3H, s), 3.0-4.0 (2H + 4H), 4.10, 4.50 (2H), 5.33 (1H, d, J=5Hz), 5.87 (1H, dd, J=5Hz, 8Hz), 7.0-7.70 (10H + 15H + 2H), 8.93 (1H, s), 9.90 (1H, d, J=8Hz) Example 29 The following compounds were obtained according to a similar manner to that of Example 28. (1) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1770, 1670, 1530 cm⁻¹ (2) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-methyl-5-oxo-6-hydroxy-4,5-dihydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 1780, 1705, 1670, 1580, 1520 cm⁻¹ (3) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-methyl-5-oxo-6-hydroxy-4,5-dihydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 1770, 1690, 1680, 1580, 1520 cm⁻¹ (4) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,3-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1670, 1620, 1530 cm⁻¹ (5) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 1780, 1670, 1620, 1530 cm⁻¹ (6) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3150, 1770, 1670, 1610, 1530 cm⁻¹ (7) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[1-(2-hydroxyethyl)-1H-tetrazol-5-yl]thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3230, 1780, 1680, 1530 cm⁻¹ (8) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[1-(2-hydroxyethyl)-1H-tetrazol-5-yl]thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1770, 1670, 1620, 1530 cm⁻¹ ( 9) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1780, 1650, 1590, 1530 cm⁻¹ (10) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1670, 1620, 1530 cm⁻¹ (11) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[1-{2-(N,N-dimethylamino)ethyl}-1H-tetrazol-5-yl]thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1660, 1530 cm⁻¹ (12) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[1-{2-(N,N-dimethylamino)ethyl}-1H-tetrazol-5-yl]thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1670, 1610, 1530 cm⁻¹ (13) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(Z)-2-cyanovinylthiomethyl]-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3250, 2210, 1780, 1720, 1680, 1520, 1490 cm⁻¹ (14) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(Z)-2-cyanovinylthiomethyl]-3-cephem-4-carboxylic acid (syn isomer) mp : 145 to 150°C (dec.) IR (Nujol) : 3260, 2210, 1770, 1675, 1620, 1560, 1530 cm⁻¹ (15) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(2-methyl-5-oxo-6-hydroxy-2,5-dihydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 125 to 130°C (dec.) IR (Nujol) : 3200, 1780, 1655, 1590, 1530 cm⁻¹ (16) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(2-methyl-5-oxo-6-hydroxy-2,5-dihydro-1,2,4-triazin-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 165 to 170°C (dec.) IR (Nujol) : 3300, 3200, 1780, 1680, 1640, 1530 cm⁻¹ (17) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-carbamoyloxymethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 125 to 130°C (dec.) IR (Nujol) : 3450, 3350, 3260, 3200, 1770, 1720, 1680, 1650, 1600, 1530 cm⁻¹ (18) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-carbamoyloxymethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 125 to 130°C (dec.) IR (Nujol) : 3200, 1775, 1710, 1670, 1590, 1520 cm⁻¹ (19) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(tetrazolo[1,5-b]pyridazin-6-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 170 to 175°C (dec.) IR (Nujol) : 3400, 3260, 3200, 1770, 1680, 1660, 1620, 1535 cm⁻¹ (20) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(tetrazolo[1,5-b]pyridazin-6-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 130 to 135°C (dec.) IR (Nujol) : 3200, 1785, 1680, 1595, 1575, 1530 cm⁻¹ (21) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1H-tetrazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 145 to 150°C (dec.) IR (Nujol) : 3300, 1770, 1670, 1620, 1530 cm⁻¹ (22) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1H-tetrazol-5-yl) thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 115 to 120°C (dec.) IR (Nujol) : 3200, 1770, 1660, 1585, 1560, 1515 cm⁻¹ (23) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-vinyl-3-cephem-4-carboxylic acid (syn isomer) mp : 105 to 110°C (dec.) IR (Nujol) : 3200, 1770, 1680, 1650, 1585, 1565, 1520 cm⁻¹ (24) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-vinyl-3-cephem-4-carboxylic acid (syn isomer) mp : 190 to 195°C (dec.) IR (Nujol) : 3420, 3320, 3250, 1770, 1670, 1615, 1530 cm⁻¹ (25) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,5-thiadiazol-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3200, 1775, 1680, 1520 cm⁻¹ (26) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,5-thiadiazol-3-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 120 to 125°C (dec.) IR (Nujol) : 3300, 3180, 1770, 1670, 1620, 1530 cm⁻¹ (27) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1780, 1680, 1530 cm⁻¹ (28) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-chloromethyl-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 1780, 1720, 1670, 1590, 1520 cm⁻¹ (29) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,3-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3200, 1780, 1680, 1520 cm⁻¹ (30) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3250, 1790, 1725, 1690, 1600, 1530 cm⁻¹ (31) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methyl-1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 135-140°C (dec.) IR (Nujol) : 3300, 3200, 1775, 1670, 1620, 1530 cm⁻¹ (32) 7-[2-(2-Trithylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-carboxy-3-hydroxy-1,2-thiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3200, 1780, 1710, 1670, 1650, 1590, 1525 cm⁻¹ (33) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-carboxy-3-hydroxy-1,2-thiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) mp : 180-185°C (dec.) IR (Nujol) : 3300, 1760, 1660, 1600, 1530 cm⁻¹ (34) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(5-methyl-1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3200, 1780, 1680, 1530 cm⁻¹ (35) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(5-methyl-1,3,4-thiadiazol-2-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3250, 1770, 1680, 1610, 1530 cm⁻¹ (36) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3200, 1780, 1720 (s), 1680, 1630, 1590, 1530 cm⁻¹ (37) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-cephem-4-carboxylic acid (syn isomer) NMR (DMSO-d₆, δ) : 3.62 (2H, m), 5.12 (1H, d, J=5Hz), 5.85 (1H, dd, J=5Hz, 8Hz), 6.47 (1H, t, J=2Hz), 6.98 (1H, s), 7.09 (1H, t, J=72Hz), 7.30 (2H, broad s), 9.90 (1H, d, J=8Hz) (38) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-ethyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 1780, 1680, 1630, 1590, 1530 cm⁻¹ (39) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-ethyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3270, 1770, 1670, 1610, 1530 cm⁻¹ (40) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-methoxy-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3150, 1770, 1670, 1635, 1610, 1560, 1515 cm⁻¹ (41) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-mesyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3160, 1770, 1670, 1610, 1530 cm⁻¹ (42) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(4-mesyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) NMR (DMSO-d₆, δ) : 3.23, 3.66 (2H, ABq, J=18Hz), 3.45 (3H, s), 5.26 (1H, d, J=5Hz), 5.45, 5.70 (2H, ABq, J=14Hz), 5.80 (1H, d, J=5Hz), 6.88 (1H, t, J=71Hz), 7.16 (1H, s), 8.58 (2H, d, J=6Hz), 9.35 (2H, d, J=6Hz) (43) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(3-methylthio-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3200, 1770, 1660, 1610, 1530 cm⁻¹ (44) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-4-pyridiniothiomethyl)-3-cephem-4-carboxylate (syn isomer) (45) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-4-pyridiniothiomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 1765, 1670, 1630, 1600, 1535 cm⁻¹ (46) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(E)-2-(3-pyridylthio)vinyl]-3-cephem-4-carboxylate (syn isomer) NMR (DMSO-d₆, δ) : 3.67-4.0 (2H, m), 5.25 (1H, d, J=5Hz), 5.77 (1H, dd, J=5Hz, 8Hz), 6.53 (1H, d, J=16Hz), 6.90-7.70 (4H + 25H), 7.70-9.0 (4H, m), 9.90 (1H, d, J=8Hz) (47) Benzhydryl 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(E)-2-(1-methyl-3-pyridiniothio)vinyl]-3-cephem-4-carboxylate iodide (syn isomer) NMR (DMSO-d₆, δ) : 3.70, 4.0 (2H, ABq, J=18Hz), 4.30 (3H, s), 5.27 (1H, d, J=5Hz), 5.80 (1H, dd, J=5Hz, 8Hz), 6.47 (1H, d, J=16Hz), 6.90-7.60 (4H + 25H), 7.90-9.10 (4H, m), 9.92 (1H, d, J=8Hz) (48) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[(E)-2-(1-methyl-3-pyridiniothio) vinyl]-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3170, 1760, 1665, 1600, 1530, 1490 cm⁻¹ (49) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-3-pyridiniothiomethyl)-3-cephem-4-carboxylate iodide (syn isomer) NMR (DMSO-d₆, δ) : 3.40-3.90 (2H, m), 3.90-4.40 (2H, m), 4.20 (3H, s), 5.25 (1H, d, J=5Hz), 5.90 (1H, dd, J=5Hz, 8Hz), 6.70-7.60 (3H + 25H), 7.70-8.0 (1H, m), 8.20-8.50 (1H, m), 8.60-8.83 (1H, m), 8.97 (1H, s), 9.83 (1H, d, J=8Hz) (50) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-3-pyridiniothiomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3180, 1760, 1670, 1600, 1530 cm⁻¹ (51) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1-methyl-1-pyrrolidiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 3180, 1770, 1670, 1610, 1535 cm⁻¹ (52) Sodium 7-[2-(2-aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-hydroxymethyl-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 1750, 1665, 1600, 1525 cm⁻¹ Example 30 The following compounds were obtained according to similar manners to those of aforementioned Examples. (1) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(2-methyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) NMR (DMSO-d₆, δ) : 2.73 (3H, s), 3.43 (2H, broad s), 5.20 (1H, d, J=5Hz), 5.63 (2H, broad s), 5.87 (1H, dd, J=5Hz, 8Hz), 6.90 (1H, t, J=72Hz), 7.05-7.60 (15H, m), 7.70-8.27 (2H, m), 8.47 (1H, dd, J=6Hz, 8Hz), 8.92 (1H, broad s), 8.97 (1H, d, J=6Hz), 9.88 (1H, d, J=8Hz) (2) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(2-methyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3250, 1770, 1660, 1610, 1530 cm⁻¹ NMR (D₂O-NaHCO₃, δ) : 2.82 (3H, s), 3.17, 3.50 (2H, ABq, J=18Hz), 5.25 (1H, d, J=5Hz), 5.31, 5.57 (2H, ABq, J=14Hz), 5.85 (1H, d, J=5Hz), 6.90 (1H, t, J=72Hz), 7.15 (1H, s), 7.75-7.98 (2H, m), 8.33 (1H, dd, J=6Hz, 8Hz), 8.70 (1H, d, J=6Hz) (3) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-[2-(2-hydroxyethyl)-1-pyridiniomethyl]-3-cephem-4-carboxylate (syn isomer) NMR (D₂O-NaHCO₃, δ) : 3.14, 3.53 (2H, ABq, J=18Hz), 3.38 (2H, t, J=6Hz), 4.03 (2H, t, J=6Hz), 5.25 (1H, d, J=5Hz), 5.42, 5.62 (2H, ABq, J=14Hz), 5.85 (1H, d, J=5Hz), 6.88 (1H, t, J=72Hz), 7.20 (1H, s), 7.77-8.10 (2H, m), 8.43 (1H, dd, J=6Hz, 8Hz), 8.78 (1H, d, J=6Hz) (4) 7-[2-(2-Tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(2,3-dimethyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3200, 1780, 1670, 1590, 1570, 1620 cm⁻¹ NMR (DMSO-d₆, δ) : 2.37 (3H, s), 2.60 (3H, s), 3.30 (2H, broad s), 5.12 (1H, d, J=5Hz), 5.62 (2H, broad s), 5.70 (1H, dd, J=5Hz, 8Hz), 7.00 (1H, t, J=72Hz), 7.03 (1H, s), 6.50-7.60 (15H, m), 7.77 (1H, m), 8.37 (1H, d, J=8Hz), 8.75 (1H, d, J=6Hz), 9.82 (1H, d, J=8Hz) (5) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(2,3-dimethyl-1-pyridiniomethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3300, 1770, 1660, 1600, 1530 cm⁻¹ NMR (D₂O, δ) : 2.47 (3H, s), 2.71 (3H, s), 3.12, 3.40 (2H, ABq, J=18Hz), 5.22 (1H, d, J=5Hz), 5.32, 5.63 (2H, ABq, J=14Hz), 5.85 (1H, d, J=5Hz), 6.87 (1H, t, J=72Hz), 7.12 (1H, s), 7.66 (1H, dd, J=6Hz, 8Hz), 8.18 (1H, d, J=8Hz), 8.55 (1H, d, J=6Hz) (6) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,3,6-tetrahydropyridin-1-ylmethyl)-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1760, 1610, 1520 cm⁻¹ NMR (D₂O-NaHCO₃, δ) : 2.40 (2H, m), 3.25 (2H, t, J=7Hz), 3.40-3.65 (4H, m), 3.77, 4.00 (2H, ABq, J=14Hz), 5.25 (1H, d, J=5Hz), 5.82 (1H, d, J=5Hz), 5.50-6.10 (2H, m), 6.90 (1H, t, J=72Hz), 7.22 (1H, s) (7) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,3,4-tetrahydroisoquinolin-2-ylmethyl)-3-cephem-4-carboxylate-1-oxide (syn isomer) IR (Nujol) : 3270, 1780, 1720, 1670, 1590, 1520 cm⁻¹ NMR (DMSO-d₆, δ) : 3.30 (8H, m), 3.48, 3.82 (2H, ABq, J=14Hz), 5.07 (1H, d, J=5Hz), 5.80 (1H, dd, J=5Hz, 8Hz), 6.97 (1H, s), 7.03 (1H, t, J=72Hz), 7.05 (1H, s), 7.32 (25H, m), 8.85 (1H, broad s), 9.47 (1H, d, J=8Hz) (8) Benzhydryl 7-[2-(2-tritylaminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,3,4-tetrahydroisoquinolin-2-ylmethyl)-3-cephem-4-carboxylate (syn isomer) IR (Nujol) : 3325, 1785, 1710, 1680, 1520 cm⁻¹ NMR (DMSO-d₆, δ) : 3.10 (2H, m), 3.60 (4H, m), 4.03 (4H, m), 5.33 (1H, d, J=5Hz), 5.83 (1H, dd, J=5Hz, 8Hz), 6.97 (1H, s), 7.02 (1H, s), 7.10 (1H, t, J=72Hz), 7.37 (29H, m), 8.95 (1H, broad s), 9.92 (1H, d, J=8Hz) (9) 7-[2-(2-Aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,3,4-tetrahydroisoquinolin-2-ylmethyl)-3-cephem-4-carboxylic acid (syn isomer) IR (Nujol) : 3300, 1770, 1670, 1600, 1530 cm⁻¹ NMR (DMSO-d₆, δ) : 2.95 (4H, m), 3.50, 3.73 (2H, ABq, J=18Hz), 3.88 (2H, m), 4.20 (2H, m), 5.21 (1H, d, J=5Hz), 5.78 (1H, dd, J=5Hz, 8Hz), 7.02 (1H, s), 7.14 (1H, t, J=72Hz), 7.18 (4H, m), 7.35 (2H, broad s), 9.85 (1H, d, J=8Hz)

Claims: A compound of the formula: wherein R¹ is amino or a protected amino group, R² is carboxy, -COO ⊖ or a protected carboxy group, R³ is thiadiazolylthiomethyl, thiadiazolylthiomethyl substituted with C₁-C₆-alkyl, thiazolylthiomethyl substituted with hydroxy and carboxy, tetrazolylthiomethyl substituted with C₁-C₆ alkyl, tetrazolylthiomethyl substituted with di(C₁-C₆)alkylamino(C₁-C₆)alkyl, tetrazolylthiomethyl substituted with hydroxy(C₁-C₆)alkyl, dihydrotriazinylthiomethyl substituted with oxo, hydroxy and C₁-C₆-alkyl, tetrazolopyridazinylthiomethyl, pyridiniomethyl substituted with two C₁-C₆-alkyl groups, pyridiniomethyl substituted with hydroxy(C₁-C₆)alkyl, pyridiniomethyl substituted with C₁-C₆-alkyl, pyridiniomethyl substituted with C₁-C₆ alkoxy, pyridiniomethyl substituted with C₁-C₆ alkylthio, pyridiniomethyl substituted with C₁-C₆-alkanesulfonyl, vinyl, hydrogen, halomethyl, cyanovinylthiomethyl, carbamoyloxymethyl, pyridiniomethyl substituted with 1 to 3 substituent(s) selected from the group consisting of C₁-C₆-alkyl, C₁-C₆-alkylthio, C₁-C₆-alkoxy, hydroxy(C₁-C₆)alkyl and C₁-C₆-alkanesulfonyl, vinyl, hydrogen, pyridiniothiomethyl having C₁-C₆-alkyl, pyridylthiovinyl, pyridiniothiovinyl having C₁-C₆-alkyl, pyrrolidiniomethyl having C₁-C₆-alkyl, hydroxymethyl, tetrahydropyridylmethyl or tetrahydroisoquinolylmethyl, Z is -S- or X is an acid residue, n is O or 1, X¹ is halogen and X² is halogen, and pharmaceutically acceptable salts thereof. Syn isomer of a compound of claim 1, wherein group is Z is -S- and n is O. A compound of claim 2, wherein R¹ is amino or ar(lower)alkylamino, and R² is carboxy, -COO ⊖ or esterified carboxy. A compound of claim 3, wherein R¹ is amino or triphenyl(C₁-C₆)alkylamino, R² is carboxy, -COO ⊖ or ar(C₁-C₆)alkoxycarbonyl, R³ is 1,3,4-thiadiazolylthiomethyl, 1,2,4-thiadiazolylthiomethyl, 1,2,5-thiadiazolylthiomethyl, 1,2,3-thiadiazolylthiomethyl, 1,2,4-thiadiazolylthiomethyl substituted with C₁-C₆- alkyl, 1,3,4-thiadiazolylthiomethyl substituted with C₁-C₆ alkyl, 1,2-thiazolylthiomethyl substituted with hydroxy and carboxy, tetrazolylthiomethyl substituted with C₁-C₆ alkyl, tetrazolylthiomethyl substituted with di(C₁-C₆)alkylamino(C₁-C₆)alkyl, tetrazolylthiomethyl substituted with hydroxy(C₁-C₆)alkyl, 4,5-dihydro-1,2,4-triazinylthiomethyl substituted with oxo, hydroxy and C₁-C₆-alkyl, 2,5-dihydro-1,2,4-triazinylthiomethyl substituted with oxo, hydroxy and C₁-C₆-alkyl, tetrazolo[1,5-b]pyridazinylthiomethyl, halomethyl, cyanovinylthiomethyl, carbamoyloxymethyl, pyridiniomethyl substituted with two C₁-C₆-alkyl groups, pyridiniomethyl substituted with hydroxy(C₁-C₆)alkyl, pyridiniomethyl substituted with C₁-C₆- alkyl, pyridiniomethyl substituted with C₁-C₆- alkoxy, pyridiniomethyl substituted with C₁-C₆-alkylthio, pyridiniomethyl substituted with C₁-C₆- alkanesulfonyl, vinyl, hydrogen, pyridiniothiomethyl having C₁-C₆- alkyl, pyridylthiovinyl, pyridiniothiovinyl having C₁-C₆- alkyl, pyrrolidiniomethyl having C₁-C₆- alkyl, hydroxymethyl, tetrahydropyridylmethyl or tetrahydroisoquinolylmethyl, X¹ is fluorine, and X² is fluorine. A compound of claim 4, wherein R¹ is amino, R² is carboxy, and R³ is 1,2,4-thiadiazolylthiomethyl. A compound of claim 5, which is 7-[2-(2-aminothiazol-4-yl)-2-difluoromethoxyiminoacetamido]-3-(1,2,4-thiadiazol-5-yl)thiomethyl-3-cephem-4-carboxylic acid (syn isomer). A process for preparing a compound of the formula: wherein R¹ is amino or a protected amino group, R² is carboxy, -COO ⊖ or a protected carboxy group, R³ is thiadiazolylthiomethyl, thiadiazolylthiomethyl substituted with C₁-C₆-alkyl, thiazolylthiomethyl substituted with hydroxy and carboxy, tetrazolylthiomethyl substituted with C₁-C₆ alkyl, tetrazolylthiomethyl substituted with di(C₁-C₆)alkylamino(C₁-C₆)alkyl, tetrazolylthiomethyl substituted with hydroxy(C₁-C₆)alkyl, dihydrotriazinylthiomethyl substituted with oxo, hydroxy and C₁-C₆-alkyl, tetrazolopyridazinylthiomethyl, pyridiniomethyl substituted with two C₁-C₆-alkyl groups, pyridiniomethyl substituted with hydroxy(C₁-C₆)alkyl, pyridiniomethyl substituted with C₁-C₆-alkyl, pyridiniomethyl substituted with C₁-C₆ alkoxy, pyridiniomethyl substituted with C₁-C₆ alkylthio, pyridiniomethyl substituted with C₁-C₆-alkanesulfonyl, vinyl, hydrogen, halomethyl, cyanovinylthiomethyl, carbamoyloxymethyl, pyridiniomethyl substituted with 1 to 3 substituent(s) selected from the group consisting of C₁-C₆- alkyl, C₁-C₆-alkylthio, C₁-C₆-alkoxy, hydroxy(C₁-C₆)alkyl and C₁-C₆- alkanesulfonyl, vinyl, hydrogen, pyridiniothiomethyl having C₁-C₆- alkyl, pyridylthiovinyl, pyridiniothiovinyl having C₁-C₆-alkyl, pyrrolidiniomethyl having C₁-C₆-alkyl, hydroxymethyl, tetrahydropyridylmethyl or tetrahydroisoquinolylmethyl, Z is -S- or X is an acid residue, n is O or 1, X¹ is halogen and X² is halogen, or a salt thereof, which comprises, (1) reacting a compound of the formula : wherein R², R³, Z, X and n are each as defined above, or its reactive derivative at the amino group or a salt thereof with a compound of the formula: wherein R¹, X¹ and X² are each as defined above, or its reactive derivative at the carboxy group or a salt thereof to give a compound of the formula: wherein R¹, R², R³, Z, X, X¹, X² and n are each as defined above, or a salt thereof, or (2) subjecting a compound of the formula: wherein R², R³, Z, X, X¹, X² and n are each as defined above, and R 1 / a is a protected amino group, or a salt thereof to elimination reaction of the amino protective group to give a compound of the formula: wherein R², R³, Z, X, X¹, X² and n are each as defined above, or a salt thereof, or (3) reacting a compound of the formula : wherein R¹, R², Z, X¹ and X² are each as defined above, and Y is an acid residue, or a salt thereof with a compound of the formula: R⁴ wherein R⁴ is pyridine substituted with 1 to 3 substituent(s) selected from the group consisting of C₁-C₆-alkyl, C₁-C₆-alkylthio, C₁-C₆-alkoxy, hydroxy(C₁-C₆)alkyl and C₁-C₆-alkanesulfonyl, pyrrolidine having C₁-C₆- alkyl, tetrahydropyridine, tetrahydroisoquinoline, or a compound of the formula: H-S-R⁵·(X ⊖ ) n wherein X and n are each as defined above, and R⁵ is heterocyclic group which may be substituted with suitable substituent(s), cyanovinyl or pyridinio having C₁-C₆-alkyl, or a salt thereof to give a compound of the formula : wherein R¹, R², Z, X¹, X² and n are each as defined above, R 4 / a is pyridinio substituted with 1 to 3 substituent(s) selected from the group consisting of C₁-C₆-alkyl, C₁-C₆- alkylthio, C₁-C₆- alkoxy, hydroxy(C₁-C₆)alkyl and C₁-C₆-alkanesulfonyl, pyrrolidinio having C₁-C₆- alkyl, tetrahydropyridyl, tetrahydroisoquinolyl, or a group of the formula: -S-R⁵ wherein R⁵ is as defined above, W is Y as defined above or X as defined above, or a salt thereof, or (4) reacting a compound of the formula : wherein R¹, Z, X¹ and X² are each as defined above, R 2 / b is carboxy or a protected carboxy group, and A is -CH₂- or -CH=CH-, or a salt thereof with a compound of the formula : X-R⁶ wherein X is as defined above, and R⁶ is C₁-C₆-alkyl, to give a compound of the formula : wherein R¹, R 2 / b, R⁶, Z, A, X, X¹ and X² are each as defined above, or a salt thereof, or (5) oxidizing a compound of the formula : wherein R¹, R², R³, X, X¹, X² and n are each as defined above, or a salt thereof to give a compound of the formula : wherein R¹, R², R³, X, X¹, X² and n are each as defined above, or a salt thereof, or (6) reducing a compound of the formula : wherein R¹, R², R³, X, X¹, X² and n are each as defined above, or a salt thereof to give a compound of the formula : wherein R¹, R², R³, X, X¹, X² and n are each as defined above, or a salt thereof. A pharmaceutical composition comprising an effective amount of a compound of claim 1 or pharmaceutically acceptable salt thereof in association with a pharmaceutically acceptable, substantially non-toxic carrier or excipient. A method for producing a pharmaceutical composition which comprises mixing a compound of claim 1 or pharmaceutically acceptable salt thereof as an active ingredient with an inert carrier. Use of the compound of claim 1 for the manufacture of a medicament for treating an infectious disease caused by pathogens.

Inventors: MATUO, TERUAKI, MIYAI, KENZI, SAKANE, KAZUO, TAKAYA, TAKAO
Applicants: FUJISAWA PHARMACEUTICAL CO., LTD.
Application year: 1986
Main classification: C07D501
IPC codes: A61K31, C07D501, A61P31, C07D277