Reaction SMILES: [S:1]1[C@@H:6]2[CH2:7][C:8](=[O:9])[N:5]2[CH:4]=[CH:3][CH2:2]1.[H][H].N[N+]1C=CC=CC=1.NC1C=C[NH+]=CC=1.O=O.[S].[Na]>>[S:1]1[C@@H:6]2[CH2:7][C:8](=[O:9])[N:5]2[CH:4]=[CH:3][CH2:2]1.[S:1]1[C@@H:6]2[CH2:7][C:8](=[O:9])[N:5]2[CH2:4][CH:3]=[CH:2]1
Reactant: [H][H]
Agent: N[n+]1ccccc1
Agent: Nc1cc[nH+]cc1
Agent: O=C1C[C@H]2SCC=CN12
Product: O=C1C[C@H]2SC=CCN12

Procedure:
The invention relates above all to 3-cephem compounds of the formula IA, wherein R1a denotes hydrogen, cyanoacetyl or an acyl group of the formula ##STR5## wherein Ra denotes phenyl or hydroxyphenyl, for example 3- or 4-hydroxyphenyl, also hydroxy-chlorophenyl, for example 3-chloro-4-hydroxyphenyl or 3,5-dichloro-4-hydroxyphenyl, it being possible for hydroxy substituents in such radicals to e protected by acyl radicals, such as optionally halogenated lower alkoxycarbonyl radicals, for example tert.-butoxycarbonyl or 2,2,2-trichloroethoxycarbonyl, as well as thienyl, for example 2- or 3-thienyl, 5-aminomethyl-2-thienyl and also pyridyl, for example 4-pyridyl, aminopyridinium, for example 4-aminopyridinium, furyl, for example 2-furyl, isothiazolyl, for example 4-isothiazolyl, or tetrazolyl, for example 1-tetrazolyl, or 1-cyclohexenyl or also 1,4-cyclohexadienyl, X represents oxygen or sulphur, m represents 0 or 1 and Rb and Rc each represent hydrogen or, if m represents 0, Rc represents hydrogen and Rb represents amino, as well as protected amino, such as acylamino, for example α-poly-branched lower alkoxycarbonylamino, such as tert.-butoxycarbonylamino, or 2-halogeno-lower alkoxycarbonylamino, for example 2,2,2-trichloroethoxycarbonylamino, 2-iodoethoxycarbonylamino or 2-bromoethoxycarbonylamino, or optionally lower alkoxy-substituted or nitro-substituted phenyl-lower alkoxycarbonylamino, for example 4-methoxybenzyloxycarbonylamino or diphenylmethoxycarbonylamino, dihydroxytriazinylcarbonylamino or 3-guanylureido, as well as sulphoamino or tritylamino and also arylthioamino, for example 2-nitrophenylthioamino, arylsulphonylamino, for example 4-methylphenylsulphonylamino, or 1-lower alkoxycarbonyl-2-propylindeneamino, for example 1-ethoxycarbonyl-2-propylideneamino, carboxyl or carboxyl present in the form of a salt, for example an alkali metal salt, such as a sodium salt, as well as protected carboxyl, for example etherified carboxyl, such as phenyl-lower alkoxycarbonyl, for example diphenylmethoxycarbonyl, sulpho or sulpho present in the form of a salt, for example an alkali metal salt, such as a sodium salt, as well as protected sulpho, hydroxyl, as well as protected hydroxyl, such as acyloxy, for example α-poly-branched lower alkoxycarbonyloxy, such as tert.-butoxycarbonyloxy, or 2-halogen-lower alkoxycarbonyloxy, such as 2,2,2-trichloroethoxycarbonyloxy, 2-iodoethoxycarbonyloxy or 2-bromoethoxycarbonyloxy, also formyloxy, or O-lower alkylphosphono or O,O'-di-lower alkylphosphono, for example O-methylphosphono or O,O'-dimethylphosphono, or denotes a 5-amino-5-carboxy-valeryl radical, wherein the amino and/or carboxyl groups can also be protected and respectively are present, for example, as acylamino, for example lower alkanoylamino, such as acetylamino, halogeno-lower alkanoylamino, such as dichloroacetylamino, benzoylamino or phthaloylamino, and as esterified carboxyl, such as phenyl-lower alkoxycarbonyl, for example diphenylmethoxycarbonyl, and m preferably denotes 1 if Ra represents phenyl, hydroxyphenyl, hydroxychlorophenyl or pyridyl, and m denotes O and Rb differs from hydrogen if Ra represents phenyl, hydroxyphenyl, hydroxychlorophenyl, thienyl, furyl, isothiazolyl, 1,4-cyclohexadienyl or 1-cyclohexenyl, or wherein m is O, Ra denotes phenyl, 2-thienyl or 2-furyl and Rb and Rc conjointly denote lower alkoxyimino, cycloalkoxyimino or phneylalkoxyimino in the syn-configuration, R1b denotes hydrogen, R2 above all represents hydroxyl and also represents lower alkoxy, especially α-poly-branched lower alkoxy, for example tert.-butoxy, 2-halogen-lower alkoxy, for example 2,2,2-trichloroethoxy, 2-iodoethoxy or 2-bromoethoxy, or diphenylmethoxy which is optionally substituted, for example by lower alkoxy, for example methoxy, for example diphenylmethoxy or 4,4'-dimethoxy-diphenylmethoxy, as well as tri-lower alkylsilyloxy, for example trimethylsilyloxy, and R3 denotes lower alkyl, for example methyl, ethyl or n-butyl, 2-amino-lower alkyl, such as 2-aminoethyl, carbo-lower alkoxy-lower alkyl, such as carbomethoxymethyl, as well as lower alkenyl, for example allyl, phenyl or phenyl-lower alkyl, for example benzyl, diphenyl or trityl, and also an aromatic heterocyclic radical which has 1 to 4 nitrogen atoms and/or an oxygen or sulphur atom and which is optionally substituted by lower alkyl, lower alkoxy or halogen, such as 1-methyl-5-tetrazolyl, as well as the 1-oxides of such 3-cephem compounds of the formula IA, and also the corresponding 2-cephem compounds of the formula IB, or salts, especially pharmaceutically usable, non-toxic salts, of such compounds having salt-forming groups, such as alkali metal salts, for example sodium salts, or alkaline earth metal salts, for example calcium salts, or ammonium salts, including those with amines, of compounds wherein R2 represents hydroxyl, or inner salts of compounds wherein R2 represents hydroxyl, and which contain a free amino group in the acyl radical of the formula B.