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].ClCl.BrBr>>[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: BrBr
Agent: ClCl
Agent: N[n+]1ccccc1
Product: O=C1C[C@H]2SC=CCN12

Procedure:
The invention above all relates to the manufacture of 3-cephem compounds of the formula IA, wherein R1a denotes hydrogen or an acyl group of the formula ##STR4## wherein Ra denotes phenyl or hydroxyphenyl, for example 3- or 4-hydroxyphenyl, and 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 be 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, 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 also 1,4-cyclohexadienyl or 1-cyclohexenyl, X represents oxygen or sulphur, m represents 0 or 1 and Rb represents hydrogen or, when m represents 0, 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, or 3-guanylureido, and also sulphoamino or tritylamino, as well as arylthioamino, for example 2-nitrophenylthioamino, arylsulphonylamino, for example 4-methylphenylsulphonylamino, or 1-lower alkoxycarbonyl-2-propylideneamino, for example 1-ethoxycarbonyl-2-propylideneamino, carboxyl or carboxyl present in the form of a salt, for example in the form of an alkali metal salt, such as in the form of the sodium salt, as well as protected carboxyl, for example esterified carboxyl, such as phenyl-lower alkoxycarbonyl, for example diphenylmethoxycarbonyl, sulpho or sulpho present in the form of a salt, for example in the form of an alkali metal salt, such as in the form of the 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-halogeno-lower alkoxycarbonyloxy, such as 2,2,2-trichloroethoxycarbonyloxy, 2-iodoethoxycarbonyloxy or 2-bromoethoxycarbonyloxy, and also formyloxy, or 0-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 groups and/or carboxyl groups can also be protected and are present, for example, as acylamino, for example lower alkanoylamino, such as acetylamino, halogeno-lower alkanoylamino, such as dichloroacetylamino, benzoylamino or phthaloylamino, or, respectively, as esterified carboxyl, such as phenyl-lower alkoxycarbonyl, for example diphenylmethoxycarbonyl, and m preferably denotes 1 when Ra represents phenyl, hydroxyphenyl, hydroxychlorophenyl or pyridyl and m denotes 0 and Ro differs from hydrogen when Ra represents phenyl, hydroxyphenyl, hydroxy-chlorophenyl, thienyl, furyl, isothiazolyl, 1,4-cyclohexadienyl or 1-cyclohexenyl, R1b denotes hydrogen, R2 above all represents hydroxyl and also represents lower alkoxy, especially α-poly-branched lower alkoxy, for example tert.-butoxy, 2-halogeno-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'-dimethoxydiphenylmethoxy, and also tri-lower alkylsilyloxy, for example trimethylsilyloxy, and R3 denotes hydrogen, lower alkyl, for example methyl, ethyl or n-butyl, as well as benzyl or diphenylmethyl which is optionally substituted, for example by halogen, such as chlorine or bromine, or lower alkoxy, such as methoxy, 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 and which contain a free amino group in the acyl radical of the formula B.