C[Si](NS([O:9][Si:10]([CH3:13])([CH3:12])[CH3:11])(=O)=O)(C)C.[C:14]([NH:22][CH:23]1[C:35](=[O:36])[N:25]2[C:26]([C:32](O)=[O:33])=[C:27]([CH3:31])[CH2:28][S:29](=[O:30])[C@H:24]12)(=[O:21])[C:15]1[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1.[Br:37]N1C(=O)CCC1=O>ClCCl>[C:14]([NH:22][CH:23]1[C:35](=[O:36])[N:25]2[C:26]([C:32]([O:9][Si:10]([CH3:11])([CH3:12])[CH3:13])=[O:33])=[C:27]([CH2:31][Br:37])[CH2:28][S:29](=[O:30])[C@H:24]12)(=[O:21])[C:15]1[CH:20]=[CH:19][CH:18]=[CH:17][CH:16]=1207 mg (0.86 mmoles) of trimethylsilyl trimethylsilylamidosulfonate were added to a suspension of 353 mg (1.06 mmoles) of 7-benzamido-3-methyl-3-cephem-4-carboxylic acid-1-oxide in 25 ml of dichloromethane and the mixture was stirred at 40° C. for 3 hours. The colorless translucent suspension was cooled in an ice-bath and bromination was carried out in half an hour using 277 mg of N-bromosuccinimide (1.56 mmoles) as the brominating agent to obtain a 49% yield of trimethylsilyl 7-benzamido-3-bromomethyl-3-cephem-4-carboxylate-1-oxide.
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