Preparation of 7-acylamino-3-(thio-substituted)-methyl 3-cephem-4-carboxylic acid-1-oxide derivatives

Abstract

A novel process for the preparation of 7-acylamino-3-(thio-substituted)-methyl-3-cephem-4-carboxylic acid 1-oxide derivatives comprising reacting a 7-acylamino-3-bromomethyl-3-cephem-4-carboxylic acid-1-oxide derivative with a silylated thiol of the formula R--S--Si(CH.sub.3).sub.3 I wherein R is an organic group, preferably a 5- or 6-membered heterocyclic group, which reaction is preferably carried out in the presence of an inert organic solvent at a temperature between -20.degree. and 80.degree. C. to obtain the corresponding 7-acylamino-3-(R-thiomethyl)-3-cephem-4-carboxylic acid-1-oxide derivatives, which are valuable intermediates in methods for the preparation of therapeutically active cephalosporins.

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