A novel process for the preparation of thioethers comprising reacting a silylated thiol of the formula R--S--SiR.sub.1 R.sub.2 R.sub.3 I wherein R is an organic group and R.sub.1, R.sub.2 and R.sub.3 are individually selected from the group consisting of alkyl of 1 to 4 carbon atoms with an organic halide, sulfate or sulfonate in the presence of hexamethylphosphoric triamide as a solvent or co-solvent preferably under neutral conditions in aprotic solvents at a temperature between 0.degree. and 150.degree. C.
An improved process for the trimethylsilylation of organic compounds with at least one active hydrogen atom with hexamethyldisilazane, the improvement comprising effecting the reaction in the presence of 0.001 to 10 mole percent of a catalyst of the formula X--NH--Y I wherein X and Y are individually an electron-withdrawing group or when X is an electron-withdrawing group, Y is selected from the group consisting of hydrogen and trialkylsilyl of 1 to 6 carbon atoms or X and Y together with the nitrogen atom to which they are attached form a cyclic electron-withdrawing group and novel trimethylsilylated thiols of the formula ##STR1## wherein R is a 5-or 6-membered heterocycle having at least one nitrogen or sulfur heteroatom and optionally substituted with at least one member of the group consisting of alkyl of 1 to 6 carbon atoms, phenyl, trimethylsilyl, trimethylsilyloxycarbonylmethyl and alkylamino of 1 to 6 carbon atoms, and novel trimethylsilylated 3'-substituted cephalosporanic acid derivatives.
Preparation of 7-acylamino-3-(thio-substituted)-methyl
申请人:Gist-Brocades N.V.
公开号:US04379923A1
公开(公告)日:1983-04-12
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.