Abstract: A novel process for the preparation of thioethers comprising reacting a silylated thiol of the formulaR--S--SiR.sub.1 R.sub.2 R.sub.3 Iwherein 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.

Abstract: 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 formulaX--NH--Y Iwherein 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.

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 formulaR--S--Si(CH.sub.3).sub.3 Iwherein 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.

Abstract: An improved process for the preparation of 3'-bromo-desacetoxycephalosphoranic acid sulfoxide compounds comprising protecting the 4-carboxy group of a 3'-unsubstituted cephalosporanic acid sulfoxide by silylating in an inert anhydrous organic solvent and brominating the silylated compound in situ which 3'-bromo compounds are valuable intermediates for the preparation of therapeutically useful cephalosporanic acid compounds.

Abstract: Novel bromo-substituted deacetoxycephalosporins of the formula ##STR1## wherein R.sub.1 is selected from the group consisting of benzamido, formamido, phenylacetamido and phenoxyacetamido, R.sub.2 is selected from the group consisting of hydrogen and bromine and R.sub.3 is a silyl group of the formula ##STR2## wherein R', R" and R'" are individually selected from the group consisting of alkyl of 1 to 6 carbon atoms, a halogen-substituted alkyl of 1 to 6 carbon atoms and aryl, which are suitable intermediates in processes for the preparation of antibiotics and their preparation.

Abstract: An improved process for the preparation of 3-bromomethyl-3-cephem sulfoxide derivatives of the formula ##STR1## wherein R.sub.1 is an acylamido group and R.sub.2 is a group protecting the carboxy radical which are valuable intermediates for the preparation of various therapeutically useful cephalosporanic acid derivatives.