PROCESS FOR THE PREPARATION OF NEW DERIVATIVES OF CEPHALOSPORINS USABLE AS ANTIBIOTICS

摘要

This invention concerns a process for the preparation of products with the formula : (1) in which COOA is an acidic radical, salt or ester, R1 represents a group: in which RA and RB are H or alkyl or form a cycloalkyl with the carbon with which they are bonded, R2 and R3 are H, alkyl or alkenyl, R4 and R5 are H, alkyl or alkenyl or form a ring with the nitrogen atom with which they are bonded. The said process consisting of causing amino- bromoethyl cepheme-3 carboxylate of tertiobutyl-4 S-oxide to react with an amino acid with the formula : followed, after elimination of the protector groups, by the reaction of the product obtained with a thiourea.