Process for the preparation of penicillins

摘要

There are prepared the compounds of the accompanying formula I <IMAGE> in which <IMAGE> represents an optionally substituted benzene ring or N-heterocycle, <IMAGE> represents a pyridine, pyrazine or pyridazine ring and X represents oxygen or sulphur. The meaning of the substituents R1, R2, R3 and Y can be taken from Patent Claim 1. Preparation takes place by formation of one of the amide bonds, located in the left-hand moiety of the formula, from the corresponding carboxylic acid or a reactive derivative thereof and the corresponding alpha -aminobenzylpenicillin or the 6-aminopenicillanic acid or an ester thereof; when using the latter the ester group is then removed. The compounds are active against Pseudomonas and have a broad antimicrobial spectrum.