Process for the preparation of beta -lactam antibiotics

摘要

The present invention provides a process for the preparation of a fused bicyclic beta -lactam containing compound having an optionally salified free carboxylic acid group which process comprises the reaction of an ester of the formula (I): <IMAGE> (I) with halide ion; wherein R is the residue of the fused bicyclic beta -lactam containing compound, R1 is an alkyl group of 1-6 carbon atoms optionally substituted by an alkoxy group of 1-4 carbon atoms or is an optionally substituted phenyl group or an alkyl group of 1-4 carbon atoms substituted by an optionally substituted phenyl group; and R2 is a hydrogen atom or an alkyl group of 1-4 carbon atoms or is joined to R2 to form part of a 5- or 6- membered carbocyclic or heterocyclic ring.