.beta.-Lactam antibacterial agents

Abstract

Compounds are described of the formula (II): ##STR1## wherein R.sub.1 is a group such that CO.sub.2 R.sub.1 is an ester group; A.sub.1 is a hydrogen atom; and A.sub.2 is a group CR.sub.2 R.sub.3 R.sub.4 wherein R.sub.2 is a hydrogen atom or a hydroxyl group; R.sub.3 is a hydrogen atom or a lower alkyl group; and R.sub.4 is a hydrogen atom or a lower alkyl group, a benzyl group, a phenyl group or is joined to R.sub.3 to form part of a C.sub.5-7 carboxylic ring or is a group of the formula CH(OH)R.sub.5 or CHX wherein R.sub.5 is a hydrogen atom or lower alkyl group and X is an oxygen atom or a CR.sub.6 R.sub.7 group where R.sub.6 is a hydrogen atom or a lower alkyl, phenyl, CN, CO.sub.2 R.sub.8 where R.sub.8 is a lower alkyl, phenyl or benzyl group and R.sub.7 is a hydrogen atom or a lower alkyl group or is joined to R.sub.6 to form part of a C.sub.5-7 carbocyclic ring. These compounds have been found to possess antibacterial properties. The preparation of these compounds is described.

Dependencies are inferred from the claim text.