6-Substituted derivatives of clavulanic acid

摘要

The present invention provides the compounds of the formula (II): <IMAGE> (II) and salts and esters thereof wherein R1 is a hydrogen atom or an alkyl group of 1-4 carbon atoms and R2 is a hydrogen atom or an alkyl group of 1-4 carbon atoms or is joined to R1 to form part of a 5-, 6- or 7 membered carbocyclic ring. These compounds are beta -lactamase inhibitors able to enhance the effectiveness of pencillins and cephalosporins. Their preparation and compositions containing them are described.