Clavulanic acid derivatives their preparation and use

摘要

This invention provides the compounds of the formula (II): <IMAGE> (II) and salts and esters thereof, wherein R1 is H and R3 is H or an aryl, aralkyl, lower alkyl or substituted lower alkyl group or R1 and R3 are joined so that the CHR1.NH.CO.R3 moiety forms a group of the sub-formula (a): <IMAGE> wherein R4 is a hydrogen atom or a NH.CO.R5 group wherein R5 is a lower alkyl, lower alkoxy lower alkyl, aryl, aralkyl, aryloxyalkyl, lower alkoxy or aryloxy group. The compounds have beta -lactamase inhibitory and anti-bacterial properties. The invention also provides a process for their preparation, and pharmaceutical compositions containing them.