PREPARATION AND STRUCTURE-ACTIVITY RELATIONSHIPS OF SOME 6α-SUBSTITUTED PENICILLINS

The influence on the antibacterial activity of introducing a 6α-methoxy group into carbenicillin, and various 6α-substituents into sulbenicillin and piperacillin was examined. Further variations of the side chain aryl group were examined in the 6α-methoxy substituted series. This led to the identification of disodium 6β-(D, L-2-carboxy-2-thien-3-ylacetamido)-6α-methoxypenicillanate (5b) as a β-lactamase stable derivative with useful activity against Enterobacteriaceae, and disodium 6β-[D-2-(4-aminophenyl)-2-sulfoacetamido]-6α-methoxypenicillanate (6e) with slightly lower activity against the Enterobacteriaceae but more active against Pseudontonas aeruginosa.