Synthesis of reactive gamma-lactams related to penicillins and cephalosporins

gamma-Lactams with structures analogous to both penicillin (1) and cephalos porin (2) antibiotics have been synthesised. These compounds show high reac tivity towards modest nucleophiles in keeping with their design as potentia l inhibitors of bacterial cell wall biosynthesis. Reactive gamma-lactam ana logues 27 and 29 of beta-lactamase inhibitors such as 22 have also been pre pared. An X-ray crystal structure of the cephalosporin analogue 8 has allow ed structural comparisons to be made with the classical beta-lactam antibio tic cephaloridine (30).