SYNTHESIS OF THE FIRST PENICILLIN DERIVATIVES WITH MEDIUM-SIZED LACTAM RING AND OF RELATED THIAZOLIDINES

The novel concept of penicillin derivatives 4 with a medium-sized inst ead of a beta-lactam ring is presented. Two synthetic paths were inven ted, resulting in the evaluation of the synthetic potential in the suc cinic, glutaric, and adipic acid series. A number of novel penicillin- derived thiazolidines were prepared, notably the derivatives 16 and 22 with anellated 7- and 13-membered lactam ring.