Synthesis of tricyclic β-lactams related to cephalosporins

Abstract

Several compounds related to the cephalosporin antibiotics and containing a novel tricyclic β-lactam system have been prepared in the expectation that they might have a more strained β-lactam ring than the parent compounds. In the event, synthetic problems required that the compounds prepared containing this system had a reduced thiazine ring. The ring strain was not exceptional as judged by the absorption frequencies in the infra red.