Cyclobutanone analogues of [beta]-lactams revisited: insights into conformational requirements for inhibition of serine- and metallo-[beta]-lactamases

New cyclobutanone analogues of penams and penems are prepared and analyzed for inhibition of class A,B,C, and D [beta]-lactamases. The cyclobutanones have represented the first type of reversible inhibitors to indicate moderate inhibition of both serine- and metallo-[beta]-lactamases and can be used for development of practical inhibitors.