A semi-empirical study of some clavulanic acid derivatives in relation to their activity as beta-lactamase inhibitors.

Clavulanic acid and some of its derivatives are inhibitors of beta-lactamases and hence enhance the activity of antibiotics such as cephaloridine, amoxycillin and ampicillin against beta-lactamase-producing bacteria. Several empirical structure-activity relationships have been proposed for these compounds; bearing these findings in mind, we have carried out a semi-empirical structural study on clavulanic acid and twelve of its derivatives lacking the carboxyl group. We relate our results to the available activity data, focusing on features such as planarity at the N atom, charge distribution and the orientation of the substituents, all of which are related to the activity of these systems.