STUDY OF THE ALKALINE-HYDROLYSIS OF THE AZETIDIN-2-ONE RING BY AB-INITIO METHODS - INFLUENCE OF THE SOLVENT

A comprehensive study of the alkaline hydrolysis of the beta-lactam ri ng of azetidin-2-one was carried out using ab initio molecular-orbital calculations at the RHF/6-31 + G level. The influence of the solvent on this reaction was investigated by using the reaction field method (SCRF); the solvent was found to suppress the interference of some gas -phase reactions and allow the presence of a transition state to be de tected as the nucleophile approaches the beta-lactam ring. The transit ion state corresponds to a structure where the OH- group lies at a dis tance of 1.927 Angstrom from the C=O group of the beta-lactam ring and exhibits a potential barrier of 13.6 kcal/mol.