Hydrolysis of activated esters catalyzed by L -histidine graft copolymers This manuscript is dedicated to Professor George M. Manecke on the occasion of his 60th birthday.

Abstract

A graft copolymer of L -histidine on polyethylenimine has been demonstrated to be an efficient catalyst for the hydrolysis of activated phenyl esters in aqueous systems. A lack of any significant cooperative effects between neighboring imidazoles or amines has been shown by a study of the catalytic solvolysis of p -nitrophenyl acetate at varying pH. A similar study with 4-acetoxy-3-nitrobenzoic acid has displayed a bell-shaped pH-rate profile indicative of electrostatic interactions between the catalyst and substrate. Hydrophobic interactions were also evident from an investigation of the hydrolytic rates of a series of 4-acyloxy-3-nitrobenzoic acids. In an attempt to demonstrate stereospecific catalyzed reactions, the hydrolyses of optically active esters catalyzed by the optically active copolymer were studied.