SYNTHESIS AND EVALUATION OF THE HYDROLYTICAL STABILITY OF ETHYL 2-(ALPHA-AMINO ACID)GLYCOLATES AND ETHYL 2-(ALPHA-AMINO ACID)LACTATES

Four depsipeptides, ethyl 2-(O-glycyl)glycolate (1), ethyl 2-(O-glycyl)lactate (2), ethyl 2-(O-alanyl)glycolate (3) and ethyl 2-(O-alanyl)lactate (4) have been synthesized under mild reaction conditions and in relatively high yield. The hydrolytic stability of these esters in methanol, in presence of water and an organic base has been studied by means of proton NMR-spectroscopy. It was found that, under these conditions, these compounds hydrolyse slowly under and that no intermolecular condensation reactions occur. It was further demonstrated that the glycolate or lactate ester bond in these compounds hydrolyses much faster when compared to the ethyl ester. The potential use of these derivatives in synthesis and application of biodegradable polymers is discussed.