Kinetics of the alkaline hydrolysis of several n-benzyloxycarbonyldipeptide methyl and ethyl esters

Abstract

The reaction rates of the alkaline hydrolysis of synthesized N -protected dipeptide methyl and ethyl esters were studied systematically. From the kinetic data the energies of activation, the pre-exponential factors and the reference values at 40°C were calculated. The rate of hydrolysis shows to be strongly dependent on the C-terminal amino acid in the sequence Gly ⪢ Ala/Met/Phe ⪢ Leu ⪢ Val/Pro. Surprisingly the N-terminal amino acid also exerts an effect, but in a different sequence. N-Terminal Phe in particular shows a relative accelerating effect. Remarkable is the significantly faster ester hydrolysis of glycine containing dipeptide ethyl esters in ethanol/water compared to the corresponding methyl esters in methanol/water.