N-Chlorosuccinimide-Promoted Oxidative Decarboxylation of α-Amino Acids in Aqueous Alkaline Medium

Kinetics of oxidation of twelve α-amino acids (AA) by N-chlorosuccinimide (NClS) in aqueous alkaline media have been studied and compared with those of N-bromosuccinimide (NBS) oxidation. Analysis of the results shows that the observed rate of oxidation is first-order in [oxidant] and zero-order in [substrate]. The rate of oxidation increases with increase in [OH−]free in [NClS], the exception being the amino acids having β-alkyl substituent such as valine, leucine etc. Perusal of the results shows that NC1S/NBS reacts with α-amino acid anion to produce α-amino acyl hypohalite which then decomposes in the rate-determining step to give the products. The intermediate α-amino acyl hypohalite is identified by UV-visible absorption spectra. Glycine behaves differently from other amino acids in both oxidants. The proposed mechanism is consistent with the observed kinetics.