Kinetics and mechanism of oxidation of alpha-amino acids by N-bromosuccinimiole

The kinetics of the oxidative decarboxylation of amino acids promoted by N-bromosuccinimiole (NBS) has been studied by spectrophotometry in aqueous acid and alkaline medium, The reaction was first order in NBS, and fractional order in amino acids, It was found that the pseudo first-order ([AA](0) much greater than [NBS](0)) rate constants decreases with the increase of [OH-](see Fig. 2), and ionic strength and diffusion have no effect on the rare constants. Based on the experimental results, a mechanism involving the formatin of an intermediate, its slow decomposition to an imine, and subsequent rapid conversion of inline to products is proposed and the derived rate law was in good agreement with the experimental observations and the preequilibrium constants, rate constant of the rate-determining step together with the activation parameters were evaluated.