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The kinetics of the Os(VII1)-catalyzed oxidation of glycine, alanine, valine, phenylalanine, isoleucine, lycine, and glutamic acid by alkaline hexacyanoferrate(II1) reveal that these reactions are zero order in hexacyanoferrate(II1) and first order in Os(VII1). The order in amino acid as well as in alkali is 1 a t [amino acid] Q2.5 X 10-2M and [OH-] S1.3 X 10-M, but less than unity a t higher concentrations of amino acids or alkali. The active oxidizing species under the experimental conditions is Os04(HzO) (OH)-. The ferricyanide is merely used up to regenerate the Os(VII1) species from Os(V1) formed during the reaction. The structural influence of amino acids on the reactivity has been discussed. The amino acids during oxidation are shown to be degraded through intermediate keto acids. The kinetic data are accommodated by considering the interaction between the conjugate base of the amino acids and the active oxidizing species of Os(VII1) to form a transient complex in the primary ratedetermining step. The catalytic effect of hexacyanoferrate(I1) has been rationalized.

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Die Reaktion der Diarylthioharnstoffe (I) mit Bromessigsäureethylester (II) zu den Thiazolidinonen (III) wird reaktionskinetisch untersucht.