A novel way for the formation of α-amino acids and their derivatives in an aqueous medium

Abstract

In the course of a study of possible mechanism for chemical evolution in the primeval sea, we observed the formation of α-amino acids and N-acylamino acids from α-oxo acids and ammonia in an aqueous medium. Glyoxylic acid reacted with ammonia to form N-oxalylglycine, which gave glycine in a 5–39% yield after hydrolysis with 6N HCl. Similarly when glyoxylic acid was treated with methylamine it yielded N-oxalylsarcosine, which could be hydrolyzed to sarcosine with 17–25% overall yield upon hydrolysis. Pyruvic acid and ammonia reacted to give N-acetylalanine, which formed alanine in a 3–7% overall yield upon hydrolysis. The pH optima in these reactions were pH 3–4. These reactions were further extended to the formation of other amino acids. Glutamic acid, phenylalanine and serine were formed from α-ketoglutaric acid, phenylpyruvic acid and hydroxypyruvic acid, respectively, under similar conditions, N-Succinylglutamic acid was obtained as an intermediate for glutamic acid synthesis. Phenylacetylphenylalanineamide was also isolated as an intermediate for phenylalanine synthesis. Alanine, rather than aspartic acid, was produced from oxaloacetic acid. These reactions provide a novel route for the prebiotic synthesis of amino acids. A mechanism for the reactions is proposed.