The Bromodecarboxylation of Amino Acids: Formation of Nitriles* “r$

In previous papers from this laboratory (1, 2) it has been reported that a-amino acids undergo a quantitative decarboxylation.in aqueous solution when treated with N-bromosuccinimide. Under the conditions used\ (a temperature of 30” and a pH of 3 to 5), the reaction was complete in 30 minutes. Anomalies in behavior were observed with glycine and /3-alanine. The consumption of N-bromosuccinimide was typically somewhat more than 2 moles per mole of amino acid and was as high as 8 moles per mole in the case of histidine, tyrosine, and tryptophan. The reagent was consumed with great rapidity-in less than 5 minutes at room temperature. It was also shown that certain of the amino acids evolved nitrogen in amounts that corresponded to from 20% to 100% of the a-amino nitrogen present in the parent compound. We have now completed a study of the nongaseous reaction products which are herein identified as nitriles and aldehydes. It should be mentioned that Schiinberg et al. (3) reported that N-bromosuccinimide, when used in the bromodecarboxylation of alanine, leucine, and phenylglycine, yields aldehydes of one less carbon atom than the parent compounds, but these authors did not discuss the fate of the amino nitrogen.