OXIDATIVE ACYLATION USING THIOACIDS

Several important prebiotic reactions, including the coupling of amino acids into polypeptides by the formation of amide linkages, involve a cylation. Theae reactions present a challenge to the understanding of prebiotic synthesis. Condensation reactions relying on dehydrating age nts are either inefficient in aqueous solution(1,2) or require strongl y acidic conditions and high temperatures(3). Activated amino acids su ch as thioester derivatives have therefore been suggested as likely su bstrates for prebiotic peptide synthesis(4-7). Here we propose a close ly related route to amide bond formation involving oxidative acylation by thioacids. We find that phenylalanine, leucine and phenylphosphate are acylated efficiently in aqueous solution by thioacetic acid and o xidizing agent, From a prebiotic point of view, oxidative acylation ha s the advantage of proceeding efficiently in solution and under mild c onditions. We anticipate that oxidative acylation should prove to be a general method for activating carboxylic acids, including amino acids .