Enzymatic synthesis of tryptamine and its halogen derivatives selectively labeled with hydrogen isotopes.

Abstract

Nine isotopomers of tryptamine and its halogen derivatives, labeled with deuterium, tritium in side chain, i.e., [(1R)-2H]-, [(1R)-3H]-, 5-F-[(1R)-2H]-, 5-F-[(1R)-3H]-, 5-Br-[(1R)-2H]-, double labeled [(1R)-2H/3H]-, 5-F-[(1R)-2H/3H]-, and ring labeled [4-2H]-, and [5-2H]-tryptamine, were obtained by enzymatic decarboxylation of l-Trp and its appropriate derivatives in deuteriated or tritiated media, respectively. Intermediates: [5′-2H]-l-Trp used for further decarboxylation was synthesized by enzymatic coupling of [5-2H]-indole with S-methyl-l-cysteine, and [4′-2H]-l-Trp was obtained by isotope exchange 1H/2H of the authentic l-Trp dissolved in heavy water induced by UV-irradiation. Doubly labeled [(1R)-2H/3H]- and 5-F-[(1R)-2H/3H]-tryptamine were obtain by decarboxylation of l-Trp or [5′-F]-l-Trp carried out in 2H3HO incubation medium.