Synthesis of 2-Substituted Tryptamines via Cyanide-Catalyzed Imino-Stetter Reaction

Herein, we describe the development of a two-step protocol for the synthesis of 2-substituted tryptamine derivatives from 2-aminocinnamyl nitriles and aldehydes. The cyanide-catalyzed imino-Stetter reaction of 2-aminocinnamyl nitriles and aldehydes provided 2-substituted indole-3-acetonitrile derivatives. Subsequent reduction of the nitrile group afforded the desired 2-substituted tryptamine derivatives. The utility of this protocol was demonstrated in the synthesis of a potential inhibitor of 15-lipoxygenase. Furthermore, the resulting 2-substituted indole-3-acetonitriles were converted to several 2,3-disubstituted indole derivatives upon transformation of the nitrile group into other functional groups.