Condensation of Acetalcarboxylic Acid Esters and Tryptamine with Pictet-Spengler Reaction

Abstract

Condensation of tryptamine with ethyl β-diethoxyethylmalonate (II) and ethyl 3-diethoxy-carbonyl-5-diethoxyvalerate (III) was carried out by the Pictet-Spengler reaction. The products of this reaction were ethyl 3-oxo-1, 2, 3, 5, 6, 11b(H)hexahydroindo1o[3, 2-g]pyrrocoline-2-carboxylate (V) (Fig.2), and diethyl 4-oxo-1, 2, 3, 4, 6, 7, 12, 12b-octahydroindolo[2, 3-a]pyrido-coline-2-dicarboxylate (VII), and a by-product, ethyl 2-ethoxycarbonyl-3-oxo-1, 2, 3, 5, 6, 11b-hexahydroindo1o[3, 2-g]pyrrocoline-2-acetate (VIII). V was identified by its derivation to the known 3-oxo-1, 2, 3, 5, 6, 11b-hexahydro-11H-indolo[3, 2-g]pyrrocoline.