Synthetic procedures of N, N-dimethyltryptamine (DMT), an alkaloid of indole type and constituent of Anadenanthera peregrina (Legminosae), Prestonia amazonicum (Apocynaceae) etc., and its synthetic homologues, N, N-diethyltryptamine (DET) and N, N-dipropyltryptamine (DPT), are described. Reaction of 3-indoleglyoxylyl chloride, obtained quantitatively from indole and oxalyl chloride, with alkylamine (methyl-, ethyl- or propyl- amine) in dehydrated ether gives N, N-dialkyl-3-indoleglyoxylamide. Reduction of N, N-dialkyl-3-glyoxylamide with lithium aluminum hydride in dehydrated tetrahydrofuran affords N, N-dialkyltryptamine. The structure of each compound was confirmed by UV-, IR-, NMR- and mass- spectrometry. The data of these are shown here.