1-Hydroxytryptamine derivatives undergo nucleophilic substitution reaction on the indolenitrogen (Na) as a general reaction by the treatment with acid, providing a novel synthetic method for 1-aryltryptamines. Depending on the structures of nucleophiles, 5- and 7-substituted tryptamines can also be produced in addition to the 1-aryltryptamines.
The 2-alkoxy-3-hydroxyindolines produced by photo-oxygenation and reduction of indoles give 3-substituted indoles on treatment with nucleophiles in the presene of Lewis acids; for example, indoles give 2,2′-bi-indolyls.