Reaction of Tryptamine and Aniline with δ-Valerolactone and Its Dehydro Derivatives. A New Synthesis of 1,2,3,4,6,7,12,12b-Octahydroindolo[2,3-a]quinolizine

Abstract

The reaction of tryptamine with δ-valerolactone in tetralin gave δ-hydroxyamide (3) as the main product and the lactam (4) as the minor product. However, the reaction of 5,6-dihydro-2-pyrone with tryptamine or aniline afforded a mixture of the corresponding αβ- and βγ-unsaturated lactams, whereas, 2-pyrone did not react with either tryptamine or aniline to give the corresponding pyridone. Cyclization of 3 or 4 by Bischler-Napieralski reaction and followed NaBH4 reduction provided a convenient synthesis of 1,2,3,4,6,7,12,-12b-octahydroindolo[2,3-a]quinolizine (23). © 1975, The Pharmaceutical Society of Japan. All rights reserved.