The Chemistry of Indoles. CVII. A Novel Synthesis of 3, 4, 5, 6-Tetrahydro-7-hydroxy-1H-azepino[5, 4, 3-cd]indoles and a New Finding on Pictet-Spengler Reaction

Abstract

Serotonins were found to produce 3, 4, 5, 6-tetrahydro-7-hydroxy-1H-azepino[5, 4, 3-cd]indoles by simple heating with amines under an oxygen atmosphere. Serotonins also reacted with various aldehydes to provide 3, 4, 5, 6-tetrahydro-7-hydroxy-1H-azepino[5, 4, 3-cd]indoles rather than β-carbolines under basic conditions. In these novel reactions, the presence of the 5-hydroxy group on the indole nucleus was suggested to be essential. Possible mechanisms are discussed.