REGIOSPECIFIC PREPARATION OF GAMMA-CARBOLINES AND PYRIMIDO[3,4-ALPHA]INDOLE DERIVATIVES BY INTRAMOLECULAR RING-CLOSURE OF HETEROCUMULENE-SUBSTITUTED INDOLES

摘要

Compounds resulting from the aza-Wittig reaction of iminophosphorane derived from 2-(2-azidoethyl)indole and carbon disulfide, diphenylketene, aldehydes and acyl chlorides undergo ring-closure under acidic, basic and thermal conditions to give either dihydro gamma-carbolines or dihydropyrimido[3,4-a]indoles in a completely regiospecific fashion. The mode of cyclization strongly depends on the cyclizating agent as well as the nature of the reagent. The related carbodiimides 9 undergo regiospecific cyclization to give dihydropyrimido[3,4-a]indoles under acidic, basic or thermal conditions. Copyright (C) 1996 Elsevier Science Ltd [References: 22]