2-(lndol-2-yl)ethyl heterocumulenes undergo ring-closure under acid, 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 heterocumulene.
Regiospecific preparation of γ-carbolines andpyrimido[3, 4-a]indole derivatives by intramolecular ring-closure of heterocumulene-substituted indoles
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 γ-carbolines ordihydropyrimido[3, 4-a]indoles in a completely regiospecific fashion. The mode of cyclization strongly depends on the cyclizating