Pyridine—Azepine Structural Modification of 3,4-Dihydro-nor-isoharmine

Abstract

Structural modification of 3,4-dihydro-nor-isoharmine through expansion of the dihydropyridine ring to dihydroazepine was accomplished in two stages including pyridine-azepine recyclization of the quaternized substrate by the action of phenacyl halides and their heterocyclic analogs. The recyclization process can be accompanied by 1,2-migration of the acyl group to give mixtures of 4-acyl-9-methoxy-3-methyl-1,2-dihydroazepino[4,5-b]indoles and their 5-acyl-substituted isomers. Factor influencing the recyclization direction and product ratio were analyzed.