Electrophilic substitution of indoles : Part XXI - Further investigation on the formation of the benzazepinone skeleton

Abstract

An interesting observation was made during the electrophilic substitution of indole with 5,5-dimethyl cyclohexane 1,3-dione resulting in the synthesis of 2,3,4,5, 10,11- hexahydro-3,3-dimelhyl-11- (indo-3-yl)-dibenz-[b,f]azepine-1-one system. The reactions with 2-methyl- and 3-methyl indoles resulted in the formation of only the 1:1 product. The structures of the products have been settled on the basis of their UV, IR.¹H and ¹³C NMR spectral studies and MS analysis.