1-Benzazepines. Novel ring transformations occurring during the reactions of 5-methyl- and 5-phenyl-1,3-dihydro-2H-1-benzazepin-2-ones with phosphoryl chloride

Abstract

Treatment of 8-substituted (H, Me, MeO) 5-methyl-1,3-dihydro-2H-1-benzazepin-2-ones with phosphoryl chloride under reflux produces two products. X-Ray structure determination of the products from the 8-methoxy derivative shows them to be 2,12-dimethoxy-5,9-dimethyl-7H-[1]benzazepino-[1′,2′ : 1,2]pyrrolo[5,4-b]quinoline (major product) and 5-chloromethyl-2,11-dimethoxy-5,8-di-methyl-5,6-dihydroquino[1′,2′ : 1,2]pyrrolo-[5,4-b]quinoline (minor product). The corresponding reaction of 8-methoxy-5-phenyl-1,3-dihydro-2H-1-benzazepin-2-one yields 2,12-dimethoxy-5,9-diphenyl-7H-[1]benzazepino[1′,2′: 1,2]pyrrolo[5,4-b]quinoline as the sole product.

A mechanistic pathway is proposed in which the first step involves condensation of two molecules of the appropriate 2-chloro-5-methyl-1H-1-benzazepine or its 3H analogue.