1-Benzazepines. The Synthesis and Reactivity of 2-Chloro-1,5-Dimethyl-1h-1-Benzazepines

Abstract

Treatment of laevulinic acid with N- methylaniline yields 1,5-dimethyl- 1H-1-benzazepin-2(3H)-one and 5-methyl-5-[4-( methylamino )phenyl]-1- phenylpyrrolidin-2-one. The structure of the latter is confirmed by a single-crystal X-ray study. The yield of benzazepinone is increased if either m- methoxy-N-methylaniline or m-methyl-N- methylaniline is allowed to react with laevulinic acid. Treatment of the benzazepinones with phosphoryl chloride in pyridine produces 2-chloro-1,5-dimethyl-1H-1- benzazepines in quantitative yields, but these compounds are highly reactive under acidic conditions, undergoing nucleophilic displacement at C2. In contrast, treatment of benzazepinones with neat phosphoryl chloride yields yellow dimers , assigned as 2′-chloro-1,1′,5,5′- tetramethyl-2,3′-bi-1H-1-benzazepines, and with stabilities only marginally greater than those of the 2-chloro-1,5-dimethyl-1H-1- benzazepines.