Some Derivatives of 1-Benzazepine. Part II

We have investigated the ring expansion of some substituted 1,4-naphthoquinones by hydrazoic acid to yield new 1-benzazepine derivatives of the "azatropolone" type. Ring contraction of those products, which are 2,5-dihydro-3-hydroxy-2,5-dioxo-1-benzazepines, gives 4-quinolone-2-carboxylic acids. Some of the reactions of the new benzazepine system were investigated. Attempts to prepare substituted derivatives suitable for making 1-benzazatrop-5-one were not successful.The effect of substituents on the ring expansion reaction is discussed and an anomalous ring expansion to a 2,5-dihydro-4-hydroxy-2,5-dioxo-1-benzazepine is described and explained mechanistically.