Specificity in the formation of a seven-membered ring in the synthesis of dihydro-1.5-benzodiazepinones from aromatic diamines

It is shown that a mixture of 7- and 8-substituted 2,3-dihydro-1,5-benzodiazepinones is formed in the reaction of unsymmetrical aromatic diamines (4-chloro-,4-methyl-, and 4-methoxy-o-phenylenediamines) with acetoacetic and benzoylacetic esters under severe conditions. The corresponding anilide of benzoylacetic acid, the cyclization of which again leads to a mixture of isomeric dehydrobenzodiazepinones, can be isolated (in the case of benzoylacetic ester) when the concentrations of the reacting substances and the reaction time are decreased; this makes it possible to assume amidation of the -keto acids as one of the steps in the high-temperature synthesis of dihydrobenzodiazepinones. The quantitative ratio of the isomers formed in the reaction was determined by UV spectroscopy. The UV, IR, and PMR spectral data are presented.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 6, pp. 834–838, June, 1977.