[Studies on 1,5-benzodiazepine. I. Derivatives of 4-amino-1,5-benzodiazepine]

Condensation of o-phenylendiamine and N,N-dialkyl-ethoxycarbonylacetamides in the presence of phosphorus oxychloride afforded 2,3-dihydro-2-oxo-4-dialkylamino-1H-1,5-benzodiazepines. These same compounds with a substituent in the 3 position were obtained when N,N-dialkylamino-alpha-ethoxycarbonyl-alpha-alkylacetamides were employed in the reaction. In a similar manner from N-phenyl-o-phenylendiamine the synthesis of 1-phenyl-2,3-dihydro-2-oxo-4-dialkylamino-1H-1,5-benzodiazepines was achieved. The formation of benzimidazole-2-acetic acid derivatives was observed in these reactions.