On the reaction of 3-nitro-1,2-phenylenediamine with ethyl acetoacetate. Condensed dihydrodiazepinones

Condensation of 3‐nitro‐1,2‐phenylenediamine with ethyl acetoacetate in boiling xylene gave two isomeric 2,3‐dihydro‐4‐methyl‐9‐nitro‐ and 2,5‐dihydro‐4‐methyl‐6‐nitro‐1H‐1,5‐benzodiazepin‐2‐ones, the 9‐nitro derivative thermal rearrangement product N‐isopropenyl‐4‐nitrobenzimidazolone and a non cyclic acetoacetamide derivative. At room temperature these reactants afforded 2,3‐dihydro‐2‐ethoxycarbonyl‐methyl‐2‐methyl‐4‐nitrobenzimidazole.