structure of the products obtained from condensation on ethyl acetoacetate with 4-ethoxy-2-nitroaniline; attempt preparation of 2,3dihydro-7-ethoxy-4-methyl1H-1,5-benzodiazepine-2-one

ABSTRACT

The condensation of ethyl acetoacetate with 4-ethoxy-2-nitroaniline involves reaction. The amino group giving 4-ethoxy-2-nitroacetoacetanilide [1]. Reduction of [1] using Fe/NaCl gave the corresponding 2-amino-4-ethoxyaceto-acetnilide [2]. The structure of [2] was confirmed from IR, NMR and from reaction with HNO2 to give 1-[alpha-oximo-alpha-acetoacetyl] 5-ethoxy-benzotriazole [3]. While, reduction of [1] using Fe/HCl gave a mixture of [2] and 6-ethoxyl-1-isopropenyl-3H-benzimidazolin-2-one [4]. Heating 2 in xylene/piperidine afforded [4] and not 2,3-dihydro-7-ethoxy-4- methyl-1H-1,5-benzodiazepin-2-one. This was evidenced from NMR, mass spectrum and from reaction with HCl to afford 5-ethoxy-3H- benzimidazolin-2-one [5]