[Condensation of N-alkyl-o-phenylendiamine with ethyl benzoylacetate]

By reaction in hot xylene of ethyl benzoylacetate with N-methyl-o-phenylenediamine (I a) and N-benzyl-o-phenylenediamine (I b) three five-membered ring compounds and one seven-membered ring compound were obtained. Compounds isolated were: 1-alkyl-2-phenacylbenzimidazoles (III), 1-alkyl-2-phenylbenzimidazoles (V), 1-alkyl-2-methylbenzimidazoles (VI) and 1-alkyl-4-phenyl-1,3-dihydro-2H-1,5-benzodiazepine-2-ones (IV). In the reaction with N-benzyl-o-phenylenediamine we isolated also the N-benzyl-2-benzoylacetamidoaniline (II b), which by further heating in xylene gave (IV b). The structures of compounds were elucidated from their chemical reactivity and their N.M.R. and I.R. spectra.