The 2,3-dichloro-1,4-naphthoquinone was reacted with diethyl methylmalonate and sodium amide in the toluene to yield 3-chloro-2-(1-methyl-1-diethoxycarbonyl)-methyl-1,4-naphthoq uinone(I). When this compound I was reacted with some alkylamines (methylamine, ethylamine, ethanolamine, 2-bromoethylamine, propylamine, isopropylamine, cyclohexylamine, benzylamine, 4-piperidylmethylamine), 3-methyl-2,3-dihydrobenz(f)indole-2,4,9-trione derivatives(IIa-i) were obtained via intramolecular cyclization.