Reaction of 1,2-diamino-4-nitrobenzene with 1,5-diketones. Synthesis and oxidative reactions of nitrobenzimidazoles

Reaction of 1,5-diketones with 1,2-diamino-4-nitrobenzene gave a mixture of the 6- and 7-nitro derivatives of 4a,9-diaza-1,2,4a,9a-tetrahydrofluorene. Oxidation of the 6-nitro derivatives with MnO₂ gives para-quinone imines with elimination of the nitro groups. Oxidation of the 7-nitro derivative and oxidative conjugation of 5-nitro-2,2-pentamethylene-1,2-dihydrobenzimidazole with primary amines in the presence of MnO₂ gives nitro ortho-quinone imines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 927–930, July, 1990.