Benzindoles. 21. Nitration of 3-formyl[4, 5]-and 3-formyl [6,7] benzindoles

It was established that products of monosubstitution of 4-nitro- and 7-nitro-3-formyl[4,5] benzindoles and products of disubstitution of 4,8-dinitro- and 7,8-dinitro-3-formyl [4,5] benzindoles are formed in low yields in the nitration of 3-formyl [4,5]benzindole with sodium nitrate in concentrated sulfuric acid. Similar nitration of 3-formyl [6,7] benzindole leads to 9-nitro- and 5, 6-dinitro-3-formyl [6,7]benzindoles. The 3-formylnitrobenzindoles obtained were converted to nitrovinyl derivatives by condensation with nitromethane.See [1] for Communication [1].Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7, pp. 949–955, July, 1980.