Synthesis of 2-R-4,6-Dinitro-2H-indazoles from 2,4,6-Trinitrotoluene

An efficient synthesis of 2-R-4,6-dinitro-2H-indazoles (R = aryl or substituted amine) from 2,4,6-trinitrotoluene was elaborated. The proposed method includes formation of C-(2,4,6-trinitrophenyl)-N-R-azomethines 1 (a - g) from TNT or the product of its transformation 2,4,6-trinitrobenzaldehyde (TNBA) with the further regiospecific substitution of the ortho-nitro group in 1 (a - g) by the azido group under the action of NaN₃. Thermolysis of the azides 2 (a - g) gives previously unknown 2-R-4,6-dinitro-2H-indazoles 3 (a - g) in high yields.

2,4,6-trinitrotoluene - 2,4,6-trinitrobenzaldehyde - azomethines - aromatic nucleophilic substitution - aromatic azides - 2-R-4,6-dinitro-2H-indazoles