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 NaN 3 . Thermolysis of the azides 2 (a-g) gives previously unknown 2-R-4,6-dinitro-2H-indazoles 3 (a-g) in high yields.
Some transformations of 2-aryl-4,6-dinitroindoles were studied. These indoles undergo jV-methylation, formylation and can be regioselectively aminated with trimethylhydrazinium iodide. Upon reduction of iV-methylated 2-aryl-4,6-dinitroindoles the corresponding diamines are obtained in good yields.
Synthesis of 2-Aryl-and 2-Hetaryl-4,6-dinitroindoles from 2,4,6-Trinitrotoluene.-The new and general synthesis of various previously unknown title indoles (9 examples) involves the condensation of TNT (I) with aromatic aldehydes (II) in the presence of a secondary amine (piperidine, morpholine or NHEt 2 ) as the catalyst followed by regioselective ortho-azidation and cyclization. -(ROZHKOV, VLADIMIR V.; KUVSHINOV, ALEXAN-DER M.; GULEVSKAYA, VALENTINA I.; CHERVIN, IVAN I.; SHEVELEV, SVYATOSLAV A.; Synthesis
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