Cyclization of arylhydrazones of nitroformaldehyde and its derivatives

2,3,4,5-Tetrahydro-1,2,4-triazine derivatives are obtained when nitroformaldehyde arylhydrazones are heated with formaldehyde and aromatic amines. Bromonitroformaldehyde arylhydrazones react with thiourea to give substituted 5-inimo-4,5-dlhydro-1,3,4-thiadiazoles and react with sodioacetoacetic ester to give 1-aryl-3-nitro-4-acetyl-5-pyrazolones. The action of chlorosulfonic acid on cyanonitroformaldehyde arylhydrazones leads to ring closing to the corresponding 1,3,5-triazines.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 425–427, March, 1974.