Preparation of 3,5-dinitro-1,2,4-triazole
To a solution of 80 g of sodium nitrite in 300 ml of water was added during 1.5 hr with stirring and cooling at 0 to -5° C a solution of 6 g (0.061 mole) of 3,5-diamino-1,2,4-triazole in 214 ml of sulfuric acid. The mixture was heated to 60° C, kept for 30 min, then cooled to 0° C, and 30% sulfuric acid added until oxides of nitrogen were no longer evolved. 4 grams of urea was then added, and the mixture extracted with 6 x 200 ml of ether. The ether extract was dried over calcium chloride, and the ether distilled off until the volume had reached 15-20 ml. The residue was dissolved in 150 ml of acetone and treated with a solution of 15-20 g of sodium bicarbonate. The excess bicarbonate was filtered off and the acetone distilled to give the sodium salt of 3,5-dinitro-1,2,4-triazole as yellow crystals, which melts at 123° C with decomposition (from alcohol), yield 8.9 g (80%). In order to obtain the free compound 3,5-dinitro-1,2,4-triazole, the residue, after removal of the ether, was kept in a vacuum desiccator over sulfuric acid until the material ceased losing weight, followed by extraction with boiling dry benzene. The benzene solution, on cooling, deposited 3,5-dinitro-1,2,4-triazole, which was filtered off and dried in a vacuum desiccator over phosphorus pentoxide. The obtained 3,5-dinitro-1,2,4-triazole is very hygroscopic material.
Khimiya Geterotsiklicheskikh Soedinenii, Vol. 6, No. 2, pp. 259-264, 1970.
3,5-dinitro-1H-1,2,4-triazole, ZINC04405530, AC1MMC03, SCHEMBL1172467, CTK0J3136, MolPort-002-686-563, STK669214, AKOS005591937, MCULE-6785830600, 1H-1,2,4-Triazole, 3,5-dinitro-, ST4007004, EU-0050745, A0458/0021141, 26621-32-9