Safer and Convenient Synthesis of 3,4-Bis(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole-2-oxide (BNFF/DNTF)

A safer, convenient, and scalable synthesis for 3,4-bis(4-nitro-1,2,5-oxadiazol-3-yl)-1,2,5-oxadiazole-2-oxide (BNFF or DNTF) is described. The obtained products were fully characterized and further confirmed by single-crystal X-ray diffraction. The reaction process of tandem nitration-cyclization was optimized, and the thermal stability of the optimal reaction system was studied. 3-Amino-4-(carboxymethyl)furazan is oxidized and then treated with dilute mixed acid (HNO3 and H2SO4) to obtain BNFF in a yield of 52% and a purity of 99% after liquid chromatography analysis. Compared with some previously reported multistep methods that relied on high-concentration hydrogen peroxide solutions and suffered from dangerous exothermic profiles, this new method used to synthesize BNFF promises to be safer and more efficient.