New methods were developed for the synthesis of [1,2,5]oxadiazolo[3,4-e][1,2,3,4]tetrazine 4,6-dioxide from 4-(tert-butyl-NNO-azoxy)-N-nitro-1,2,5-oxadiazol-3-amine or its alkali metal salts and acid anhydrides (or chlorides) in the presence of strong acids. The yield of [1,2,5]oxadiazolo[3,4-e][1,2,3,4]tetrazine 4,6-dioxide in acetic anhydride in the presence of sulfuric acid or sulfuric anhydride at 20°C in 20 min attained 83%. A general mechanism was proposed for the reactions under study. Acetyl group behaved for the first time as departing group in the synthesis 1,2,3,4-tetrazine 1,3-dioxides, and [1,2,5]oxadiazolo[3,4-e][1,2,3,4]tetrazine 4,6-dioxide was obtained in 47% yield from N-[4-(acetyl-NNO-azoxy)-1,2,5-oxadiazol-3-yl]acetamide.

A computer simulation of cocrystal structures of [1,2,5]oxadiazolo[3,4-e][1,2,3,4]tetrazine-4,6-dioxide (FTDO) with benzotrifuroxan (BTF) in ratios of (1 : 1), (2 : 1) and (3 : 1) was performed, and their thermodynamic stability and physical–chemical characteristics were calculated. According to calculations, the (3 : 1) cocrystal is thermodynamically most stable. Therefore, it is the most preferable for cocrystallization, and we successfully obtained a cocrystal only for the (3 : 1) ratio. The cocrystal was characterized by X-ray diffraction and vibrational spectroscopy. In the vibrational spectra, some new bands were observed compared with the parent compounds spectra. In addition, some bands of pure FTDO and BTF disappeared, which is typical for a molecular complex formation. The thermal decomposition and sensitivity to impact and friction of the cocrystal were investigated. The impact sensitivity (2.8 J) turned out to be equal to the sensitivity of the less sensitive component (BTF). In addition, the sensitivity to friction (14 N) decreased by three times compared with the highly sensitive FTDO, which is unusual for cocrystals of high-energy compounds. The (3 : 1) cocrystal had a high density of 1.888 (calc.) and 1.865 g cm⁻³ (exp.). The calculated detonation velocity (9.14 km s⁻¹) and Chapman–Jouguet pressure (38.08 GPa) are high, and indicate favorable prospects for using this cocrystal.