Construction of Heterocyclic-Triazolopyrimidine Framework for Energetic Compounds: High-Energy, Low-Sensitivity...

This study reports the synthesis of three novel heterocycle triazolopyrimidine compounds with vicinal amino-nitro groups by introducing dinitropyrazole, nitrooxadiazole, and trinitromethyl groups into the fused-ring framework, respectively. Target compounds 3, 6, and 9 were obtained by subjecting substrates 1, 4, and 7, respectively, to a nucleophilic substitution cyclization reaction with 3,3-diethoxypropionitrile, followed by a nitration step. Among them, 2-(4,5-dinitro-1H-pyrazol-3-yl)-6-nitro-[1,2,4]triazolo[1,5-a]pyrimidin-7-amine (3) and 6-nitro-2-(4-nitro-1,2,5-oxadiazol-3-yl)-[1,2,4]triazolo[1,5-a]pyrimidin-7-amine (6) exhibited moderate detonation performance (D_v = 7769 m·s^-1and P = 25.1 GPa ; D_v = 8258 m·s^-1 and P = 29.4 GPa), low sensitivity (IS = 30 and 24 J; FS = 288 and 240 N) and high thermal stability (T_d = 277 and 263 °C). Even more outstanding is 6-nitro-2-(trinitromethyl)-[1,2,4]triazolo[1,5-a]pyrimidin-7-amine (9), which exhibits detonation performance (D_v = 8716 m·s^-1) close to that of the classic explosive cyclotrimethylenetrinitramine (RDX: D_v = 8795 m·s^-1, IS = 7.5 J, FS = 120 N), but exhibiting lower sensitivity (IS = 16 J, FS = 168 N), making it highly promising as a novel high-energy, low-sensitivity energetic material. This work expands their potential applications as high-energy, low-sensitivity explosives.