From Nitro- to Heterocycle-Functionalized 1,2,4-Triazol-3-one Derivatives: Achieving High-Performance Insensitive Energetic Compounds

5-Nitro-1,2,4-triazol-3-one, a nitro-functionalized 1,2,4-triazol-3-one (TO) derivative, shows excellent energetic properties and promising application potential. However, the use of the TO skeleton as an energetic material is still largely underexplored both theoretically and practically. We report here a mild and efficient method for obtaining the TO skeleton via a reaction of aminocarbohydrazide with BrCN. Two energetic compounds (2 and 5) were synthesized and fully characterized by ¹⁵N nuclear magnetic resonance, two-dimensional ¹H-¹⁵N heteronuclear multiple-bond correlation, and single-crystal X-ray diffraction. The reaction mechanism was also studied with the aid of quantum calculations. Compound 2 shows promising properties as a high-performance insensitive energetic material.