Energetic Functionalization of the Pyridazine Scaffold: Synthesis and Characterization of 3,5‐Diamino‐4,6‐dinitropyridazine‐1‐Oxide

Abstract

The synthesis of 3,5‐diamino‐4,6‐dinitropyridazine‐1‐oxide (8) is reported. It is prepared in a six‐step synthetic procedure starting from acyclic compounds, and shows good properties (detonation velocity DC–J = 8486 m s–1, detonation pressure pC–J = 302 kbar), and sensitivity toward mechanical stimuli. Compound 8 and its precursor (7, 3,5‐dimethoxy‐4,6‐dinitropyridazine‐1‐oxide) were characterized by means of multinuclear (1H, 13C, 14N, 15N) NMR spectroscopy, mass spectrometry, vibrational spectroscopy (IR and Raman), elemental analysis and differential thermal analysis (DTA) measurements. Compounds 4, 5, 6, 7, 8 and 9 were also characterized by low‐temperature single‐crystal X‐ray diffraction. The heats of formation for 7 and 8 were calculated using the atomization method based on CBS‐4M enthalpies. Using the experimentally determined (X‐ray) densities and the calculated standard molar enthalpies of formation, several detonation parameters such as the detonation pressure, energy and velocity were predicted by using the EXPLO5 code (V6.03). The sensitivities of 3,5‐dimethoxy‐4,6‐dinitropyridazine‐1‐oxide (7) and 3,5‐diamino‐4,6‐dinitropyridazine‐1‐oxide (8) toward impact, friction and electrical discharge were tested according to BAM standards. In addition, the shock reactivity of 8 was measured by applying the small‐scale shock reactivity test, showing similar values to HNS, PYX and TKX‐55.