Synthesis and Characterization of the Potential Energetic Propellant Plasticizer 3‐Nitratoethyl‐N‐nitramino‐5‐nitratomethyl Isoxazole

The synthesis of 3‐(nitratoethyl‐N‐nitramino)‐5‐(nitratomethyl) isoxazole (C6H7N5O9, 1) is presented, and its energetic properties were ascertained and analyzed for energetic applications potential. 1 was found to be a solid without melting behavior, begins to decompose at 140 °C, and has a thermal onset decomposition temperature of 171.5 °C. 1 was synthesized in 5 steps from glyoxylic acid, and was found to exhibit acceptable sensitivities to impact, friction, and electrostatic discharge. The presence of the nitratoethyl nitramino (NENA) moiety, coupled with the high density (1.71 g cm−3) and superior calculated specific impulse (247.6 s) over the commonly employed gun propellant n‐butyl NENA (density=1.22 g cm−3, specific impulse=221 s), makes 1 a potential energetic plasticizer for next generation gun and rocket propellants. In addition, a modified procedure for the synthesis of dibromoformaldoxime (DBFO) was developed to provide this material in respectable yields on one mole scale. The safety considerations of DBFO are also highlighted, in which this compound sublimes, and must be handled with care, as it will cause burns upon contact with the skin. The synthesis, characterization and x‐ray crystal structure of 3‐nitratoethyl‐N‐nitramino‐5‐nitratomethyl isoxazole is described. This energetic material was made in a 5 step, 45 % overall yielding process, is a potential energetic rocket‐ and gun‐propellant plasticizing ingredient. This material was found to possess a good sensitivity to impact, friction and electrostatic discharge, with a high specific impulse.