Synthesis of Biisoxazoletetrakis(methyl nitrate): A Potential Nitrate Plasticizer and Highly Explosive Material

Abstract

The efficient and scalable synthesis of 3,3′‐biisoxazole‐4,4′,5,5′‐tetrakis(methyl nitrate) and its energetic properties are described. The synthesis features a metal‐free [3+2] cycloaddition of an electron‐rich internal alkyne and a nitrile oxide by simple heating, without using halogenated solvents. The material has favorable sensitivity properties, and its energetic properties point toward its potential as a nitrate plasticizer and highly explosive material.

Bis(1,2,4‐oxadiazolyl) Furoxan: A Promising Melt‐Castable Eutectic Material of Low Sensitivity

“…%methyl nitroguanidine/6.3 wt. % nitroguanidine) is an example of one such formulation in which an optimal melting point below 100 °C has been achieved, with a recent example of a potential melt‐castable eutectic ingredient being bisisoxazole tetrakis(methyl nitrate) . Despite the aforementioned research examples, the number of melt‐castable materials available for practical use remains quite limited on the bases of cost, performance and sensitivity.…”

Synthesis of bis‐Isoxazole‐bis‐Ethylene Dinitrate and bis‐Isoxazole‐tetra‐Ethylene Tetranitrate: Potential Energetic Plasticizers

“…The 3,3'-bis-isoxazole ring system is formed through the cyclization of an alkyne with dichloroglyoxime. The extended alkyl chains result in somewhat lower cyclization yields than the previously reported methyl derivatives [7,8].…”

“…Both molecules are centrosymmetric with each asymmetric unit containing one-half the molecule and the other half generated by the symmetry codes 2Àx, 1Ày, 1Àz (2) or 1Àx, y, 1/2Àz (4). Their bond lengths and angles are in the usual ranges of typical isoxazole and alkyl nitric ester compounds [8,[23][24][25][26]. The isoxazole rings adopt a trans planar configuration [r.m.s deviation of 0.0019 (3) and 0.0015 (4) for molecule 2 and 4, respectively], suggesting a delocalized aromatic p system with reduced nitrogen atoms' lone pair interaction.…”

“…The compounds described herein are the ethyl derivatives of the previously reported 3,3'-bis-isoxazole-5,5'bis-methylene dintrate [7] and 3,3'-bis-isoxazole-4,4',5,5'-tetramethylene dinitrate [8]. Extending an alkyl chain is known to soften a material, so the materials reported herein are ex-pected to show greater miscibility and plasticizing properties.…”

Synthesis and Characterization of Isoxazole‐Based Energetic Plasticizer Candidates EEIN and IDN

“…However, in the context of energetic materials (EMs), these structural motifs have been less prominent. Recently, our laboratory disclosed the synthesis of nitrate ester‐functionalized bi‐isoxazolebis (methyl nitrate) (BIDN) and bi‐isoxazoletetrakis (methyl nitrate) (BITN) , . Entry to the 3,3′ system was realized via an efficient metal‐free double 1,3‐dipolar cycloaddition.…”