3-Amino-4-(1-amino-2-cyanovinyl)furazans: synthesis and cyclization

Synthesis and Crystal Structure of 3-(4-Cyano-3-nitro-1H-pyrazol-5-yl)-4-nitrofurazan: Comparison of the Influence of the NO2 and CN Groups on Crystal Packing and Density

The title compound was synthesized and characterized by IR and NMR spectroscopy and single crystal X-ray diffraction. The analysis of the crystal packing of the title compound and its analog, bearing a nitro group instead of a nitrile one, allowed a direct comparison of two common explosophoric groups: CN and NO2. By using ΔOED-based densification approach, it is shown that the CN group is lighter in mass, less dense, and participates in intermolecular bonding to a lesser extent in comparison to the NO2 group. As a result, the cyano compound has a lower density and a looser crystal packing than the nitro analog.

Synthetic Strategies Toward Nitrogen-Rich Energetic Compounds Via the Reaction Characteristics of Cyanofurazan/Furoxan

The structural units of amino-/cyano-substituted furazans and furoxans played significant roles in the synthesis of nitrogen-rich energetic compounds. This account focused on the synthetic strategies toward nitrogen-rich energetic compounds through the transformations based on cyanofurazan/furoxan structures, including 3-amino-4-cyanofurazan, 4-amino-3-cyano furoxan, 3,4-dicyanofurazan, and 3,4-dicyanofuroxan. The synthetic strategies toward seven kinds of nitrogen-rich energetic compounds, such as azo (azoxy)-bridged, ether-bridged, methylene-bridged, hybrid furazan/furoxan-tetrazole–based, tandem furoxan–based, hybrid furazan-isofurazan–based, hybrid furoxan-isoxazole–based and fused framework–based energetic compounds were fully reviewed, with the corresponding reaction mechanisms toward the nitrogen-rich aromatic frameworks and examples of using the frameworks to create high energetic substances highlighted and discussed. The energetic properties of typical nitrogen-rich energetic compounds had also been compared and summarized.