Engaging DBFO as a C1N1 two-atom synthon in [3+2] cycloaddition reaction: synthesis of the energetic material 5-azidotetrazotate 1N-oxide

We report a formal [3 + 2] annulation of dibromoformaloxime (DBFO) and sodium azide for the synthesis of tetrazole- based energetic materials. Several energetic salts were prepared and fully characterized by X-ray diffraction, Raman spectroscopy, multinuclear NMR spectroscopy, elemental analysis, differential scanning calorimetry (DSC) and impact and friction sensitivity testing. The heat of formation of nitrogenrich salts 8 and 9 was calculated by experiments, and detonation parameters were estimated using the EXPLO5 software. This is the first example of using DBFO as a unique C1N1 two-atom synthon in the synthesis of tetrazoles. Furthermore, this reaction not only unlocks a different strategy for 5-azidotetrazole synthesis, but also exploits a new reactivity of DBFO.

Automated summary

A new method using DBFO and sodium azide for the synthesis of tetrazole-based energetic materials was reported, and the synthesized energetic salts were fully characterized using various analytical techniques. The heat of formation and detonation parameters of nitrogen-rich salts were calculated, confirming the effectiveness of this reaction. This method not only offers a new synthetic route for tetrazoles, but also reveals a new reactivity of DBFO.