Achieving heat-resistant energetic compounds via silver-catalyzed one-pot cycloaddition of ethyl 2-isocyanoacetate and nitrogen-rich diazonium

Abstract

1,2,4-Triazoles are privileged structural motifs found in many fields, including pharmaceuticals and natural products as well as energetic materials. However, the limited synthetic strategies toward 1,2,4-triazoles have hindered the development of new scaffolds. Herein, we first developed an efficient strategy to construct carboxylate triazoles via a silver oxide catalyzed [3 + 2] cycloaddition reaction of heterocyclic diazonium (2, 3, 4 or 5) with ethyl 2-isocyanoacetate. Compounds 2a–5a were fully characterized and were used to prepare four nitrogen-rich heat-resistant explosives TTTN (2c), BTTN (3c), DTTN (4c) and ATTN (5c). All of the compounds (2c–5c) have high nitrogen contents of >50%. In addition, compound ATTN (5c) shows good performances (D = 8473 m s⁻¹, P = 25.0 GPa, IS > 40 J, and FS > 360 N) and high thermal stability (T_d = 318 °C), which suggests its potential as a heat-resistant explosive.