Anions Containing Tripoid Conjugated N4- System: Salts of 5-(Substituted Amino)-[1,2,3]triazolo[4,5- c][1,2,5]oxadiazol-5-ium-4-ides, as well as Their Synthesis, Structure, and Thermal Stability

Abstract

A strategy for the synthesis of 5-((2-cyanoethyl)-X-amino)-[1,2,3]triazolo[4,5-c][1,2,5]oxadiazol-5-ium-4-ides (X = H; CH₂CH₂CN; NO₂ (4a); CN (4b); CO₂Et (4c)) starting from 3-amino-4-azido-1,2,5-oxadiazole was developed. The key step in this strategy is the intramolecular thermolytic cyclization of the azido group and the bis(2-cyanoethyl)triazene group. Removal of the 2-cyanoethyl protecting group from amides 4a-c gave potassium salt of the corresponding nitramide and sodium salts of cyano- and ethoxycarbonylamide. The structure and thermal stability of the synthesized compounds were studied experimentally using multinuclear NMR spectroscopy, X-ray crystallography, thermogravimetry, and differential scanning calorimetry.

Keywords: 1,2,3-triazoles; 1,2,5-oxadiazoles; NMR; X-ray; diazonium; heterocycles; triazenes.