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.

Insight into the structural and energetic features of substituted triazolofurazans

“…The main distinguishing feature of this salt in comparison with salts 2a and 3b is the non-coplanarity of N-NO 2 fragment and furazanotriazole scaffold with a dihedral angle of 47.7°(in K-salt of TFNA this angle is equal to 58.2°). 20 It is probably a common deviation from flatness for this type of compounds because a similar situation is observed in the case of pyridine-1-nitroimide, 25 4-nitramino-1,2,4-triazole, 26 and salts of 1-nitroamino-1,2,3triazole 27 as well as 1,3-bis(nitroimido)-1,2,3-triazole 28 with dihedral angle ranging from approx. 40°to 82°.…”

“…stages 7 → 8 → 9 → 6a were previously reported. 20 Scheme 2 Previously developed synthesis of TFO salts 3b and 3c. 19 This journal is © The Royal Society of Chemistry 2024 and then acidified using ion-exchange resins (Amberlite IRC 120, H-form) to afford H-form 5.…”

“…Earlier we published the strategy for the synthesis of K salt 6a starting from 3-amino-4-azido-1,2,5-oxadiazole 7 (Scheme 3). 20 Ammonium salt 6b was synthesized in two steps: first, K salt 6a was acidified using ion-exchange resins (Amberlite IRC 120, H-form) in methanol to give low stability H-form 10 (see below) which without isolation was treated with aq. NH 3 , affording salt 6b in quantitative yield.…”

Quantum-Chemical Study of Gas-Phase 5/6/5 Tricyclic Tetrazine Derivatives

“…The development of flat condensed polynitrogen polynuclear structures and their functionalization with explosophoric groups is one of the promising trends in the search for new highenergy density materials (HEDMs) [1][2][3][4]. Particularly, it is fused tricyclic tetrazines annelated with azoles that have a high energy potential [5,6].…”

“…Previously, we made a research of approaches to calculating ∆H • f for several series of tetrazines condensed with nitropyrroles and nitrotriazoles [7,8]. It is obvious that derivatives of this class of tricyclic compounds containing nitroimidazole nuclei are also of interest, since the first synthesized representative of tricyclic imidazotetrazines, 3,8-diazido-2,9dinitroimidazo[1,2-d:2',1'-f] [1,2,3,4]tetrazine showed quite promising energy characteristics [9]. It is worth mentioning that in recent decades a significant progress has been made in the synthesis of energy-intensive nitroimidazoles [10,11].…”