5-Azido-4-dimethylamino-1-methyl-1,2,4-triazolium Hexafluoridophosphate and Derivatives

Abstract

5-Azido-4-(dimethylamino)-1-methyl-1,2,4-triazolium hexafluoridophosphate was synthesized from the corresponding 5-bromo compound with NaN 3 . Reaction with bicyclo[2.2.1]hept-2-ene yielded a tricyclic aziridine, addition of an N-heterocyclic carbene resulted in a triazatrimethine cyanine, and reduction with triphenylphosphane gave the 5-amino derivative. The crystal structures of three nitrogen-rich salts were determined. Thermoanalysis of the cationic azide and triazene showed exothermal decomposition. The triazene exhibited negative solvatochromism in polar solvents involving the dipolarity π* and hydrogen-bond donor acidity α of the solvent.

Azide‐Substituted 1,2,3‐Triazolium Salts as Useful Synthetic Synthons: Access to Triazenyl Radicals and Staudinger Type Reactivity

“…The electronic structures of the azido‐triazolium salts were probed via IR spectroscopy. Indeed, an intense characteristic band was observed between 2153 cm −1 and 2155 cm −1 for all three compounds (Figure S31), which is in accordance with values reported for related azide containing compounds in the literature [28,16,15] …”

“…Indeed, an intense characteristic band was observed between 2153 cm À 1 and 2155 cm À 1 for all three compounds (Figure S31), which is in accordance with values reported for related azide containing compounds in the literature. [28,16,15] To investigate their reactivity, the cationic azido-triazolium salts reacted with triphenylphosphine (PPh 3 ) under irradiation of light or under thermal conditions following a Staudinger type protocol (Scheme 3). [5] In these types of reactions, usually the terminal nitrogen of the azide reacts with triphenylphosphine, resulting in an iminophosphorane after loss of dinitrogen.…”

“…[8] These azido-azolium salts are well established and described in the literature. [9] Several examples are known where such azido-azolium salts are used for the synthesis of triazenyl compounds, [10][11][12][13][14] aziridines with diverse substituents, [15] for diazo-transfer to primary amines, [16] or in a Staudinger type reaction leading to the formation of iminophosphoranes. [10] Recently, E. Lee and co-workers synthesized a variety of different unsymmetrical NHC substituted triazenyl compounds, which can be used as anolytes for nonaqueous organic redox flow batteries.…”