Electrooxidative synthesis of 1,2,3-triazolone 1-amines†

A new method for the synthesis of newly reported heterocycles, namely 1,2,3-triazolone 1-amines, via electrochemically induced intramolecular N–N bond formation was developed. The process involves electrooxidative cyclization of readily available α-aminocarbonyl hydrazones, occurs under mild conditions and enables the preparation of a diverse series of target compounds, although nitrophenyl-substituted substrates undergo decomposition upon electrolysis. Cyclic voltammetry (CV) measurements were also conducted to determine the reaction mechanism and to explain the observed scope limitations. In addition, thermal behavior studies demonstrated moderate thermal stability of several synthesized 1,2,3-triazolone 1-amines in the range of 110–140 °C. Overall, this study represents a promising contribution to the electroorganic synthesis of neglected nitrogen heterocycles for various biomedical and materials science applications.