Theoretical investigation of tautomerism of 3-amino-1H-1,2,4-triazol-5(4H)-one in solution phase: Comparison between water and chloroform

In recent years, water has become the solvent of choice to perform many organictransformations for reasons of cost, safety, and environmental concerns. Furthermore, insome cases, rate acceleration and higher selectivity have also been achieved in aqueousreaction media as compared to those inorganic solvents [1].1,2,4-Triazole and its derivativesconstitute an important class of organic compounds with diverse biological activities, such asanticonvulsant, antidepressant, anti-inflammatory, antitumor, analgesic, antiviral, andantibacterial [2]. Recently, much attention has been focused on derivatives of 1,2,4-triazolebecause of their fungicidal activities. They are also used as intermediates for the synthesis ofantifungal agents such as fluconazole, voriconazole, and itraconazole [3].In this research we have investigated the tautomerism of one of the new derivatives of 1,2,4-Triazole in two solvents, water and chloroform. However no studies on the tautomerisation ofin 3-amino-1H-1,2,4-triazol-5(4H)-one (ATO) are reported in the literatures. In the presentwork, the effects of solvent on the equilibrium and rate constants between six tautomers ofATO (Fig. 1) were investigated at the B3LYP/6-311++G(d,p) level of theory.