Synthesis, antimicrobial and antioxidant activities of imidazotriazoles and new multicomponent reaction toward 5-amino-1-phenyl[1,2,4]triazole derivatives

The Groebke-type multicomponent reaction between 5-amino-1,2,4-triazole derivatives, aromatic aldehydes and isocyanides has been studied from the viewpoint of convenient generation of combinatorial arrays of imidazo[2,1-c][1,2,4]triazoles. The reaction is considered to proceed via the formation of an iminium species followed by a [4 + 1] cyclo addition with the isocyanides using scandium triflate as a Lewis acid catalyst. The synthesized imidazo[2,1-c][1,2,4]triazole derivatives 4a, 4b, 4f and 4g were screened for antibacterial, antifungal and antioxidant activities. Among the tested compounds, 4b followed by 4f showed potent antibacterial and antifungal activities. All of these compounds were also screened in vitro for the antioxidant activity using DPPH assay. Most of them have shown very significant antioxidant activity.