Synthesis of (E)-2-(1H-tetrazole-5-yl)-3-phenylacrylenenitrile derivatives catalyzed by new ZnO nanoparticles embedded in a thermally stable magnetic periodic mesoporous organosilica under green conditions.

ZnO nanoparticles embedded in a magnetic isocyanurate-based periodic mesoporous organosilica (Fe3O4@PMO-ICS-ZnO) were prepared through a modified environmentally-benign procedure for the first time and properly characterized by appropriate spectroscopic and analytical methods or techniques used for mesoporous materials. The new thermally stable Fe3O4@PMO-ICS-ZnO nanomaterial with proper active sites and surface area as well as uniform particle size was investigated for the synthesis of medicinally important tetrazole derivatives through cascade condensation and concerted 1,3-cycloaddition reactions as a representative of the Click Chemistry concept. The desired 5-substituted-1H-tetrazole derivatives were smoothly prepared in high to quantitative yields and good purity in EtOH under reflux conditions. Low catalyst loading, short reaction time and the use of green solvents such as EtOH and water instead of carcinogenic DMF as well as easy separation and recyclability of the catalyst for at least five consecutive runs without significant loss of its activity are notable advantages of this new protocol compared to other recent introduced procedures.