Synthesis of 3-Pyrazolyl-4H-1,2,4-triazoles Using Fe3O4@SiO2@Tannic Acid Nanoparticles as an Efficient, Green, and Magnetically Separable Catalyst

Tannic acid-functionalized silica-coated Fe3O4 nanoparticles (Fe3O4@SiO2@tannic acid) were synthesized and characterized by transmission electron microscopy (TEM), field emission scanning electron microscopy (FE-SEM), vibrating sample magnetometry (VSM), and Fourier-transform infrared spectroscopy (FT-IR). The synthesized catalyst was utilized in environmentally friendly procedure for the preparation of some novel 3-pyrazolyl-4H-1,2,4-triazoles through a one-pot three-component reaction of semicarbazide, alcohols, and pyrazolecarbaldehydes. The catalyst can be reused for six cycles without loss of its catalytic activity. The structure of the newly synthesized 3-pyrazolyl-4H-1,2,4-triazole derivatives was confirmed by H-1 and C-13 NMR and FTIR spectral data and elemental analyses.