One pot synthesis of different 2-pyrazoles using magnetized Fe3O4 nanoparticles functionalized with sulfonated tris(hydroxymethyl)aminomethane /copper (II) nitrate by in situ oxidation

Document Type : Research Article


1 Department of Chemistry, Faculty of Science, Arak University, Zip Code 38156-8-8349 Arak, Iran.

2 Department of Chemistry, Faculty of Science, Arak University, Arak, 38156-8-8349, Iran


in this study, first, iron oxide magnetic nanoparticles functionalized based on sulfonated tris(hydroxymethyl)aminomethane /copper (II) nitrate were synthesized as a new, effective and recyclable magnetic catalyst and then, in the next step, were used in the preparation of 2 different pyrazolines. Finally, the prepared under one-pot conditions 2-pyrazolines were in situ oxidized to the corresponding 2-pyrazoles, so, under optimal conditions, a wide and different range of α,β unsaturated ketones (E-chalcones) that have the various functional groups, including both electron-releasing and also electron-withdrawing groups, were successfully transformed into relevant goal products in easy and mild conditions. All products were obtained with good to excellent yields and not any by-product was observed. The new synthesized magnetic nanocatalyst characterized by various techniques such as infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis, Energy-dispersive X-ray spectroscopy (EDAX), elemental analysis (CHN) and thermal gravimetric analysis (TGA). The catalyst was easily recycled by an external magnetic field and was used several times without observing a significant and notable lack of effective catalytic activity. Also, the structure of different synthesized 2-pyrazole products were confirmed by comparing their physical properties including melting point with reported samples and also by infrared spectroscopy (FT-IR), proton core magnetic resonance spectroscopy (1H-NMR), Carbon core magnetic resonance (13C-NMR) spectra as well as elemental analysis. Finally, the absence of harsh reaction conditions, the absence of any by-products, as well as the ability to recycle and reuse the catalyst made it an environmentally friendly method.


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