Eco-Efficient, Green, and Scalable Synthesis of 1,2,3-Triazoles Catalyzed by Cu(I) Catalyst on Waste Oyster Shell Powders

An efficient and recyclable waste oyster shell powders (OSPs)-supported CuBr catalyst (OSPs–CuBr) has been successfully prepared and well characterized by Fourier transform infrared (FTIR) spectroscopy, thermal gravimetric analysis (TGA), atomic absorption spectroscopy (AAS), and powder X-ray diffraction (XRD). Then, OSPs–CuBr was used as a heterogeneous catalyst for the one-pot multicomponent synthesis of 1,4-disubstituted 1,2,3-triazole derivatives via a Cu­(I)-catalyzed azide–alkyne 1,3-dipolar cycloaddition (CuAAC) reaction. Compared with a CaCO3–CuBr catalyst, the OSPs–CuBr catalyst showed higher catalytic activity and stability characteristics. The chitin and protein molecules on the OSP particles surfaces play an important role in the chelation of the CuBr species, which leads to the better chemical stability of OSPs–CuBr. The 1,2,3-triazoles are readily obtained in good to excellent yields and on a multigram scale by the reaction of aryl/alkyl halides, alkynes, and NaN3 under microwave irradiation conditions. It also showed good reusability, could be easily recovered through filtration and washing, and was reused at least eight times with virtually no evident loss of catalytic performance.