An Fe3O4@Keratin-Ag(I) Magnetic Nanocatalyst for Facile One-Pot Sonochemical Synthesis of Isoxazole and Isoxazoline-1,2,3-Triazole Hybrids in Water

In this research, we report a one-pot sequential synthesis of novel hybrid isoxazole or isoxazoline-1,2,3-triazole compounds in four steps. The synthetic route involves sulfonylation, 1,3-dipolar cycloaddition, azidation, and click reaction. The key feature of this methodology is its environmentally friendly approach, which is highlighted by the use of water as a benign solvent and ultrasound activation to increase the efficiency of the heterogeneous reactions. Additionally, a novel magnetic nanocatalyst was prepared by adsorbing silver(I) on keratin extracted from chicken feathers, which both valorizes biomass and strengthens the eco-friendly nature of the process. The methodology proved its effectiveness by yielding the final products 6a-i and 7a-i with remarkable selectivity and high yields (85%–96%) within a significantly reduced reaction time (2.5h). Moreover, the catalyst demonstrated excellent stability, maintaining its performance over five consecutive cycles, confirming its robustness and reusability. The characterization of the nanocomposite catalyst Fe₃O₄@KNPs-Ag(I) and the final products 6a-i and 7a-i has been performed using various analytical methods, including FTIR, XRD, SEM-EDX, ICP-OES, TEM, HRTEM, TGA, DSC, ¹H NMR, ¹³C NMR, ¹⁹F NMR, and HRMS.