Quinuclidine Stabilized on FeNi3 Nanoparticles as Catalysts for Efficient, Green, and One-Pot Synthesis of Triazolo[1,2-a]indazole-triones

A new magnetically separable catalyst consisting of quinuclidin-3-thiol supported on propylsilane-functionalized silica-coated FeNi3 nanoparticles (FeNi3/quinuclidine) has been prepared. The synthesized catalyst was characterized by powder X-ray diffraction, transmission electron microscopy, vibrating sample magnetometry, thermogravimetric analysis, and Fourier transform infrared spectroscopy. The immobilized FeNi3/quinuclidine was shown to be an efficient heterogeneous catalyst for the synthesis of triazolo[1,2-a]indazole-triones under solvent-free conditions at room temperature. The catalyst is readily recovered by simple magnetic decantation and can be recycled several times with no significant loss of catalytic activity.