Preparation and Characterization of New Organocatalysts Supported on Nanomagnetic Particles as Green Nanocatalysts and Their Applications in Organic Synthesis

Surface functionalization of nano-magnetic nanoparticles is a well-designed way to bridge thegap between heterogeneous and homogeneous catalysis [1-3]. Organocatalysts created a homogenouspart which starting materials easily converted to the desired products(s), heterogeneouspart of these advanced catalysts separated easily using an external magnet [1-3]. Thus,high conversions in reaction and an easy work-up procedure cause to prepare desired compoundsin high pure isolated yields [1-3]. (3-Oxo-[1,2,4]triazolidin-1-yl)bis(butane‐1‐sulfonicacid) functionalized magnetic γ-Fe2O3 (γ-Fe2O3@Oxo-triazolidin-sultone) nanoparticles as anovel and heterogeneous nanocatalyst was prepared. The novel nanocatalyst was characterizedby X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), vibratingsample magnetometry (VSM), Field Emission Scanning Electron Microscopy (FE-SEM), andthermal gravimetric analysis (TGA). The superparamagnetic γ-Fe2O3@Oxo-triazolidinsultonenanoparticles showed enhanced catalytic performance for the preparation of novel spiro[indeno[1,2-b]quinoxaline derivatives via the four-component condensation of amines, ninhydrin,isatoic anhydride, and о-phenylenediamine derivatives. The nanocatalyst can be easilyseparated from the reaction mixture by an external magnet, recycled, and reused severaltimes without a noticeable decrease in catalytic activity. Glycine-proline-glutamic acid (Gly-Pro-Glu) supported on superparamagnetic silica encapsulated γ-Fe2O3 as a novel heterogeneouscatalyst was designed and synthesized. The nanocatalyst was characterized by severaltechniques. MNPs γ-Fe2O3@SiO2-linker- Gly-Pro-Glu as catalyst was used for the facile synthesisof thiazoloquinoline, thiazolopyridine, and thiazolonaphthyridine derivatives.