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Abstract
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Guanine stabilized on the surface of silica-modified magnetic nanoparticles, by the propyl group as a linker, (Fe3O4@SiO2-n-(propyl)-guanine), was prepared, identified and used as a recyclable base in the synthesis of novel spirooxindole compounds and highly substituted dihydro-2-oxopyrroles in aqueous media. Fe3O4@SiO2-n-(propyl)-guanine was characterized via some spectroscopic and microscopic techniques such as Infrared spectroscopy (IR), X-ray diffraction spectroscopy (XRD), Energy dispersive X-ray spectroscopy (EDX), Vibrating sample magnetometry (VSM), Scanning electron microscopy (SEM), High resolution transmission electron microscopy (HR-TEM), Thermo-gravimetric analysis (TGA) and NMR-detected hydrogen/deuterium (H/D) exchange technique. The synthesized nanocomposite was employed as a new base catalyst for the synthesis of some novel spirooxindole compounds and highly substituted dihydro-2-oxopyrroles in aqueous media with good to excellent yields. This heterogeneous base catalyst could be recycled and reused up to ten times without appreciable loss of activity.
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