Novel Inorganic-Bioorganic Functionalized Silica-Magnetized Core-Shell (Nano SO3H-D-Leu@SiO2-Fe3O4) as Reusable Promoter for the Synthesis of 7,7'-((Aryl)Methylene)Bis(N-Cyclohexyl-2-(Aryl)-6-Methyl-3H-Imidazo[1,2-b]Pyrazol-3-Imine) Derivatives

Abstract

In this research, a new bio multilayered nanostructure based on commercial nanomagnetite has been prepared. Gradually the silica and D-leucine amino acid, as the bio part, anchored on the surface of nano Fe3O4 followed by functionalization step, accomplished with chlorosulfonic acid. This bio-nano organic–inorganic core-shell hybrid (nano SO3H-D-Leu@SiO2-Fe3O4) characterized by FESEM, EDAX, FT-IR, TGA/DTG, TEM, VSM, and XRF techniques. Its efficient catalytic activity examined for the synthesis of 7,7'-((aryl/alkyl)methylene)bis(N-cyclohexyl-2-(aryl/alkyl)-6-methyl-3H-imidazo[1,2-b]pyrazol-3-imine) derivatives through a pseudo-seven component one-pot and one-step reaction of various aldehydes, 3-amino-5-methylpyrazole, and cyclohexyl isocyanide in ethanol solvent at room temperature with excellent yields. The condensed products obtained via construction of various new C-C and C = N bonds. The interpreted protocol included advantages, such as easy preparation approach for nano-sized bio core-shell organic–inorganic hybrid, short reaction times, simple work-up process due to separation of the catalyst by an external magnet, recovery, and reusability of the nanocatalyst for three runs without notable activity loss (the recovered nanostructure characterized by FESEM and EDAX techniques), utilizing different class of aldehydes successfully, and regioselectivity of the procedure.