Applications of a novel nano magnetic catalyst in the synthesis of 1,8-dioxo-octahydroxanthene and dihydropyrano[2,3-c]pyrazole derivatives

• Novel magnetic nano particles with ionic liquid tag: [nano-Fe3O4@SiO2@(CH2)3-Imidazole-SO3H]Cl or [MNP-PIm-SO3H]Cl as a heterogeneous catalyst.
• Synthesis of 1,8-dioxo-octahydroxanthenes and dihydropyrano[2,3-c]pyrazole derivatives catalyzed by {[MNP-PIm-SO3H]Cl under solvent-free conditions.
• This method has the ability to tolerate a good range of substitutions.
• This procedure has the shorter reaction times, high yield and agreement with the green chemistry protocols.
• Easy recovery and reusability of heterogeneous nano magnetic catalyst.

Imidazole-based ionic liquid-stabilized on silica coated Fe3O4 magnetic nano particles [nano-Fe3O4@SiO2@(CH2)3-Imidazole-SO3H]Cl as a novel heterogeneous acidic catalyst was designed, synthesized and fully characterized by FT-IR, thermo gravimetric analysis (TGA), differential thermal analysis (DTA), energy-dispersive x-ray spectroscopy (EDX), X-ray diffraction patterns (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), Brunauer–Emmett–Teller (BET) and inductively coupled plasma (ICP) analysis. The nano-structured organo solid catalyst as a novel, mild and full-fledged catalyst was used for the cascade synthesis of 1,8-dioxo-octahydroxanthene derivatives by the condensation reaction between dimedone and various aldehydes at 80 °C under solvent-free conditions. Similarly, dihydropyrano[2,3-c]pyrazole derivatives were synthesized by the one-pot three-component condensation reaction of aldehydes, malononitrile and 3-methyl-1-phenyl-2-pyrazoline-5-one under solvent-free conditions at room temperature. To the knowledge of our science, this is the main investigation on the synthesis of [nano-Fe3O4@SiO2@(CH2)3-Imidazole-SO3H]Cl as a worthy heterogeneous nano magnetic solid acid for acid catalyzed organic reactions.

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