Chitosan synergistically enhanced by successive Fe3O4 and silver nanoparticles as a novel green catalyst in one-pot, three-component synthesis of tetrahydrobenzo[α]xanthene-11-ones

•Silver NPs are implanted on nontoxic, biocompatible magnetic chitosan.•The resulting Fe3O4/CS-Ag NPs is a “green” heterogeneous and reusable catalyst.•It proves efficient in synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[α]xanthene-11-ones.•The reaction is fast, one-pot, three-component, with green solvent and excellent yields.•The catalyst is removed by a magnet and recycled without significant loss of its activity.

Chitosan (CS) is modified with Fe3O4 nanoparticles composite through in situ co-precipitation of Fe3+ and Fe2+ ions via NH4OH in an aqueous solution, resulting in magnetic Fe3O4/CS NPs. Adsorption of Ag+ ions on the surface of the latter, followed by green reduction of Ag+via ascorbic acid, renders Fe3O4/CS-Ag NPs which shows an excellent catalytic activity toward one-pot, three-component synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[α]xanthene-11-one derivatives. The composition of the nanocatalyst is analyzed by FT-IR, XRD, TGA, VSM, ICP, SEM and TEM. Hence unique heterogeneous Fe3O4/CS-Ag NPs acts as an excellent green catalyst giving high yield product with good recyclability and without significant loss of the activity.

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