An efficient and green one-pot synthesis of tetrahydrobenzo[a]xanthenes, 1,8-dioxo-octahydroxanthenes and dibenzo[a,j]xanthenes by Fe 3 O 4 @Agar-Ag as nanocatalyst.

Agar-coated Fe 3 O 4 nanoparticles (Fe 3 O 4 @agar) were prepared simply through in situ co-precipitation of Fe 2+ and Fe 3+ ions via NH 4 OH in an aqueous solution of Agar. Coating of Ag + ions on the surface of the latter followed by mild reduction of Ag + with NaBH 4 gives Fe 3 O 4 @Agar-Ag NPs. The magnetic Fe 3 O 4 @Agar-Ag nanocatalyst was characterized thoroughly by FT-IR, XRD, SEM, TEM, VSM, EDX, TGA, and ICP analyses. Its catalytic activity was assessed in the synthesis of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthene-11-one, 14-aryl-14H-dibenzo[a,j]xanthenes, and 1,8-dioxo-octahydroxanthene derivatives through a one-pot condensation of dimedone, 2-naphthol, and aryl aldehydes in EtOH. This novel method represents lots of advantages compared to the previous researches, such as avoiding the toxic catalysts, easy method for isolation of the products, satisfying yields, totally clean conditions, and simplicity of the methodology. This catalytic system is attributed to an eco-friendly process, high catalytic activity, and facility of recovery using an external magnet. A novel and magnetically recyclable catalyst known as Fe3O4@Agar-Ag NPs as a heterogeneous catalyst were synthesized by a simple method. Using this facile, efficient, and eco-friendly Nanocomposite, for the different models of xanthene reaction was represented.