Fe3O4@SiO2–imid–PMAn magnetic porous nanospheres as recyclable catalysts for the one-pot synthesis of 14-aryl- or alkyl-14H-dibenzo[a,j]xanthenes and 1,8-dioxooctahydroxanthene derivatives under various conditions

Abstract

A facile, efficient and environmentally-friendly protocol for the synthesis of 14-aryl- or alkyl-14H-dibenzo[a,j]xanthenes and 1,8-dioxooctahydroxanthenes has been developed by one-pot condensation of various aldehydes with (i) β-naphthol and (ii) cyclic 5,5-dimethyl-1,3-cyclohexanedione, in the presence of Fe₃O₄@SiO₂–imid–H₃PMo₁₂O₄₀ nanoparticles as magnetic catalysts under various conditions. Different types of aromatic and aliphatic aldehydes are used in the reaction and in all cases the products synthesized successfully. The present approach offers several advantages such as short reaction times, high yields, easy purification, a cleaner reaction and ease of recovery and reusability of the catalyst by a magnetic field. Also, the aforementioned nanocatalyst can be easily recovered by a magnetic field and reused for subsequent reactions at least 5 times without noticeable deterioration in catalytic activity.