Synthesis of SCMNPs@imine/SO3H magnetic nanocatalyst by chlorosulfonic acid as sulfonating agents and their application for the preparation of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-one and 1,8-dioxooctahydroxanthene derivatives

In this survey, new recoverable sulfonated magnetic nanocatalysts (SCMNPs@imine/SO3H) was synthesized by covalent attachment of a Schiff base ligand on the surface of SCMNPs@APTES/sucanh through reaction with 4-[(Pyridin-2-ylmethylene)-amino]-phenol and subsequent reaction with chlorosulfonic acid. The synthesized nanocatalyst was characterized by several techniques such as FTIR, TGA, VSM, XRD, UV–vis and EDX analysis. The nanocatalyst was evaluated in the preparation of 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-one and 1,8-dioxooctahydroxanthene derivatives with pharmacologically and biologically remarkable activity. 12-aryl-8,9,10,12-tetrahydrobenzo[a]xanthen-11-one and 1,8-dioxooctahydroxanthene derivatives were respectively prepared via one-pot, three-component reactions of 2-naphthol, dimedone and aldehydes, as well as the reaction between dimedone and aldehydes in the presence of SCMNPs@imine/SO3H under solvent-free conditions. The merits of this synthesis are high-to-excellent yields, short reaction time, mild basic conditions and high catalytic activity. Also, the SCMNPs@imine/SO3H with suitable magnetic strength can be easily separated from the reaction solution using an external magnetic field.