Synthesis and application of novel urea–benzoic acid functionalized magnetic nanoparticles for the synthesis of 2,3-disubstituted thiazolidin-4-ones and hexahydroquinolines

In this work, we reported the synthesis and application of a new urea–benzoic acid containing ligand [(OEt)(3)Si(CH(2))(3)–urea–benzoic acid] for the functionalization of silica coated magnetic nanoparticles. The resulting structure, namely Fe(3)O(4)@SiO(2)@(CH(2))(3)–urea–benzoic acid, was characterized through different techniques including FT-IR, SEM, EDX-Mapping, VSM and TGA/DTG analysis. Then, Fe(3)O(4)@SiO(2)@(CH(2))(3)–urea–benzoic acid was applied as a heterogeneous dual acidic and hydrogen bonding catalyst for the synthesis of 2,3-disubstituted thiazolidin-4-ones and hexahydroquinolines under mild and green reaction conditions. More importantly, all of the desired products were obtained with relatively good yields. Also, the catalyst was recovered and reused for four successive runs without significant reduction in yield of the model reaction.