This paper reports an efficient heterogeneous catalyst based on sulfonic acid functionalization of magnetic nanoparticles. This new catalyst was prepared using the reaction between magnetic nanoparticles and sodium 2-bromoethane-1-sulfonate. Magnetic nanoparticles functionalized ethane sulfonic acid (MNESA) was found as efficient catalyst for the synthesis of coumarin derivatives using Pechmann condensation under mild condition. This reaction was catalyzed by MNESA under solvent-free condition at 90°C, to give the corresponding products in excellent yields. The catalyst is easily separated from the reaction condition and can be reused for several times with consistence in the activity.

N-Substituted 2-amino-1,3-benzothiazoles and 2,3-disubstituted indoles were prepared by C-S and C-C cross-coupling reactions of 2-iodoanilines with isothiocyanates or 1,3-dicarbonyl compounds, respectively, in the presence of magnetic nanoparticles functionalized with a copper(II)-Schiff base complex as an efficient and reusable catalyst.

The catalyst is recyclable and reusable at least four times without any significant loss in yield.