Fe3O4 nanoparticles were prepared and decorated on the surface of nanobentonite (NB), and subsequently modified by the organic and inorganic linkers and then sulfonic acid immobilization on the nanoparticles. The NB‐Fe3O4@SiO2@CPTMO@DEA‐SO3H catalyst was characterized via Fourier transform‐infrared spectroscopy, scanning electron microscopy, energy‐dispersive X‐ray spectroscopy, vibrating‐sample magnetometer, X‐ray diffraction patterns, Brunauer–Emmett–Teller and thermal gravimetric analysis. The new catalyst benefits from a simple preparation method, and environmentally friendly and high magnetic properties of the nanocatalyst, Accordingly, we used it for the synthesis of dihydropyrano[2,3c]pyrazole derivatives in water and ethanol mixture as a green solvent under reflux conditions. Use of mild conditions, easy catalyst separation, cost‐effectiveness, short reaction time, reusability of the catalyst, excellent yield and easy work‐up are the main advantages of the present method.

No abstract