Application of a biological-based nanomagnetic catalyst in the synthesis of bis-pyrazols and pyrano[3,2-c]pyrazoles

{Fe3O4@SiO2@(CH2)(3)-thiourea dioxide-SO3H/HCl}, a newly reported nanomagnetic core-shell supported solid acid catalyst, was successfully employed in the preparation of 4,4'-(arylmethylene)bis(1H-pyrazol-5-ol) and pyrano[3,2-c]pyrazole derivatives. The presented methods are very efficient and high-yielding. Also, the catalyst exhibited powerful potential for reusability in both types of reactions.