A highly efficient and sustainable synthesis of dihydropyrano[2,3-c] pyrazoles using polystyrenesupported p- toluenesulfonic acid as reusable catalyst

A simple, expedient, and ecofriendly protocol for the one-pot synthesis of dihydropyrano[2,3-c] pyrazole derivatives using polystyrene-supported p-toluenesulfonic acid as a highly active and reusable heterogeneous catalyst in water has been developed. The core advantages of the present protocol are excellent yields, mild reaction conditions, broad substrate scope, and easy work-up procedure. This new protocol exemplifies the operationally simple synthesis of dihydropyrano[2,3-c] pyrazoles in a time- efficient and cost-effective manner.