Nano-silica sulfuric acid as an efficient catalyst for the synthesis of substituted pyrazoles

A convenient and direct approach has been developed for the preparation of pyrazole derivatives by condensing 1,3-diketones and hydrazines in the presence of nano-silica sulfuric acid. This thermal solvent-free procedure offers some advantages such as short reaction time, simple work-up, high yields, and reusability of the catalyst.