Synthesis and characterization of highly substituted pyrazoles using silica- phosphoric acid nanoparticles as a recoverable heterogeneous solid acid catalyst

Abstract

Highly substituted pyrazoles have been prepared by condensing 1,3-diketones and various hydrazine derivatives using silica-phosphoric acid nanoparticles (nano-SPA). This nano solid catalyst has been prepared by the reaction of nano silica chloride with dry phosphoric acid. This green methodology has advantages such as short reaction times, simple work-up, high efficiency, reusability of the catalyst and no use of any solvents.