Synthesis of Pyranopyrazoles using a Magnetically Separable Modified Preyssler Heteropoly Acid.

The article focuses on the discovery and improvement of multi-component reactions (MCRs) with recyclable catalysts. Topics include the economic and environmental importance of the design and preparation of recyclable catalysts, the production of magnetic nanoparticles, and the availability of fourteen acidic hydro-gens, high thermal stability and high hydrolytic stability found in Preyssler heteropoly acid.