A New, Simple, Catalyst-free Method for the Synthesis of Pyrazolopyranopyrimidines in Magnetized Water

Background: The design of biologically-active compounds is a challenging viewpoint in medicinal chemistry, and pyranopyrazoles and pyranopyrimidine play a crucial role as biologically-active molecules. Methods: At the moment, a few examples have been reported for the synthesis of pyrazolopyranopyrimidine derivatives. In this work, magnetized water was applied as a green promoting medium for one-pot, practical, efficient, and environmentally benign four-component reaction of an aldehyde, ethyl acetoacetate, hydrazine hydrate, and thiobarbituric acid under catalyst-free conditions. Results: The reactions proceeded rapidly for aromatic aldehydes with the electron-withdrawing or electron-donating groups at different positions of the ring, and heteroaryl aldehydes, and the desired products were isolated in high yields without any side product formation in very short reaction times. Conclusion: An efficient, catalyst-free, green, and convenient method was proposed for the synthesis of pyrazolopyranopyrimidines in magnetized water in good-to-high yields.. This method offers the advantages of short reaction times, low costs, quantitative yields, simple work-up, green, and no need of any organic solvent.