Background: The design of biologically-active compounds is a challenging viewpoint in
medicinal chemistry, and pyranopyrazoles and pyranopyrimidine play a crucial role as biologicallyactive
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.