ABSTRACT An efficient protocol has been developed for the synthesis of highly functionalized pyrano 2,3‐ c pyrazole derivatives using ethyl acetoacetate, hydrazine hydrate, malononitrile, and various arylaldehydes, in the presence of a catalytic amount of DBN in ethanol‐water, affording 85%–95% yields. The developed cascade method offers several advantages, including high yield, the use of metal‐free catalysts, mild reaction conditions, and a simple work‐up process, all of which are consistent with the principles of green chemistry. The synthesized compounds were further evaluated for their antioxidant activity.
Yadav et al. (Sun,) studied this question.