An Efficient One-Pot Green Protocol for the Synthesis of Dihydrochromeno[4,3-<i>b</i>]Pyrazolo[4,3-<i>e</i>]Pyridin-6(7<i>H</i>)-Ones Mediated by Diisopropyl Ethyl Ammonium Acetate at Room Temperature

Development of a green protocol to access pharmaceutically relevant functionalized coumarin-pyrazole molecular hybrids, dihydrochromeno[4,3-b]Pyrazolo[4,3-e]pyridin-6(7H)-ones, has been accomplished based on a three-component tandem reaction between aromatic aldehydes, 4-hydroxycoumarin and 3-aminopyrazoles in presence of Diisopropyl Ethyl Ammonium Acetate (DIPEAc) as catalyst and solvent at room temperature is reported. The remarkable features of this new procedure are high yields, short reaction times, simple experimental and work-up procedures, mild and environmentally friendly reaction conditions, and the economic availability of the catalyst. </p