Knoevenagel condensation reactions in an ionic liquid

The condensation reaction of 4-oxo-(4H)-1-benzopyran-3-carbaldehydes and of aromatic aldehydes with 3-methyl-1-phenylpyrazolin-5-(4H)-one were carried out in an ionic liquid, ethylammonium nitrate, at room temperature in shorter times with higher yields of 78-92 and 70-75%, respectively, than found using conventional procedures.