ChemInform Abstract: Highly Efficient Solvent‐Free Synthesis of Pyranopyrazoles by a Broensted‐Acidic Ionic Liquid as a Green and Reusable Catalyst.

Abstract Biologically active substituted dihydropyrano[2,3‐c]pyrazole derivatives (IV) are obtained by a simple, green, and efficient four‐component reaction of various benzaldehydes (II), ethyl acetoacetate (I), malononitrile (III), and hydrazine hydrate using an acidic ionic liquid as catalyst.