Catalyst-free domino reaction in water/ethanol: an efficient, regio- and chemoselective one-pot multi-component synthesis of pyranopyrazole derivatives

The synthesis of pyrano[2,3-c]pyrazole derivatives has been described by regio- and chemoselective four-component reaction of a dialkyl 3-oxopentanedioate, an active carbonyl compound, hydrazine and malononitrile in water/ethanol as a green medium under catalyst-free condition.