Fe2O3 as an Environmentally Benign Natural Catalyst for One-Pot and Solvent-Free Synthesis of Spiro-4H-Pyran Derivatives

In this work, a simple and economical procedure for the synthesis of spiro-4H-pyranderivatives has been found through the three-component, one-pot condensation of isatin/acenaphthequinone, malononitrile and different reagents including 1, 3-dicrbonyl compounds, naphthol and 4-hydroxycumarin under thermal and solvent-free conditions in the presence ofFe2O3 as an efficient catalyst. The major advantages of this methodology are mild reaction conditions, eco-friendly, environmentally benign, non-toxic and inexpensive catalyst, experimentally simplicity, good yields and short reaction times.