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-pyran derivatives 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 of fe2o3 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.