One-Pot, Catalyst-Free Synthesis of Spirooxindole and 4H-Pyran Derivatives

Abstract

The synthesis of biologically valuable spirooxindoles and 4H-pyrans is described under catalyst-free conditions through sequential Knoevenagel–Michael–cyclization reactions from isatin or aromatic aldehyde, malononitrile, and 1,3-dicarbonyl compounds. The reaction conditions are very simple, providing excellent yield.

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GRAPHICAL ABSTRACT

Keywords:

• Catalyst-free
• isatin
• malononitrile
• 4H-pyrans
• spirooxindoles

ACKNOWLEDGMENTS

The authors thank the Department of Science and Technology, New Delhi, for assistance under the IRHPA Program for the NMR facility at Madurai Kamaraj University and thank Orchid Chemicals and Pharmaceuticals Ltd. for providing facilities.

Notes

^a Isolated yield.

^a Isolated yield.

^b The reaction was carried out at 70 °C.