Cross-linked sulfonated polyacrylamide (Cross-PAA-SO3H) attached to nano-Fe3O4 as a superior catalyst for the synthesis of oxindoles

Document Type: Original Research Paper

Authors

1 Young Researchers and Elite Club, Kashan Branch, Islamic Azad University, Kashan, Iran, E-mail addresses: hossien_shahbazi@yahoo.com Department of Organic Chemistry, Faculty of Chemistry, University of Kashan, Iran

2 Department of Organic Chemistry, Faculty of Chemistry, University of Kashan, Iran

10.22034/jna.2019.668029

Abstract

Cross-linked sulfonated polyacrylamide (Cross-PAA-SO3H) attached to nano-Fe3O4 as an efficient
heterogeneous solid acid catalyst has been used for the preparation of spiro[pyrazoloquinoline-oxindoles]
and spiro[chromenopyrazolo-oxindoles] through a four-component reactions of phenylhydrazine
or hydrazine hydrate, isatins, ketoesters and naphthylamine or 2-naphthol under reflux conditions in
ethanol. The remarkable advantages of this methodology are easy work-up, short reaction times, high
to excellent product yields, operational simplicity, low catalyst loading and reusability of the catalyst.

Keywords