Catalyst-free synthesis of 3-substituted-3-hydroxy-2-oxindoles by reaction of isatin and cyclic enaminone in water

Abstract

An easy protocol for the synthesis of enaminone attached 3-substituted-3-hydroxy-2-oxindoles has been demonstrated by reaction of isatin and cyclic enaminone in water. The developed catalyst-free reaction has the advantage of being atom-economical, eco-friendly, and benign reaction conditions. The broader substrate scope, experimentally simple procedures, and easy purification of products with high yield further make this method attractive and useful.

Graphical Abstract

Keywords:

• Dimedone
• enaminone
• isatin
• oxindole
• water

Acknowledgments

We are thankful to Dr. S. J. S. Flora, Director, NIPER, Raebareli for his support and encouragement in carrying out this research work. S.R.T., V.K., and P.S.M. are thankful to the Department of Pharmaceuticals, Ministry of Chemicals and Fertilizers, Govt. of India for providing fellowship. The authors are thankful to SAIF, CSIR-CDRI, Lucknow for providing spectral data. Communication no. NIPER-R/Communication/038.