Kaolin/KOH Is an Efficient Heterogeneous Catalyst for the Synthesis of 3-Hydroxy-3-indolyl Oxindoles

Abstract

3-Hydroxy-3-indolyl oxindoles were synthesized from isatins and indoles in good to excellent yields by using heterogeneous catalyst kaolin preloaded with KOH.

Graphical Abstract

Keywords:

• Heterogeneous catalyst
• indole
• isatin
• kaolin/KOH

ACKNOWLEDGMENTS

We thank Dr. J. S. Yadav (director) and Dr. V. V. N. Reddy (head of department) of the Indian Institute of Chemical Technology, Hyderabad, for constant encouragement and financial support.

Notes

^aAll products were characterized by IR, ¹H NMR, and mass spectroscopy.

^bIsolated and unoptimized yields.