Kaolin/KOH Is an Efficient Heterogeneous Catalyst for the Synthesis of 3-Hydroxy-3-indolyl Oxindoles
摘要:
3-Hydroxy-3-indolyl oxindoles were synthesized from isatins and indoles in good to excellent yields by using heterogeneous catalyst kaolin preloaded with KOH.
[GRAPHICS]Various 3-indolyl-3-hydroxy oxindoles were prepared for the first time by supramolecular catalysis involving the reaction of beta-CD:isatin complexes with indoles under neutral conditions in water. beta-Cyclodextrin can be recovered and reused a number of times without loss of activity.