Table 5.

Synthesis of 3-hydroxy-3-indolylindoline-2-ones in the presence of β-CD-SO₃H in water at reflux temp^a

Sr. No.	Isatin	Indole	Product	Time (min)	Yieldb (%)
3a				5	86
3b				5	92
3c				15	88
3d				5	96
3e				10	86
3f				5	88

^aReaction condition: isatin (1.0 mmol), indole (1.0 mmol), β-CD-SO₃H (0.1 mmol), water (2 mL).

^bIsolated yield.