Table 1. Effect of Different Catalysts on Model Reaction^a.

entry	catalyst	time (min)b	yieldc (%)
1	no catalyst	30	trace
2	NdCl3	21	46
3	LaCl3	18	53
4	CeCl3	12	62
5	PTA	12	72
6	STA	10	75
7	STANPs	9	78
8	Nd@STANPs	12	81
9	La@STANPs	13	80
10	Ce@STANPs	9	88
11	STANPs/ZrO2	15	81
12	Ce@STANPs/ZrO2	5	94
13	Ce@STANPs/SiO2	12	91
14	Ce@STANPs/Al2O3	11	90

^aReaction conditions: isatin 1 (2 mmol), benzaldehyde 2d (2 mmol), ammonium acetate 3 (5 mmol), catalysts (80 mg), water, T = 100 °C, MW.

^bReaction progress monitored by thin-layer chromatography (TLC).

^cIsolated yield.