Table 3.

The effects of samples in the reaction of indole with benzaldehyde.^a

Entry	Catalyst	Isolated yield (%)
1	LDH-4	33
2	MMO-1	53
3	MMO-2	58
4	MMO-3	87
5	MMO-4	98
6	CuO and Al2O3	16

^aReaction condition: indole (2 mmol), benzaldehyde (1 mmol), catalyst (10 mg), solvent-free microwave irradiation at 160 °C, 10 min.