Optimizing of the reaction conditions for the synthesis of 1a^a.

Entry	Solvent	Temperature (°C)	Catalyst loading (mg)	Time (min.)	Yieldb (%)
1	—	120	20	20	80
2 c	—	110	20	20	80
3	—	110	30	20	78
4		110	10	20	67
5	—	110	—	20	Trace
6	—	110	—	120	45
7	—	100	20	30	50
8	—	90	20	60	40
9	—	80	20	60	Trace
11	H2O	Reflux	20	240	—
12	EtOH	Reflux	20	240	—
13	n-Hexane	Reflux	20	240	Trace
14	EtOAc	Reflux	20	240	35
15	CH2Cl2	Reflux	20	240	20
16	THF	Reflux	20	240	45

^aReaction conditions: benzaldehyde (1 mmol, 0.106 g), ke3 (1 mmol, 0.370 g), 3-(1H-indol-3-yl)-3-oxopropanenitrile (1 mmol, 0.184 g) and ammonium acetate (1.5 mmol, 0.115 g).

^bRelated to isolated yields.

^cOptimal data.