Table 2. Optimization of the Solvent for the Synthesis of Compound 3f^a.

entry	solvent	time (h)	1:2 (mmol)	%yieldb
1.	methanol	5	1:2	78
2.	ethanol	3	1:2	96
3.	acetonitrile	10	1:2	62
4.	chloroform	12	1:2	47
5.	acetone	18	1:2	35
6.	H2O	23	1:2	traces
7.	EtOAc	18	1:2	32
8.	DCM	18	1:2	28
9.	MeOH/H2O (1:1)	8	1:2	68
10.	DMF	8	1:2	60

^aReaction conditions: 3-methyl-1-phenyl-2-pyrazoline-5-one (2 mmol) and 4-ethylbenzaldehyde (1 mmol) under blue LEDs at room temperature.

^bIsolated yields.