Screening of solvents for the synthesis of 2,4,5-triarylimidazole using CuB₄O₇.

Entry	Catalysta	Solventb	Yieldc (%)
1	CuB4O7	Methanol	92
2		Ethanol	88
3		DMF	86
4		DMSO	82
5		Water	32
6		Silica gel	91
7		Neat	98

^aThe reaction was performed with benzil 1 (1 mmol), 2-nitrobenzaldehyde 2 (1 mmol), and NH₄OAc 3 in the presence of different copper(ii) salts in different solvent/neat conditions at 80 °C for 2 h except for neat condition.

^bUnder neat condition, the reaction completed in 10 min.

^cIsolated yield.