One-pot synthesis of trisubstituted imidazoles in the presence of MC–SO₃H catalyst^a.

Comp.	α-Diketone	R	Yield (%)	Mp (°C)	Ref.
3a	1a	4-Br–C6H4	96	251–253	249–251 (ref. 49)
3b	1a	4-F–C6H4	95	187–189	189–190 (ref. 50)
3c	1a	3-F–C6H4	91	>260	284–285 (ref. 50)
3d	1a	2,6-diCl–C6H4	83	231–232	229–230 (ref. 51)
3e	1a	4-CN–C6H4	97	>260	259–261 (ref. 49)
3f	1a	3-NO2–C6H4	90	>260	301–303 (ref. 49)
3g	1a	4-OMe–C6H4	89	222–224	219–221 (ref. 49)
3h	1a	2-Thiophene	87	254–256	257–259 (ref. 49)
3i	1b	C6H4	89	>260	311–313 (ref. 52)
3j	1b	4-Br–C6H4	95	>260	280–282 (ref. 52)
3k	1b	4-Cl–C6H4	93	>260	274–276 (ref. 52)
3l	1b	2-Cl–6-F–C6H4	87	>260	—
3m	1b	4-NO2–C6H4	93	>260	335–337 (ref. 52)
3n	1b	2-NO2–C6H4	94	>260	267 (ref. 53)
3o	1b	4-iPr–C6H4	90	>260	—
3p	1b	4-Ph–C6H4	94	>260	258–259 (ref. 54)
3q	1b	2-OH–5-NO2–C6H4	88	>260	259–260 (ref. 55)
3r	1b	4-OMe–C6H4	91	252–254	254–255 (ref. 56)

^aReaction conditions: 4-bromobenzaldehyde (1 mmol), benzil (1 mmol), ammonium acetate (3 mmol), EtOH (4 mL).