Dimethyl Sulfoxide → 1-methyl-4-phenyl-1H-imidazole

Participants

Reaction Steps

Add 20 mL dimethyl sulfoxide (35 mL; 492.74 mmoles) to powdered potassium hydroxide (20.81 mmoles; 1.17 g). Add 5-phenyl-1H-imidazole (13.87 mmoles; 2.00 g) at room temperature and solid quickly dissolves giving an orange solution. After stirring 5 min add methyl iodide (15.26 mmoles; 950.36 μL) in one portion. Stir 4h at room temp. Dilute with water and extract with ethyl acetate (2×), then wash the organics with saturated aq. sodium chloride/water (2×) solution, dry over MgSO4, filter, evaporate to give 1.71 g yellow solid. Purify the crude by using ISCO chromatography over a biotage 40M column eluting with a gradient of 0.5% MeOH/DCM to 5% MeOH/DCM at a flow rate of 40 mL/min. Dry product fractions to give 1.43 g (65% yield) off-white solid. (7% of undesired regioisomer) MS (ES): (m/z)=159.0 [M+H].

Provenance & Evidence