Potassium Carbonate → ethyl 1-(4-ethylphenyl)-1H-imidazole-5-carboxylate

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4-Ethylaniline (2.08 mL, 16.6 mmol) and ethyl oxoacetate (50% solution in toluene, 3.30 mL, 16.6 mmol) were combined in ethanol (40 mL) and stirred at room temperature for 3 hours. Potassium carbonate (5.75 g, 41.6 mmol) and isocyanomethyl 4-methylphenyl sulfone (98%, 3.98 g, 20.0 mmol) were added and the reaction mixture was heated to reflux for 3 hours. After cooling to room temperature, the reaction mixture was filtered through Celite. The filtrate was concentrated in vacuo, dissolved in ethyl acetate, washed with water, dried over magnesium sulfate, filtered, and concentrated under reduced pressure. Purification via silica gel chromatography (Gradient: 0% to 33% ethyl acetate in heptane) afforded the product as a clear brown oil that solidified upon standing. Yield: 3.03 g, 12.4 mmol, 75%. LCMS m/z 245.0 (M+1). 1H NMR (400 MHz, CDCl3) δ 1.24 (t, J=7.1 Hz, 3H), 1.29 (t, J=7.6 Hz, 3H), 2.73 (q, J=7.6 Hz, 2H), 4.21 (q, J=7.1 Hz, 2H), 7.27 (br AB quartet, JAB=8.6 Hz, ΔνAB=24 Hz, 4H), 7.66 (d, J=1.1 Hz, 1H), 7.85 (d, J=1.1 Hz, 1H).

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