To a suspension of 1H-imidazole-2-carbaldehyde (480 mg, 5 mmol) and anhydrous potassium carbonate (936 mg, 6 mmol) in N,N-dimethylformamide (7 mL) was added ethyl iodide (829 mg, 6 mmol). The reaction mixture was heated at 50 °C with stirring for 5 hours. After completion of the reaction, the solvent was removed by distillation under reduced pressure. The residue was subjected to liquid-liquid partitioning with distilled water (30 mL) and ethyl acetate (30 mL). The aqueous phase was further extracted with ethyl acetate (20 mL x 3). All organic phases were combined, washed with saturated sodium chloride solution, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to afford 1-ethyl-1H-imidazole-2-carbaldehyde as a light yellow oil (520 mg, 84% yield). The product was characterized by 1H NMR (400 MHz, CDCl3): δ 1.42-1.46 (t, J = 7.2 Hz, 3H), 4.42-4.47 (q, 2H), 7.19 (s, 1H), 7.29 (s, 1H), 9.82 (s, 1H). lC-MS (ESI) m/z: 125 (M + 1)+.
