2-Chloro-1-methyl-1H-imidazole

616-47-7

253453-91-7

Step A: Preparation of 2-chloro-1-methyl-1H-imidazole. N-methylimidazole (4.1 g, 0.05 mol) and anhydrous THF (25 mL) were added to a 300 mL three-necked round-bottomed flask equipped with a magnetic stirrer and a nitrogen inlet under nitrogen protection. Stirring was initiated and the reaction mixture was cooled to -78 °C. n-Butyllithium (2.5 M hexane solution, 22 mL, 0.055 mol) was added slowly via syringe and the reaction solution turned golden yellow. After maintaining stirring at this temperature for 30 minutes, a THF (25 mL) solution of hexachloroethane (13 g, 0.055 mol) was slowly added via syringe. Stirring of the reaction mixture was continued at -78 °C for 1 h. The reaction was subsequently quenched with saturated aqueous NaHCO3 solution (25 mL). The cooling bath was removed and after the reaction mixture was brought to room temperature, it was transferred to a 500 mL split funnel and extracted with ethyl acetate (150 mL). The organic layer was separated, washed sequentially with water and saturated saline and dried over anhydrous Na2SO4. After filtration, the solvent was removed by concentration under reduced pressure to give an oily crude product. The crude product was purified by distillation under reduced pressure to afford 2-chloro-1-methyl-1H-imidazole (4.75 g, 80% yield) as a colorless liquid with a boiling point of 54 °C/2 Torr. IR (thin film): 1515, 1420, 1367, 1277, 1127, 912, 740, 689, 665 cm-1. 1H NMR (400 MHz, CDCl3 ): δ 6.92 (d, J = 1.5 Hz, 1H), 6.85 (d, J = 1.5 Hz, 1H), 3.55 (s, 3H).13C NMR (100 MHz, CDCl3): δ 132.4, 128.0, 122.3, 33.5.HRMS (EI): m/z calculated value C4H6ClN2 [M+H]+, . 117.0223; measured value, 117.0220.