2232-08-8

288-32-4

98-59-9

2232-08-8

(a) In a three-necked round-bottomed flask equipped with a charging funnel, oil collector, magnetic stirring bar and protected by argon, imidazole (5.502 g, 0.081 mol) was dissolved in 25 mL of anhydrous dichloromethane. After cooling the solution to 0°C, p-toluenesulfonyl chloride (6.78 g, 0.036 mol) dissolved in 25 mL of anhydrous dichloromethane was added slowly and dropwise. The reaction mixture was stirred at room temperature for 2 h. The reaction mixture was subsequently filtered through silica gel and the residual solid was washed with 50 mL hexane/ethyl acetate (1:1, v/v). The filtrate was concentrated in a rotary evaporator, redissolved in 6 mL of ethyl acetate and precipitation was induced by the addition of 60 mL of hexane. The resulting white solid was filtered and dried to give 7.12 g of 1-tosylimidazole (0.032 mol, 89% yield).