6310-09-4

96-43-5

108-24-7

6310-09-4

Example 8: In a 100 mL four-necked flask equipped with a stirrer, a condenser, a thermometer, and a dropping funnel, 5.9 g of activated white clay (a product of Nacalai Tesque, Inc.) and 25.5 g (0.25 mol) of acetic anhydride were added sequentially. The temperature of the reaction system was maintained at 45 °C to 55 °C and 29.6 g (0.25 mol) of 2-chlorothiophene was slowly added dropwise over 1 h in this temperature range. After the dropwise addition was completed, the reaction was continued with stirring at 50 °C for 72 hours. Upon completion of the reaction, the activated white clay was removed by filtration to give a dark brown filtrate. Subsequently, unreacted 2-chlorothiophene, acetic anhydride and the by-product acetic acid were removed from the filtrate by distillation, resulting in 20.9 g (0.13 mol) of 2-acetyl-5-chlorothiophene.