反应详情

温度

0 °C

33.8 g of aluminium chloride were suspended in 200 g of fluorobenzene, and a solution of 37.8 g of thiophene-2-carbonyl chloride in 50 ml of fluorobenzene was added dropwise to this at 0° C. over the course of 30 minutes. The mixture was stirred at 0° C. for 2 hours and then slowly warmed, and heated under reflux at 85° C. for 2 hours until evolution of hydrogen chloride ceased. The solution was cooled to 70° C. and then, at this temperature, added dropwise over the course of 30 minutes to a stirred suspension of 7.2 g of of sodium borohydride in 50 ml of diglyme. The mixture was then stirred at 70° C. for 90 minutes and, after cooling, discharged into a mixture of 250 g of ice, 200 ml of water and 62.5 g of concentrated aqueous hydrochloric acid. After addition of 100 ml of fluorobenzene, the organic phase was separated off, extracted by shaking with 100 ml of water and concentrated. Yield: 58.3 g of product with a content of 61.8% by weight of 2-(4-fluorobenzyl)thiophene (GC), corresponding to a yield of 75.1% of theory. An organic phase was obtained from the aqueous mother liquor by extraction with methylene chloride and concentration and contained a further 33.7% by weight of the required product (GC), corresponding to an additional yield of 4.6% of theory. Distillation of the organic phase resulted in a 99.2% pure 2-(4-fluorobenzyl)thiophene.

1. temperatureslowly warmed
2. temperatureheated
3. temperatureThe solution was cooled to 70° C.
4. stirringThe mixture was then stirred at 70° C. for 90 minutes
5. temperatureafter cooling
6. customthe organic phase was separated off
7. extractionextracted
8. stirringby shaking with 100 ml of water
9. concentrationconcentrated
10. customAn organic phase was obtained from the aqueous mother liquor by extraction with methylene chloride and concentration