反应详情

温度

100 °C

A solution of potassium fluoride (0.367 g, 9.55 mmol) in water (15 ml) was added to a solution of 2-chloro-4-fluoro-3-(trifluoromethyl)-5-(trimethylsilyl)benzoic acid (1 g, 3.18 mmol) in tetrahydrofuran (50 ml) and the mixture was stirred at 100° C. overnight. An additional aliquot of water (15 ml) and potassium fluoride (0.370 g, 9.62 mmol) was added and heating at 100° C. was continued for a further 4 hrs. The tetrahydrofuran was evaporated in vacuo and replaced with enough dimethylformamide to dissolve all solids. The mixture was heated overnight at 100° C. but starting material still remained so more potassium fluoride (0.367 g, 9.55 mmol) was added and heating at 100° C. continued for 7 days. At this stage almost all of the starting material had disappeared so the reaction was evaporated to dryness under vacuum and taken up in 2N aqueous hydrogen chloride (75 ml) and diethyl ether (50 ml). The aqueous layer was separated and extracted with more diethyl ether (2×50 ml) and then the combined organic fractions were dried over sodium sulphate and evaporated to give crude product as a white solid. This was purified by recrystallisation from toluene to give pure 2-chloro-4-fluoro-3-(trifluoromethyl)benzoic acid (0.566 g) as a white solid.

1. temperatureheating at 100° C.
2. waitwas continued for a further 4 hrs
3. customThe tetrahydrofuran was evaporated in vacuo
4. dissolutionto dissolve all solids
5. temperatureThe mixture was heated overnight at 100° C.
6. additionwas added
7. temperatureheating at 100° C.
8. waitcontinued for 7 days
9. customwas evaporated to dryness under vacuum
10. customThe aqueous layer was separated
11. extractionextracted with more diethyl ether (2×50 ml)
12. dry with materialthe combined organic fractions were dried over sodium sulphate
13. customevaporated
14. customto give crude product as a white solid
15. customThis was purified by recrystallisation from toluene