反应 #302896

反应方程式

water

n-butyllithium

1-fluoro-2-methylthio-3-(trifluoromethyl)benzene

carbon dioxide

→

crude product

2-fluoro-3-methylthio-4-(trifluoromethyl)benzoic acid

溶剂

Diethyl ether

THF

反应条件

后处理

1. 1
   其他exceed −65° C
2. 2
   其他did not exceed −45° C
3. 3
   温度The mixture was then warmed to RT
4. 4
   温度once more cooled to 0° C
5. 5
   其他formed
6. 6
   workup.DISSOLUTIONhad dissolved
7. 7
   萃取the organic phase was extracted three times with water
8. 8
   萃取The aqueous phase was extracted repeatedly with dichloromethane
9. 9
   洗涤the combined organic phases were washed with saturated aqueous NaCl solution
10. 10
    干燥dried over sodium sulfate

实验过程

Under an atmosphere of inert gas, 27.5 ml (1.6 M in hexane, 44 mmol) of n-butyllithium were added dropwise to a solution, cooled to −78° C., of 7.98 g (38 mmol) of 1-fluoro-2-methylthio-3-(trifluoromethyl)benzene in 60 ml of anhydrous THF, where the temperature of the reaction mixture should not exceed −65° C. The mixture was stirred at −78° C. for 3 h, and at this temperature a carbon dioxide stream was then introduced such that the temperature of the reaction mixture did not exceed −45° C. The mixture was then warmed to RT and then once more cooled to 0° C. For work-up, water was added dropwise at this temperature until the precipitate formed had dissolved. Diethyl ether was added, and the organic phase was extracted three times with water. The combined aqueous phases were acidified with 10 percent strength hydrochloric acid. The aqueous phase was extracted repeatedly with dichloromethane, the combined organic phases were washed with saturated aqueous NaCl solution and dried over sodium sulfate and the filtrate was then freed from the solvent. The crude product obtained in this manner was then recrystallized from gasoline (80-110° C.)/ethyl acetate. This gave 6.8 g of 2-fluoro-3-methylthio-4-(trifluoromethyl)benzoic acid.

来源