反应详情

温度

90 °C

Ethyl 3-methyl-2,4,5-trifluorobenzoate (61.0 g, 279 mmol) was dissolved in benzene (1,000 mL). N-Bromosuccinimide (76.2 g, 428 mmol) and 2,2′-azobisisobutyronitrile (100 mg) were added thereto, and the mixture was refluxed for 3 days. The reaction mixture was left to cool, and the solid matter that precipitated was separated through filtration and washed with benzene. Subsequently, the filtrate and the wash solution were combined. The mixture was concentrated under reduced pressure. The residue was subjected to silica gel chromatography (eluent; n-hexane:ethyl acetate=20:1 to 10:1), to thereby yield a mixture of the starting material and ethyl 3-bromomethyl-2,4,5-trifluorobenzoate (about 1:1, 57.8 g). The mixture was dissolved in DMF (290 mL), and sodium acetate (22.1 g, 269 mmol) was added thereto, followed by stirring for 30 minutes at 90° C. The reaction mixture was left to cool, and ethyl acetate (1,000 mL) was added thereto. The mixture was washed with water (500 mL×2) and saturated brine (500 mL), and dried with sodium sulfate anhydrate. After filtration, the filtrate was concentrated under reduced pressure. The residue was subjected to silica gel chromatography (eluent; n-hexane:ethyl acetate=20:1), whereby the starting material was recovered in an amount of 27.4 g (45%) and the title compound was obtained as a pale yellow oily substance (26.5 g, 34%).

1. temperaturethe mixture was refluxed for 3 days
2. waitThe reaction mixture was left
3. temperatureto cool
4. customthe solid matter that precipitated
5. customwas separated through filtration
6. washwashed with benzene
7. concentrationThe mixture was concentrated under reduced pressure
8. customto thereby yield
9. waitThe reaction mixture was left
10. temperatureto cool
11. washThe mixture was washed with water (500 mL×2) and saturated brine (500 mL)
12. dry with materialdried with sodium sulfate anhydrate
13. filtrationAfter filtration
14. concentrationthe filtrate was concentrated under reduced pressure
15. customwas recovered in an amount of 27.4 g (45%)