反应详情

2.5 g of sodium percarbonate were added over 1 h to a solution of 2.2 g (10 mmol) of 3,4-difluorobenzophenone and 20 ml of trifluoroacetic acid (0° C.) and the temperature was then allowed to rise to 20° C. The mixture was stirred for 16 h at this temperature and 50 g of ice were then added. The mixture was subsequently extracted twice with dichloromethane and the organic phases were washed (NaHCO3) until the washings were neutral. The solvent was then removed. Working-up as described in Example 22 gave 1.2 g (7.6 mmol, 76%) of 3,4-difluorobenzoic acid, which can be obtained analytically pure from water (melting point 113°-120.5° C.).

1. customto rise to 20° C
2. additionwere then added
3. extractionThe mixture was subsequently extracted twice with dichloromethane
4. washthe organic phases were washed (NaHCO3) until the washings
5. customThe solvent was then removed