反应详情

To a solution of (1-(trifluoromethyl)cyclopentyl)methanol (2.80 g, 16.65 mmol) in anhydrous dimethylsulfoxide (50 ml) was added potassium tert-butoxide (4.50 g, 40.106 mmol) and the reaction mixture was stirred at ambient temperature for 30 minutes. 5-chloro-2,4-difluorobenzoic acid (3.20 g, 16.62 mmol) was added to the reaction mixture, and stirring was continued for 2 hours. The reaction mixture was acidified to pH=1 with 5% aqueous hydrochloric acid solution and extracted with ethyl acetate, the combined organic extracts was washed with brine; dried over anhydrous sodium sulfate and concentrated in vacuo. Purification of the residue by column chromatography (30% ethyl acetate in hexanes) afforded the title compound (5.00 g, 88%) containing o-substituted regioisomer, which was used for next step without further purification: MS (ES−) m/z 339.2, 341.2 (M−1).

1. stirringstirring
2. waitwas continued for 2 hours
3. extractionextracted with ethyl acetate
4. washthe combined organic extracts was washed with brine
5. dry with materialdried over anhydrous sodium sulfate
6. concentrationconcentrated in vacuo
7. customPurification of the residue by column chromatography (30% ethyl acetate in hexanes)