反应详情

A solution of 5-difluoromethyl-pyridine-2-carboxylic acid methyl ester (700 mg, 3.7 mmol) in ethanol (8.0 ml) was treated with a solution of sodium hydroxide (5M, 1.5 ml) at 0° C. Then the reaction mixture was allowed to attain room temperature and was stirred for 5 hours. For the workup, ethanol was removed at reduced pressure. The resulting solid was dissolved in water (5 ml) and the solution was washed with ethyl acetate (2×5 ml). The aqueous layer acidified with a solution of citric acid (10%, pH˜4), followed by extraction with a 7:3-mixture of dichloromethane and methanol (5×10 ml). The combined organic layers were washed with brine (20 ml), dried over sodium sulphate, and evaporated at reduced pressure. The 5-difluoromethyl-pyridine-2-carboxylic acid was obtained as a white solid (400 mg, 62% of theory).

1. customto attain room temperature
2. customFor the workup, ethanol was removed at reduced pressure
3. dissolutionThe resulting solid was dissolved in water (5 ml)
4. washthe solution was washed with ethyl acetate (2×5 ml)
5. extractionfollowed by extraction with a 7
6. washThe combined organic layers were washed with brine (20 ml)
7. dry with materialdried over sodium sulphate
8. customevaporated at reduced pressure