反应详情

To a solution of 3-hydroxy-pyridine-2-carboxylic acid methyl ester (200 mg, 1.3 mmol) in N,N-dimethylformamide (2.0 ml) was added at 22° C. sodium hydride (55% in oil, 64 mg) and stirring was continued until gas evolution ceased. The suspension was cooled to 0° C. and treated with trifluoroethyl trifluoromethanesulfonate (728 mg) and stirring was continued at 22° C. for 2 hours. The mixture was partitioned between saturated sodium hydrogen-carbonate solution and ethyl acetate, and the organic layer was dried and evaporated. The residue was purified by chromatography on silica using n-heptane and ethyl acetate (3:1) as the eluent to give 3-(2,2,2-trifluoro-ethoxy)-pyridine-2-carboxylic acid methyl ester as a pale green oil. Mass (calculated) C9H8F3NO3 [235.16]; (found) [M+H]+=236. b) A solution of 3-(2,2,2-trifluoro-ethoxy)-pyridine-2-carboxylic acid methyl ester (216 mg, 0.9 mmol) in methanol (1 ml) was treated with a solution of lithium hydroxide (78 mg, 3.3 mmol) in water (0.1 ml) and stirring was continued at 22° C. for 2 hours. The solution was evaporated and the residue triturated with 1N aqueous hydrochloric acid. The suspension was filtered, the residue washed with water and dried to give 3-(2,2,2-trifluoro-ethoxy)-pyridine-2-carboxylic acid as a colorless solid. Mass (calculated) C8H6F3NO3 [221.14]; (found) [M−H]−=220.

1. customThe solution was evaporated
2. customthe residue triturated with 1N aqueous hydrochloric acid
3. filtrationThe suspension was filtered
4. washthe residue washed with water
5. customdried