反应详情

To a suspension of 2-hydroxy-4-pyridinecarboxylic acid (Journal of the Chemical Society (1960), 1430-4; 8.45 g, 60.8 mmol) in methanol (200 ml) under nitrogen was added thionyl chloride (7.23 g, 60.8 mmol) dropwise at room temperature. The mixture was then heated under reflux for 4 hrs before being cooled to room temperature. The solvent was removed under vacuum and the residue was dissolved in ethyl acetate. A saturated aqueous solution of sodium bicarbonate was added which formed a precipitate that was removed by filtration. The filtrate was further basified with 2N aqueous sodium hydroxide. The layers were separated and the organic phase was further extracted with ethyl acetate. The combined organic extracts were washed with brine (×2), dried over magnesium sulphate and concentrated under vacuum to give the title compound as a pale brown oil (3.4 g).

1. temperatureThe mixture was then heated
2. temperatureunder reflux for 4 hrs
3. customThe solvent was removed under vacuum
4. dissolutionthe residue was dissolved in ethyl acetate
5. additionA saturated aqueous solution of sodium bicarbonate was added which
6. customformed a precipitate that
7. customwas removed by filtration
8. customThe layers were separated
9. extractionthe organic phase was further extracted with ethyl acetate
10. washThe combined organic extracts were washed with brine (×2)
11. dry with materialdried over magnesium sulphate
12. concentrationconcentrated under vacuum