反应详情

3-hydroxy-5-methoxypicolinic acid (200 mg, 1.18 mmol) was dissolved in ethanol (10 mL). To the mixture was added one drop of sulfuric acid. The mixture was refluxed with stirring for 3 days. After cooling to room temperature, the mixture was concentrated in vacuo to afford an oil. The residual oil was dissolved in ethyl acetate and washed with aq. sodium bicarbonate and brine. The extract was dried over sodium sulfate and concentrated in vacuo to afford an oil. The residual oil was purified by silica gel column chromatography (ethyl acetate/hexane 1:3 to 1:1) to afford 178 mg (76%) of the title compound as a white solid.

1. temperatureThe mixture was refluxed
2. concentrationthe mixture was concentrated in vacuo
3. customto afford an oil
4. washwashed with aq. sodium bicarbonate and brine
5. dry with materialThe extract was dried over sodium sulfate
6. concentrationconcentrated in vacuo
7. customto afford an oil
8. customThe residual oil was purified by silica gel column chromatography (ethyl acetate/hexane 1:3 to 1:1)