反应详情

温度

90 °C

The 2,3-dimethyl-4-(2-(2-propyl-1,3-dioxan-2-yl)ethoxy)pyridine 1-oxide (3.9 g, 13.2 mmol) obtained in the step (8c) was mixed with acetic anhydride (16 ml). The mixture was stirred at 90° C. for 2 hours. After cooled to room temperature, the reaction mixture was concentrated under reduced pressure. To the residue, methanol (20 ml) and a 5N aqueous sodium hydroxide solution (10 ml) were added and the mixture was stirred at room temperature for 2 hours. The reaction mixture was concentrated and the residue was separated by use of a saturated saline solution and ethyl acetate. The organic layer was dried over anhydrous magnesium sulfate, filtered and concentrated, and the residue was purified by silica gel column chromatography (elution solvent: heptane/ethyl acetate, ethyl acetate/methanol) to obtain the title compound (1.69 g, yield: 43.3%) as a yellow oil.

1. temperatureAfter cooled to room temperature
2. concentrationthe reaction mixture was concentrated under reduced pressure
3. additionTo the residue, methanol (20 ml) and a 5N aqueous sodium hydroxide solution (10 ml) were added
4. stirringthe mixture was stirred at room temperature for 2 hours
5. concentrationThe reaction mixture was concentrated
6. customthe residue was separated by use of a saturated saline solution and ethyl acetate
7. dry with materialThe organic layer was dried over anhydrous magnesium sulfate
8. filtrationfiltered
9. concentrationconcentrated
10. customthe residue was purified by silica gel column chromatography (elution solvent: heptane/ethyl acetate, ethyl acetate/methanol)