Acetic Anhydride → (4-(((4R)-2,2-dimethyl-1,3-dioxolan-4-yl)methoxy)-3-methylpyridin-2-yl)methanol

Temperature

80 °C

The 4-(((4R)-2,2-dimethyl-1,3-dioxolan-4-yl)methoxy)-2,3-dimethylpyridine1-oxide (10.5 g, 41.5 mmol) obtained in the step (14a) was mixed with acetic anhydride (20 ml). The mixture was stirred at 80° C. for one hour. After cooled to room temperature, the reaction mixture was concentrated under reduced pressure. To the residue, methanol (40 ml) and a 5N aqueous sodium hydroxide solution (20 ml) were added and the mixture was stirred at room temperature for 1.5 hours. The reaction mixture was concentrated and the residue was partitioned between 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: ethyl acetate/methanol) to obtain the title compound (3.77 g, yield: 41.9%) as a yellow oil.

1. temperatureAfter cooled to room temperature
2. concentrationthe reaction mixture was concentrated under reduced pressure
3. additionTo the residue, methanol (40 ml) and a 5N aqueous sodium hydroxide solution (20 ml) were added
4. stirringthe mixture was stirred at room temperature for 1.5 hours
5. concentrationThe reaction mixture was concentrated
6. customthe residue was partitioned between 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: ethyl acetate/methanol)

ORD record

ord-23e6350c8d7b4e29a9ce8c41b5544a19

Source dataset

uspto-grants-2008_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07425634B2