反应详情

温度

50 °C

The 2,3-dimethyl-4-((8-methyl-1,4,7,9-tetraoxaspiro[4.5]dec-8-yl)methoxy)pyridine 1-oxide (1.20 g, 3.84 mmol) obtained in the step (5d) was mixed with acetic anhydride (10 ml). To the mixture, triethylamine (0.8 ml, 5.74 mmol) was added and the mixture was stirred at 50° C. for 2 hours. The reaction mixture was concentrated and methanol (10 ml) was added to the residue. Thereafter a 5N aqueous sodium hydroxide solution (7 ml) was added to the mixture, and stirred at room temperature for 30 minutes. To the resultant mixture, a saturated aqueous ammonium chloride solution (7 ml) was added and the pH was adjusted to about 10. The reaction mixture was diluted with ethyl acetate, and the organic layer was washed with a 2N aqueous sodium hydroxide solution, water, and a saline solution, dried over anhydrous sodium sulfate and concentrated. The obtained crude product was purified by silica gel column chromatography (elution solvent: ethyl acetate/methanol=1/0-4/1 gradient) and a desired fraction(s) was concentrated to obtain the title compound (312 mg, 26.1% yield) as a light yellow solid.

1. concentrationThe reaction mixture was concentrated
2. additionmethanol (10 ml) was added to the residue
3. additionThereafter a 5N aqueous sodium hydroxide solution (7 ml) was added to the mixture
4. stirringstirred at room temperature for 30 minutes
5. additionTo the resultant mixture, a saturated aqueous ammonium chloride solution (7 ml) was added
6. additionThe reaction mixture was diluted with ethyl acetate
7. washthe organic layer was washed with a 2N aqueous sodium hydroxide solution, water
8. dry with materiala saline solution, dried over anhydrous sodium sulfate
9. concentrationconcentrated
10. customThe obtained crude product
11. customwas purified by silica gel column chromatography (elution solvent: ethyl acetate/methanol=1/0-4/1 gradient)
12. concentrationa desired fraction(s) was concentrated