Acetic Anhydride → (4-(2-(8-Ethyl-1,4,7,9-tetraoxaspiro[4.5]dec-8-yl)ethoxy)-3-methylpyridin-2-yl)methanol

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Reaction Conditions

Reaction Steps

The 4-(2-(8-ethyl-1,4,7,9-tetraoxaspiro[4.5]dec-8-yl)ethoxy)-2,3-dimethylpyridine 1-oxide (947 mg, 2.79 mmol) obtained in the step (4f) was mixed with acetic anhydride (10 ml). To the mixture, triethylamine (0.6 ml, 4.3 mmol) was added and stirred at 50° C. for 2 hours. The reaction mixture was concentrated and methanol (10 ml) was added to the residue and thereafter, a 5N aqueous sodium hydroxide solution (7 ml) was added and stirred at room temperature for one hour. To the mixture, a saturated aqueous ammonium chloride solution (7 ml) was added and the pH of the resultant solution 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 (564 mg, yield: 59.6%) as a light yellow solid.

Provenance & Evidence