反应详情

Under an argon atmosphere, trifluoroacetic anhydride (20.6 ml, 0.146 mol) was added to a dichloromethane solution (100 ml) solution of 4-bromo-2,5-dimethylpyridine 1-oxide (9.8 g, 48.5 mmol) under ice cooling. The resulting mixture was stirred for 20 minutes and then, stirred at room temperature for 7.5 hours. The reaction mixture was concentrated under reduced pressure. To a dichloromethane solution (50 ml) of the residue was added a saturated aqueous solution (100 ml) of sodium bicarbonate. The resulting mixture was stirred for 14 hours. The reaction mixture was extracted with dichloromethane. The extract was dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue thus obtained was subjected to silica gel column chromatography. The fraction obtained from the hexane:ethyl acetate (=1:1) eluate was concentrated under reduced pressure to give the title compound (8.17 g, 40.4 mmol, 83%) as a yellow powder.

1. stirringstirred at room temperature for 7.5 hours
2. concentrationThe reaction mixture was concentrated under reduced pressure
3. additionTo a dichloromethane solution (50 ml) of the residue was added a saturated aqueous solution (100 ml) of sodium bicarbonate
4. stirringThe resulting mixture was stirred for 14 hours
5. extractionThe reaction mixture was extracted with dichloromethane
6. dry with materialThe extract was dried over anhydrous sodium sulfate
7. concentrationconcentrated under reduced pressure
8. customThe residue thus obtained
9. concentrationethyl acetate (=1:1) eluate was concentrated under reduced pressure