反应详情

20 ml of tetrahydrofuran was cooled to −78° C., 4.17 ml of n-butyllithium (1.6 M, hexane solution) was added thereto, and the mixture was stirred. A solution of 1.59 g of 5-bromo-2-methoxy-3-pyridinecarboxaldehyde dimethyl acetal dissolved in 5 ml of tetrahydrofuran was added dropwise thereinto. After 30 minutes, 0.66 ml of dimethyldisulfide was added dropwise thereinto, and the mixture was further stirred for 1.5 hours. water was added to the reaction solution, and the mixture was extracted with ethyl acetate. The organic layer was washed with water and brine, and then dried over anhydrous magnesium sulfate. The solvent was evaporated, to give a pale yellow oil. The oil was dissolved in 30 ml of dichloromethane, 5.12 g of sodium bicarbonate and 2.32 g of m-chloroperbenzoic acid were added thereto, and the mixture was stirred for 30 minutes under ice-cooling. An aqueous sodium thiosulfate was added to the reaction solution, and the mixture was extracted with ethyl acetate. The organic layer was washed with water, a 1N aqueous sodium hydroxide and brine, and then dried over anhydrous magnesium sulfate. The solvent was evaporated, and the crude product was purified by silica gel column chromatography (n-hexane:ethyl acetate=2:1), to give 0.81 g of the title compound as a white solid.

1. additionwas added dropwise
2. stirringthe mixture was further stirred for 1.5 hours
3. extractionthe mixture was extracted with ethyl acetate
4. washThe organic layer was washed with water and brine
5. dry with materialdried over anhydrous magnesium sulfate
6. customThe solvent was evaporated
7. customto give a pale yellow oil
8. stirringthe mixture was stirred for 30 minutes under ice-
9. temperaturecooling
10. extractionthe mixture was extracted with ethyl acetate
11. washThe organic layer was washed with water
12. dry with materiala 1N aqueous sodium hydroxide and brine, and then dried over anhydrous magnesium sulfate
13. customThe solvent was evaporated
14. customthe crude product was purified by silica gel column chromatography (n-hexane:ethyl acetate=2:1)