反应详情

To a solution of 5-(2-methylprop-1-en-1-yl)pyridine-2-carbaldehyde (9.40 g) in a mixed solvent of dimethylsulfoxide (230 mL) and water (1.89 mL) was added N-bromosuccinimide (18.7 g) at 0° C. The reaction solution was warmed to room temperature and stirred at room temperature for 1 hr. To the reaction mixture was added saturated aqueous sodium hydrogen carbonate solution, and the mixture was extracted with ethyl acetate. The extract was washed successively with water and saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. To a solution of the residue in tetrahydrofuran (200 mL) was added 4.5M aqueous sulfuric acid solution, and the mixture was stirred at room temperature for 3 hr. The reaction mixture was neutralized with aqueous sodium hydroxide solution and saturated aqueous sodium hydrogen carbonate solution, and the mixture was extracted with ethyl acetate. The extract was washed successively with water and saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (ethyl acetate:hexane=20:80-100:0, volume ratio) to give the title compound (9.00 g, yield 79%) as a pale-yellow oil. MS: 196 (MH+).

1. extractionthe mixture was extracted with ethyl acetate
2. washThe extract was washed successively with water and saturated brine
3. dry with materialdried over anhydrous sodium sulfate
4. concentrationconcentrated under reduced pressure
5. additionTo a solution of the residue in tetrahydrofuran (200 mL) was added 4.5M aqueous sulfuric acid solution
6. stirringthe mixture was stirred at room temperature for 3 hr
7. extractionthe mixture was extracted with ethyl acetate
8. washThe extract was washed successively with water and saturated brine
9. dry with materialdried over anhydrous sodium sulfate
10. concentrationconcentrated under reduced pressure
11. customThe residue was purified by silica gel column chromatography (ethyl acetate:hexane=20:80-100:0, volume ratio)