反应详情

In a dried 3 neck flask fitted with magnetic stirrer and condensor was placed metal magnesium (12 mmol) and ether (1.8 mL). Neat bromoethane (2.5 mmol) was added via syringe and the reaction was started immediately. A solution of bromoethane (10.5 mmol) in toluene (30 mL) was added to the solution slowly. After completion of the addition, the solution was stirred at room temperature for 30 min under nitrogen before adding neat diethylamine (24 mmol). The solution was further stirred at room temperature for 15 min. The solution was cooled to 0° C. and a mixture of 1-(pyridin-2-yl)ethanone (XVIII) (12 mmol) and 2-bromoisobutyrophenone (XVII) (13 mmol) was added to the solution. The solution was further stirred for 3 h at 0° C. under nitrogen. Aqueous 5% H2SO4 (20 mL) was added to the solution and the solution was warmed to room temperatue. The organic layer was separated, dried over MgSO4 and filtered. The organic layer was then treated with Et3N (10 mmol) and allowed to stir overnight at room temperature. The solution was then washed with water, dried over MgSO4, filtered and concentrated. The residue was purified by flash chromatography eluting with 1-5% EtOAc in hexane gradient to give 2,2-dimethyl-1-phenyl-4-(pyridin-2-yl)butane-1,4-dione 9 as a colorless viscous oil (11% yield). 1H NMR (CDCl3, 400 MHz): δ ppm 1.47 (s, 6H), 3.80 (s, 2H), 7.34-7.50 (m, 4H), 7.65-7.75 (m, 2H), 7.80 (m, 1H), 7.94 (m, 1H), 8.67 (m, 1H); ESIMS found C17H17NO2 m/z 268 (M+H).

1. customIn a dried 3 neck flask
2. customfitted with magnetic stirrer
3. additionAfter completion of the addition
4. stirringThe solution was further stirred at room temperature for 15 min
5. temperatureThe solution was cooled to 0° C.
6. additionwas added to the solution
7. stirringThe solution was further stirred for 3 h at 0° C. under nitrogen
8. temperaturethe solution was warmed to room temperatue
9. customThe organic layer was separated
10. dry with materialdried over MgSO4
11. filtrationfiltered
12. stirringto stir overnight at room temperature
13. washThe solution was then washed with water
14. dry with materialdried over MgSO4
15. filtrationfiltered
16. concentrationconcentrated
17. customThe residue was purified by flash chromatography
18. washeluting with 1-5% EtOAc in hexane gradient