反应详情

温度

80 °C

2,2,6,6-Tetramethylcyclohexane-1,3,5-trione (5 g, 0.027 mol) and 4-dimethylamino-pyridine (16.47 g, 0.135 mol) are added to a mixture of chloroform (100 ml) and toluene (25 ml). The reaction mixture is flushed with nitrogen for 15 minutes at ambient temperature. 4-Bromo-2-ethylphenyllead triacetate (17.16 g, 0.03 mol) is added in one portion and the reaction mixture is stirred and heated to 80° C. (pre-heated oil bath) under an atmosphere of nitrogen for 1 hour. The reaction mixture is cooled to room temperature, acidified to pH 1 with 2N aqueous hydrochloric acid, filtered through a plug of diatomaceous earth and the two phases are separated. The organic phase is collected, and the aqueous phase is extracted with dichloromethane (2×75 ml). the organic phases are combined, washed with water, and dried over anhydrous sodium sulfate. The mixture is filtered, and the filtrate is evaporated under reduced pressure. The residue is purified by column chromatography on silica gel to give 4-(4-bromo-2-ethylphenyl)-2,2,6,6-tetramethyl-cyclohexane-1,3,5-trione as a white solid (3.5 g).

1. customThe reaction mixture is flushed with nitrogen for 15 minutes at ambient temperature
2. temperature(pre-heated oil bath) under an atmosphere of nitrogen for 1 hour
3. temperatureThe reaction mixture is cooled to room temperature
4. filtrationfiltered through a plug of diatomaceous earth
5. customthe two phases are separated
6. customThe organic phase is collected
7. extractionthe aqueous phase is extracted with dichloromethane (2×75 ml)
8. washwashed with water
9. dry with materialdried over anhydrous sodium sulfate
10. filtrationThe mixture is filtered
11. customthe filtrate is evaporated under reduced pressure
12. customThe residue is purified by column chromatography on silica gel