反应详情

温度

7.5 °C

To an ice cold solution of 2-(4-bromo-2-ethylphenyl)-4,6-diethyl-4,6-dimethyl-1,5-dioxaspiro[2.4]heptan-7-one (15 g, 0.0397 mol) in dichloromethane (7.5 ml) is added concentrated sulphuric acid (45 ml), dropwise over 50-60 minutes, maintaining the temperature of the reaction mixture at 5-10° C. The reaction mixture is maintained at 5-10° C. for 10-15 minutes, quenched into crushed ice (225 g) and extracted with dichloromethane (3×100 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)-2,6-diethyl-2,6-dimethylpyran-3,5-dione (2 g) as a white solid.

1. temperatureThe reaction mixture is maintained at 5-10° C. for 10-15 minutes
2. customquenched
3. custominto crushed ice (225 g)
4. extractionextracted with dichloromethane (3×100 ml)
5. washwashed with water
6. dry with materialdried over anhydrous sodium sulfate
7. filtrationThe mixture is filtered
8. customthe filtrate is evaporated under reduced pressure
9. customThe residue is purified by column chromatography on silica gel