反应详情

Ethyl (2Z,4E)-3-cyclopropyl-5-[8-hydroxy-2,3,7,9-tetramethyl-9-(trifluoromethyl)-1,4-dioxaspiro[4.5]dec-6-en-8-yl]penta-2,4-dienoate (40 mg, 0.09 mmol) was dissolved in acetone (4 ml) under argon in a round-bottom flask, and a few drops of conc. hydrochloric acid were added. The resulting reaction solution was stirred at room temperature for 4 h and then water was added. After removing acetone under reduced pressure, the aqueous phase was extracted repeatedly with dichloromethane. The combined organic phases were dried over magnesium sulfate, filtered and concentrated under reduced pressure. By column chromatography purification of the resulting crude product (ethyl acetate/heptane gradient), ethyl (2Z,4E)-3-cyclopropyl-5-[1-hydroxy-2,6-dimethyl-4-oxo-6-(trifluoromethyl)cyclohex-2-en-1-yl]penta-2,4-dienoate (15 mg, 45% of theory) was obtained in the form of a colorless oil. 1H-NMR (400 MHz, CDCl3 δ, ppm) 7.88 (d, 1H), 6.37 (d, 1H), 6.01 (s, 1H), 5.64 (s, 1H), 4.17 (q, 2H), 2.92 (d, 1H), 2.52 (d, 1H), 2.39 (br. s, 1H, OH), 1.98 (s, 3H), 1.59 (m, 1H), 1.30 (t, 3H), 1.28 (s, 3H), 0.88 (m, 2H), 0.59 (m, 2H).

1. customThe resulting reaction solution
2. customAfter removing acetone under reduced pressure
3. extractionthe aqueous phase was extracted repeatedly with dichloromethane
4. dry with materialThe combined organic phases were dried over magnesium sulfate
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure
7. customBy column chromatography purification of the resulting crude product (ethyl acetate/heptane gradient)