反应详情

To a solution of 2-acetyl-2-[2-(ethoxycarbonyl)ethyl]-cyclohexanone (see Preparation 4) (40 g, 0.16 mol) in tert-butanol (85 ml) was added, dropwise, a 30% aqueous solution of hydrogen peroxide (21.7 ml, 0.19 mol) and concentrated sulfuric acid (0.25 ml, 98% w/w) at room temperature. The mixture was further stirred for 24 hours, partitioned between dichloromethane (100 ml) and distilled water (100 ml) and the layers separated. The dichloromethane layer was washed with 5% aqueous sodium sulphite solution, dried over magnesium sulphate, filtered and concentrated under reduced pressure to give a yellow oil, (34.35 g). Purification of this material by chromatography on silica by eluting with ethyl acetate/hexane (1:2 changing to 1:1), followed by neat ethyl acetate in the latter stages, gave, after combination and evaporation of appropriate fractions, the title compound as a yellow oil, (22.96 g, 67%). RF. 0.28 (silica, ethyl acetate/hexane, 1:1). 1H-NMR (300 MHz, CDCl3): =1.31 (t, 3H), 1.47-1.62 (m, 2H), 1.62-1.82 (m, 4H), 1.92-2.08 (m, 2H), 2.10-2.27 (m, 2H), 2.32-2.46 (m, 2H), 4.19 (q, 2H) ppm. 13C-NMR (75.5 MHz, CDCl3) 14.26, 25.15, 31.21, 33.56, 36.15, 53.21, 60.49, 173.38, 183.52 ppm.

1. customat room temperature
2. custompartitioned between dichloromethane (100 ml)
3. distillationdistilled water (100 ml)
4. customthe layers separated
5. washThe dichloromethane layer was washed with 5% aqueous sodium sulphite solution
6. dry with materialdried over magnesium sulphate
7. filtrationfiltered
8. concentrationconcentrated under reduced pressure
9. customto give a yellow oil, (34.35 g)
10. customPurification of this material by chromatography on silica
11. washby eluting with ethyl acetate/hexane (1:2 changing to 1:1)
12. customgave
13. customafter combination and evaporation of appropriate fractions