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. 13 C-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