反应详情

8 g of 1,2-di-(methoxycarbonyl)-4-ethylidene-cyclohexane, prepared as described in Example 2, was dissolved in aqueous acetone containing 4.8 ml of acetic acid. An aqueous solution of potassium permanganate was added, and the mixture was allowed to stand for 60 minutes at room temperature. The excess oxidant was then destroyed and the reaction mixture, diluted with water, was extracted with ethyl acetate. The organic phase, washed with water and dried over anhydrous sodium sulphate, was evaporated to dryness under vacuum. The residue (9 g) was dissolved in benzene and refluxed for 60 minutes in the presence of a catalytic amount of p-toluenesulphonic acid. 4 ml of ethylene glycol was added and the reaction mixture was refluxed for a further 2 hours. After conventional work-up, the residue, obtained by evaporating off the solvent, was purified by chromatography on a column of silica gel using as eluent a toluene:acetone mixture (15:1 by volume). 3.0 g of the title compound was isolated (yield 33%): m.p. 69°-71° C.; m/z 271 (MH+.).

1. customThe excess oxidant was then destroyed
2. additionthe reaction mixture, diluted with water
3. extractionwas extracted with ethyl acetate
4. washThe organic phase, washed with water
5. dry with materialdried over anhydrous sodium sulphate
6. customwas evaporated to dryness under vacuum
7. dissolutionThe residue (9 g) was dissolved in benzene
8. temperaturerefluxed for 60 minutes in the presence of a catalytic amount of p-toluenesulphonic acid
9. addition4 ml of ethylene glycol was added
10. temperaturethe reaction mixture was refluxed for a further 2 hours
11. customAfter conventional work-up, the residue, obtained
12. customby evaporating off the solvent
13. customwas purified by chromatography on a column of silica gel using as eluent a toluene