反应详情

20 mg of p-toluenesulphonic acid are added to a solution of 327 mg of 13-ethinyl-3,3;17,17-bis-(ethylenedioxy)-10-methyl-gon-5-ene in 15 ml of acetone and 0.5 ml of water and the mixture is heated under reflux for 5 hours. The reaction mixture is concentrated to about 5 ml, diluted with ethyl acetate, washed with water and saturated sodium chloride solution, dried and evaporated. Chromatography on silica gel using a mixture of hexane/ethyl acetate (3:1) as the eluant gives only 13-ethinyl-10-methyl-gon-4-ene-3,17-dione, which is recrystallised from ether/hexane; melting point 148°-150° C, [α]D25 = +63°.

1. temperatureunder reflux for 5 hours
2. concentrationThe reaction mixture is concentrated to about 5 ml
3. additiondiluted with ethyl acetate
4. washwashed with water and saturated sodium chloride solution
5. customdried
6. customevaporated
7. additionChromatography on silica gel using a mixture of hexane/ethyl acetate (3:1) as the eluant