反应详情

Into 6 ml of dioxane, were dissolved 500 mg of 4-hydroxy-5-allyl-2-cyclopentenone and 450mg of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. The solution was left standing at room temperature for 16 hours and the precipitated 2,3-dichloro-5,6-dicyanohydroquinone was collected by filtration and washed with methylene chloride. The filtrate together with the washings was concentrated. The concentration residue was dissolved in 50 ml of methylene chloride, washed with a 10% aqueous sodium hydroxide solution, then with water until the washings had become neutral. The residue thus treated was dried over anhydrous sodium sulfate, stripped of the solvent by distillation, and purified by column chromatography using 20 g of a silica gel (Wako Gel C-200) and an ethyl acetate-n-hexane (2:3 by volume) mixture as eluent, to obtain 450 mg (91% yield) of 4-keto-5-allyl-2-cyclopentenone.

1. waitThe solution was left
2. filtrationthe precipitated 2,3-dichloro-5,6-dicyanohydroquinone was collected by filtration
3. washwashed with methylene chloride
4. concentrationThe filtrate together with the washings was concentrated
5. dissolutionThe concentration residue was dissolved in 50 ml of methylene chloride
6. washwashed with a 10% aqueous sodium hydroxide solution
7. additionThe residue thus treated
8. dry with materialwas dried over anhydrous sodium sulfate
9. distillationstripped of the solvent by distillation
10. custompurified by column chromatography