反应详情

温度

55 °C

Into 350 ml of a water-acetone (1:6 by volume) mixture, was dissolved 10 g of 2-(1-hydroxy-3-butenyl) furan. To the solution heated at b 55° C. under reflux, was added dropwise 6.6 g of polyphosphoric acid. After having been stirred at 55° C. for 48 hours, the reaction mixture was stripped of the acetone by distillation and the residue was extracted twice with 300 ml of ether. The extract solution was washed with an aqueous sodium hydrogencarbonate solution, then with saturated sodium chloride solution, dried over anhydrous sodium sulfate, and freed from the solvent by distillation to obtain 9.5 g of a concentrate. On distillation of the concentrate, there were obtained 4.2 g of 2-(1-hydroxy-3-butenyl)furan (b.p. 78° C./10 mmHg) and 3.8 g (65.5% yield based on consumed starting material) of the intended 4-hydroxy-5-allyl-2-cyclopentenone (b.p. 97° C./0.7 mmHg).

1. temperatureunder reflux
2. distillationthe reaction mixture was stripped of the acetone by distillation
3. extractionthe residue was extracted twice with 300 ml of ether
4. washThe extract solution was washed with an aqueous sodium hydrogencarbonate solution
5. dry with materialwith saturated sodium chloride solution, dried over anhydrous sodium sulfate
6. distillationfreed from the solvent by distillation
7. customto obtain 9.5 g of a concentrate
8. distillationOn distillation of the concentrate