反应详情

温度

0 °C

A solution of 2-(3,4,5-trimethoxyphenyl)-4-hydroxy-cyclopent-2-en-1-one (3 gm, 11.36 mmol) in dichloromethane (30 ml) was cooled to 0° C. using ice-salt bath. To the cold solution dry pyridine (1.70 gm, 1.73 ml; 26.0 mmol) was added and stirred at 0° C. for 10 min. To the stirred solution, acetic anhydride (1.63 gm, 1.50 ml, 16.0 mmol) was added dropwise while maintaining the temperature below 0° C. The reaction mixture was stirred at room temperature for 15 h (monitored by TLC) then quenched by adding cold, dilute hydrochloric acid. The organic layer was washed three times with water, 10% sodium bicarbonate solution and finally brine. The organic layer was dried over sodium sulfate and concentrated to dryness under reduced pressure using a rotary evaporator. The crude residue was purified by column chromatography using silica gel (petroleum ether: acetone as eluent) to collect the pure 4-acetoxy-2-(3,4,5-trimethoxy-phenyl)-cyclopent-2-en-1-one (2.56 gm, 73.47%).

1. temperaturewhile maintaining the temperature below 0° C
2. stirringThe reaction mixture was stirred at room temperature for 15 h (monitored by TLC)
3. customthen quenched
4. additionby adding cold
5. washThe organic layer was washed three times with water, 10% sodium bicarbonate solution and finally brine
6. dry with materialThe organic layer was dried over sodium sulfate
7. concentrationconcentrated to dryness under reduced pressure
8. customa rotary evaporator
9. customThe crude residue was purified by column chromatography
10. customto collect the pure 4-acetoxy-2-(3,4,5-trimethoxy-phenyl)-cyclopent-2-en-1-one (2.56 gm, 73.47%)