反应详情

温度

5 °C

A mixture of 120 g (0.238 mol) of 5, 3.0 liters of 95% ethanol, and 350 mL of water in a 5 liter round bottom flask is cooled to 5° C. in an ice bath for 30 minutes. Concentrated H2SO4 (650 mL) is added to this mixture over a period of 10 minutes in 50 mL portions. Any large chunks of suspended material are broken up mechanically. The mixture is heated under reflux for 20-24 hours. The brownish reaction mixture is cooled to 20° C. using an ice bath and then poured into 7 Kg of ice in a 12 liter carboy. The paste-like precipitate is collected on a Buchner funnel using either polypropylene filter cloth (Aldrich) or three layers of Whatman #1 filter paper, which is occasionally scratched to facilitate filtration. The pale-yellow cake is washed three times with 1 liter of cold water and dissolved in 1 liter of hot methanol, to which 1 liter of hexane and 50 mL of hot water are added. The resulting two-phase system is heated on a steam bath until all solid material is dissolved. This mixture is allowed to cool for 2-3 hours to 20° C.; at this point crystals begin to form at the solvent interface. The mixture is then cooled overnight at -15° C. to give a brown upper hexane phase, a lower light yellow aqueous phase, and white crystalline material. The crystals (roughly 90% pure by TLC) are collected by suction filtration and recrystallized again from methanol/hexane/water (2:2:1) as described above.

1. temperatureThe mixture is heated
2. temperatureunder reflux for 20-24 hours
3. customThe brownish reaction mixture
4. temperatureis cooled to 20° C.
5. customThe paste-like precipitate is collected on a Buchner funnel
6. filtrationfilter cloth (Aldrich) or three layers of Whatman #1
7. filtrationfilter paper, which
8. filtrationfiltration
9. washThe pale-yellow cake is washed three times with 1 liter of cold water
10. dissolutiondissolved in 1 liter of hot methanol, to which 1 liter of hexane and 50 mL of hot water
11. additionare added
12. temperatureThe resulting two-phase system is heated on a steam bath until all solid material
13. dissolutionis dissolved
14. temperatureto cool for 2-3 hours to 20° C.
15. customto form at the solvent interface
16. temperatureThe mixture is then cooled overnight at -15° C.
17. filtrationThe crystals (roughly 90% pure by TLC) are collected by suction filtration
18. customrecrystallized again from methanol/hexane/water (2:2:1)