反应详情

温度

80 °C

Into a 1,000 ml beaker containing sulfuric acid (300 ml), lapachol (30 g, 0.124 mol) was added in portions slowly over 5 minutes at room temperature while stirring vigorously. After addition, the dark mixture was stirred for an additional 30 min and then poured into ice water (800 g) with manual stirring in a 2,000 ml beaker. The mixture was transferred into a 2,000 ml separatory funnel and extracted twice with toluene (600 ml and 400 ml). The toluene phases were pooled and washed successively with 1% aqueous sodium chloride (800 ml), 1% aqueous sodium bicarbonate (400 ml) and 1% aqueous sodium chloride (800 ml), and then dried with sodium sulfate (50 g). After filtration, the filtrate was evaporated to dryness by Rotovap and then ethanol (300 ml) was added for co-evaporation to completely remove residual toluene. The residue was dissolved in 75% ethanol or absolute ethanol, preferably absolute ethanol (ethanol/water, 3:1, 300 ml) with heating in an 80° C. water bath, then was filtered and cooled to 4° C. slowly. Pure β-lapachone was isolated by filtration, then washed with cold 75% ethanol (4° C., 100 ml), dried under vacuum, packed under Argon atmosphere and stored at −20° C. in the dark.

1. additionwas added in portions slowly over 5 minutes at room temperature
2. additionAfter addition
3. stirringthe dark mixture was stirred for an additional 30 min
4. stirringstirring in a 2,000 ml beaker
5. customThe mixture was transferred into a 2,000 ml separatory funnel
6. extractionextracted twice with toluene (600 ml and 400 ml)
7. washwashed successively with 1% aqueous sodium chloride (800 ml), 1% aqueous sodium bicarbonate (400 ml) and 1% aqueous sodium chloride (800 ml)
8. dry with materialdried with sodium sulfate (50 g)
9. filtrationAfter filtration
10. customthe filtrate was evaporated to dryness by Rotovap
11. additionethanol (300 ml) was added for co-evaporation to completely remove residual toluene
12. dissolutionThe residue was dissolved in 75% ethanol
13. filtrationwas filtered
14. temperaturecooled to 4° C. slowly