反应详情

温度

40 °C

Methanesulfonyl chloride (1.5 g) was added to a solution of 9 (1.2 g) in pyridine (2 ml). After being kept at room temperature for 2 days, ice was added and the mixture was extracted with chloroform. The organic layer was washed with water and evaporated to give methyl 4,6-O-isopropylidene-1,3-di-O-methanesulfonyl-α-L-sorbofuranoside as a syrup. The syrup was stirred in 60% acetic acid at 55° C. for 2.5 hours. The solution was brought up to pH about 10 with 10N sodium hydroxide and heated at 40° C. for 3 hours. The reaction mixture was neutralized with 10N sulfuric acid and concentrated. The residue was triturated with ethanol. After the salt was filtered off, the ethanol solution was concentrated and the residue was dissolved in a mixture of ethanol and 10N sulfuric acid (1:4). The solution was heated to 80° C. for 30 min. Ethanol was evaporated off and the mixture was heated for 5 minutes. The reaction mixture was neutralized with 10N sodium hydroxide and the salt was removed by repeated precipitation with ethanol. After filtration, the filtrate was concentrated to give L-fructose in more than 85% yield.

1. concentrationconcentrated
2. customThe residue was triturated with ethanol
3. filtrationAfter the salt was filtered off
4. concentrationthe ethanol solution was concentrated
5. dissolutionthe residue was dissolved in a mixture of ethanol and 10N sulfuric acid (1:4)
6. temperatureThe solution was heated to 80° C. for 30 min
7. customEthanol was evaporated off
8. temperaturethe mixture was heated for 5 minutes
9. customthe salt was removed
10. customprecipitation with ethanol
11. filtrationAfter filtration
12. concentrationthe filtrate was concentrated