反应详情

温度

-10 °C

A mixture of 15 g (833 millimoles) of L-sorbose, 0.38 ml of boron trifluoride etherate and 333 ml of acetone was refluxed for 6 hours. 40 g of a molecular sieve (3 Å) were present in a Soxhlet extractor between the flask and the reflux condenser. When the reaction was complete, the reaction mixture was cooled to -10° C., and 10 ml of aqueous sodium bicarbonate solution were added. Thereafter, the acetone was distilled off under reduced pressure, the residue was taken up in 200 ml of toluene, and the solution was extracted twice with 30 ml of 5% strength aqueous NaHCO3 solution. This solution was then washed with 10 ml of dilute NaCl solution and dried over sodium sulfate, and the toluene was distilled off under reduced pressure to give 18.7 g (86%) of 2,3:4,6-di-O-isopropylidene-α-L-sorbofuranose. After the product had been recrystallized from hexane, its melting point was measured as 78°-79.5° C.

1. temperaturewas refluxed for 6 hours
2. distillationThereafter, the acetone was distilled off under reduced pressure
3. extractionthe solution was extracted twice with 30 ml of 5% strength aqueous NaHCO3 solution
4. washThis solution was then washed with 10 ml of dilute NaCl solution
5. dry with materialdried over sodium sulfate
6. distillationthe toluene was distilled off under reduced pressure