L-(-)-Sorbose → Diacetone L-sorbose

Participants

Reaction Steps

To 250 ml of acetone were added 10.0 g of L-sorbose and 125 mg of anhydrous cupric chloride, and the mixture was stirred for 4 hours under reflux in a warm-water bath at 57° to 58° C. The refluxing solvent was continuously dried with 14 g of molecular sieves 3A which was placed between the reaction vessel and the cooling tube. After cooling, a small amount of aqueous sodium hydrogencarbonate is added to the reaction mixture, and the acetone was distilled off under reduced pressure. The residue was dissolved in about 150 ml of benzene and the benzene solution was washed with aqueous sodium hydrogencarbonate and water, and dried over anhydrous magnesium sulfate. When the benzene was distilled off under reduced pressure, there was obtained 12.1 g (84%) of 2,3:4,6-di-O-isopropylidene-L-sorbofuranose (purity of not less than 98%) as a residue. Its infra-red absorption spectrum and nuclear magnetic resonance spectrum were in accordance with those of the crystals as obtained in Example 5.

Provenance & Evidence