Demannose → 2,3:5,6-Di-O-isopropylidene-alpha-D-mannofuranose

Participants

Reaction Steps

To 250 ml of acetone were added 10.0 g of D-mannose and 125 mg of anhydrous cupric chloride, and the mixture was stirred for 3 hours under reflux in a warm-water bath at 57° to 58° C. The refluxing solvent was continuously dried with 20 g of molecular sieves 3A which was placed between the reaction vessel and the cooling tube. After the conclusion of the reaction, a small amount of aqueous sodium hydrogencarbonate was added to the reaction mixture, and the acetone was distilled off under reduced pressure. The residue was dissolved in 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 13.0 g (90%) of 2,3:5,6-di-O-isopropylidene-α-D-mannofuranose (purity of not less than 92%). The compound, when recrystallized from petroleum ether, showed a melting point of 122° to 123° C.

Provenance & Evidence