Cyclohexanone → 2,3:5,6-DI-O-Cyclohexylidene-alpha-D-mannofuranose

Participants

Reaction Steps

To a mixed solution of 150 ml of cyclohexanone and 120 ml of dichloromethane were added 10.0 g of D-mannose and 125 mg of anhydrous cupric chloride, and the mixture was stirred for 9 hours under reflux in a warm-water bath at 63° to 65° C. The refluxing solvent was continuously dried with 20 g of molecular sieves 3A which was placed between the reaction vessel and cooling tube. The reaction solution was diluted with benzene, washed with aqueous sodium hydrogencarbonate and water, and dried over anhydrous magnesium sulfate. When the solvent and cyclohexanone were distilled off under reduced pressure, there was obtained 17.9 g (95%) of 2,3:5,6-di-O-cyclohexylidene-α-D-mannofuranose (purity of not less than 95%) as a residue. The compound, when recrystallized from n-hexane, showed a melting point of 122° to 124° C.

Provenance & Evidence