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

Reaction equation

[CH3:1][C:2]([CH3:4])=[O:3].O=[CH:6][C@H:7]([C@H:9]([C@@H:11]([C@@H:13]([CH2:15][OH:16])[OH:14])[OH:12])[OH:10])[OH:8].I.N1C=C[CH:21]=[CH:20][CH:19]=1>>[CH3:1][C:2]1([CH3:4])[O:8][C@@H:7]([C@H:9]2[O:10][C@H:15]([OH:16])[C@H:13]3[O:14][C:20]([CH3:21])([CH3:19])[O:12][C@@H:11]23)[CH2:6][O:3]1

Participants

Reactant 4

HCID 180Acetone

HCID 1049Pyridine

HCID 24841Hydrogen iodide

HCID 161658Demannose

Product 1

HCID 71571882,3:5,6-Di-O-isopropylidene-alpha-D-mannofuranoseYield 80%

Conditions

Temperature: 60 °C

Procedure

To 200 ml of acetone were added 10.0 g of D-mannose and 100 mg of hydrogen iodide and the mixture was refluxed with stirring in a water bath at 60° C.for 5 hours. During this reaction, the refluxing solvent was dried with 20 g of Molecular Sieves 3A interposed between the reaction vessel and the cooling jacket. After completion of the reaction, a small amount of pyridine was added. The acetone was then distilled off under reduced pressure and the residue was dissolved in benzene, washed with aqueous sodium bicarbonate and water and dried over anhydrous magnesium sulfate. The benzene was distilled off under reduced pressure to give 11.5 g (80%) of 2,3:5,6-di-O-isopropylidene-α-D-mannofuranose. After recrystallization from petroleum ether, it melted at 122°-123° C.