Reaktion #445312

Reaktionsgleichung

pyridine

acetone

D-galactose

hydriodic acid

→

1,2:3,4-di-O-isopropylidene-α-D-galactopyranose

Ausbeute 59.0%

Reaktionsbedingungen

Aufarbeitung

1. 1
   Temperaturthe mixture was refluxed
2. 2
   SonstigeDuring this reaction
3. 3
   Trocknenthe refluxing solvent was dried with 20 g of Molecular Sieves 3A
4. 4
   SonstigeAfter completion of the reaction
5. 5
   workup.DISTILLATIONThe acetone was then distilled off under reduced pressure
6. 6
   workup.DISSOLUTIONthe residue was dissolved in benzene
7. 7
   Waschenwashed with aqueous sodium bicarbonate and water
8. 8
   Trocknendried over anhydrous magnesium sulfate
9. 9
   workup.DISTILLATIONThe benzene was distilled off
10. 10
    workup.DISTILLATIONthe residue was further distilled under reduced pressure

Vorschrift

To 200 ml of acetone were added 10.0 g of D-galactose and 175 mg of hydriodic acid (57%) and the mixture was refluxed with stirring in a water bath at 60° C. for 8 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 and the residue was further distilled under reduced pressure, whereby 8.5 g (59%) of 1,2:3,4-di-O-isopropylidene-α-D-galactopyranose was obtained as a fraction boiling at 129°-133° C./0.2 mmHg.

Quelle