Reaktion #64317

Reaktionsgleichung

1,6-anhydro-3,4-dideoxy-β-D-threo-hex-3-enopyranose

methanol

iodine

ammonia water

→

1,6:3,4-dianhydro-β-D-talopyranose

Ausbeute 93.8%

Lösungsmittel

acetic acid

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.STIRRINGAfter the reaction mixture was stirred for 5 hours at room temperature under a nitrogen atmosphere
2. 2
   Temperaturcooling
3. 3
   workup.STIRRINGwas stirred for overnight at room temperature
4. 4
   Filtrationwas filtered off
5. 5
   Sonstigethe solvent was removed from the filtrate under reduced pressure
6. 6
   SonstigeThe residue was purified by means of silica gel column chromatography (hexane: ethyl acetate=1: 1)

Vorschrift

0.13 g (1.00 mmol) of 1,6-anhydro-3,4-dideoxy-β-D-threo-hex-3-enopyranose represented by the above formula [3] was dissolved in 4.6 ml of acetic acid, and further 0.33 g (2.00 mmol) of silver acetate was added thereto. While vigorously stirring the solution at room temperature, 0.27 g (1.05 mmol) of iodine was gradually added to the solution. After the reaction mixture was stirred for 5 hours at room temperature under a nitrogen atmosphere, 40 ml of 25% ammonia water was gradually added to the solution while ice-cooling to convert it to a basic solution. Further 40 ml of methanol was added to the basic solution, which was stirred for overnight at room temperature. Undissolved material was filtered off, and the solvent was removed from the filtrate under reduced pressure. The residue was purified by means of silica gel column chromatography (hexane: ethyl acetate=1: 1), thereby obtaining 1.09 g (yield: 93.8%) of 1,6:3,4-dianhydro-β-D-talopyranose represented by the following formula [4] . This was recrystallized from a hexane-diethyl ether mixed solvent (hexane:diethyl ether=1:4). ##STR13##

Quelle