Reaktion #6878

Reaktionsgleichung

sodium hydrogen carbonate

4,4′-dimethoxytrityl chloride

nucleoside

(1S,3R,4R,7R)-7-hydroxy-1-hydroxymethyl-3-(thymin-1-yl)-2,5-dioxabicyclo [2.2.1]heptane

4,4′-dimethoxytrityl chloride

→

nucleoside

Ausbeute 50.0%

(1R,3R,4R,7R)-1-(4,4′-dimethoxytrityloxymethyl )-7-hydroxy-3-(thymin-1-yl)-2,5-dioxabicyclo[2.2.1]heptane

Ausbeute 50.0%

Lösungsmittel

pyridine

Reaktionsbedingungen

Aufarbeitung

1. 1
   workup.ADDITIONwas added
2. 2
   Extraktionextraction
3. 3
   WaschenThe combined organic phase was washed with saturated aqueous solutions of sodium hydrogen carbonate (3×20 cm3) and brine (3×25 cm3)
4. 4
   Trocknendried (Na2SO4)
5. 5
   Sonstigeevaporated to dryness under reduced pressure
6. 6
   SonstigeThe residue was purified by silica gel column chromatography

Vorschrift

To a stirred solution of nucleoside 9 (0.500 g, 1.85 mmol) in anhydrous pyridine (10 cm3) was added 4,4′-dimethoxytrityl chloride (0.941 g, 2.78 mmol) and the mixture was stirred for 25 h at room temperature for 25 h after which additional 4,4′-dimethoxytrityl chloride (0.062 g, 0.18 mmol) was added and stirring at room temperature was continued for another 21 h. A saturated aqueous solution of sodium hydrogen carbonate (50 cm3) was added and extraction was performed using dichloromethane (3×25 cm3). The combined organic phase was washed with saturated aqueous solutions of sodium hydrogen carbonate (3×20 cm3) and brine (3×25 cm3), dried (Na2SO4) and evaporated to dryness under reduced pressure. The residue was purified by silica gel column chromatography using dichloromethane/methanol/pyridine (1–4% methanol, 0.5% pyridine, v/v/v) as eluent to give nucleoside 10 (0.53 g, 50%) as a white solid material after evaporation of the solvents under reduced pressure (0.307 g, 28.9%).

Quelle