Reaction #6875

Reaction equation

4,4′-dimethoxytrityl chloride

nucleoside

1-(3-O-Benzyl-4-C-(p-Toluenesulphonyloxymethyl)β-D-xylofuranosyl)thymine

4,4′-dimethoxytrityl chloride

→

nucleoside

Yield 75.0%

1-(3-O-Benzyl-5-O-(4,4′-dimethoxytrityl)-4-C-(p-toluenesulphonyloxymethyl)-β-D-xylofuranosyl)thymine

Yield 75.0%

Solvents

dichloromethane

pyridine

Conditions

Workup

1. 1
   workup.STIRRINGstirring
2. 2
   workup.WAITwas continued for 36 h at room temperature
3. 3
   OtherThe organic phase was separated
4. 4
   Washwashed with saturated aqueous solutions of sodium hydrogen carbonate (25 cm3×3) and brine (40 cm3×3)
5. 5
   Dryingdried (Na2SO4)
6. 6
   Otherevaporated to dryness under reduced pressure
7. 7
   OtherThe residue was purified by silica gel column chromatography

Procedure

To a solution of nucleoside 6 (3.66 g, 6.88 mmol) in anhydrous pyridine (25 cm3) was added N,N-(dimethylamino)pyridine (0.84 g, 6.81 mmol) and 4,4′-dimethoxytrityl chloride (3.5 g, 13.2 mmol) and the mixture was stirred for 23 h at room temperature. Additional N,N-(dimethylamino)pyridine (0.250 g, 2.06 mmol) and 4,4′-dimethoxytrityl chloride (0.700 g, 2.06 mmol) was added, and stirring was continued for 36 h at room temperature. Ice cold H2O (50 cm3) was added and the reaction mixture was diluted with dichloromethane (150 cm3). The organic phase was separated and washed with saturated aqueous solutions of sodium hydrogen carbonate (25 cm3×3) and brine (40 cm3×3), dried (Na2SO4) and evaporated to dryness under reduced pressure. The residue was purified by silica gel column chromatography using dichloromethane/methanol/pyridine (0.75–1.5% methanol; 0.5% pyridine, v/v/v) as eluent to afford nucleoside 7 (4.28 g, 75%) as a white solid material after evaporation of the solvents under reduced pressure.

Source