1,1'-(Chlorophenylmethylene)bis(4-methoxybenzene) → (1R,3R,4R,7R)-1-(4,4'-Dimethoxytrityloxymethyl)-7-Hydroxy-3-(Thymin-1-yl)-2,5-Dioxabicyclo[2.2.1]Heptane

Beteiligte Stoffe

Reaktionsschritte

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%).

Herkunft & Nachweise