Thymine → 1(2-O-Acetyl5-O-benzoyl-4-C-benzoyloxymethyl-3-O-benzyl-beta-D-xylofuranosyl)thymine

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

To a stirred suspension of the anomeric mixture 3 (7.26 g, 0.013 mol) and thymine (3.25 g, 0.028 mol) in anhydrous acetonitrile (80 cm3) was added N,O-bis(trimethylsilyl)acetamide (19.1 cm3, 0.077 mol). The reaction mixture was stirred at 60° C. for 1 h and then cooled to 0° C. Trimethylsilyl triflate (4.1 cm3, 0.023 mol) was added drop-wise during 10 min and the mixture was subsequently heated for 22 h under reflux. After cooling to room temperature, a saturated aqueous solution of sodium hydrogen carbonate (30 cm3) was added and extraction was performed using dichloromethane (100 cm3×3). The combined organic phase was washed with saturated aqueous solutions of sodium hydrogen carbonate (30 cm3×3) and brine (50 cm3×3), dried (Na2SO4) and concentrated under reduced pressure. The residue was purified by silica gel column chromatography using dichloromethane/methanol (0.5–2.0% methanol, v/v) as eluent to give nucleoside 4 (6.88 g, 85%) as a white solid material after evaporation of the solvents under reduced pressure.

Herkunft & Nachweise