Acetyl protection of 2'-fluoro-2'-deoxyuridine. 2'-fluoro-2'-deoxyuridine (1) (3 g, 12.185 mmol) was dissolved in pyridine (150 mL) and then cooled to 0°C. Acetic anhydride (12.39 g, 121.364 mmol) was added, and the reaction was stirred for 1 hour at 0°C, then for an additional hour at room temperature. The reaction was monitored by TLC (Ethyl Acetate/MeOH 20:1). The solvent was then removed in vacuo. The residue was then dissolved in methanol (100 mL) and the solvent was removed in vacuo again. A white powdered solid was collected, 2'-Fluoro-3',5'-di-O-acetyl-2'-deoxyuridine (2) (3.82 g, 98.7%). NMR spectra were obtained on a Bruker AVII 400 MHz spectrometer and were calibrated to the centre of the set solvent peak and chemical shifts were reported in parts per million (ppm).