An investigation on stereospecific fluorination at the 2′-arabino-position of a pyrimidine nucleoside: radiosynthesis of 2′-deoxy-2′-[18F]fluoro-5-methyl-1-β-d-arabinofuranosyluracil

Direct fluorination at the 2′-arabino-position of a pyrimidine nucleoside has been a long-standing challenge, yet we recently reported such a stereospecific fluorination for the first time in the synthesis of [18F]FMAU, albeit in low yields. Herein we report the results of an investigation on stereospecific fluorination on a variety of precursors for synthesis of [18F]FMAU. Several precursors were synthesized in multiple steps and fluorination was performed at the 2′-arabino-position using K[18F]/kryptofix 2.2.2. All precursors produced [18F]FMAU in low yields.