Synthesis of 2 '-deoxy-2-fluoro-1-beta-D-arabinofuranosyl uracil derivatives: A method suitable for preparation of [F-18]-labeled nucleosides

N-glycosylation of 2,4-bis-O-(trimethylsilyl)-pyrimidine bases with 2-deoxy-2-fluoro-3,5-di-O-benzoyl-1-(Br, OBz)-alpha-D-arabinose derivatives are reported. I-Bromo-arabinose provides high yield and a favorable anomeric ratio (beta/alpha) of pyrimidine nucleoside in either MeCN or CH2Cl-CH2Cl. This method should be suitable for the synthesis of 2'-deoxy-2-[F-18]fluoro-1-beta-D-arabinofuranosyluracil derivatives.