Radiosynthesis of F-18 labeled cytidine analog 2'-fluoro-5-iodo-l-beta-d-arabinofuranosylcytosine ([(18)F]FIAC).

We reported the synthesis of 2'-deoxy-2'-[(18)F]fluoro-5-iodo-1-beta-d-arabinofuranosyl-5-iodo-cytosine ([(18)F]FIAC) with 15-20% radiochemical yield (decay corrected) in 3.5h. 2-deoxy-2-[(18)F]fluoro-1,3,5-tri-O-benzoyl-alpha-d-arabinofuranose was prepared following literature procedures with some modifications (yield>70%). The (18)F-fluorosugar was converted to 1-bromo-(18)F-fluorosugar, and then coupled with 5-iodocytocine silyl ether. A mixture of acetonitrile (ACN) and 1,2-dichloroethane (DCE) were employed to achieve optimum radiochemical yield and acceptable beta-anomer selectivity (alpha/beta=1/3). After hydrolyzed with sodium methoxide, the crude product was purified using HPLC to afford the beta-[(18)F]FIAC with high radiochemical purity (>or=98%).