Synthesis of 3′-deoxy-3′-[18F]fluoro-1-β-D-xylofurano-syluracil ([18F]-FMXU) for PET

The synthesis of a pyrimidine analog, 3'-deoxy-3'-[F-18]-fluoro-1-beta-D-xylofuranosyluracil ([F-18]-FMXU) is reported. 5-Methyluridine 1 was converted to its dimethoxytrityl derivatives 2 and 3 as a mixture. After separation the 2', 5'-di-methoxytrityluridine 2 was converted to its 3'-triflate 4 followed by derivatization to the respective N(3-)t-Boc product 5. The triflate 5 was reacted with tetrabutylammonium[F-18]fluoride to produce 6, which by acid hydrolysis yielded compound 7. The crude preparation was purified by HPLC to obtain the desired product [F-18]-FMXU. The radiochemical yields were 25-40% decay corrected (d.c.) with an average of 33% in four runs. Radiochemical purity was > 99% and specific activity was > 74GBq/mu mol at the end of synthesis (EOS). The synthesis time was 67-75 min from the end of bombardment (EOB). Copyright (c) 2005 John Wiley & Sons, Ltd.