ABSTRACT: 2-Thymidine has been produced from methane via phosgene and urea. Anhydrous urea was prepared from phosgene by reaction with liquid ammonia. This novel approach avoids the problems associated with the synthesis of anhydrous urea from cyanide. A fully automated system based on a modular approach and under PLC control has been developed. The system provides 2-thymidine reliably and reproducibly for clinical PET studies. The radiosynthesis takes 45–50 min from methane and the average yield was 1.5–3.3 GBq (40–90 mCi). The specific radioactivity was typically in the range 29.6–51.8 GBq μmol−1 (0.8–1.4 Ci μmol−1) at EOS corresponding to 6–12 μg of stable thymidine. The radiochemical yield of 2-thymidine was ca. 14% from methane.
Applied Radiation and Isotopes.