Radiosynthesis of [¹¹C]docetaxel

Docetaxel (Taxotere®) is an accepted chemotherapeutic agent for the treatment of breast cancer and non‐small cell lung cancers. A potential means of predicting response is measuring tumor uptake of [ 11 C]docetaxel using Positron Emission Tomography (PET). The synthetic approach to introduce the 11 C isotope in the 2‐benzoyl moiety of docetaxel unfortunately was unsuccessful. The radiosynthesis of [ 11 C]docetaxel ( 6b , Scheme 1), with the 11 C isotope in the BOC moiety, was however, successful using a second synthetic approach. It started with the reaction of [ 11 C] tert ‐butanol with 1,2,2,2‐tetrachloroethyl chloroformate to give [ 11 C] tert ‐butyl‐l,2,2,2‐tetrachloroethyl carbonate in a good overall yield (62±9%). In the final step, the [ 11 C] tert ‐butoxycarbonylation of the free amine of docetaxel gave [ 11 C]docetaxel 6b in a satisfactory decay corrected yield of 10±1% (from [ 11 C]CO 2 ).