Synthesis of a ¹¹C-labelled taxane derivative by [1-¹¹C]acetylation

The ¹¹C-labelling of the taxane derivative BAY 59-8862 (1), a potent anticancer drug, was carried out as a module-assisted automated multi-step synthesis procedure. The radiotracer [¹¹C]1 was synthesized by reacting [1-¹¹C]acetyl chloride (6) with the lithum salt of the secondary hydroxy group of precursor 3 followed by deprotection. After HPLC purification of the final product [¹¹C]1, its solid phase extraction, formulation and sterile filtration, the decay-corrected radiochemical yield of [¹¹C]1 was in the range between 12 and 23% (related to [¹¹C]CO₂; n = 10). The total synthesis time was about 54 min after EOB. The radiochemical purity of [¹¹C]1 was greater than 96% and the chemical purity exceeded 80%. The specific radioactivity was up to 20 GBq/µmol at EOS starting from 80 GBq of [¹¹C]CO₂.