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

The 11 C‐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 [ 11 C]1 was synthesized by reacting [1‐ 11 C]acetyl chloride ( 6 ) with the lithium salt of the secondary hydroxy group of precursor 3 followed by deprotection. After HPLC purification of the final product [ 11 C]1 , its solid‐phase extraction, formulation and sterile filtration, the decay‐corrected radiochemical yield of [ 11 C]1 was in the range between 12 and 23% (related to [ 11 C]CO 2 ; n =10). The total synthesis time was about 54 min after EOB. The radiochemical purity of [ 11 C]1 was greater than 96% and the chemical purity exceeded 80%. The specific radioactivity was 16.8±4.7 GBq/µmol ( n =10) at EOS starting from 80 GBq of [ 11 C]CO 2 . Copyright © 2006 John Wiley & Sons, Ltd.