SYNTHESIS OF [19-C-11]ARACHIDONIC ACID

The preparation of (all Z)-1,17-dichloro-4,7,10,13-heptadecatetraene is reported. The synthesis was performed in five steps with a total yield of 22 %, starting from 5-chloro-1-pentyne. The corresponding bisGrignard reagent was used in a copper-mediated coupling reaction with [1-C-11]ethyl iodide followed by a carbonation with CO2 to afford [19-C-11]arachidonic acid in 23 % decay corrected radiochemical yield within 52 min. The radiochemical purity of the final product was 98 %. In a typical run starting with 20 GBq [C-11]O-2, 760 MBq of [19-C-11]arachidonic acid was obtained, with a specific activity of 1.6 GBq/mu mol.