Synthesis of [1-11C]-2-octynoic acid, [1-11C]-2-decynoic acid and [1-11C]-3-(R,S)-methylocatanoic acid as potential markers for PET studies of fatty acid metabolism

[1-11C]-2-Octynoic acid, [1-11C)-2-decynoic acid and 1-11C]-3-(R,S)-methyloctanoic acid have been synthesized in order to evaluate these compounds as PET (Positron Emission Tomography) tracers for imaging in vivo medium-chain acyl-CoA dehydrogenase and medium-chain fatty acid utilization. The synthesis was performed by the Grignard reaction between alkylmagnesium bromides and [11C]CO2. The radiochemical yields of [1-11C]-2-octynoic acid, [1-11C]-2-decynoic acid, and [1-11C]-3-(R,S)-methyloctanoic acid were 10, 7 and 1% based on the [11C]CO2 used, respectively. Radiochemical purity was >99% in all cases.