Palladium-mediated carboxylation of aryl halides (triflates) or benzyl halides using [13C]/[11C]carbon monoxide with tetrabutylammonium hydroxide or trimethylphenylammonium hydroxide

[Carbonyl-C-11] carboxylic acids were synthesised using palladium-mediated reaction of [C-11] carbon monoxide with aryl halides/triflates and benzyl halides in combination with either tetrabutylammonium hydroxide or trimethylphenylammonium hydroxide. The radiochemical yields were in the range 20-85%. In a typical experiment starting with 2.1 GBq [C-11] carbon monoxide, 0.6 GBq of HPLC-purified 1-[carbonyl-C-11] naphthoic acid (13) was obtained within 25 min of the start of the carbonylation reaction (67% decay-corrected radiochemical yield). The specific radioactivity of [carbonyl-C-11] nicotinic acid (17) was in the order of 750 GBq mumol(-1) using 10.0 muAh bombardment. [Carbonyl-C-13] nicotinic acid (17) was synthesised to verify the position of the labelling (delta 166.1) determined by C-13 NMR.