No-carrier-added electrochemical nucleophilic radiofluorination of aromatics

Direct nucleophilic radiosynthesis of di-tert-butyl-(4-[18F]fluoro-1,2-phenylene)-dicarbonate was conducted through no-carrier-added electrochemical reactions. 10 mM of triethylamine acetic acid (Et3N·3HAc) in acetonitrile was used to release [18F]fluoride ion trapped in the quaternary ammonium anion exchange resin. The relationship between radiofluorination efficiency, concentration of the Et3N·3HAc, and the working potential were studied with a di-tert-butyl-(4-(tert-butyl)-1,2-phenylene)-dicarbonate substrate in nonaqueous acetonitrile solution. Radiochemical yields of 6.8 ± 1.3 % with specific activity of up to 13 GBq/µmol were achieved with a precursor concentration of 50 mM after a reaction time of 57 min at 0 °C.