Radiofluorination of arylboronic acids pinacol esters (arylBPin) mediated by copper triflate pyridine complex is one of the more promising synthetic approaches for the direct introduction of nucleophilic [18F]fluoride into non-activated arenes and heteroarenes. However, the application of this method to the production of positron emission tomography (PET) radiotracers in automated synthesizers remains a challenging task. The choice of phase-transfer catalyst (PTC) and corresponding base used for the generation of reactive [18F]fluoride species has a profound impact on the efficiency of the 18F-fluorination process. Herein we report the development of a simple procedure involving trapping of the aqueous [18F]fluoride on a weak anion-exchange resin (WAX) and its release by elution with pyridinium sulfonate in dimethyl acetamide. Obtained reactive [18F]fluoride was used as-is in a copper-catalyzed fluorination reaction employing pyridinium salt as both PTC and base. High radiochemical conversion rates (RCCs) achieved for a series of simple arylBPin substrates and 4-[18F]fluoro-D,L-phenylalanine demonstrate the efficiency of this novel 18F-processing approach. Notably, the proposed method obviates conventional azeotropic drying steps, solvents evaporation and/or changeover and can be implemented on commercial automated synthesizers.
Предметные области Scopus
- Физическая и теоретическая химия
- Органическая химия
- radiopharmaceuticals • arenes • phase-transfer catalysis • copper mediated radiofluorination • [18F]fluoride • pinacol esters of arylboronic acids • positron emission tomography • pyridinium sulfonates