Iodonium Ylide-Mediated Radiofluorination of ^sup 18^F-FPEB and Validation for Human Use

Translation of new methodologies for labeling nonactivated aromatic molecules with ...F remains a challenge. Here, we report a one-step, regioselective, metal-free ...F-labeling method that uses a hypervalent iodonium(III) ylide precursor, to prepare the radiopharmaceutical ...F-3-fluoro-5-[(pyridin-3-yl)ethynyl]benzonitrile (...F-FPEB). Automated radiosynthesis of ...F-FPEB was achieved by reaction of the ylide precursor (4 mg) with ...F-Et...NF in dimethylformamide at 80°C for 5 min and formulated for injection within 1 h. ...F-FPEB was synthesized in 20% ± 5% (n = 3) uncorrected radiochemical yields relative to ...F-fluoride, with specific activities of 666 ± 51.8 GBq (18 ± 1.4 Ci)/μmol at the end of synthesis and was validated for human use. Radiofluorination of iodonium (III) ylides proved to be an efficient radiosynthetic strategy for synthesis of ...F-labeled radiopharmaceuticals. (ProQuest: ... denotes formulae/symbols omitted.)