Synthesis of No-Carrier-Added 4-[18F]Fluorophenol from 4-Benzyloxyphenyl-(2-thienyl)iodonium Bromide
4-[(18)F]Fluorophenol is a versatile synthon for the synthesis of more complex radiopharmaceuticals bearing a 4-[(18)F]fluorophenoxy moiety. In order to prepare 4-[(18)F]fluorophenol in no-carrier-added (n.c.a.) form only a nucleophilic labelling method starting from [(18)F]fluoride is suitable. In this paper a new, two step radiosynthesis starting from 4-benzyloxyphenyl-(2-thienyl)iodonium bromide and [(18)F]fluoride with subsequent deprotection is described, yielding n.c.a. [(18)F]fluorophenol in 34 to 36% radiochemical yield.
Synthesis, radiofluorination and first evaluation of (±)-[18F]MDL 100907 as serotonin 5-HT2Areceptor antagonist for PET
In some psychiatric disorders 5-HT2A receptors play an important role. In order to investigate those in vivo there is an increasing interest in obtaining a metabolically stable, subtype selective and high affinity radioligand for receptor binding studies using positron emission tomography (PET). Combining the excellent in vivo properties of [11C]MDL 100907 for PET imaging of 5-HT2A receptors and the more suitable half-life of fluorine-18, MDL 100907 was radiofluorinated in four steps using 1-(2-bromoethyl)-4-[18F]fluorobenzene as a secondary labelling precursor. The complex reaction required an overall reaction time of 140 min and (±)-[18F]MDL 100907 was obtained with a specific activity of…