Radiosynthesis of Carbon-11 labelled N-methyl-2-(arylthio)benzylamines: Potential radiotracers for the serotonin reuptake receptor

Article abstract of DOI:10.1002/(SICI)1099-1344(19991230)42:13<1277::AID-JLCR284>3.0.CO;2-Q

The potent and selective serotonin reuptake inhibitor, N,N-dimethyl-2-(2-amino-4-trifluoromethylphenylthio)benzylamine (1), and a potential metabolite, N-methyl-2-(2-amino-4-trifluoromethylphenylthio)benzylamine (2) were radiolabelled with Carbon-11 as potential positron emission tomography (PET) radiotracers. Both [¹¹C]-(1) and [¹¹C]-(2) were obtained in good radiochemical yield by alkylation of their respective normethyl precursors with [¹¹C]-iodomethane in dimethylformamide. Upon HPLC purification and formulation radiochemically pure products were obtained in 25-30% yield (from [¹¹C]-iodomethane, uncorrected) with specific activities of 25-40 GBq/mole. To further establish the site of labeling, [¹³C]-(1) and [¹³C]-(2) were also synthesised, using [¹³C]-iodomethane, for ¹³C NMR analysis. Preliminary biodistribution studies in rats show that both [¹¹C]-(1) and [¹¹C]-(2) efficiently and rapidly cross the blood brain barrier.