IMPROVED SYNTHESIS OF SOME COMMONLY USED PET RADIOLIGANDS BY THE USE OF [C-11] METHYL TRIFLATE

[C-11]Methyl triflate was compared with [C-11]methyl iodide as a label led precursor in the synthesis of some commonly used PET radioligands, L-[C-11]deprenyl, [C-11]m-hydroxyephedrine (MHED), [C-11]beta-CIT, [C -11]beta-CFT and [C-11]SCH 39166 which have been prepared previously i n comparatively low yields from C-11]methyl iodide. A new dopamine reu ptake radioligand, [C-11]alpha-CIT, was also prepared. The results dem onstrate that higher yields are obtained with shorter reaction times, lower reaction temperatures and smaller amounts of precursors with [C- 11]methyl triflate.