Improved synthesis of some commonly used PET radioligands by the use of [11C]methyl triflate.

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