Radiosynthesis of [5-[11C]methanesulfonyl-2-((S)-2,2,2-trifluoro-1-methyl-ethoxy)-phenyl]-[5-(tetrahydro-pyran-4-yl)-1,3-dihydro-isoindol-2-yl]-methanone ([11C]RO5013853), a novel PET tracer for the glycine transporter type I (GlyT1)

The glycine transporter type 1 (GlyT1) has emerged as a key novel target for the treatment of schizophrenia. We have recently discovered and developed [C-11]RO5013853 as a novel positron emission tomography tracer for GlyT1 for which a reliable five-step synthetic route was established. The incorporation of the radioisotope was achieved in the final step through methylation of a sodium sulfinate precursor, itself easily accessible upon reduction of the corresponding sulfonyl-chloride analog. [C-11]RO5013853 was prepared with high specific activity (>49GBq/mu mol) and high radiochemical purity (100%). A validation study of [C-11]RO5013853 in animal imaging studies is in progress.