Synthesis of carbon-11-labeled piperidine ring of N-[omega-(6-methoxynaphthalen-1-yl)alkyl] derivatives as new selective PET sigma1 receptor probes.

Carbon-11-labeled piperidine ring of N-[omega-(6-methoxynaphthalen-1-yl)alkyl] derivatives were first designed and synthesized as new selective PET sigma(1) receptor probes. The target tracers were prepared by O-[(11)C]methylation of their corresponding phenolic hydroxyl precursors using [(11)C]CH(3)OTf under basic conditions and isolated by a simplified SPE method in 40-50% radiochemical yields based on [(11)C]CO(2) and decay corrected to EOB. The overall synthesis time from EOB was 15-20 min, the radiochemical purity was >99%, and the specific activity at EOS was 111-185 GBq/micromol.