Syntheses of [11C]2- and [11C]3-trifluoromethyl-4-aminopyridine: potential PET radioligands for demyelinating diseases.

Trifluoromethyl groups are of great interest in PET radiopharmaceuticals. Radiolabelled 4-aminopyridine (4AP) derivatives have been proposed for imaging demyelinating diseases. Here, we describe methods for producing 11C-trifluoromethylated derivatives of 4AP and present early imaging results with [11C]3-trifluoromethyl-4AP in a rhesus macaque. This study shows the utility of [11C]CuCF3 for labelling pyridines and provides initial evidence for the potential use of [11C]3-trifluoromethyl-4AP as a PET radioligand.