Structural studies on McN-5652-X,a high-affinity ligand for the serotonin transporter in mammalian brain

McN-5652-X, (+)-1, is a potent, selective inhibitor of serotonin reuptake in mammalian brain. When radiolabeled with (11)C, it has served as a positron-emission tomography (PET) radiotracer for in vivo imaging of central serotonin transporters. We have determined the solid-state structures of (+)-1.HClO(4) and (+)-1.(+)-(2R,3R)-tartrate by single-crystal X-ray diffraction, thereby confirming the trans relative configuration (Chemical Abstracts Service rules of nomenclature) and the 6S,10bR absolute configuration for (+)-1. Results from a vibrational circular dichroism (VCD) study on (+)-1 in CDCl(3) are consistent with the 6S,10bR absolute configuration.