Structure-activity relationship studies of novel 4-[2-[bis(4-fluorophenyl)methoxy]ethyl]-1-(3-phenylpropyl)piperidine analogs: Synthesis and biological evaluation at the dopamine and serotonin transporter sites

Several analogs of the potent dopamine (DA) transporter ligand 4-[2-[bis(4-fluorophenyl)methoxy]ethyl]-1-(3-phenylpropyl)piperidine, 1b, were made and biologically evaluated for their binding at the DA and serotonin (5HT) transporters in rat striatal membranes. Different alkyl chain lengths and substitutions were introduced in these molecules to generate an optimum activity and selectivity for the DA transporter. In general, unsubstituted and fluoro-substituted compounds were the most active and selective for the DA transporter. The compound 4-[2-(diphenylmethoxy)ethyl]-1-benzylpiperidine, 9a, showed high potency and was the most selective for the DA transporter (5HT/DA = 49) in this series of compounds. Some of these novel analogs were found to be more selective in binding at the DA transporter than the original GBR 12909 molecule, 1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-(3-phenylpropyl)piperi dine.