Synthesis and biological evaluation of 2-substituted 3beta-tolyltropane derivatives at dopamine, serotonin, and norepinephrine transporters.

A series of eight 2-substituted 3-tolyltropane derivatives were synthesized, and the in vitro and in vivo biological activities as dopamine uptake inhibitors were determined. From the in vitro structure-activity data, it is apparent that a tolyl group in the 2-position, independent of the stereochemical attachment to the tropane ring system, provided compounds (9-12, 14) that exhibit high-affinity binding at the dopamine transporter (DAT). Although a slight stereochemical preference in binding affinity at the DAT was observed for the 2beta-(R)-alcohol 10 over the 2beta-(S)-isomer 11, no significant differences in behavioral effects were observed. Furthermore, despite a relatively low potency of 10 for the inhibition of dopamine uptake compared to its affinity for the DAT, its behavioral profile did not vary significantly from cocaine. These data indicate that a behavioral characterization of compounds is a critical feature of efforts to discover pharmacological treatments for cocaine abuse.