The Discovery of an Unusually Selective and Novel Cocaine Analog: Difluoropine. Synthesis and Inhibition of Binding at Cocaine Recognition Sites

Cocaine is a stimulant drug with a high abuse liability. Although it inhibits several monamine transporters in the mammalian brain, its primary mechanism of action has been ascribed to its inhibition of the dopamine transporter. The synthesis, characterization, and receptor binding properties of all eight isomers of a unique tropane analog, 2-carbomethoxy-3-[bis(4-fluorophenyl)-methoxy]tropane is described. In addition, we report that the S-enantiomer, (S)-(+)-2 beta- carbomethoxy-3 alpha-[bis(4-fluorophenyl)methoxy]tropane, Difluoropine, is a potent (IC50 10.9 nM) and selective (324 [DA/5HT]) ligand for the dopamine transporter.