1-(3-Chlorophenyl)-4-(2-phenylethyl)piperazine (3C-PEP) is a psychoactive recreational drug of the piperazine class. 3C-PEP is related to meta-cholorophenylpiperazine (mCPP) and phenethylamine that can be thought of as mCPP having a phenylethyl group attached to the nitrogen atom at its 4-position. It was first described in 1994 in a patent disclosing a series of piperazine compounds as sigma receptor ligands. Later, it was discovered to be a highly potent dopamine reuptake inhibitor. Rather serendipitously, since the investigators were looking for compounds that bind to the sigma receptor as sigma ligands have been proposed as potential treatment of psychostimulant abuse including cocaine and methamphetamine abuse.
3C-PEP is one of the most potent dopamine transporter (DAT) ligand reported to date. It is highly selective for the dopamine transporter (DAT dissociation constant Ki = 0.04 nM) with relatively low affinity for the closely related Norepinephrine transporter NET (Ki = 1107 nM ) and the Serotonin Transporter SERT (Ki = 802 nM). In addition, the compound has little or no affinity for D2-like receptor (Ki = 327 nM), Serotonin 5-HT2 receptor, (Ki = 53 nM) Opioid receptor (Ki>10000 nM) and the PCP/NMDA receptor (Ki>10000 nM).
With a DAT dissociation constant Ki of 0.04 nM, 3C-PEP is one of the most potent dopamine transporter ligand described to date in the literature. In comparison, cocaine which is a prototypical DAT ligand and reuptake inhibitor has a dissociation constant Ki of 435 nm thus making 3C-PEP about 10,000 times more potent than cocaine as a dopamine transporter inhibitor in vitro.
3C-PEP is not scheduled at the federal level in the United States,
3C-PEP is not scheduled under the Controlled Drugs and Substances Act.