Ortho-Methoxyphenylpiperazine

Not to be confused with ortho-Methylphenylpiperazine.

ortho-Methoxyphenylpiperazine (oMeOPP), also known as 2-methoxyphenylpiperazine (2-MeOPP), is a phenylpiperazine derivative which is known to act as a serotonergic agent.^[1][2] Along with various other phenylpiperazines, like benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP), oMeOPP has been found in illicit drug samples.^[3]

ortho-Methoxyphenylpiperazine

Clinical data
Other names	o-Methoxyphenylpiperazine; oMeOPP; 2-Methoxyphenylpiperazine; 2-MeOPP
Drug class	Serotonin 5-HT1A receptor agonist; Antipsychotic; Antihypertensive[1][2]
Identifiers
IUPAC name 1-(2-methoxyphenyl)piperazine
CAS Number	35386-24-4
PubChem CID	1346
UNII	81NJO1330A
ChEBI	CHEBI:104020
ChEMBL	ChEMBL9666
CompTox Dashboard (EPA)	DTXSID40188871
ECHA InfoCard	100.047.747
Chemical and physical data
Formula	C11H16N2O
Molar mass	192.262 g·mol−1
3D model (JSmol)	Interactive image
SMILES COC1=CC=CC=C1N2CCNCC2
InChI InChI=1S/C11H16N2O/c1-14-11-5-3-2-4-10(11)13-8-6-12-7-9-13/h2-5,12H,6-9H2,1H3 Key:VNZLQLYBRIOLFZ-UHFFFAOYSA-N

Pharmacology

The drug has been found to have high affinity for the serotonin 5-HT_1A receptor, where it acts as a partial agonist (E_maxTooltip maximal efficacy ≈ 70%), but shows no affinity for the serotonin 5-HT₂ receptor or the dopamine receptors.^[1][2][4] This is in contrast to the related drug meta-chlorophenylpiperazine (mCPP), which shows high affinity for both the serotonin 5-HT_1A and 5-HT₂ receptors.^[5][2]

oMeOPP and mCPP have both been found to suppress conditioned avoidance responses (CARs) without markedly affecting escape behavior in animals, indicative that they have antipsychotic-like effects.^[2] The serotonin receptor antagonist metergoline reversed the suppression of CARs by mCPP but not by oMeOPP.^[2] oMeOPP also reversed amphetamine-induced stereotypy in animals, whereas mCPP did not do so.^[2] The suppression of CARs by oMeOPP may be mediated by serotonin 5-HT_1A receptor activation.^[6][2]

In contrast to other related phenylpiperazines, which are known to act as monoamine releasing agents and/or reuptake inhibitors, the activities of oMeOPP at the monoamine transporters do not appear to have been described.^{[7][8][9][10][11]}

History

oMeOPP was studied in the 1950s as an antihypertensive agent and produced side effects such as drowsiness that could be interpreted as antipsychotic-like.^[2][12][13]

Other drugs

oMeOPP has been said to be a metabolite of a variety of drugs including dropropizine, enciprazine, milipertine, MJ-7378, oxypertine, and urapidil.^{[14][15][16][17]} Certain other drugs, such as solypertine, also contain oMeOPP within their chemical structures.^[18] However, subsequent research found that oMeOPP is not a metabolite of enciprazine.^[16]

See also

• Substituted piperazine