1,2-Diarylethylamine

Class of chemical compounds vanc 6 1,2-Diarylethylamine 1,2-Diphenylethylamine.svg skin-invert-image 200px Skeletal formula of 1,2-diphenylethylamine 1,2-Diphenylethylamine, the parent structure of most of the 1,2-diarylethylamines 1,2-Diphenylethylamines Research chemicals; some as designer drugs Dissociative Antagonist NMDA receptor Arylalkylamine 1,2-Diarylethylamines are a class of psychoactive compounds defined by two aryl groups attached to adjacent carbon atoms on an ethylamine backbone. Wallach J, Brandt SD 1,2-Diarylethylamine-and Ketamine-Based New Psychoactive Substances. Maurer H, Brandt S New Psychoactive Substances Handbook of Experimental Pharmacology 2018 252 305–352 10.1007/164_2018_148 30196446 978-3-030-10560-0 These compounds display a range of pharmacological activities, most notably as NMDA receptor antagonists, and have attracted attention as dissociative designer drugs that produce feelings of detachment from reality or oneself. Wallach J, Kang H, Colestock T, Morris H, Bortolotto ZA, Collingridge GL, Lodge D, Halberstadt AL, Brandt SD, Adejare A Pharmacological Investigations of the Dissociative 'Legal Highs' Diphenidine, Methoxphenidine and Analogues PLOS ONE 11 6 e0157021 2016 27314670 4912077 10.1371/journal.pone.0157021 free 2016PLoSO..1157021W History The synthesis of diphenidine reported as far back as 1924 by Christiaen. The parent structure of the class, 1,2-diphenylethylamine was first synthesized in the 1940s and showed weak analgesic activity. Dodds EC, Lawson W, Simpson SA, Williams PC Testing diphenylethylamine compounds for analgesic action The Journal of Physiology 104 1 47–51 June 1945 16991666 1393527 10.1113/jphysiol.1945.sp004105 However it was not until the early 2010s that 1,2-diarylethylamines gained prominence as dissociative designer drugs. This shift occurred following legislative controls on arylcyclohexylamines (such as ketamine and phencyclidine analogues) in the United Kingdom in 2013, which prompted the introduction of diphenidine and related compounds like methoxphenidine (MXP) and ephenidine to the grey market as "legal highs" or "research chemicals". Chemistry 1,2-Diarylethylamines contain the substructure ArCH2CH(Ar')NRR', where Ar, Ar' = aryl and R, R' = H or organyl. A chiral center exists at the ethylamine carbon atom bearing the two aryl groups. The enantiomers often have a large difference in pharmacological activity. For example, (+)-(S)-diphenidine has 40 times higher affinity than (−)-(R)-form for the NMDA receptor. According to a review by Jason Wallach and Simon Brandt (2018), most psychoactive 1,2-diarylethylamines reported in the scientific literature contain non-heteroaromatic aryl groups (i.e., both rings are carbocyclic). Some exceptions include lanicemine and an analogue N-ethyl-lanicemine, which feature a heteroaromatic pyridyl ring. Additional heteroaromatic analogues have been disclosed in the patent literature. 0346791 1,2‑Diarylethylamines for treatment of neurotoxic injury Gray NM, Cheng BK EP 6 April 1994 12 June 1989 14 June 1988 GD Searle LLC Pharmacology Pharmacodynamics 1,2-Diarylethylamines primarily antagonize NMDA receptors, leading to dissociative effects like those of ketamine or phencyclidine (PCP). Many also interact with dopamine/norepinephrine transporters (DAT/NET) and sigma receptors, contributing to stimulant or hallucinogenic properties. + Receptor binding affinities of 1,2-diarylethylamines at key CNS receptor sites Compound NMDAR (Ki, nM) NET (Ki, nM) DAT (Ki, nM) SERT (Ki, nM) Diphenidine (DPH) 29 3,104 274 13,514 (+)-(S)-DPH 18– – – (−)-(R)-DPH 4,960 – – – 2-MXP 103 6,900 3,858 15,000 Ephenidine 162 841 379 >10,000 1,2-Diarylethylamines exert their primary effects as uncompetitive antagonists of the N-methyl-D-aspartate receptor (NMDAR), similar to phencyclidine (PCP) and ketamine. This mechanism is believed to underlie their characteristic dissociative, hallucinogenic, and anesthetic properties. Compounds such as diphenidine, methoxphenidine (MXP), and ephenidine display high to moderate affinity for the NMDAR PCP-binding site (e.g., diphenidine Ki ≈ 18–39 nM). Additionally, some members of this class exhibit secondary interactions with monoamine transporters, including the dopamine and norepinephrine transporters (DAT and NET), as well as modest binding to sigma-1 and sigma-2 receptors, serotonin 5-HT2A receptors, alpha-adrenergic receptors, and the kappa opioid receptor. Despite potent NMDAR binding, several compounds exhibit reduced in vivo potency, potentially due to pharmacokinetic factors. Pharmacokinetics 1,2-Diarylethylamines are generally lipophilic, allowing for extensive tissue distribution, particularly in adipose tissue. For example, diphenidine has been found at concentrations exceeding 11,000 ng/g in fat tissue during postmortem analysis. These compounds are typically active via oral and parenteral routes, with exposure ranging from 3 to 8 hours depending on the compound and dosage. Metabolism primarily occurs via hepatic cytochrome P450 enzymes, including CYP1A2, CYP2B6, CYP2C9, CYP2C19, and CYP3A4, leading to hydroxylated, dealkylated, and oxidized metabolites. Phase II conjugation processes such as glucuronidation and sulfation also occur. Metabolites are excreted in urine and have been detected in both clinically and in forensic settings. Research A number of 1,2-diarylethylamines have been explored in pharmaceutical research. Clinical analogs such as lanicemine (AZD6765) and remacemide have shown potential in the treatment of depression, epilepsy, and neurodegenerative diseases. Diphenidine and ephenidine have been used in animal models to investigate NMDAR-mediated neurophysiological processes, including synaptic plasticity and long-term potentiation. The unique pharmacological profiles of these compounds have also made them subjects of interest in studies of schizophrenia and psychosis. Despite promising in vitro and in vivo data, no 1,2-diarylethylamines have yet achieved widespread medical approval for psychiatric or analgesic indications. Examples 30em DiphenidineCritical Review Report: Diphenidine https://cdn.who.int/media/docs/default-source/controlled-substances/43rd-ecdd/diphenidine-report-complete.pdf?sfvrsn=4f7ad16d_2 Geneva World Health Organization (WHO) October 2020 7 June 2025 PDF English WHO Expert Committee on Drug Dependence, Forty-third Meeting Diphenidine is a dissociative substance of the 1,2-diarylethylamine class. 5, 7 Fluorolintane (fluorinated analog of diphenidine) Methoxphenidine (2-MeO-diphenidine, MXP) Ephenidine (NEDPA, EPE) Lanicemine MT-45 (exhibits opioid activity) Remacemide Society and culture Since the early 2010s, several 1,2-diarylethylamines have emerged as new psychoactive substances (NPS) on the recreational drug market. Compounds such as diphenidine and MXP were sold online as "research chemicals" or "legal highs," often in response to regulatory crackdowns on ketamine and arylcyclohexylamine derivatives. These substances have gained popularity among users seeking dissociative effects akin to PCP and ketamine but outside legal control. Online forums and user reports have documented a range of subjective experiences, from euphoria and altered perception to confusion and dissociation. However, hospitalizations and fatalities associated with their combined use with other drugs have prompted increasing regulatory scrutiny. Their sale and use have raised concerns regarding public health, leading to bans or restrictions in several countries. See also List of designer drugs § 1,2-Diarylethylamines References Category:Designer drugs Category:Dissociative drugs Category:Arylalkylamines Category:Benzylamines