Amides of lysergic acid are collectively known as lysergamides, and include a number of compounds with potent agonist and/or antagonist activity at various serotonin and dopamine receptors. Lysergamides contain an embedded tryptamine structure, and as a result can produce similar, often psychedelic, effects to those of the true tryptamines.
NMDA receptor antagonists are a class of drugs that work to antagonize, or inhibit the action of, the N-Methyl-D-aspartate receptor (NMDAR). They are commonly used as anesthetics for humans and animals; the state of anesthesia they induce is referred to as dissociative anesthesia.
Budipine is an antiparkinson agent marketed for the treatment of Parkinson's disease.
Lysergic acid 2,4-dimethylazetidide (LA-SS-Az, LSZ) is an analog of LSD developed by the team led by David E. Nichols at Purdue University. It was developed as a rigid analog of LSD with the diethylamide group constrained into an azetidine ring in order to map the binding site at the 5-HT2A receptor. There are three possible stereoisomers around the azetidine ring, with the (S,S)-(+) isomer being the most active, slightly more potent than LSD itself in drug discrimination tests using trained rats.
Arylcyclohexylamines, also known as arylcyclohexamines or arylcyclohexanamines, are a chemical class of pharmaceutical, designer, and experimental drugs.
3-Methoxyphencyclidine (3-MeO-PCP) is a dissociative hallucinogen of the arylcyclohexylamine class related to phencyclidine (PCP) which has been sold online as a designer drug. It has been used across Europe and the United States. In some cases, consumption has been known to be fatal. It acts mainly as an NMDA receptor antagonist, though it has also been found to interact with the sigma σ1 receptor and the serotonin transporter. The drug does not possess any opioid activity nor does it act as a dopamine reuptake inhibitor.
4-Methoxyphencyclidine is a dissociative anesthetic drug that has been sold online as a research chemical. The synthesis of 4-MeO-PCP was first reported in 1965 by the Parke-Davis medicinal chemist Victor Maddox. A 1999 review published by a chemist using the pseudonym John Q. Beagle suggested the potency of 4-MeO-PCP in man was reduced relative to PCP, two years later Beagle published a detailed description of the synthesis and qualitative effects of 4-MeO-PCP, which he said possessed 70% the potency of PCP. 4-MeO-PCP was the first arylcyclohexylamine research chemical to be sold online, it was introduced in late 2008 by a company trading under the name CBAY and was followed by several related compounds such as 3-MeO-PCP and methoxetamine. 4-MeO-PCP has lower affinity for the NMDA receptor than PCP, but higher affinity than ketamine, it is orally active in a dosage range similar to ketamine, with some users requiring doses in excess of 100 mg for desired effects. Users have reported substantial differences in active dose, these discrepancies can be partially explained by the presence of unreacted PCC and other impurities in samples sold on the grey market. 4-MeO-PCP has Ki values of 404 nM for the NMDA receptor, 713 nM for the norepinephrine transporter, 844 nM for the serotonin transporter, 296 nM for the σ1 receptor and 143 nM for the σ2 receptor.
MT-45 (IC-6) is an opioid analgesic drug invented in the 1970s by Dainippon Pharmaceutical Co. It is chemically a 1-substituted-4-(1,2-diphenylethyl) piperazine derivative, which is structurally unrelated to most other opioid drugs. Racemic MT-45 has around 80% the potency of morphine, with almost all opioid activity residing in the (S) enantiomer. It has been used as a lead compound from which a large family of potent opioid drugs have been developed, including full agonists, partial agonists, and antagonists at the three main opioid receptor subtypes. Fluorinated derivatives of MT-45 such as 2F-MT-45 are significantly more potent as μ-opioid receptor agonists, and one of its main metabolites 1,2-diphenylethylpiperazine also blocks NMDA receptors.
AD-1211 is an opioid analgesic drug invented in the 1970s by Dainippon Pharmaceutical Co. It is chemically a 1-substituted-4-prenyl-piperazine derivative, which is structurally unrelated to most other opioid drugs. The (S)-enantiomers in this series are more active as opioid agonists, but the less active (R)-enantiomer of this compound, AD-1211, is a mixed agonist–antagonist at opioid receptors with a similar pharmacological profile to pentazocine, and has atypical opioid effects with little development of tolerance or dependence seen after extended administration in animal studies.
Hamilton Morris is an American journalist, documentarian, and scientific researcher. He is the creator and director of the television series Hamilton's Pharmacopeia, in which he investigated the chemistry, history, and cultural impact of various psychoactive drugs. In September 2021, Morris left Vice to work as a chemistry consultant at the biotechnology startup, Compass Pathways.
Diphenidine is a dissociative anesthetic that has been sold as a designer drug. The synthesis of diphenidine was first reported in 1924, and employed a Bruylants reaction analogous to the one that would later be used to discover phencyclidine in 1956. Shortly after the 2013 UK ban on arylcyclohexylamines, diphenidine and the related compound methoxphenidine became available on the grey market. Anecdotal reports describe high doses of diphenidine producing "bizarre somatosensory phenomena and transient anterograde amnesia." Diphenidine and related diarylethylamines have been studied in vitro as treatments for neurotoxic injury and are antagonists of the NMDA receptor. In dogs diphenidine exhibits greater antitussive potency than codeine phosphate.
Methoxphenidine is a dissociative of the diarylethylamine class that has been sold online as a designer drug. Methoxphenidine was first reported in a 1989 patent where it was tested as a treatment for neurotoxic injury. Shortly after the 2013 UK ban on arylcyclohexylamines methoxphenidine and the related compound diphenidine became available on the gray market, where it has been encountered as a powder and in tablet form. Though diphenidine possesses higher affinity for the NMDA receptor, anecdotal reports suggest methoxphenidine has greater oral potency. Of the three isomeric anisyl-substituents methoxphenidine has affinity for the NMDA receptor that is higher than 4-MeO-Diphenidine but lower than 3-MeO-Diphenidine, a structure–activity relationship shared by the arylcyclohexylamines.
Ephenidine is a dissociative anesthetic that has been sold online as a designer drug. It is illegal in some countries as a structural isomer of the banned opioid drug lefetamine, but has been sold in countries where it is not yet banned.
3-Methoxyeticyclidine (3-MeO-PCE), also known as methoxieticyclidine, is a dissociative anesthetic that is qualitatively similar to PCE and PCP and has been sold online as a designer drug.
3-MeO-PCMo is a dissociative anesthetic drug which is similar in structure to phencyclidine and been sold online as a designer drug. The inhibitory effect of 3-MeO-PCMo on the reduction in the density of the drebrin clusters by NMDAR stimulation with glutamic acid is lower than that of PCP or 3-MeO-PCP, with half maximal inhibitory concentration (IC50) values of 26.67 μM (3-MeO-PCMo), 2.02 μM (PCP) and 1.51 μM (3-MeO-PCP).
3-Hydroxyphencyclidine (3-HO-PCP) is a dissociative of the arylcyclohexylamine class related to phencyclidine (PCP) that has been sold online as a designer drug.
Substituted phenylmorpholines, or substituted phenmetrazines alternatively, are chemical derivatives of phenylmorpholine or of the psychostimulant drug phenmetrazine. Most such compounds act as releasers of monoamine neurotransmitters, and have stimulant effects. Some also act as agonists at serotonin receptors, and compounds with an N-propyl substitution act as dopamine receptor agonists. A number of derivatives from this class have been investigated for medical applications, such as for use as anorectics or medications for the treatment of ADHD. Some compounds have also become subject to illicit use as designer drugs.
Diphenpipenol is an opioid analgesic drug invented in the 1970s by Dainippon Pharmaceutical Co. It is chemically a 1-substituted-4-(1,2-diphenylethyl)piperazine derivative related to compounds such as MT-45 and AD-1211, but diphenpipenol is the most potent compound in the series, with the more active (S) enantiomer being around 105 times the potency of morphine in animal studies. This makes it a similar strength to fentanyl and its analogues, and consequently diphenpipenol can be expected to pose a significant risk of producing life-threatening respiratory depression, as well as other typical opioid side effects such as sedation, itching, nausea and vomiting.
3-Methyl-PCPy (3-Me-PCPy) is an arylcyclohexylamine derivative with an unusual spectrum of pharmacological effects, acting as both a potent NMDA antagonist and also a triple reuptake inhibitor which inhibits reuptake of all three monoamine neurotransmitters serotonin, dopamine and noradrenaline. It also acts as a high affinity sigma receptor ligand, selective for the σ2 subtype. It produces both stimulant and dissociative effects in animal behavioural studies.
Alpha-D2PV (DPPE) is a substituted cathinone derivative which has been sold as a designer drug. It was invented in the 1950s, and first identified by forensic laboratories as a designer drug in 2020, though anecdotal reports suggest it may have emerged earlier than this. It is similar in structure to the potent designer stimulant drug alpha-PVP but with the propyl side chain replaced by a phenyl ring, and while it is less potent than alpha-PVP itself, Alpha-D2PV is still a reasonably potent stimulant and has been known to cause poisoning when misrepresented as less potent drugs such as MDMA. While it is also similar in structure to the dissociative drug diphenidine, Alpha-D2PV appears to produce only stimulant effects.
