Empathogens or entactogens are a class of psychoactive drugs that induce the production of experiences of emotional communion, oneness, relatedness, emotional openness—that is, empathy or sympathy—as particularly observed and reported for experiences with 3,4-methylenedioxymethamphetamine (MDMA). This class of drug is distinguished from the classes of hallucinogen or psychedelic, and amphetamine or stimulants. Major members of this class include MDMA, MDA, MDEA, MDOH, MBDB, 5-APB, 5-MAPB, 6-APB, 6-MAPB, methylone, mephedrone, GHB, αMT, and αET, MDAI among others. Most entactogens are phenethylamines and amphetamines, although several, such as αMT and αET, are tryptamines. When referring to MDMA and its counterparts, the term MDxx is often used. Entactogens are sometimes incorrectly referred to as hallucinogens or stimulants, although many entactogens such as ecstasy exhibit psychedelic or stimulant properties as well.
David Earl Nichols is an American pharmacologist and medicinal chemist. Previously the Robert C. and Charlotte P. Anderson Distinguished Chair in Pharmacology at Purdue University, Nichols has worked in the field of psychoactive drugs since 1969. While still a graduate student, he patented the method that is used to make the optical isomers of hallucinogenic amphetamines. His contributions include the synthesis and reporting of escaline, LSZ, 6-APB, 2C-I-NBOMe and other NBOMe variants, and several others, as well as the coining of the term "entactogen".
2C-B-FLY is a psychedelic phenethylamine and designer drug of the 2C family. It was first synthesized in 1996 by Aaron Monte, Professor of Chemistry at UW-La Crosse.
TCB-2 is a hallucinogen discovered in 2006 by Thomas McLean working in the lab of David Nichols at Purdue University. It is a conformationally-restricted derivative of the phenethylamine 2C-B, also a hallucinogen, and acts as a potent agonist for the 5-HT2A and 5-HT2C receptors with a Ki of 0.26 nM at the human 5-HT2A receptor. In drug-substitution experiments in rats, TCB-2 was found to be of similar potency to both LSD and Bromo-DragonFLY, ranking it among the most potent phenethylamine hallucinogens yet discovered. This high potency and selectivity has made TCB-2 useful for distinguishing 5-HT2A mediated responses from those produced by other similar receptors. TCB-2 has similar but not identical effects in animals to related phenethylamine hallucinogens such as DOI, and has been used for studying how the function of the 5-HT2A receptor differs from that of other serotonin receptors in a number of animal models, such as studies of cocaine addiction and neuropathic pain.
5-(2-Aminopropyl)-2,3-dihydrobenzofuran is a putative entactogen drug of the phenethylamine and amphetamine classes. It is an analogue of MDA where the heterocyclic 3-position oxygen from the 3,4-methylenedioxy ring has been replaced by a methylene bridge. 6-APDB is an analogue of 5-APDB where the 4-position oxygen has been replaced by a methylene bridge instead. 5-APDB was developed by a team led by David E. Nichols at Purdue University as part of their research into non-neurotoxic analogues of MDMA.
2CBCB-NBOMe (NBOMe-TCB-2) is a compound indirectly derived from the phenethylamine series of hallucinogens, which was discovered in 2007 at Purdue University as part of the ongoing research program of the team led by David Nichols focusing on the mapping of the specific amino acid residues responsible for ligand binding to the 5HT2A receptor. 2CBCB-NBOMe acts as a potent and selective agonist for the 5-HT2A and 5-HT2C receptors, with a Ki of 0.27 nM at the human 5-HT2A receptor, a similar potency to other agonists such as TCB-2, NBOMe-2C-I and Bromo-DragonFLY.
2CBFly-NBOMe is a compound indirectly derived from the phenethylamine hallucinogen 2C-B, and related to benzodifurans like 2C-B-FLY and N-benzylphenethylamines like 25I-NBOMe. It was discovered in 2002, and further researched by Ralf Heim at the Free University of Berlin, and subsequently investigated in more detail by a team at Purdue University led by David E. Nichols. It acts as a potent partial agonist for the 5-HT2A serotonin receptor subtype.
2,5-Dimethoxy-4-fluoroamphetamine (DOF) is a psychedelic drug of the phenethylamine and amphetamine classes. Alexander Shulgin briefly describes DOF in his book PiHKAL:
Animal studies that have compared DOF to the highly potent DOI and DOB imply that the human activity will be some four to six times less than these two heavier halide analogues.
6-(2-Aminopropyl)-2,3-dihydrobenzofuran is a stimulant and entactogen drug of the phenethylamine and amphetamine classes. It is an analogue of MDA where the heterocyclic 4-position oxygen from the 3,4-methylenedioxy ring has been replaced with a methylene bridge. 5-APDB (3-Desoxy-MDA) is an analogue of 6-APDB where the 3-position oxygen has been replaced with a methylene instead. 6-APDB, along with 5-APDB, was first synthesized by David E. Nichols in the early 1990s while investigating non-neurotoxic MDMA analogues.
6-APB is an empathogenic psychoactive compound of the substituted benzofuran and substituted phenethylamine classes. 6-APB and other compounds are sometimes informally called "Benzofury" in newspaper reports. It is similar in structure to MDA, but differs in that the 3,4-methylenedioxyphenyl ring system has been replaced with a benzofuran ring. 6-APB is also the unsaturated benzofuran derivative of 6-APDB. It may appear as a tan grainy powder. While the drug never became particularly popular, it briefly entered the rave and underground clubbing scene in the UK before its sale and import were banned. It falls under the category of research chemicals, sometimes called "legal highs." Because 6-APB and other substituted benzofurans have not been explicitly outlawed in some countries, they are often technically legal, contributing to their popularity.
2CB-Ind is a conformationally-restricted derivative of the phenethylamine hallucinogen 2C-B, discovered in 1974 by Alexander Shulgin. It acts as a moderately potent and selective agonist for the 5-HT2A and 5-HT2C receptors, but unlike the corresponding benzocyclobutene derivative TCB-2 which is considerably more potent than the parent compound 2C-B, 2CB-Ind is several times weaker, with racemic 2CB-Ind having a Ki of 47nM at the human 5-HT2A receptor, only slightly more potent than the mescaline analogue (R)-jimscaline.
6-MAPB is a psychedelic and entactogenic drug which is structurally related to 6-APB and MDMA. It is not known to have been widely sold as a "designer drug" but has been detected in analytical samples taken from individuals hospitalised after using drug combinations that included other benzofuran derivatives. 6-MAPB was banned in the UK in June 2013, along with 9 other related compounds which were thought to produce similar effects.
5-MAPDB (1-(2,3-dihydrobenzofuran-5-yl)-N-methylpropan-2-amine) is a chemical compound which acts as an entactogenic drug. It is structurally related to drugs like 5-APDB and 5-MAPB, which have similar effects to MDMA and have been used as recreational drugs. 5-MAPDB has been studied to determine its pharmacological activity, and was found to be a relatively selective serotonin releaser, though with weaker actions as a releaser of other monoamines and 5-HT2 receptor family agonist, similar to older compounds such as 5-APDB.
6-MAPDB is a chemical compound which might be an entactogenic drug. It is structurally related to drugs like 6-APDB and 6-MAPB, which have similar effects to MDMA and have been used as recreational drugs. 6-MAPDB has never been studied to determine its pharmacological activity, though it is the N-methyl derivative of 6-APDB which is known to be a selective serotonin releaser.
25B-NBOH is a derivative of the phenethylamine derived hallucinogen 2C-B which has been sold as a designer drug. It acts as a potent serotonin receptor agonist with similar affinity to the better-known compound 25B-NBOMe at 5-HT2A and 5-HT2C receptors with pKis values of 8.3 and 9.4, respectively.
2C-B-BUTTERFLY is a conformationally-restricted derivative of the phenethylamine hallucinogen 2C-B, which was discovered in 1999 by Michael S. Whiteside and Aaron Monte. It is a ring-expanded homologue of the better known compound 2C-B-FLY, and has similar properties as an agonist for serotonin receptors, but with more selectivity for 5-HT2C over 5-HT2A.
25B-NBF is a derivative of the phenethylamine hallucinogen 2C-B, which acts as a highly potent partial agonist for the human 5-HT2A receptor.
The 25-NB (25x-NBx) series, sometimes alternatively referred to as the NBOMe compounds, is a family of serotonergic psychedelics. They are substituted phenethylamines and were derived from the 2C family. They act as selective agonists of the serotonin 5-HT2A receptor. The 25-NB family is unique relative to other classes of psychedelics in that they are, generally speaking, extremely potent and relatively selective for the 5-HT2A receptor. Use of NBOMe series drugs has caused many deaths and hospitalisations since the drugs popularisation in the 2010s. This is primarily due to their high potency, unpredictable pharmacokinetics, and sellers passing off the compounds in the series as LSD.
DOB-FLY is a recreational designer drug with psychedelic effects. It can be regarded as the alpha-methyl derivative of 2C-B-FLY or the partially saturated counterpart of bromo-dragonfly. Unlike bromo-dragonfly, DOB-FLY is only slightly more potent than DOB itself, with an active dose in humans of around 1 mg.
2C-E-FLY is a recreational designer drug with psychedelic effects. It is slightly less potent than 2C-E or 2C-B-FLY in animal studies but retains drug-appropriate responding.
