25B-NBOMe, also known as NBOMe-2C-B, Cimbi-36, or as N-(2-methoxybenzyl)-4-bromo-2,5-dimethoxyphenethylamine, is a psychedelic drug of the phenethylamine, 2C, and 25-NB (NBOMe) families. It is the N-(2-methoxybenzyl) derivative of 2C-B. The drug is taken sublingually, bucally, or intranasally.
It acts as a potent full agonist for the serotonin 5-HT<sub>2A</sub> receptor.
25B-NBOMe was first described in the scientific literature by Ralf Heim and colleagues at the Free University of Berlin by 1999. After 25I-NBOMe and along with 25C-NBOMe, 25B-NBOMe is one of the most widely used 25-NB psychedelics.
The dose range of 25B-NBOMe has been given as 50 to 700üg or more sublingually, with a typical dose estimate of 400üg. Doses over 800üg are said to be very strong. It may also be taken buccally or intranasally. The intranasal dose range has been give as 50 to 500mg or more and is slightly lower than the sublingual dose range. 25-NB drugs like 25B-NBOMe are not orally active. 25B-NBOMe's onset sublingually is said to be 45 to 75minutes or 15 to 120minutes and to be longer than that of LSD. The drug's duration is 8 to 12hours.
25B-NBOMe is a selective serotonin 5-HT<sub>2</sub> receptor agonist. It showed roughly the same affinity for the serotonin 5-HT<sub>2A</sub>, 5-HT<sub>2B</sub>, and 5-HT<sub>2C</sub> receptors in one study (K<sub>i</sub> = 0.5âÂÂ1.7nM). However, in another study, it showed 12- to 20-fold selectivity for the serotonin 5-HT<sub>2A</sub> receptor (K<sub>i</sub> = 0.5nM) over the serotonin 5-HT<sub>2B</sub> and 5-HT<sub>2C</sub> receptors (K<sub>i</sub> = 10 and 6.2nM, respectively). The drug is highly selective for the serotonin 5-HT<sub>2</sub> receptors over a variety of other serotonin receptors, as well as over various other monoamine receptors and over the monoamine transporters (>200-fold selectivity). However, 25B-NBOMe is a low-potency partial agonist of the rat and mouse trace amine-associated receptor 1 (TAAR1) but is inactive at the human TAAR1.
25B-NBOMe has been found to increase levels of glutamate, serotonin, dopamine, and acetylcholine in the frontal cortex, striatum, and nucleus accumbens in rats. Other serotonergic psychedelics like LSD and DOI have also been found to increase glutamate levels in the frontal cortex in rodents, and this effect can be blocked by the serotonin 5-HT<sub>2A</sub> receptor antagonist volinanserin (MDL-100,907). 25B-NBOMe shows an inverted U-shaped doseâÂÂresponse curve in terms of neurotransmitter elevations in multiple brain areas. This may be due to an inhibitory effect of serotonin 5-HT<sub>2C</sub> receptors at higher doses. 25B-NBOMe produces the head-twitch response, a behavioral proxy of psychedelic effects, in rodents, and this effect shows an inverted U-shaped doseâÂÂresponse curve similarly to its influences on neurotransmitter levels. The head twitches and hallucinogenic effects of 25B-NBOMe may be due to increased cortical glutamate release secondary to serotonin 5-HT<sub>2A</sub> receptor activation. The effects of 25B-NBOMe on levels of other neurotransmitters, such as accumbal dopamine concentrations, may also be mediated by activation of serotonin 5-HT<sub>2A</sub> receptors and glutamate elevation. It has been suggested that the serotonin elevations with 25B-NBOMe may be involved in its production of serotonin syndrome in humans.
Unlike many other serotonergic psychedelics, 25B-NBOMe has been found to produce reinforcing effects in rodents, including conditioned place preference (CPP) and self-administration, and hence may have misuse potential. Accordingly, 25B-NBOMe robustly increased dopamine levels in the nucleus accumbens in rodents similarly to but a lesser extent than methamphetamine, and its reinforcing effects could be blocked by the dopamine receptor antagonists SCH-23390 and haloperidol. Serotonin 5-HT<sub>2A</sub> receptor activation is known to increase dopamine release in the mesolimbic pathway. However, the reinforcing effects of 25B-NBOMe were not blocked by the selective serotonin 5-HT<sub>2A</sub> receptor antagonist ketanserin. Similarly to 25B-NBOMe, 25N-NBOMe has also shown reinforcing effects in rodents. More research is needed to elucidate how 25B-NBOMe and other NBOMe drugs produce reinforcing effects in animals.
25B-NBOMe has been found to decrease locomotor activity in rodents.
25B-NBOMe has been found to produce neurotoxicity in rodents.
Analogues of 25B-NBOMe include 2C-B, DOB, 25B-NB, DOB-NBOMe, 25I-NBOMe, 25C-NBOMe, 25B-NBOH, 25B-NBF, 2CBFly-NBOMe, 2CBCB-NBOMe (NBOMe-TCB-2), DMBMPP, and 25B-NAcPip, among others.
Analogues of 25B-NBOMe with the methoxy group at the 5 position of the core phenyl ring replaced, such as 5-DM-25B-NBOMe (5-O-desmethyl-25B-NBOMe), have been studied and found to be active.
The carbon-11 labeled version of this compound ([<sup>11</sup>C]Cimbi-36) was synthesized and validated as a radioactive tracer for positron emission tomography (PET) in Copenhagen. As a 5-HT<sub>2A</sub> receptor agonist PET radioligand, [<sup>11</sup>C]Cimbi-36 was hypothesized to provide a more functional marker of these receptors. Also, [<sup>11</sup>C]Cimbi-36 is investigated as a potential marker of serotonin release and thus could serve as an indicator of serotonin levels in vivo. [<sup>11</sup>C]Cimbi-36 is now undergoing clinical trials as a PET-ligand in humans.
25B-NBOMe was first described in the scientific literature, in the form of conference abstracts, by Ralf Heim and colleagues at the Free University of Berlin by 1999.
As of October 31, 2016; 25B-NBOMe is a controlled substance (Schedule III) in Canada.
As of October 2015 25B-NBOMe is a controlled substance in China.
25B-NBOMe is banned in the Czech Republic.
Scheduled in the "government decree on substances, preparations and plants considered to be narcotic drugs".
Banned as a narcotic drug since May 5, 2015.
In Sweden, the Riksdag added 25B-NBOMe to schedule I ("substances, plant materials and fungi which normally do not have medical use") as narcotics in Sweden as of August 1, 2013, published by the Medical Products Agency in their regulation LVFS 2013:15 listed as 25B-NBOMe 2-(4-bromo-2,5-dimetoxifenyl)-N-(2-metoxibensyl)etanamin.
In November 2013, the U.S. Drug Enforcement Administration placed 25B-NBOMe (along with 25I-NBOMe and 25C-NBOMe) in Schedule I of the Controlled Substances Act, making it illegal to manufacture, buy, possess, process, or distribute.