The substituted benzofurans are a class of chemical compounds based on the heterocyclic and polycyclic compound benzofuran. Many medicines use the benzofuran core as a scaffold, but most commonly the term is used to refer to the simpler compounds in this class which include numerous psychoactive drugs, including stimulants, psychedelics and empathogens. In general, these compounds have a benzofuran core to which a 2-aminoethyl group is attached (at any position), and combined with a range of other substituents. Some psychoactive derivatives from this family have been sold under the name Benzofury.
Benzofurans like 5-APB and 6-APB are said to have relatively minor psychedelic effects.
Benzofurans like 5-APB and 6-APB act as serotoninâÂÂnorepinephrineâÂÂdopamine releasing agents and as serotonin 5-HT<sub>2</sub> receptor agonists. In addition, some benzofurans, including 5-MAPB, 6-MAPB, BK-5-MAPB, and BK-6-MAPB, have unexpectedly been found to be potent serotonin 5-HT<sub>1B</sub> receptor agonists. Along with serotonin release and other actions, this property may be involved may be involved in their entactogenic effects. Conversely, MDMA is much less potent as an agonist of the serotonin 5-HT<sub>1B</sub> receptor.
The 2,3-dihydrobenzofurans 5-APDB and 6-APDB were described by David E. Nichols and colleagues at Purdue University as MDMA analogues in 1993. Subsequently, the benzofurans 5-APB and 6-APB emerged as novel designer drugs in 2010. Prior to this, they had been patented by Eli Lilly and Company as serotonin 5-HT<sub>2C</sub> receptor agonists for potential treatment of eating disorders and seizures in 2000 and 2006. 5-APB and 6-APB are often confused with 5-APDB and 6-APDB. The pharmacology of various benzofurans and 2,3-dihydrobenzofurans was further clarified in the mid-2010s and thereafter.
Substituted benzofurans saw widespread use as recreational drugs by being sold as research chemicals making them exempt from drug legislation. Many of the more common compounds were banned in the UK in June 2013 as temporary class drugs, while others have been made permanently illegal in various jurisdictions.
The derivatives may be produced by substitutions at six locations of the benzofuran molecule, as well as saturation of the 2,3- double bond.
The following table displays notable derivatives that have been reported: