6-APB

6-APB

Clinical data
Routes of administration	By mouth, insufflation
Drug class	Serotonin–norepinephrine–dopamine releasing agent; Serotonin 5-HT2 receptor agonist; Entactogen; Stimulant; Psychedelic
ATC code	None
Legal status
Legal status	AU: S9 (Prohibited substance) CA: Schedule III DE: Anlage II (Authorized trade only, not prescriptible) UK: Class B UN: Unscheduled
Pharmacokinetic data
Onset of action	30–60 minutes
Duration of action	7–10 hours
Identifiers
IUPAC name 1-(1-benzofuran-6-yl)propan-2-amine
CAS Number	286834-85-3 N 286834-84-2 (HCl)
PubChem CID	9794343
ChemSpider	7970110 Y
UNII	285VE60914
CompTox Dashboard (EPA)	DTXSID401010105
Chemical and physical data
Formula	C11H13NO
Molar mass	175.231 g·mol−1
3D model (JSmol)	Interactive image
SMILES NC(C)CC1=CC(OC=C2)=C2C=C1
InChI InChI=1S/C11H13NO/c1-8(12)6-9-2-3-10-4-5-13-11(10)7-9/h2-5,7-8H,6,12H2,1H3 Y Key:FQDAMYLMQQKPRX-UHFFFAOYSA-N Y
NY (what is this?)  (verify)

6-APB (6-(2-aminopropyl)benzofuran) is an empathogenic psychoactive drug of the substituted benzofuran and substituted phenethylamine classes.^[1] 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.^{[citation needed]}

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” if uncontrolled. Because 6-APB and other substituted benzofurans have not been explicitly outlawed in some countries, they are often technically legal, contributing to its popularity.^{[citation needed]}

This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources in this section. Unsourced material may be challenged and removed. (October 2024) (Learn how and when to remove this message)

6-APB can be found in freebase, hydrochloride, and succinate form. The freebase is purportedly 20% stronger than the hydrochloride salt and 65% stronger than the succinate. This means 100 mg of 6-APB HCl is equivalent to 83 mg of 6-APB freebase and 100 mg of 6-APB succinate is equivalent to 60 mg of 6-APB freebase. Different production batches may have impurities and should be treated with care.^{[citation needed]}

Based on anecdotal reports, the dosages for 6-APB hydrochloride are the following:

The dosages for freebases or succinates have to be adjusted accordingly.

6-APB is reported to produce entactogenic, stimulant, and mild psychedelic effects in humans.^[2][3]

Acute psychosis has been associated with recreational use of 6-APB in combination with the synthetic cannabinoid JWH-122.^[4]

6-APB acts as a serotonin–norepinephrine–dopamine releasing agent (SNDRA), with EC₅₀Tooltip half-maximal effective concentration values for monoamine release of 36 nM for serotonin, 14 nM for norepinephrine, and 10 nM for dopamine in rat brain synaptosomes.^[5][6] Simultaneously, 6-APB is a serotonin–norepinephrine–dopamine reuptake inhibitor (SNDRI), with affinities (K_i) of 117 nM for the norepinephrine transporter (NET), 150 nM for the dopamine transporter (DAT), and 2,698 nM for the serotonin transporter (SERT)^[1] as well as IC₅₀Tooltip half-maximal effective concentration values for monoamine reuptake inhibition of 930 nM for serotonin, 190 nM for norepinephrine, and 3,300 nM for dopamine.^[6]

In addition to actions at the monoamine transporters, 6-APB is a potent high-efficacy partial agonist or full agonist of the serotonin 5-HT_2B receptor (K_i = 3.7 nM; EC₅₀Tooltip half-maximal effective concentration = 140 nM; E_maxTooltip maximal efficacy = 70%).^[1] It has higher affinity for this target than any other site.^[7] Moreover, unlike MDMA, 6-APB shows 100-fold selectivity for the serotonin 5-HT_2B receptor over the serotonin 5-HT_2A and 5-HT_2C receptors in terms of affinity.^[7][8] It is notably both more potent and more selective as an agonist of the serotonin 5-HT_2B receptor than the reference serotonin 5-HT_2B receptor agonist, BW-723C86, which is commonly used for research into the serotonin 5-HT_2B receptor.^{[citation needed]} Although much more potent at the serotonin 5-HT_2B receptor, 6-APB is also a partial agonist of the serotonin 5-HT_2A receptor (EC₅₀ = 5,900 nM; E_max = 43%) and shows affinity for the serotonin 5-HT_2C receptor (K_i = 270 nM) and the serotonin 5-HT_1A receptor (K_i = 1,500 nM).^[6] It has been reported to act as an agonist of the serotonin 5-HT_2C receptor similarly to the serotonin 5-HT_2A and 5-HT_2B receptors.^[2][9]

Besides the serotonin 5-HT₂ receptors, 6-APB has been found to bind with high affinity to the α_2C-adrenergic receptor (K_i = 45 nM), although the significance of this action in humans is unknown.^[1] 6-APB showed little other affinity at a wide selection of other sites, with some exceptions like the rodent trace amine-associated receptor 1 (TAAR1).^[1][6]

The potent agonism of the serotonin 5-HT_2B receptor makes it likely that 6-APB would be cardiotoxic with chronic or long-term use, as seen with other serotonin 5-HT_2B receptor agonists such as the withdrawn serotonergic anorectic fenfluramine.^[1][10]

The pharmacokinetics of 6-APB have not been studied, however, some information can be extracted from user reports. These suggest a slow onset of 40–120 minutes. The drugs peak effects last 7 hours, followed by a comedown phase of approximately 2 hours, and after effects for up to 24 hours.^[11]

Although limited literature is available, there is some data on metabolism of 6-APB in rats. Its Phase I metabolism involves hydroxylation of the furan ring, then cleavage of the ring, followed by a reduction of the unsaturated aldehyde from the previous step. The resulting aldehyde may then take two paths. It is either oxidized to a carboxylic acid or reduced to an alcohol, and then hydroxylated. Phase II metabolism consists of glucuronidation. The most prevalent metabolites in rats were 3-carboxymethyl-4-hydroxyamphetamine and 4-carboxymethyl-3-hydroxyamphetamine.^[12]

6-APB and its structural isomer 5-APB have been tested with a series of agents including: Marquis, Liebermann, Mecke, and Froehde reagents.^[13] Exposing compounds to the reagents gives a colour change which is indicative of the compound under test.

6-APB succinate is reported to be practically insoluble in CHCl₃ as well as very minimally soluble in cold water. A batch seized by the DEA contained a 2:1 ratio of succinate to 6-APB.^[14]

The synthesis by Briner et al.^[8] entailed refluxing 3-bromophenol with bromoacetaldehyde diethylacetal and sodium hydride to give the diethyl acetal, which then was heated with polyphosphoric acid to give a mixture of bromobenzofuran structural isomers: 4-bromo-1-benzofuran and 6-bromo-1-benzofuran. The isomers were separated by silica gel column chromatography, then converted to their respective propanone derivatives, and then reductively aminated to give 6-APB and 4-APB, both of which were converted to their HCl ion pairs for further examination.

In 1999, amphetamines were changed from Schedule III to Schedule I as a result of the Safe Streets Act. Some have speculated that 6-APB's structure qualifies it as a Schedule I drug as an analog of MDA.^{[15][unreliable source?]}

In 2014, a study funded by the Canadian Institutes of Health Research noted that 6-APB "may or may not be legal in Canada depending on how one interprets the current Act"^[16] and that it could be purchased for academic purposes without an exemption from Health Canada. The study also noted how, unlike the MDMA it often serves as a replacement for in countries like the US, 6-APB's benzofuran structure does not make it a direct analogue of amphetamine despite similarities in effects.

6-APB has been a controlled substance in China since 1 July 2024^[17]

6-APB is scheduled in government decree on narcotic substances, preparations and plants and hence is illegal.^[18]

6-APB is illegal in France.^[19]

6-APB is illegal in Germany since the 17th of July, 2013, when it was added to Anlage II of the Betäubungsmittelgesetz.^{[citation needed]}

6-APB is illegal in Italy.^[20]

In Luxembourg, 6-APB is not cited in the list of prohibited substances.^[21] Therefore, it is still a legal substance.

6-APB, as well as multiple substances based on the phenylethamine structure, like most cathinones and amphetamines, are banned under the Opium Law since July 1st, 2025,^[22] following an amendment to deal with New Psychoactive Substances (NPS) in the Netherlands. Since this is a structural ban instead of a direct one, later substances that differ slightly but use the same skeleton will also be preemptively banned.

Certain countries contain a "substantially similar" catch-all clause in their drug law, such as New Zealand and Australia. This includes 6-APB as it is similar in chemical structure to the class A drug MDA, meaning 6-APB may be viewed as a controlled substance analogue in these jurisdictions.^[23]

In Sweden, as of 27 December 2009 6-APB is classified as "health hazard" under the act Lagen om förbud mot vissa hälsofarliga varor (translated Act on the Prohibition of Certain Goods Dangerous to Health).^[24]

It is also classified as a narcotic substance since 2020.^[25]

On June 10, 2013 6-APB and a number of analogues were classified as Temporary Class Drugs in the UK following an ACMD recommendation.^[10] This means that sale and import of the named substances are criminal offences and are treated as for class B drugs.^[26] On November 28, 2013 the ACMD recommended that 6-APB and related benzofurans should become Class B, Schedule 1 substances.^[10] On March 5, 2014 the UK Home Office announced that 6-APB would be made a class B drug on 10 June 2014 alongside every other benzofuran entactogen and many structurally related drugs.^[27]

6-APB is not scheduled at the federal level in the United States,^{[28][failed verification]} but it may be considered an analog of amphetamine, in which case purchase, sale, or possession could be prosecuted under the Federal Analog Act.^[29]

• Borax combo
• 5-APB
• 6-APBT
• 6-API
• 6-APDB