6-(2-aminopropyl)benzofuran (also known as 6-APB or by the brand-name Benzofury) is a popular synthetic entactogen of the phenethylamine and benzofuran chemical classes that produces a powerful, long-lived array of typical MDA-like entactogenic effects such as sedation, enhanced feelings of empathy, love, and sociability, muscle relaxation, anxiety relief and physical and cognitive euphoria when administered.
C11H13NO • HCl
A crystalline solid
207, 246, 276, 285 nm
6APB is a serotonin–norepinephrine–dopamine reuptake inhibitor (SNDRI) with Ki values of 117, 150, and 2698 nM for the norepinephrine transporter (NET), dopamine transporter (DAT), and serotonin transporter (SERT), respectively. In addition, 6APB not only blocks the reuptake of these monoamine neurotransmitters but is also a releasing agent of them; that is, it is a serotonin-norepinephrine-dopamine releasing agent (SNDRA). In addition to actions at the monoamine transporters, 6-APB is a potent full agonist of the serotonin 5-HT2B receptor (Ki = 3.7 nM), with higher affinity for this target than any other site. Moreover, unlike MDMA, 6-APB shows 100-fold selectivity for the 5-HT2B receptor over the 5-HT2A and 5-HT2C receptors. It is notably both more potent and more selective as an agonist of the 5-HT2B receptor than the reference 5-HT2B receptor agonist, BW-723C86, which is commonly used for research into the 5-HT2B receptor. Aside from the 5-HT2B receptor, 6-APB has also been found to bind with high affinity to the α2C-adrenergic receptor subtype (Ki = 45 nM), although the clinical significance of this action is unknown. 6-APB showed little other affinity at a wide selection of other sites.
The potent agonism of the 5-HT2B receptor makes it likely that 6-APB would be cardiotoxic with chronic or long-term use, as seen with other 5-HT2B receptor agonists such as the withdrawn serotonergic anorectic fenfluramine.