3-APBT

3-APBT (former developmental code name SKF-6678), also known as 3-(2-aminopropyl)benzo[β]thiophene, is a monoamine releasing agent and serotonin receptor agonist of the benzothiophene group. It is an analogue of α-methyltryptamine (AMT) in which the indole ring has been replaced with a benzothiophene ring.

The drug acts as a potent and well-balanced serotonin–norepinephrine–dopamine releasing agent (SNDRA). It is also a full agonist of the serotonin 5-HT₂ receptors, including of the serotonin 5-HT_2A, 5-HT_2B, and 5-HT_2C receptors. 3-APBT produces the head-twitch response, a behavioral proxy of psychedelic effects, in rodents. It does not stimulate locomotor activity in rodents, suggesting that it does not possess stimulant-type effects. The drug has been reported be a weak monoamine oxidase inhibitor (MAOI), specifically of monoamine oxidase A (MAO-A) (IC₅₀Tooltip half-maximal inhibitory concentration = 16,200 nM).

3-APBT was developed by Smith, Kline & French (SKF) as a potential pharmaceutical drug in the late 1950s. The drug and its positional isomer 2-APBT were reported to produce various central nervous system (CNS) effects and to be useful as a "ataractics, psychic energizers, and analgetics". 3-APBT has also been reported to have appetite suppressant effects in rodents, but to have considerably lower potency than AMT as an "analeptic" in rodents.