4-APB is a positional isomer of the designer drug 6-APB , also known as benzo fury, found in recreational drugs. [1] It is also an analog of MDA in which the 3,4-methylenedioxyphenyl ring system has been replaced with a benzofuran ring. 4-EAPB is an analog of 4-APB that is characterized by an ethyl group added to the amine. The physiological and toxicological properties of this compound are not known. This product is intended for forensic and research applications.
Reference:
[1]. Stanczuk, A., Morris, N., Gardner, E.A., et al. Identification of (2-aminopropyl)benzofuran (APB) phenyl ring positional isomers in internet purchased products. Drug Test.Anal. 5(4), 270-276 (2013).