Analysis of Benzo Fury usually finds it to contain the chemical 6-(2-aminopropyl) benzofuran (6-APB) or its related isomer 5-APB but using standard analysis methods it is impossible to differentiate between 6-APB and 5-APB. Little is known about the pharmacological or toxicological differences between the two isomers if any. 6-APB is an analogue of the class A drug MDA and has similar effects to MDMA (Ecstasy). The name comes from the benzofuran ring in the chemical structure and should not be
confused with benzodiazepines,

Druglink/DrugWatch factsheet – Benzo Fury (PDF)

NOTE: Benzo Fury is now controlled under the Psychoactive Substances Act 2016