Thiofentanyl

Thiofentanyl is an opioid analgesic that is an analogue of fentanyl.

Thiofentanyl was sold briefly on the black market in the early 1980s, before the introduction of the Federal Analog Act which for the first time attempted to control entire families of drugs based on their structural similarity rather than scheduling each drug individually as they appeared. Thiofentanyl is made with the same synthetic route as fentanyl, but by substituting 2-(2-bromoethyl)thiophene for phenethyl bromide in the synthesis.