Fentanyl tropane

Fentanyl tropane (tropafentanyl) is an opioid derivative which is an analogue of fentanyl, where the central piperidine ring has been bridged with a two carbon chain to form a tropane ring. It is made from tropinone in a similar manner to how fentanyl is made from 4-piperidone, and has two isomers, with the 3β isomer being around half the potency of fentanyl while the 3α isomer is much weaker, only around the same potency as morphine.