What is fentanyl?

Fentanyl, also spelled fentanil, (molecular formula C22H28N2O) is a potent opioid used as an analgesic and anesthetic. It is also used as a recreational drug, sometimes mixed with heroin, cocaine or methamphetamine, and its potentially fatal overdose effects can be neutralized with naloxone.

Fentanyl is also used to manufacture counterfeit drugs marketed as oxycontin, xanax, adderall and other types of pills.

Its IUPAC name is N-phenyl-N-[1-(2-phenylethyl)piperidin-4-yl]propanamide.

3D structure

Fentanyl has the chemical structure of phenylethylpiperidone.

Total synthesis of fentanyl

Fentanyl and derivatives are synthesized by modifications of meperidine. Meperidine is a fully synthetic opioid, and other members of the phenylpiperidine family, such as alfentanil and sufentanil, are complex versions of this structure.

A total synthesis of fentanyl has been reported by Suh et al. in 1998, starting from a single phenylethylamine and by a four-step sequence.
The key step in this synthesis involves efficient construction of the phenylethylpiperidone skeleton via aminomethylation-cyclization followed by Swern oxidation.

total fentanyl synthesis
Total synthesis of fentanyl.

Physico-chemical properties

Fentanyl has a density of 1.1 g/cm3. Its melting point is 87.5 ºC, and its molar mass is 336.479 g/mol.

Like other opioids, fentanyl is a weak base that is highly lipid-soluble, protein-bound and protonated at physiological pH. All these factors allow it to rapidly cross cell membranes, which contributes to its rapid effect on the body and the central nervous system.

International Chemical Identifier

We provide identifiers InChI key of the IUPAC for, the main compounds described in this section in order to facilitate the nomenclature and formulation of chemical compounds and the search for information on the Internet for these compounds.