It is used as an intermediate in the manufacture of chemicals and pharmaceutical drugs such as fentanyl.
Because of its possible use in the illicit manufacture of fentanyl, the United States Drug Enforcement Administration (DEA) placed NPP under control as a List 1 Chemical in 2007.
[3] N-Phenethyl-4-piperidinone can be prepared from 4-piperidinone and phenethyl bromide in biphasic conditions with a variety of phase transfer catalysts.
[citation needed] N-Phenethyl-4-piperidinone is useful in the synthesis of addictive drugs, primarily fentanyl and its analogs.
[4] The Siegfried method (shown below and published on The Hive) involves reacting N-phenethyl-4-piperidinone with aniline, and then reducing the imine product with sodium borohydride to 4-anilino-N-phenethylpiperidine (ANPP).