Synthetic Routes from ۱-(۲-phenylethyl)-۴-piperidinone (PPD) to Fentanyl; A Short Review

Fentanyl, a potent synthetic opioid widely used in clinical anesthesia and pain management, has attracted sustained attention due to both its therapeutic significance and public health concerns. Central to its preparation is the key intermediate ۱-(۲-phenylethyl)-۴-piperidinone (PPD), which serves as the strategic starting point for nearly all reported synthetic routes. This mini-review provides a focused overview of the major pathways leading from PPD to fentanyl, highlighting the classical approach through ۴-anilino-N-phenethylpiperidine (۴-APPD), subsequent optimizations aimed at improving yield and operational simplicity, and recent innovations including continuous-flow methodologies. Rather than offering an exhaustive account, this concise review emphasizes the recurring role of PPD as a pivotal hub in synthetic design, as well as the implications for pharmaceutical development, process control, and forensic monitoring. By centering on PPD-derived routes, this work aims to provide a compact yet informative perspective on the state of fentanyl citrate synthesis.

کلیدواژه ها:

Fentanyl ، ۱-(۲-phenylethyl)-۴-piperidinone (PPD) ، Synthetic routes ، Mini-review ، Pharmaceutical intermediates