1-Boc-4-AP
1-Boc-4-AP (tert-butyl 4-(phenylamino)piperidine-1-carboxylate) is a compound used as an intermediate in the manufacture of fentanyl, as well as various related derivatives such as butyrylfentanyl, furanylfentanyl, benzylfentanyl and homofentanyl, among others. It is an N-protected derivative of 4-anilinopiperidine which can be readily converted to fentanyl or related analogues in several straightforward synthetic steps.