n-phenethylnormorphine n-phenethylnormorphine n-phenethylnormorphine is an opioid analgesic drug derived from morphine by replacing the n-methyl group with β-phenethyl. it is around eight to fourteen times more potent than morphine as a result of this modification, in contrast to most other n-substituted derivatives of morphine, which are substantially less active, or act as antagonists. binding studies have helped to explain the increased potency of n-phenethylnormorphine, showing that the phenethyl group extends out to reach an additional binding point deeper inside the μ-opioid receptor cleft, analogous to the binding of the phenethyl group on fentanyl. n-phenethylnormorphineidentifiers iupac name 3,6-dihydroxy-7,8-didehydro-4,5α-epoxy-17-(2-phenylethyl)morphinan pubchem cid46908217chemspider34254115 ychemblchembl3275472chemical and physical dataformulac24h25no3molar mass375.468 g·mol−13d model (jsmol)interactive image smiles c1ccc(cc1)ccn2cc34c5c6ccc(c5o3(c=c42c6)o)o inchi inchi=1s/c24h25no3/c26-19-8-6-16-14-18-17-7-9-20(27)23-24(17,21(16)22(19)28-23)11-13-25(18)12-10-15-4-2-1-3-5-15/h1-9,17-18,20,23,26-27h,10-14h2/t17-,18+,20-,23-,24-/m0/s1key:bxkjggvenhtvbf-jfdovzfrsa-n (verify)