pentamorphone pentamorphone pentamorphone (14β-pentylaminomorphinone, rx-77989) is a semi-synthetic opiate derivative related to compounds such as morphine, hydromorphone and oxymorphone. developed in 1984, it is a potent opioid analgesic several times stronger than fentanyl, and with a similarly fast onset of effects and short duration of action. it was found to produce relatively little respiratory depression compared to other potent opioid agonists, but its analgesic effects were somewhat disappointing in human trials, and while pentamorphone had some slight advantages over fentanyl these were not sufficient to warrant its introduction into clinical use. pentamorphoneclinical dataatc codenonelegal statuslegal status us: schedule i identifiers iupac name 4,5α-epoxy-3-hydroxy-14β-pentylamino-17-methyl-7,8-didehydromorphinan-6-one cas number68616-83-1pubchem cid5464186chemspider4576571uniimm4487b4mwkeggd05416 ychemical and physical dataformulac22h28n2o3molar mass368.477 g·mol−13d model (jsmol)interactive image smiles cccccn12c=cc(=o)314ccn(2cc5=c4c(=c(c=c5)o)o3)c inchi inchi=1s/c22h28n2o3/c1-3-4-5-11-23-22-9-8-16(26)20-21(22)10-12-24(2)17(22)13-14-6-7-15(25)19(27-20)18(14)21/h6-9,17,20,23,25h,3-5,10-13h2,1-2h3/t17-,20+,21+,22-/m1/s1key:nrpcwsujmwefok-kdxivrhgsa-n (verify)