ohmefentanyl ohmefentanyl ohmefentanyl (also known as β-hydroxy-3-methylfentanyl, omf and rti-4614-4) is an extremely potent opioid analgesic drug which selectively binds to the µ-opioid receptor. ohmefentanylclinical dataatc codenonelegal statuslegal status ca: schedule i de: anlage i (authorized scientific use only) uk: class a us: schedule i un: psychotropic schedule i identifiers iupac name n--n-phenylpropanamide cas number78995-14-9 ypubchem cid62279drugbankdb01570chemspider56080 yuniiy8263089zxchemblchembl333410comptox dashboard (epa)dtxsid50868495 chemical and physical dataformulac23h30n2o2molar mass366.505 g·mol−13d model (jsmol)interactive image smiles ccc(=o)n(c1ccccc1)c2ccn(cc2c)cc(o)c3ccccc3 inchi inchi=1s/c23h30n2o2/c1-3-23(27)25(20-12-8-5-9-13-20)21-14-15-24(16-18(21)2)17-22(26)19-10-6-4-7-11-19/h4-13,18,21-22,26h,3,14-17h2,1-2h3 ykey:frprnnrjtconec-uhfffaoysa-n y (verify) there are eight possible stereoisomers of ohmefentanyl. these stereoisomers are among the most potent μ-opioid receptor agonists known, comparable to super-potent opioids such as carfentanil and etorphine which are only legally used for tranquilizing large animals such as elephants in veterinary medicine. in mouse studies, the most active stereoisomer, 3r,4s,βs-ohmefentanyl, was 28 times more powerful as a painkiller than fentanyl, the chemical from which it is derived, and 6300 times more powerful than morphine. ohmefentanyl has three stereogenic centers and eight stereoisomers, which are named f9201–f9208. researchers are studying the different pharmaceutical properties of these isomers. the 4″-fluoro analogue (i.e., substituted on the phenethyl ring) of the 3r,4s,βs isomer of ohmefentanyl is one of the most potent opioid agonists yet discovered, possessing an analgesic potency approximately 18,000 times that of morphine. other analogues with potency higher than that of ohmefentanyl itself include the 2′-fluoro derivative (i.e., substituted on the aniline phenyl ring), and derivatives where the n-propionyl group was replaced by n-methoxyacetyl or 2-furamide groups, or a carboethoxy group is added to the 4-position of the piperidine ring. the latter is listed as being up to 30,000 times more potent than morphine. side effects of fentanyl analogues are similar to those of fentanyl itself, which include itching, nausea and potentially serious respiratory depression, which can be life-threatening. illicitly used fentanyl analogues have killed hundreds of people throughout europe and the former soviet republics since the most recent resurgence in use began in estonia in the early 2000s, and novel derivatives continue to appear. the chemical structure of fentanyl has been used as a basis in modern chemistry for the discovey and nomenclature of many new fentanyl analogues, sometimes called fentalogs. molecular structure of four of the eight ohmefentanyl isomers molecular structure of all of the eight ohmefentanyl isomers synthesis ohmefentanyl synthetic pathway