despropionyl-p-fluorofentanyl despropionyl-p-fluorofentanyl despropionyl-p-fluorofentanyl is an inactive synthetic opioid analgesic drug precursor to 4-fluorofentanyl. it is an analog of fentanyl. despropionyl-p-fluorofentanylidentifiers iupac name n-phenyl-n-4-piperidinyl-butanamide, cas number122861-41-0pubchem cid21812144chemspider10551386 nuniir8zh1eq95ycomptox dashboard (epa)dtxsid10618291 chemical and physical dataformulac19h23fn2o0molar mass298.405 g·mol−13d model (jsmol)interactive image smiles fc3ccc(nc2ccn(ccc1ccccc1)cc2)cc3 inchi inchi=1s/c19h23fn2/c20-17-6-8-18(9-7-17)21-19-11-14-22(15-12-19)13-10-16-4-2-1-3-5-16/h1-9,19,21h,10-15h2key:wwdhlolwlhhfbh-uhfffaoysa-n