4-fluoroethylphenidate 4-fluoroethylphenidate 4-fluoroethylphenidate (4f-eph) is a recreational designer drug from the phenidate family, with stimulant effects. it was first identified in france in march 2016. it has been used as a nootropic drug, and was made illegal in the uk in 2017, and in sweden in 2018. 4-fluoroethylphenidateidentifiers iupac name ethyl 2-(4-fluorophenyl)-2-(piperidin-2-yl)acetate cas number2160555-59-7pubchem cid123133727chemical and physical dataformulac15h20fno2molar mass265.328 g·mol−13d model (jsmol)interactive image smiles fc1ccc(cc1)c(c(=o)occ)c1ccccn1 inchi inchi=1s/c15h20fno2/c1-2-19-15(18)14(13-5-3-4-10-17-13)11-6-8-12(16)9-7-11/h6-9,13-14,17h,2-5,10h2,1h3key:rkxqywfdjdysen-uhfffaoysa-n