Flumexadol (INN; developmental codes CERM-1841 and 1841-CERM) is a drug described and researched as a non-opioid analgesic which was never marketed. It has been found to act as an agonist of the serotonin 5-HT<sub>1A</sub> (pK<sub>i</sub> = 7.1) and 5-HT<sub>2C</sub> (pK<sub>i</sub> = 7.5) receptors and, to a much lesser extent, of the 5-HT<sub>2A</sub> (pK<sub>i</sub> = 6.0) receptor. According to Nilsson (2006) in a paper on 5-HT<sub>2C</sub> receptor agonists as potential anorectics, "The (+)-enantiomer of this compound showed [...] affinity for the 5-HT<sub>2C</sub> receptor (K<sub>i</sub>) 25 nM) [...] and was 40-fold selective over the 5-HT<sub>2A</sub> receptor in receptor binding studies. The racemic version [...], also known as 1841 CERM, was originally reported to possess analgesic properties while no association with 5-HT<sub>2C</sub> receptor activity was mentioned." It is implied that flumexadol might be employable as an anorectic in addition to analgesic. Though flumexadol itself has never been approved for medical use, oxaflozane (brand name Conflictan) is a prodrug of the compound that was formerly used clinically in France as an antidepressant and anxiolytic agent.
Halogenation of 2-chloroethyl vinyl ether (1) with molecular bromine gives 1,2-dibromo-1-(2-chloroethoxy)ethane (2). Grignard reaction with 3-bromobenzotrifluoride (3) gives 1-[2-bromo-1-(2-chloroethoxy)ethyl]-3-(trifluoromethyl)benzene (4). Treatment with benzylamine gives 4-benzyl-2-[3-(trifluoromethyl) phenyl]morpholine (5). Catalytic hydrogenation strips the benzyl protecting group completing the synthesis of flumexadol (6).