3H-1,2,4-Triazol-3-one, 5-[[(2R,3R)-2-[(1R)-1-[3,5-bis(trifluoromethyl)phenyl]ethoxy]-3-(4'-fluoro[1,1'-biphenyl]-4-yl)-4-morpholinyl]methyl]-1,2-dihydro-, rel-

(R)-4-Flourophenyl Aprepitant is an impurity of Aprepitant (170729-80-3 #CAS), which is a neurokinin-1 antagonist and an antiemetic agent (1). It is used to prevent chemotherapy-induced nausea and vomiting (CINV) in colorectal cancer patients (2) Aprepitant has also been shown to induce apoptotic cell death and G1 arrest through Akt/p53 axis in pre-B acute lymphoblastic leukemia cells (3).