Aprepitant EP Impurity A 

Chemical Name:  5-[[(2R,3S)-2-[(1R)-1-[3,5-Bis(trifluoromethyl)phenyl]ethoxy]-3-phenylmorpholin-4-yl]methyl]-1,2-dihydro-3H-1,2,4-triazol-3-one (as per EP) ; (5-{[(2R,3S)-2-{(R)-1-[3,5-Bis(trifluoromethyl)phenyl]ethoxy}-3-phenylmorpholino]methyl}-2H-1,2,4-triazol-3(4H)-one) (as per USP)

Synonym: Desfluoro Aprepitant