A series of novel five-membered urea derivatives as potent NK1 receptor antagonists is described. The effects of substitution of a 4-fluoro group at the phenyl ring and the introduction of an α-methyl group at the benzylic position to improve potency was found. 3,5-Bis(trifluoromethyl)benzyl bromide has been used as derivatization reagent in detection of uracil in DNA by GC and negative chemical ionization mass spectrometry.
