clear colorless viscous liquid
(S)-(-)-alpha-Methoxy-alpha-(trifluoromethyl)phenylacetic acid is used as a chiral derivatizing agent, it reacts with an alcohol or amine of unknown stereochemistry to form an ester or amide. The absolute configuration of the ester or amide is then determined by proton and/or 19F NMR spectroscopy.
(S)-(-)-α-Methoxy-α-(trifluoromethyl)phenylacetic acid is commonly used as a derivatizing agent in Mosher ester analysis and Mosher amide analysis, which are NMR-based methods for determining the absolute configuration of the chiral carbon center in secondary alcohols and amines, respectively.
A likely impurity is phenylethylamine from the resolution. Dissolve the acid in Et2O/*benzene (3:1), wash with 0.5N H2SO4, then water, dry over magnesium sulfate, filter, evaporate and distil it. [Dale et al. J Org Chem 34 2543 1969, J Am Chem Soc 75 512 1973.]
