white crystalline low melting solid
(R)-(+)-alpha-Methoxy-alpha-(trifluoromethyl)phenylacetic acid is widely used reagent for determination of optical purities of alcohols and amines by 1H or 19F NMR.
Mosher′s acid chloride is used as a dervatization agent for β-arylethylamines, enantiomeric alcohols, and enantiomeric amines. It is also a reagent used for the determination of enantiomeric purity and absolute configuration of alcohols and amines by NMR.
Mosher′s acid chloride is generally used as a chiral derivatizing agent. It is easily available in enantiomerically pure form. It can form diastereomers with both alcohols and amines.
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.]