Chiral high-performance liquid chromatographic studies of 2-(4-chloro-2-methylphenoxy)propanoic acid

The direct enantiomeric resolution of the racemic herbicide 2-(4-chloro-2-methylphenoxy)propanoic acid (CMPP) was demonstrated on an Enantiopac (alpha 1-acid glycoprotein) chiral high-performance liquid chromatographic (HPLC) column. The HPLC separation of various amide derivatives of CMPP on a chiral "Ionic Pirkle" column comprising of N-(3,5-dinitrobenzoyl) (R)-(-)phenylglycine as chiral ligand, was also accomplished. These amides and racemic ibuprofen, however could not be separated on the Enantiopac system. The performance, stability and cost of the two systems were compared. Using optically pure CMPP enantiomers the elution order was determined and shown to reverse between the two systems. It was also shown that negligible racemisation occurred during derivatization.