OPTICAL RESOLUTION OF ARYLOXYPROPIONIC ACIDS AND THEIR ESTERS BY HPLCON CELLULOSE TRIS-3,5-DIMETHYL-TRIPHENYLCARBAMATE DERIVATIVE

Chiral chromatographic resolution of a series of antiphlogistic 2-aryl oxypropionic acids and their methyl- and ethyl esters was performed us ing a Chiralcel OD column. The CSP selected resolved most of the acids and esters efficiently, the enantiomers being well separated without requiring time consuming analysis. Chromatographic separation of R enr iched samples was performed to determine the correct elution order. Us ing eluting systems such as hexane and 2-propanol, or hexane, 2-propan ol and formic acid, the S enantiomer of all acids and esters was alway s found to elute first. We also considered the role of electron-donati ng or electron-withdrawing substituents (at the aryloxylic moiety) on the chiral resolution. It was shown that the electronic features of th e substituents have more influence on the chiral interactions between the solutes and the CSP than their steric hindrance. Finally we determ ined, by molecular models, the interaction between CSP and solutes. In this way were able to determine all the potential sites for interacti ons, which are compatible with the conformations of the compounds and the structure of the stationary phase, and point out those interaction s which enable chiral resolution.