A combined DSC, X-ray diffraction, and molecular modelling study of chiral discrimination in the purification of enantiomeric mixtures of cis-permethrinic acid

Abstract

Purification of the non-racemic enantiomeric mixtures of cis-permethrinic acid has been performed by selective precipitation of the diastereoisomeric homo-(RCPAC) and hetero-(RSCPAC) dimers of the acid. The differences between the properties of the dimers have been studied using DSC and X-ray diffraction measurements. Molecular mechanics and quantum chemical calculations have been performed in order to describe quantitatively the energy differences and intermolecular interactions formed and to shed light on the mechanism of chiral discrimination in the separation of cis-permethrinic acid isomers.