Enantiomeric resolution of kielcorin derivatives by HPLC on polysaccharide stationary phases using multimodal elution

Analytical HPLC methods using carbamate chiral stationary phases of polysaccharide derivatives were developed for the enantiomeric resolution of five racemic mixtures of xanthonolignoids: rac-trans-kielcorin C, rac-cis-kielcorin C, rac-trans-kielcorin D, rac-trans-isokielcorin D, and rac-trans-kielcorin E. The separations were evaluated with the stationary phases cellulose tris-3,5-dimethylphenylcarbamate, amylose tris-3,5-dimethylphenylcarbamate, amylose tris-(S)-1-phenylethylcarbamate, and amylose tris-3,5-dimethoxyphenylcarbamate under normal, reversed-phase, and polar organic elution conditions. Chiral recognition of those chiral stationary phases, the influence of mobile phases on the enantiomers separation, and the effects of structural features of the solutes on the chiral discrimination observed are discussed. The best performance was achieved on an amylose tris-3,5-dimethylphenylcarbamate phase. Polar organic conditions gave shorter retention factors and better resolutions and were a valuable alternative to the alcohol-hexane or reversed-phase conditions.