Preparation And Chiral Resolution Of CSPs Of Cyclodextrin Derivatives Bearing Different Side Chain Structure

With the rapid development of the bioengineering and bioscience, it was widelyrecognized that the chiral drugs with different optical activity showed different biologicalactivity. So the demands for the quantity and purity of the optical pure single enantiomerpromoted significantly the development of single enantiomer preparation and separation.Specifically, the direct chiral separation using chiral stationary phases (CSPs) forhigh-performance liquid chromatography (HPLC) has developed during the past decades.From the viewpoint of these recent trends in chiral HPLC, the immobilized-type CSPs basedon the cyclodextrin derivatives have been recognized as the one of most powerful for bothanalytical and preparative separations. The current studies are focused on hydroxyl groupmodified in cyclodextrin, and the influence of the structure and the position of the substituenton chiral recognition. The novel cyclodextrin-based CSPs with stable physical, chemicalproperties and higher immobilization efficiency will be prepared.Firstly, five cyclodextrin derivatives having both substituent were synthesized bycyclodextrin with corresponding isocyanates in this paper. Another five cyclodextrinderivatives bearing different substituent (including phenylcarbamate and benzoate groups)were synthesized by the regioselective procedures. And their structures were characterized byFT-IR, NMR and TGA spectroscopy. Then, the immobilized cyclodextrin-based derivativesCSPs were prepared by coating on the aminopropyl silica gel, immobilization and packingprocedures. Finally, the chiral recognition abilities of the cyclodextrin-based derivatives CSPwere evaluated through enantioseparation of the nine racemates by normal-phase HPLC.It was found that the cyclodextrin-based derivatives CSP bearing3,5-dichlorophenylcarbamate groups exhibited better resolution compared to the others. And the chiralrecognition abilities of cyclodextrin-based derivatives were affected significantly by thebenzoate group at2-position in glucose unit of cyclodextrin. The chiral recognition abilities ofcyclodextrin-based derivatives CSPs having both substituent were higher when a mobilephase consisted of hexane and2-propanol was90/10(v/v). And the chiral recognition abilitiesof the CSPs bearing different ester groups was higher when a mobile phase consisted ofhexane and2-propanol was99/1(v/v).