Synthesis Of Cyclodextrin-based Chiral Separation Phaseand Enantioseparation Of Several Chiral Pharmaceuticals And Pesticides

The studies on separating and purifying single enantiomers of racemic drugs have attracted wide attention in recent years because many enantiomers of chiral pharmaceuticals and pesticides show different biological activities and toxicity, so the separation of enantiomers is very important. The enantioseparation of several typical chiral pharmaceuticals and pesticides was investigated on self-preparedβ-cyclodextrin-derivative chiral stationary phases and commercial polysaccharide-derivative,macrocyclic antibiotic and cyclodextrin-based chiral columns using high performance liquid chromatography and supercritical fluid chromatography.In first part, perphenylcarbamoylatedβ-cyclodextrin CSP was prepared step by step through Staudinger reaction. The self-prepared chiral stationary phases were characterized by FT-IR. In the second part, three flavanone derivatives (4'-, 5-, 6-Methoxyflavanone) were studied on self-prepared column. The influence of mobile phase additives and concentration on the enantioseparation was studied. The results show thatπ-πinteraction might act an important factor in the enantioseparation of 4'-, 5-, 6-Methoxyflavanone on the cyclodextrin-based CSPs.In the third part, The enantioseparation of three neonicotinoid insecticides (identified as compounds 1, 2, and 3 ) were performed on three commercial polysaccharide-type chiral columns (Chiralcel OD-H, Chiralpak AD-H and Chiralpak IB), two commercial macrocyclic antibiotic chiral columns (Chirobiotic V and Chirobiotic T) and a commercial cyclodextrin-base chiral column (Nucleodexβ-PM) by high-performance liquid chromatography (HPLC) and supercritical fluid chromatography (SFC). Effects of the modifier percentage and column temperature on chiral recognitions of chiral stationary phases were also studied. Both 1 and 2 could be resolved on all three columns selected, with the highest Rs values obtained on Chiralpak AD-H and Chiralcel OD-H, respectively. However, satisfactory separation of the four stereoisomers of 3 was only achieved on Chiralcel OD-H. Moreover, partial separation could be observed on Chirobiotic V and Chirobiotic T for compound 2 and 3, while no separation could be observed on Nucleodexβ-PM column. In comparison to HPLC, a shorter run time were achieved for 1 and 2 by SFC. However, 3 could not be stereoselectively resolved using SFC.