Synthesis of Dendrimer-Type Chiral Stationary Phases Based on the Selector of (1S,2R)-(+)-2-Amino-1,2-diphenylethanol Derivate and Their Enantioseparation Evaluation by HPLC

In our recent work, a series of dendritic chiral stationary phases (CSPs) were synthesized, in which the chiral selector was L-2-(P-toluenesulfonamido)-3-phenylpropionyl chloride (selector I), and the CSP derived from three-generation dendrimer showed the best separation ability. To further investigate the influence of the structures of dendrimer and chiral selector on enantioseparation ability, in this work, another series CSPs (CSPs 1-4) were prepared by immobilizing (1S,2R)-1,2-diphenyl-2-(3-phenylureido)ethyl 4-isocyanatophenylcarbamate (selector II) on one- to four-generation dendrimers that were prepared in previous work. CSPs 1 and 4 demonstrated the equivalent enantioseparation ability. CSPs 2 and 3 showed the best and poorest enantioseparation ability respectively. Basically, these two series of CSPs exhibited the equivalent enantioseparation ability although the chiral selectors were different. Considering the enantioseparation ability of the CSP derived from aminated silica gel and selector II is much better than that of the one derived from aminated silica gel and selector I, it is believed that the dendrimer conformation essentially impacts enantioseparation. Chirality 22:69-76, 2010. (C) 2009 Wiley-Liss, Inc.