Preparation and enantioseparation of a mixed selector chiral stationary phase derived from benzoylated tartaric acid and 1,2-diphenylethylenediamine.

L-Dibenzoyl tartaric acid was mono-esterified with benzyl alcohol, and then chlorinated with SOCl(2) to give (2S,3S)-1-(benzyloxy)-4-chloro-1,4-dioxobutane-2,3-diyl dibenzoate (Selector 1). (1R,2R)-1,2-Diphenylethylenediamine was mono-functionalized with phenyl isocyanate and phenylene diisocyanate in sequence to give (1R,2R)-1,2-diphenyl-2-(3-phenylureido)ethyl 4- isocyanatophenylurea (Selector 2). Two brush-type chiral stationary phases (CSPs) of single selector were prepared by separately immobilizing selectors 1 and 2 on aminated silica gel. Selectors 1 and 2 were simultaneously immobilized on aminated silica gel to give a mixed selector CSP. The enantioseparation ability of these CSPs was studied. The CSP of selector 1 has strongest separation ability, while the enantioseparation ability of the mixed selector CSP is relatively lower.