Synthesis And Chiral Recognition Of Xylan Derivatives

Polysaccharide-based chiral stationary phases (CSPs) for high-performance liquid chromatography (HPLC) are well-known to exhibit excellent chiral recognitions, especially cellulose and amylose derivatives, and the influence of substituents of their side-chains on the chair recognition has ever been reported. Xylan, another kind of polysaccharide which possesses almost the same structure as cellulose without 6-hydrogen, could exibit different chair resolutions from cellulose derivatives, and few reports have been published on it so far.In order to develop new excellent polysaccharide-based CSPs,a series of phenylcarbamate derivatives of xylan bearing varieties of substituents were synthesized and their chiral recognition mechanism was further elucidated on the molecular level.Twelve kinds of xylan phenylcarbamate derivatives were synthesized by reacting with a variety of phenyl isocyanates bearing different substituents, and their structures were characterized by FT-IR and 1H NMR. The CSPs based on the obtained xylan derivatives for HPLC were prepared by slurry method after coating onto the aminopropyl silica gel. The chiral recognition abilities of xylan derivatives were evaluated through enantioseparation of nine kinds of typical racemates based on the novel CSPs for HPLC.In this study, twelve kinds of xylan phenylcarbemate derivatives were successfully synthesized and the CSPs based on the obtained xylan derivatives were well prepared. Their chiral recognition abilities were evaluated by enantioseparation of nine chiral compounds. It could be found that the chiral recognition abilities of these derivatives could significantly change depending on the electronegativity, position and number of the substituents of the phenylcarbamate side-chains at 2- and 3-position of the glucose.