Synthesis And Chiral Recognition Properties Of Chitin Derivatives Bearing Selective Substituents

Cellulose and amylose derivatives have excellent chiral recognition ability and have been widely used in the preparation of high performance liquid chromatography(CSP).Chitin,as a natural macromolecule with different structure from traditional polysaccharide,has good biocompatibility and has great development potential.However,there are relatively few studies on chitin derivatives and their chiral recognition performance.The 2-position in the glucosamine unit has a unique amide group,which may lead to the development of a new generation of chiral recognition materials with high-efficiency chiral recognition performance and solvent tolerance.Based on this situation,the synthesis of new chitin derivatives with two different structure phenyl carbamate substituents on chitin glycosamine unit was studied,and the chiral recognition performance of chitin derivatives and its influencing factors were further discussed.Firstly,a series of chitin phenylcarbamate derivatives with different substituents at 3-position and 6-position of chitin glycoammonia unit were synthesized by regioselective esterification.The structure and purity of the intermediates and final products were characterized and analyzed by FT-IR and ~1H NMR.Then,based on the synthesis of chitin derivatives,a new chitin chiral stationary phase was prepared by coating method,and the coating rate of the chiral stationary phase was determined by TGA,and the HPLC column was prepared by homogenate method.Finally,based on the prepared chiral column,10 typical chiral compounds were separated by high performance liquid chromatography,and the chiral recognition performance of the synthesized chitin derivatives with regioselective substituents was further evaluated.The results show that the regioselective substitution of chitin derivatives have better chiral recognition than the single substituted chitin derivatives for the chiral compounds of cobalt tris(acetylacetonate)(Rac-6)and flavone(Rac-7).Among them,the series of new chitin derivatives have unique and efficient chiral recognition performance for Rac-7,and the separation factors all exceed 1.20.Moreover,the 3-,6-position of the derivatives with electron-withdrawing substituent have better chiral recognition performance than those with electron-donating substituent.In addition,for the chiral compounds of cobalt tris(acetylacetonate)acid(Rac-6),flavanone(Rac-7)and binaphthol(Rac-9),the regioselective substitution of chitin derivatives has better chiral recognition performance than cellulose derivatives,and the separation factor reached 1.40,1.31,and 1.14,respectively.This indicates that the unique amide group of 2-position in chitin glycoammonia unit has special structural advantages for the recognition of some chiral compounds such as cobalt tris(acetylacetonate),flavone and binaphthol.