Preparation of 6-amino-6-deoxy cellulose and its derivatives used as chiral separation materials.

In order to find a facile and practical method to synthesize amino cellulose in bulk with high regional selectivity and high degree of substitution, the reaction conditions to brominate cellulose and to reduce azido group were carefully studied and some interesting phenomena were observed. With the optimized method, 6-amino-6-deoxy cellulose could be easily prepared with very simple separation techniques. The degree of substitution of the amino group amounted to 0.97 which was determined by 1H NMR spectrum of 6-benzamido-6-deoxy cellulose. Moreover, the amino group was evidenced to be at the C6 of glucose unit by 1H-1H COSY NMR and 1H-13C HSQC NMR spectra. In addition, three cellulose 6-acetamido-6-deoxy-2,3-bis(phenylcarbamate)s were prepared from the 6-amino-6-deoxy cellulose prepared with the techniques optimized in the present study. The developed cellulose derivatives were used as chiral selectors with which chiral stationary phases (CSPs) were prepared. The CSPs exhibited enantioseparation power to some chiral compounds.

Performances comparison of enantiomeric separation materials prepared from shrimp and crab shells.

Previously reported studies demonstrate that many chitin/chitosan derivatives are promising for enantioseparation of chiral compounds. The aim of the present study is to investigate influence of the chitin sources on performances of the chitosan type enantiomeric separation materials. Therefore, the chitosans were prepared from crab and shrimp shells, from which two sets of chiral selector, i.e. chitosan bis(3,5-dimethylphenylcarbamate)-(octanamide)s and chitosan bis(3,5-dichlorophenylcarbamate)-(octanamide)s were synthesized. The chitosan bis(3,5-dimethylphenylcarbamate)-(octanamide)s, respectively, derived from crab and shrimp shells were close in swelling capacity and enantioseparation capability, and the same feature was found for the other two chiral selectors of chitosan bis(3,5-dichlorophenylcarbamate)-(octanamide). On the other hand, although most of the chiral analytes were eluted out in the same elution order, there were two analytes were in reversed elution orders when separated by the two chiral stationary phases of chitosan bis(3,5-dichlorophenylcarbamate)-(octanamide). Based on the observed results, we conclude that enantiomeric separation materials may be developed either with shrimp chitin or crab chitin, depending on the source accessibility.