Chiral recognition ability of curdlan triacetate: solvent and temperature effects

Abstract

The chiral recognition ability of the chiral stationary phase (CSP) consisting of curdlan (beta-1,3-glucan) triacetate coated on silica gel was clearly changed by the contacting solvents and heat treatment. The chiral recognition ability significantly decreased, particularly at temperatures above 45 degrees C, depending on the racemates. The molecular weight of the curdlan triacetate slightly influenced its ability. The recognition abilities of curdlan tricetate that was lost by heat treatment were partially recovered by contact with methanol. However, when it was contacted with ethanol a different selectivity was observed. The labile chiral recognition ability of curdlan triacetate is in striking contrast to the very stable chiral recognition of cellulose (beta-1,4-glucan) triacetate (Chiralcel OA). This difference may be ascribed to the conformational stability of the acetates consisting of curdlan (beta-1,3-glucan) and cellulose (beta-1,4-glucan) with different sugar linkages.

Efficient Separation of Enantiomers Using Stereoregular Chiral Polymers

“…In addition to cellulose and amylose, other polysaccharides, such as chitin, chitosan, xylan, dextran, etc., have also been used to prepare the CSPs for enantioseparation. ,,− Among these, the 3,5-dimethylphenylcarbamates of chitosan and xylan exhibited relatively higher recognition abilities for some racemates compared to those on the cellulose and amylose derivatives, implying the potential to develop new CSPs with a high chiral recognition ability. The chitosan possesses a structure similar to that of the cellulose except for the groups at the 2 position: the former has an amino group and the latter a hydroxy group. , The treatment of chitosan with a phenyl isocyanate affords a 3,6-diphenylcarbamates-2-urea derivative ( 82 in Figure ).…”

Properties, Chemistry, and Applications of the Bioactive Polysaccharide Curdlan

“…Toga and co-workers 64 synthesized curdlan triacetate (Figure 7) using an acid-catalyzed esterification technique. Dry curdlan powder was first suspended in warm water for 1 h to activate it toward esterification.…”

“… 1 H NMR spectrum of curdlan triacetate . Reprinted with permission from Toga, Y.; Ichida, A.; Shibata, T.; Tachibana, K.; Namikoshi, H. Chiral recognition ability of curdlan triacetate: solvent and temperature effects.…”

Structure Control of Polysaccharide Derivatives for Efficient Separation of Enantiomers by Chromatography

“…Besides the cellulose and amylose derivatives, various carbamate derivatives of polysaccharides, such as chitin, chitosan, galactosamin, xylan, dextran, curdlan, and inulin, have been prepared and applied as CSPs for HPLC. ,− Their recognition abilities significantly depend on the linkage positions, anomeric configurations, and nature of the monomeric units. Among them, the chitin ( 32 ) , and chitosan ( 33 ) derivatives as shown in Figure exhibited a relatively high recognition ability for a wide range of chiral compounds including drugs.…”