Separation of derivatized glucoside anomers using supercritical fluid chromatography

Preparative scale supercritical fluid chromatography was used to separate derivatized anomeric monosaccharides. Methyl 2,3,4,6-tetra-O-benzoyl-α-d-glucopyranoside and methyl 2,3,4,6-tetra-O-benzoyl-β-d-glucopyranoside were synthesized by benzoyl derivatization of the parent anomerically pure monosaccharides. The elution profiles of each anomer were studied, suggesting that separation was possible. Mixtures of the compounds were then prepared at different ratios and separation was achieved using carbon dioxide/ethanol mixtures as the mobile phase and GreenSep™ 5 micron particle size silica as the stationary phase. Ethanol co-solvent in the mobile phase was required to give a successful separation of the anomers however over the range 6.5-10.4 wt% ethanol concentration studied here there was little variation in the degree of separation. In fractionation trials, separation of mixtures into fractions with >98% purity was achieved, with recoveries greater than 96%.