Norihiro Ikemoto

Ferric chloride, an anomerization catalyst for the preparation of alkyl α-glycopyranosides

Anhydrous FeCl3 in CH2Cl2 has been found to readily anomerize β-glycopyranosides to their corresponding α-anomers in good yields and selectivities at room temperatures. Acetyl- and benzoyl-protected oxygen sugars yielded the best results.

Oligosaccharide microscale analysis by circular dichroic spectroscopy: Reference spectra for chromophoric d-fructofuranoside derivatives

The microscale analytical method that is being developed in this group for the structure determination of oligosaccharides yields monosaccharide derivatives bearing two types of chromophores suitable for exciton-coupling, namely, 4-bromobenzoate (lambda max 245 nm) and 4-methoxycinnamate (lambda max 311 nm). Comparison of the circular dichroic (CD) curves of these subunits to those in the reference library allows for the determination of the sugar identities, linkage positions, and the absolute configurations. The 32 possible derivatives of methyl alpha- and beta-D-fructofuranosides bearing four chromophores were prepared and their CD spectra recorded. These data serve to extend the CD library, which already encompasses pyranoside derivatives with the gluco-, galacto-, and manno-configurations, and extend the utility of this methodology to the analysis of fructose-containing oligosaccharides.