Development of Selective Synthetic Reactions of Sugars Based on Their Complexation.

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(1) Development of Selective Synthetic Reactions of Sugars.Ribose solubilized in carbon tetrachloride via hydrogen-bonding complexation with resorcinolaldehyde cyclotetramer was found to undergo methylation with methanol to give methyl betaribofuranoside highly stereoselectively.(2) Molecular Recognition of Sugars via Hydrogen-Bonding.Resorcinol-aldehyde cyclotetramer was found to discriminate slight structural differences in sugars in their hydrogen-bonding fixation. It was thus possible to differentiate fructose vs glucose and alpha anomer of methyl glucopyranoside from the beta anomer.(3) Determination of Sugar Conformation Based on Induced Circular Dichroism.The sugar complexes of resorcinol-aldehyde cyclotetramer exhibit circular dichroism with split Cotton effects. The signs of the Cotton effects could be correlated with the conformation of the sugar, wither C1 or 1C.(4) Development of a New Class of Sugar Binder.A new class of macrocycle based on an octaazamacrocycle was prepared. It was functionalized by eight long-alkyl chains having polar OH groups. This macrocycle in chloroform was found to extract various polar materials including sugars from water. Not only monosaccharides (glucose and fructose) but also disaccharides could be solubilized in this manner.This work thus opens the door to an entirely new field of sugar chemistry, based on apecific host-guest interactions in apolar organic media. This concept can be applied to the synthetic, analytical, structural, and organic aspects of the sugars.