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[摘要]:synthesized and analyzed by NMR and CD techniques. As in their b-anomer series, the rotational populations of the hydroxymethyl group involved in the inter-glycosidic linkage (torsion angle w) are shown to depend on the aglycon and the solvent. However, for this a-anomer series the rotational dependence arises directly from steric effects. steric parameters, but not Taft's steric parameters (b-anomers), of the alkyl substituents were obsd. The conformational domino effect previously predicted from alkyl b-(1?)-diglucopyranosides is now supported by the conformational properties of their a-anomers, the anomeric configuration controlling the domino effect. In addn., the depend weakly on the structure of the aglycon and the anomeric configuration. |
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