Conformational Properties of Aryl S-Glucosides in Solution.

Bhavesh Deore, Ryan W Kwok, Malika Toregeldiyeva, Jesús T Vázquez, Mateusz Marianski, Carlos A Sanhueza

The Journal of organic chemistry 2023 Nov 17

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The conformational study of saccharides and glycomimetics in solution is critical for a comprehensive understanding of their interactions with biological receptors and enabling the design of optimized glycomimetics. Here, we report a nuclear magnetic resonance (NMR) study centered on the conformational properties of the hydroxymethyl group and glycosidic bond of four series of aryl S-glucosides. We found that in acetyl-protected and free aryl S-β-glucosides, the rotational equilibrium around the C5-C6 bond (hydroxymethyl group) exhibits a linear dependence on the electronic properties of the aglycone, namely, as the aryl's substituent electron-withdrawing character increases, the dominance of the gg rotamer declines and the gt contribution rises. Likewise, the conformational equilibrium around the glycosidic C1-S bond also depends on the aglycone's electronic properties, where glucosides carrying electron-poor aglycones exhibit stiffer glycosidic bonds in comparison to their electron-rich counterparts. In the case of the α anomers, the aglycone's effect over the glycosidic bond conformation is like that observed on their β isomers; however, we observe no aglycone's influence over the hydroxymethyl group conformation in the α-glucosides.

Citation

Bhavesh Deore, Ryan W Kwok, Malika Toregeldiyeva, Jesús T Vázquez, Mateusz Marianski, Carlos A Sanhueza. Conformational Properties of Aryl S-Glucosides in Solution. The Journal of organic chemistry. 2023 Nov 17;88(22):15569-15579