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Characteristic 1H NMR spectra of β-d-ribofuranosides and ribonucleosides: factors driving furanose ring conformations† † Electronic supplementary information (ESI) available. CCDC 2164567. For ESI and crystallographic data in CIF or other electronic format see DOI: https://doi.org/10.1039/d2ra04274f

ABSTRACT: A series of β-d-ribofuranosides and ribonucleosides fused with 2,3-O-isopropylidene ring was synthesized and studied in terms of their conformational preferences. Based on the 1H NMR spectra, DFT calculations, and X-ray analysis the E0-like and E4-like conformations adopted by these furanosides are identified. The 3E-like and 2E-like conformations are assigned to ribonucleosides without the 2,3-O-isopropylidene group. The studies are supported by analysis of the structural data of β-d-ribofuranosides and ribonucleosides deposited in the Cambridge Crystallographic Data Center (CCDC) database.† Finally, the factors influencing the conformational preferences of the furanose ring with the β-d-ribo configuration are indicated. These are the unfavorable ecliptic orientation of the 2-OH and 3-OH groups, the 1,3-pseudodiaxial interaction of the aglycone and terminal hydroxymethyl group and the endo-anomeric effect. It is also proved that the exo-anomeric effect acts in β-d-ribofuranosides. The 2,3-O-isopropylidene group locks β-d-ribofuranosides in the E0-like conformation whereas ribonucleosides in the E4-like conformation. The conformational preferences of β-d-ribofuranosides are determined by the anomeric effect.

SUBMITTER: Walczak D

PROVIDER: S-EPMC9557318 | biostudies-literature | 2022 Oct

REPOSITORIES: biostudies-literature

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