Conformational effects due to stereochemistry and C3-substituents in xylopyranoside derivatives as studied by NMR spectroscopy
Ronnols, Jerk ; Manner, Sophie LU ; Ellervik, Ulf LU
and Widmalm, Goran
(2014)
In Organic and Biomolecular Chemistry
12(40).
p.8031-8035
- Abstract
- Glycosaminoglycans contain a beta-D-xylopyranose residue at its reducing end, which links the polysaccharide to the protein in proteoglycans. 2-Naphthyl beta-D-xylopyranosides have shown inhibition of tumor growth and we herein investigate conformation and dynamics of compounds structurally and stereochemically modified at the C3 position as well as the influence of solvent. The 3-deoxygenated compound, the 3-C-methyl-substituted beta-D-xylopyranoside, beta-D-ribopyranoside, the 3-C-methyl-substituted beta-D-ribopyranoside as well as 2-naphthyl beta-D-xylopyranoside were analyzed by NMR spectroscopy. Conformational equilibria were dependent on the solvent of choice, either methanol-d(4) or chloroform-d, with mainly C-4(1) and C-1(4)... (More)
- Glycosaminoglycans contain a beta-D-xylopyranose residue at its reducing end, which links the polysaccharide to the protein in proteoglycans. 2-Naphthyl beta-D-xylopyranosides have shown inhibition of tumor growth and we herein investigate conformation and dynamics of compounds structurally and stereochemically modified at the C3 position as well as the influence of solvent. The 3-deoxygenated compound, the 3-C-methyl-substituted beta-D-xylopyranoside, beta-D-ribopyranoside, the 3-C-methyl-substituted beta-D-ribopyranoside as well as 2-naphthyl beta-D-xylopyranoside were analyzed by NMR spectroscopy. Conformational equilibria were dependent on the solvent of choice, either methanol-d(4) or chloroform-d, with mainly C-4(1) and C-1(4) conformations present but also skew conformations to some extent. Intramolecular hydrogen bonding was concluded to be important for the 3-C-methyl-substituted beta-D-xylopyranosides in the non-polar solvent. Dynamic NMR (DNMR) spectroscopy was carried out for the 3-deoxygenated compound, which at 25 degrees C in methanol-d(4) exists with equally populated states of the C-4(1) and the C-1(4) conformations, but at -100 degrees C only a few percent is present of the latter. Using C-13 NMR detection for DNMR, resonance lines were shown to broaden at -40 degrees C and to sharpen again below -90 degrees C, without the emergence of a second set of NMR resonances, a typical behavior for an unequally populated equilibrium. The enthalpy and entropy activation barriers were calculated and resulted in Delta H-double dagger = 47.3 kJ mol(-1) and Delta S-double dagger = 54 J mol(-1) K-1. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/4796225
- author
- Ronnols, Jerk
; Manner, Sophie
LU
; Ellervik, Ulf
LU
and Widmalm, Goran
- organization
- publishing date
- 2014
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Organic and Biomolecular Chemistry
- volume
- 12
- issue
- 40
- pages
- 8031 - 8035
- publisher
- Royal Society of Chemistry
- external identifiers
-
- wos:000342992400019
- scopus:84907494632
- pmid:25183410
- ISSN
- 1477-0539
- DOI
- 10.1039/c4ob01422g
- language
- English
- LU publication?
- yes
- id
- 9259c25e-36dd-46c7-b354-a2b610a18093 (old id 4796225)
- date added to LUP
- 2016-04-01 10:05:57
- date last changed
- 2024-02-21 07:59:29
@article{9259c25e-36dd-46c7-b354-a2b610a18093,
abstract = {{Glycosaminoglycans contain a beta-D-xylopyranose residue at its reducing end, which links the polysaccharide to the protein in proteoglycans. 2-Naphthyl beta-D-xylopyranosides have shown inhibition of tumor growth and we herein investigate conformation and dynamics of compounds structurally and stereochemically modified at the C3 position as well as the influence of solvent. The 3-deoxygenated compound, the 3-C-methyl-substituted beta-D-xylopyranoside, beta-D-ribopyranoside, the 3-C-methyl-substituted beta-D-ribopyranoside as well as 2-naphthyl beta-D-xylopyranoside were analyzed by NMR spectroscopy. Conformational equilibria were dependent on the solvent of choice, either methanol-d(4) or chloroform-d, with mainly C-4(1) and C-1(4) conformations present but also skew conformations to some extent. Intramolecular hydrogen bonding was concluded to be important for the 3-C-methyl-substituted beta-D-xylopyranosides in the non-polar solvent. Dynamic NMR (DNMR) spectroscopy was carried out for the 3-deoxygenated compound, which at 25 degrees C in methanol-d(4) exists with equally populated states of the C-4(1) and the C-1(4) conformations, but at -100 degrees C only a few percent is present of the latter. Using C-13 NMR detection for DNMR, resonance lines were shown to broaden at -40 degrees C and to sharpen again below -90 degrees C, without the emergence of a second set of NMR resonances, a typical behavior for an unequally populated equilibrium. The enthalpy and entropy activation barriers were calculated and resulted in Delta H-double dagger = 47.3 kJ mol(-1) and Delta S-double dagger = 54 J mol(-1) K-1.}},
author = {{Ronnols, Jerk and Manner, Sophie and Ellervik, Ulf and Widmalm, Goran}},
issn = {{1477-0539}},
language = {{eng}},
number = {{40}},
pages = {{8031--8035}},
publisher = {{Royal Society of Chemistry}},
series = {{Organic and Biomolecular Chemistry}},
title = {{Conformational effects due to stereochemistry and C3-substituents in xylopyranoside derivatives as studied by NMR spectroscopy}},
url = {{http://dx.doi.org/10.1039/c4ob01422g}},
doi = {{10.1039/c4ob01422g}},
volume = {{12}},
year = {{2014}},
}