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Resonance assignments of diastereotopic CH 2 protons in the anomeric side chain of selenoglycosides by means of 2 J (Se,H) spin‐spin coupling constants
Author(s) -
Rusakov Yury Yu.,
Krivdin Leonid B.,
Kumar Ambati Ashok,
Szilágyi László,
Kövér Katalin E.
Publication year - 2012
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.3824
Subject(s) - chemistry , geminal , coupling constant , conformational isomerism , anomer , substituent , crystallography , stereochemistry , side chain , resonance (particle physics) , computational chemistry , atomic physics , molecule , physics , organic chemistry , quantum mechanics , polymer
Unambiguous resonance assignments of diastereotopic CH 2 protons in the anomeric side chain of nine alkyl‐ and aralkylselenoglycosides have been carried out on the basis of experimental CPMG‐HSQMBC measurements and theoretical second order polarization propagator approach (SOPPA) calculations of geminal 77 Se‐ 1 H spin‐spin coupling constants involving diastereotopic pro‐R and pro‐S protons. Theoretical conformational analyses have been performed at the MP2/6‐311G** level. The conformational space of each of the selenoglycosides under study could be adequately described as a mixture of six interconverting conformers with the molar fractions depending on the nature of the side chain substituent at the selenium atom. The good agreement observed between measured and the weighted conformational averaged values of the calculated coupling constants provides a basis for reliable diastereotopic assignments in this type of carbohydrate structures. Copyright © 2012 John Wiley & Sons, Ltd.