Experimental and computational studies of nJ(77Se,1H) selenium–proton couplings in selenoglycosides

✍ Scribed by Katalin E. Kövér; Ambati Ashok Kumar; Yury Yu. Rusakov; Leonid B. Krivdin; Tünde-Zita Illyés; László Szilágyi

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 240 KB
• Volume: 49
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.2731

✦ Synopsis

Abstract

Selenoglycosides are important starting materials in synthetic carbohydrate chemistry and play a role in biological interactions as well. Both aspects are influenced by the conformation around the glycosidic bond. Here, we present a combined experimental and computational approach to measure and evaluate ^n^J(^77^Se,^1^H) coupling constants for their use in conformational analysis. The measurements were carried out using a modified CPMG‐HSQMBC pulse scheme which yields pure absorption antiphase multiplets to allow accurate determination of the ^n^J~XH~ values regardless of the size of the proton‐proton couplings. Theoretical calculations were performed at the Second‐Order Polarization Propagator Approach (SOPPA) level. Population‐averaged values calculated for geminal and vicinal couplings are in a good agreement with experiment indicating an adequate theoretical level of the calculations. Experimental observations and computations alike have indicated that two‐bond ^77^Se‐^1^H couplings, ^2^J(^77^Se,^1^H), in a H1‐C1‐Se‐X moiety are very sensitive to the torsion angle around the C1‐Se‐bond and will, therefore, be useful for conformational studies. Copyright © 2011 John Wiley & Sons, Ltd.