Affiliation: | a Research Group for Antibiotics, Hungarian Academy of Sciences, L. Kossuth University, PO Box 70, H-4010 Debrecen, Hungary b Department of Organic Chemistry, L. Kossuth University, PO Box 20, H-4010 Debrecen, Hungary |
Abstract: | Relatively few details are known about the conformational preferences of hydroxyl groups in carbohydrates in water solution, though these would be informative about solvation and H-bonding. We show that highly concentrated solutions of sucrose and trehalose exhibit surprisingly well-resolved 1H NMR spectra in a deuterium oxide–water solvent mixture at subzero temperatures. Measurement conditions are suitable to extract nearly all homonuclear and, for the first time, heteronuclear coupling constants of OH groups of carbohydrates in their natural abundance. For 2,3JHO,C coupling constants new, powerful variants of HETLOC and HECADE techniques were applied. The present data do not support the presence of persistent H-bonds in these two cryogenic disaccharides. |