The Composition and Conformation of Sugars in Solution

The conformations of the aldoses in solution, and the compositions of the equilibrium mixtures formed from aldoses after dissolution in water, have been determined by NMR spectroscopy. Calculations based on non‐bonded interactions and on the anomeric effect account for the observed conformations, and allow an approximate prediction of the α:β ratio of pyranoses in equilibrium and of the extent of anhydride formation from sugars in acid solution. In certain circumstances the furanose forms are more stable than the pyranose forms.