Zusammenhang zwischen Konformation der Glucopyranoseeinheiten und Molekülkonfiguration der Amylose

Relationship between the Conformation of the Glucopyranoside Units and the Molecular Configuration of Amylose. As a consequence of the tetrahedral valence angle as well as of the interactions between the H and OH groups attached to the C atoms the most probable form of D‐glucopyranose is the Cl conformation. The rotation around the oxygen‐bridge between the two glucopyranose units in maltose is hindered to such an extent that the existence only of that form seems to be probable, in which all similar substituents are placed on the same side of the molecule. The non‐bonded interaction between H–1 and H–4′ is diminished by a slight twisting of the plane of the two rings about the glucosidic bond in opposite directions. This arrangement renders possible the forming of O–2… O–3′ hydrogen bonds which contributes to the stabilization of the helical structure. Therefore under such conditions when this H bond is stable, the homologues of maltose – amylose too – achieve a helical molecular configuration.