Synthesis and conformational analysis of methyl 2‐O‐(α‐D‐Mannopyranosyl)‐α‐D‐mannopyranoside

NMR experiments such as steady state NOE experiments and spin lattice ¹H relaxation time measurements were performed on the synthetic disaccharide 10 that constitutes part of the polysaccharide backbone in fungal mannans. The spectro‐scopic data were compared with a theoretical model that is based upon the HSEA force field and statistical mechanics, taking into account the flexibility around the glycosidic linkage. Potential energy calculations were performed with a modified version of the GESA program in order to derive the global minimum conformation of disaccharide 10 and to calculate ensemble average NOE and T₁ values by averaging all energetically accessible conformational microstates, using a normalized Boltzmann distribution function. The fit between experimental and theoretical results improved significantly when we applied a dynamic model instead of a single state model based solely on the global minimum conformation of 10. Efficient synthesis of 10 was achieved by a recently published protocol for the in situ activation of thioglycosides.