Hydrogen bonding in the crystal structure of alpha,beta-panose.

The crystal structure of panose, O-alpha-D-glucopyranosyl-(1----6)-O-alpha-D-glucopyranosyl-(1----4)-D-gl ucose, C18H32O16, has been refined using low-temperature, 123 K, CuK alpha X-ray data. Difference syntheses and least-squares refinement showed a 16% substitution of alpha-panose by the beta anomer. All the hydrogen atoms were located on difference synthesis with the exception of one attached to the low occupancy (beta) O-1". The final R-factor was 0.036 for 2135 observed structure amplitudes. The molecular conformation is stabilized by two interresidue intramolecular hydrogen bonds. All the hydroxyls and glycosidic oxygen atoms are involved in the hydrogen bonding, which is a two-dimensional network formed from finite and infinite chains.