CRYSTAL AND MOLECULAR-STRUCTURE OF METHYL IDEOXY-BETA-D,L-GLYCERO-HEX-4-ENOZ-2-ULOPYRANOSIDE

The unsaturated monosaccharide C9H14O5 crystallizes in the monoclinic space group Cc (Z=4). The unit cell parameters are: a=13.905(3), b=7.3 56(1), c=11.522(2)Angstrom, beta=123.54(3)degrees. The structure was s olved by direct methods and refined by anisotropic full-matrix least-s quares method. The final R (wR) factors were 0.032 (0.042) for 1452 ob served reflections, The dihydropyranone ring adopts a deformed sofa co nformation with C2 atom deviating 0.477(2)Angstrom from the least-squa res plane and methoxy and dioxolanyl substituents are in pseudoaxial a nd pseudoequatorial positions, respectively. The average planes of six -membered and five-membered rings are approximately co-planar.