THE MODULATED STRUCTURE OF 4-HYDROXYPHENYL DROXY-2-METHYLENEBUTANOYL]-BETA-D-GLUCOPYRANOSIDE, C17H22O10

The crystal structure of 4-hydroxyphenyl 6-O[(3-R)-3 droxy-2-methylene butanoyl]-beta-D-glucopyranoside, C17H22O10, P2(1), a = 12.121(2) Angs trom, b = 5.090(1) Angstrom, c = 31.316(4) Angstrom, beta = 90.61(1)de grees, Z = 4, is a modulation of an idealised parent structure of orth orhombic P2(1)2(1)2(1) symmetry and can be described as two pseudo sym metry re lated substructures of exact P12(1)1 symmetry. Each substruct ure contains hydrogen-bonded layers perpendicular to c and layers fro m separate substructures alternate along c. To a first approximation t he layers of separate substructures are essentially geometrically iden tical, the modulation being dominantly a distortion of the unit cell a nd not the layers. A final value of R(F) = 0.062 was obtained for the 2397 independent reflections used in refinement, I(h) > 3 sigma(I(h)).