Macrocyclic substructure of tricolorin A -: The first crystal structure of a resin glycoside

The structure of a tricolorin A derivative (11S)-11-[[4, 6-O-benzylidene-beta-D-glucopyranosyl-(1 --> 2)-3. 4-O-isopropylidene-beta-D-fucopyranosyl]oxy]hexasecanoic acid 3(gluc)-lactone 2, a member of the resin glycosides, has been determined. This crystal structure is the first example for this class of natural products. At 100 K the lattice parameters in monoclinic space group P2(1) are: a = 22.502(5) A, b = 17.339(4) A, c = 25.011(5) A, beta = 92.49(3)degrees, V = 9749(3) A(3), Z = 10. M = 705.67, e = 1.202 Mg m(-3), mu = 0.087 mm(-1), F(000)=3824. The five crystallographically independent molecules show upon superpositioning the expected preservation of the glycosidic link geometry, however the alkyl part of the macrocyclic ring expresses a larger degree of freedom while conserving gauche and anti conformations in six of nine torsion angles.