(2R,3S)-2-Benzyl-3-(2,3,4,6-tetra-O-acetyl-β-d-glucopyranosyloxy)butanolide

The title compound, C25H30O12, which demonstrates a significant hepatoprotective effect, has comparable geometrical parameters to those of similar compounds. The absolute configuration of the title compound, viz. 2R,3S, was identified from the Flack parameter of 0.05 (17) and the Hooft parameter of 0.04 (6).

The title compound, C 25 H 30 O 12 , which demonstrates a significant hepatoprotective effect, has comparable geometrical parameters to those of similar compounds. The absolute configuration of the title compound, viz. 2R,3S, was identified from the Flack parameter of 0.05 (17) and the Hooft parameter of 0.04 (6).
In order to determine the absolute configuration of the title compound, the data collection was performed using Cu Kα.

Refinement
All H atoms were placed in geometrically idealised positions and constrained to ride on their parent atoms with C-H distances in the range of 0.95-1.00 Å, with a displacement parameter U iso set to 1.2 (CH and CH 2 ) or 1.5(CH 3 ) times U eq of the parent atom.

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors (gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.