(1S,4S,5S,8R)-8-Nitrooxy-2,6-dioxabicyclo[3.3.0]octan-4-yl 3,4,5-triacetoxybenzoate

In the title compound, C19H19NO13, one of the two fused furanose rings adopts an envelope conformation whereas the other displays a twisted conformation. The crystal structure is stabilized by intermolecular C—H⋯π interactions between a methine H atom and the triacetoxyphenyl ring of an adjacent molecule, and by weak non-classical intermolecular C—H⋯O hydrogen bonds.

In the title compound, C 19 H 19 NO 13 , one of the two fused furanose rings adopts an envelope conformation whereas the other displays a twisted conformation. The crystal structure is stabilized by intermolecular C-HÁ Á Á interactions between a methine H atom and the triacetoxyphenyl ring of an adjacent molecule, and by weak non-classical intermolecular C-HÁ Á ÁO hydrogen bonds.

Comment
The title compound is synthesized by esterification of 3,4,5-triacetoxybenzoic acid with Isosorbide Mononitrate.It can be rapidly metabolized to 3,4,5-trihydroxybenzoic acid and Isosorbide Mononitrate in vivo (Carini et al.,2002). 3,4,5-trihydroxybenzoic acid is a bioactivesubstance which can scavenge oxygen free radicals and Isosorbide Mononitrate is a classical nitric oxide-donor drug. This bifunctional molecule may have better bioactivity but do bring fewer side effect.
The molecule is built up from the isosorbide mononitrate skeleton substituted on C4 by the 3,4,5-triacetoxybenzoate ( Owing to the know absolute configuration of the starting isosorbide mononitrate, the absolute configuration of the title compound could be deduced to be 1S,4S,5S,8R. The molecular packing is stabilized by weak non-classical intermolecular C-H···O hydrogen bonds and by intermolecular C-H···π interaction between methine H atom of perhydrofurofuranyl system and the triacetoxyphenyl ring of an adjacent molecule (Table 1, Cg1 is the centroid of C42-C47 phenyl ring).

Refinement
All H atoms were positioned geometrically and treated as riding with aromatic C-H = 0.93 Å, methine C-H = 0.98 Å, methylene C-H = 0.97Å & methyl C-H = 0.96 Å. The H atom isotropic displacement parameters were fixed; U iso (aromatic H, methine H) = 1.2 times U eq of the parent atom; U iso (methylene H, methyl H) = 1.5 times U eq of the parent atom.
supplementary materials sup-2 In the absence of significant anomalous scattering, the absolute configuration could not be reliably determined and then the Friedel pairs were merged and any references to the Flack parameter were removed. The enantiomer has been assigned by reference to unchanging chiral centres in the synthetic procedure.

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 Rfactors(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.