4-Methoxy-5-[4-(4-methoxy-1,3-benzodioxol-5-yl)perhydro-1H,3H-furo[3,4-c]furan-1-yl]-1,3-benzodioxole

The 1,3-benzodioxole ring systems in the title compound, C22H22O8, are almost planar. The perhydrofurofuranyl system linking them adopts a distorted double-envelope conformation. Supramolecular aggregation is effected by C—H⋯O, C—H⋯π and π–π [centroid–centroid distance of 3.755 Å, interplanar distance of 3.633 Å and dihedral angle of 14.6°] interactions.


Experimental
Ethanolic extract of powdered root of Ecbolium Viride (Forssk) spring was charged on a column and eluted with solvents ranging from non-polar to polar at the rate of 30 drops per minute. 34 fractions were collected, each of volume 25 ml with supplementary materials sup-2 different ratios of solvents. The fractions collected were monitored by thin layer chromatography (TLC) for homogenity and similar fractions were pooled together. The title compound was isolated from one such pool. Diffraction quality crystals of the title compound were obtained by recrystallization from chloroform.

Refinement
Hydrogen atoms were positioned geometrically (aromatic C-H = 0.93 Å, methine C-H = 0.98 Å, methylene C-H = 0.97Å & methyl C-H = 0.96 Å) and refined using a riding model. The hydrogen atom isotropic displacement parameters were fixed; U iso (aromatic H, methine H, methylene H) = 1.2 times U eq of the parent atom; U iso (methyl H) = 1.5 times U eq of the parent atom.
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. Fig. 1. The asymmetric unit of (I) with the atoms labelled and displacement ellipsoids depicted at the 50% probability level for all non-H atoms. H-atoms are drawn as spheres of arbitrary radius.

Special details
Experimental. Psi-scan (North, et al.,1968). Number of psi-scan sets used was 3 Theta correction was applied. Averaged transmission function was used. No Fourier smoothing was applied. 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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å 2 )
x y z U iso */U eq C1