Constituents ofPaulownia tomentosa stem (III): The crystal structure of methyl 5-hydroxy-dinaphtho [1,2-2′,3′] furan-7, 12-dione-6-carboxylate

Abstract

The molecular structure of a natural compound was determined by single crystal X-ray diffraction analysis. The compound was isolated by methanol extraction and repeated chromatography from the stem ofPaulownia tomentosa. Yellow prismatic crystals of the compound, which were recrystallized from tetrahydrofuran, are triclinic, witha=7.310(6),b=10.753(6),c=11.586(5) Å, α=93.30(6), β=105.62(10), γ=109.49(7)°,D _x =1.514,D _m =1.51 g/cm³, space group$P\bar 1$ andZ=2. The structure was solved by direct method, and refined by least-squares procedure to the finalR-value of 0.032 for 1271 independent reflections (F≤3σ(F)). The compound is one of new furanquinone analogue. The molecule has a nearly planar conformation with an intramolecular hydrogen bond. In the crystal, the planar molecules are arranged as a parallel sheet-like pattern, and these stackings are stabilized by the O-H…O type intermolecular hydrogen bonds. The other intermolecular contacts appear to be the normalvan der Waals interactions.