Acta Cryst. (2006). E62, o130-o132  [ doi:10.1107/S1600536805040328 ]

12-(1,1-Dimethyl-2-propenyl)-5,9,10-trihydroxy-2,2-dimethyl-2H,6H-pyrano[3,2-b]xanthen-6-one

H.-K. Fun, S.-L. Ng, I. A. Razak, N. Boonnak and S. Chantrapromma

Abstract: In the title compound, C₂₃H₂₂O₆, the xanthene ring system is essentially planar and the chromene ring is in a screw-boat conformation. Position 1 of the 1,1-dimethyl-2-propenyl substituent is coplanar with the attached ring. O-HO intramolecular hydrogen bonds are observed in the structure. The molecules form centrosymmetric hydrogen-bonded dimers via weak intermolecular C-HO interactions. The molecules are linked by intermolecular O-HO hydrogen bonds to form a one-dimensional chain along [010].

Online 10 December 2005

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