Abstract
The crystal structure of the brominated compound, C35Ha9OisBr, has been determined in order to confirm the molecular structure and to determine the absolute configuration of paeoniflorin, C23H28Olb a monoterpene glucoside isolated from Paeonia albiflora Pallas. The crystals are orthorhombic with space group P2~2121 and the unit cell dimensions are a= 13.58, b= 21.74, c= 12.61/1,; Z=4. The crystal structure was solved by the heavy atom method and refined by the block-matrix least-squares method. The final R value for 1844 observed reflexions was 0.107. The molecular structure of paeoniflorin deduced from the present X-ray study of the brominated compound was in complete agreement with the proposed structure, a novel glucoside of a monoterpene of the pinane group. The absolute configuration was determined by the use of the anomalous dispersion effect of the bromine atom for Cu K~ radiation, which is compatible with the fact that the glucosidic residue is of D-glucose.
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