Acta Crystallographica Section C

Crystal Structure Communications

Volume 58, Part 3 (March 2002)

organic compounds

bk1627 scheme

Acta Cryst. (2002). C58, o195-o198 [ doi:10.1107/S0108270102000689 ]

Three ginkgolide hydrates from Ginkgo biloba L.: ginkgolide A monohydrate, ginkgolide C sesquihydrate and ginkgolide J dihydrate, all determined at 120 K

J.-P. Zhao, I. Muhammad, D. C. Dunbar, I. A. Khan, N. H. Fischer and F. R. Fronczek

Abstract: A low-temperature structure of ginkgolide A monohydrate, (1R,3S,3aS,4R,6aR,7aR,7bR,8S,10aS,11aS)-3-(1,1-dimethylethyl)-hexahydro-4,7b-dihydroxy-8-methyl-9H-1,7a-epoxymethano-1H,6aH-cyclopenta[c]furo[2,3-b]furo[3',2':3,4]cyclopenta[1,2-d]furan-5,9,12(4H)-trione monohydrate, C₂₀H₂₄O₉·H₂O, obtained from Mo K [alpha] data, is a factor of three more precise than the previous room-temperature determination. A refinement of the ginkgolide A monohydrate structure with Cu K [alpha] data has allowed the assignment of the absolute configuration of the series of compounds. Ginkgolide C sesquihydrate, (1S,2R,3S,3aS,4R,6aR,7aR,7bR,8S,10aS,11S,11aR)-3-(1,1-dimethylethyl)-hexahydro-2,4,7b,11-tetrahydroxy-8-methyl-9H-1,7a-epoxymethano-1H,6aH-cyclopenta[c]furo[2,3-b]furo[3',2':3,4]cyclopenta[1,2-d]furan-5,9,12(4H)-trione sesquihydrate, C₂₀H₂₄O₁₁·1.5H₂O, has two independent diterpene molecules, both of which exhibit intramolecular hydrogen bonding between OH groups. Ginkgolide J dihydrate, (1S,2R,3S,3aS,4R,6aR,7aR,7bR,8S,10aS,11aS)-3-(1,1-dimethylethyl)-hexahydro-2,4,7b-trihydroxy-8-methyl-9H-1,7a-epoxymethano-1H,6aH-cyclopenta[c]furo[2,3-b]furo[3',2':3,4]cyclopenta[1,2-d]furan-5,9,12(4H)-trione dihydrate, C₂₀H₂₄O₁₀·2H₂O, has the same basic skeleton as the other ginkgolides, with its three OH groups having the same configurations as those in ginkgolide C. The conformations of the six five-membered rings are quite similar across ginkgolides A-C and J, except for the A and F rings of ginkgolide A.

Formula: C₂₀H₂₄O₉·H₂O, C₂₀H₂₄O₁₁·1.5H₂O and C₂₀H₂₄O₁₀·2H₂O


	Structure factor file (CIF format) (203.1 kbytes) Contains datablock I

	Structure factor file (CIF format) (289.9 kbytes) Contains datablock III

	Structure factor file (CIF format) (132.3 kbytes) Contains datablock IV

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