Acta Cryst. (2009). E65, o2564-o2565  [ doi:10.1107/S160053680903829X ]

11,13-Dihydrolactucin-8-O-acetate hemihydrate

C. F. Fronczek, M. L. Gomez-Barrios, N. H. Fischer and F. R. Fronczek

Abstract: The title structure (systematic name: 9-hydroxymethyl-3,6-dimethyl-3-methylene-2,7-dioxo-3,3a,4,5,9a,9b-hexahydroazuleno[4,5-b]furan-4-yl acetate hemihydrate), C₁₇H₂₀O₆·0.5H₂O, from Lactuca floridana, has two independent sesquiterpene lactone molecules in the asymmetric unit. Both have their seven-membered rings in the chair conformation. In the crystal, the OH groups and the water molecule form classical O-HO hydrogen bonds with OO distances in the range 2.6750 (17)-2.8160 (18) Å.

Online 30 September 2009

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