title: 11β,13-Dihydro-lactucin-8-O-acetate hemihydrate.
abstract: THE TITLE STRUCTURE (SYSTEMATIC NAME: 9-hydroxy-methyl-3,6-di-methyl-3-methyl-ene-2,7-dioxo-3,3a,4,5,9a,9b-hexa-hydro-azu-leno[4,5-b]furan-4-yl acetate hemihydrate), C(17)H(20)O(6)·0.5H(2)O, from Lactuca floridana, has two independent sesquiterpene lactone mol-ecules in the asymmetric unit. Both have their seven-membered rings in the chair conformation. In the crystal, the OH groups and the water mol-ecule form classical O-H⋯O hydrogen bonds with O⋯O distances in the range 2.6750 (17)-2.8160 (18) Å.
authors.affiliation: Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803-1804, USA.
authors.forename: Chris F
authors.initials: CF
authors.lastname: Fronczek
authors.forename: Marco L
authors.initials: ML
authors.lastname: Gomez-Barrios
authors.forename: Nikolaus H
authors.initials: NH
authors.lastname: Fischer
authors.forename: Frank R
authors.initials: FR
authors.lastname: Fronczek