title: Limbetazulone: a new 'decahydro-8-oxanaphtho[2,1-f]azulen-7-one' diterpenoid from Ballota limbeta, and occurrence of two conformational isomers in the crystal.
abstract: A new diterpenoid, limbetazulone (= (3S,4S,4aR,12bS)-1,2,3,4,4a,5,6,11,12,12b-decahydro-3-hydroxy-4-(hydroxymethyl)naphtho[1',2': 5,6]cyclohepta[1,2-b]furan-7(7H)-one; 1), with the very rare 'naphtho[2,1-f]azulene-7-one' skeleton, was isolated from the aerial parts of the Asian medicinal plant Ballota limbeta. Its structure was established by extensive spectroscopic investigations, especially 1D and 2D NMR. X-Ray diffraction studies showed the presence of two conformational isomers (1a and 1b) in the crystal.
authors.affiliation: Department of Chemistry, University of Paderborn, Warburger Strasse 100, D-33098 Paderborn.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Riaz
authors.forename: Karsten
authors.initials: K
authors.lastname: Krohn
authors.forename: Abdul
authors.initials: A
authors.lastname: Malik
authors.forename: Ulrich
authors.initials: U
authors.lastname: Flörke
mesh_terms: D031329:Ballota; D003460:Crystallization / Q000379:methods; D018360:Crystallography, X-Ray / Q000379:methods*; D004224:Diterpenes / Q000737:chemistry*; D019686:Lamiaceae; D010936:Plant Extracts / Q000737:chemistry; D018514:Plant Structures; D010946:Plants, Medicinal / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D004224:Diterpenes; D010936:Plant Extracts