title: New diterpenes from the gorgonian Solenopodium excavatum.
abstract: Seven new briariane diterpene lactones were isolated from the gorgonian Solenopodium excavatum collected in New Guinea. One structure (4) was determined by X-ray diffraction and the remainder were elucidated by spectroscopic analysis. Six of the new briareolides, 4-9, exist in a conformation that is quite uncommon for representatives of this fairly large family of compounds, namely one in which the bonds joining the 10-membered ring to the 6-membered ring are nearly diaxially oriented. Conformational energy calculations are discussed as are the structural features that are responsible for the uncommon conformation. Mild cytotoxic activity was confirmed for 4.
authors.affiliation: Department of Chemistry and Biochemistry, University of Oklahoma, Norman 73019-0370.
authors.forename: F J
authors.initials: FJ
authors.lastname: Schmitz
authors.forename: M M
authors.initials: MM
authors.lastname: Schulz
authors.forename: J
authors.initials: J
authors.lastname: Siripitayananon
authors.forename: M B
authors.initials: MB
authors.lastname: Hossain
authors.forename: D
authors.initials: D
authors.lastname: van der Helm
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D003063:Cnidaria / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D007941:Leukemia P388 / Q000188:drug therapy; D009682:Magnetic Resonance Spectroscopy; D051379:Mice; D008968:Molecular Conformation; D009512:New Guinea; D014407:Tumor Cells, Cultured / Q000187:drug effects
chemical_list: D000970:Antineoplastic Agents; D004224:Diterpenes