title: Koumbalones A and B, new casbane diterpenes from Maprounea africana.
abstract: The organic extract of Maprounea africana yielded koumbalones A [1] and B [2], defined by spectral methods as new variations on the casbane ring system. The gross structures, relative configurations, and solution conformations were determined by a combination of spectral analyses and molecular modeling. Because koumbalone A spontaneously converts to koumbalone B at room temperature, koumbalone B may be an artifact of isolation.
authors.affiliation: Laboratory of Drug Discovery Research & Development, National Cancer Institute, Frederick, MD 21702.
authors.forename: Y
authors.initials: Y
authors.lastname: Kashman
authors.forename: M W
authors.initials: MW
authors.lastname: Bernart
authors.forename: M
authors.initials: M
authors.lastname: Tischler
authors.forename: J H
authors.initials: JH
authors.lastname: Cardellina
authors.forename: M R
authors.initials: MR
authors.lastname: Boyd
mesh_terms: D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010946:Plants, Medicinal / Q000737:chemistry*
chemical_list: D004224:Diterpenes; C087547:koumbalone A; C087548:koumbalone B