Koumbalones A and B, new casbane diterpenes from Maprounea africana.
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.
Kashman
Y
Y
Laboratory of Drug Discovery Research & Development, National Cancer Institute, Frederick, MD 21702.
Bernart
M W
MW
Tischler
M
M
Cardellina
J H
JH
Boyd
M R
MR
D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification*; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D010946:Plants, Medicinal / Q000737:chemistry*
D004224:Diterpenes; C087547:koumbalone A; C087548:koumbalone B