P-15 沖縄近海産海綿より単離された新規骨格をもつステロイドおよびその類縁体の構造(ポスター発表の部)

概要

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During our search for naturally occurring compounds with medicinal potential, we have isolated five new steroid-related compounds (1-5) and six new steroids (6-11) from an Okinawan marine sponge Plakortis nigra. Their structures were elucidated by the use of one and two dimensional NMR techniques. Compounds 1 and 2 possess a novel skeleton with a spiro ring structure which could be formed by the rearrangement of the C-C bond between C-1 and C-10 in the usual steroidal ring to the C-5 position. In addition, 1 and 2 are revealed to have a cross conjugating double bonds in the rings B and C. As for the stereochemistries of 1 and 2, the absolute stereochemistries were determined to be 3S and SR by the combination of NOE correlations and the modified Mosher's method. Absolute stereochemistries of the other chiral centers were suggested to be 11R,13R,17R,20R such as usual steroids. Compounds 3-5 also possess novel skeletons in which the usual steroidal ring B collapsed and the original rings A and C were bound through a ester linkage. Stereochemistries of 3-5 in the ring A are under investigation. Stereochemistries of 6-11 possessing normal steroidal skeletons were established by the analysis of NOE correlations and the modified Mosher's method.
天然有機化合物討論会の論文
2006-09-15