31 発癌プロモーターindolactam類の立体構造 : 動的構造解析(口頭発表の部)

概要

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Indolactam-V(1), which is a partial structure of tumor promote teleocidins, olivoretins and their derivatives, has a nine membered ring containing an amide bond, and exists in two conformational states in solution, SOFA and TWIST (1:2 in CD_3OD). The conformation of the nine membered ring in indolatams depends on the substituent at C12-position, and determines the relative positions of hetero atoms and orientations of hydrogen bonding whic'h act significant roles on the tumor promoter recepter. The conformations of the nine membered ring of teleocidins and olivoretins determined by X-ray crystallography have been reported to be an alternative of two conformers, SOFA and TWIST. In this paper we report two new conformations of the nine membered ring of indolactams, ie. (±)-indolactam-G(3) and (±)-epi-indolactam-V(2) which have slight or no activity of tumor promotion, determined by X-ray crystallography and NMR spectroscopy. Quantitative analyses of these four conformations by molecular mechanics were performed. To these compounds, we have applied molecular dynamical calculations for the purpose of analyzing the process of ring conformational changes and obtaining the structures of the unknown conformers observed in NMR spectra. We have successflly made clear the favorable path of TWIST-SOFA conversion as well as the equilibrium between several conformers for each compound.
天然有機化合物討論会の論文
1988-09-26