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[摘要]
作者针对文献关于 ent- kauran- 16 β,17- diol(Ⅰ)碳信号指认有误的问题,用化学合成方法和 2 D-NMR技术对 的结构进行全面分析和论证,首次归属了每个氢质子的信号,并再次证实其结构中的 C- 1、C- 7和 C- 14互为颠倒,该研究对 ent- kaurane骨架二萜结构的鉴定有实际意义。
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[Abstract]
The authors, in their study of the structure of fritillebin A, an ent-kauran diterpenoid dimer, by 2D-NMR, found that one of its hydrolytic product, the ent-kaurane-16β,17-diol (Ⅰ), though, in all respects, were identical with the authentic sample, yet the 2D-NMR, and especially the NOESY showed an error in the attribution of carbon signals, reported in the literature. To further proved the identity of I in their possession, the compound was compared with the product obtained from ent-kaurane by oxidizing with KMnO4 in argon in the presence of phase transfer catalyst, which proved that the synthetic product was in all respects identical to (Ⅰ) obtained from natural origin. But on attribution of each proton signal, it was found that the chemical shift of C-1, C-7 and C-14 should be 40.3, 42.1 and 37.3 instead of 42.0, 37.2 and 40.4 respectivly as reported in the literature. The authors further noticed that similar errors also appeared in other compounds reported, therefore the correction of these errors may provide some practical significance for the structural elucidation of ent-kaurane diterpenoids.
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