ABSTRACT
The difficulty in the structure elucidation of natural products is in the elucidation of stereochemistry, especially the determination of absolute configuration, which generally involves the key techniques of structure elucidation of natural products. This paper shows some examples of our work in elucidating the stereochemistry of new chiral natural products by the application of several physicochemical techniques, such as the dimolybdenum tetraacetate [Mo2(OAc)4] induced CD (ICD, Snatzke’s method), empirical rules of classical CD, modified Mosher’s method, theoretical ECD calculation and modified Marfey’s analysis. The fundamental rules of the techniques and our experiences in the application of these techniques are also described for related researcher’s reference in relevant studies.
ABSTRACT
A new decahydronaphthalenylpropenal derivative, (+)-camerarialdehyde (1), a new tetrahydrofuran lignan, (-)-diepiolivil (2), and two known lignans were isolated from a methanol-soluble extract of the stems of Cameraria latifolia, which was obtained from a repository donated to IHVR by Merck Research Laboratories. The structures of compounds 1 and 2 were determined by interpretation of their spectroscopic data, with the absolute configuration of 1 being established by analysis of its CD spectrum. The absolute configuration of the 1,3-diol moiety of 2 was proposed from the CD spectrum induced with dimolybdenum tetraacetate in DMSO solution. All compounds isolated were evaluated against HT-29 human colon cancer cells, and compound 1 was found to show cytotoxicity toward this cell line.