## LSU Historical Dissertations and Theses

1989

Dissertation

#### Degree Name

Doctor of Philosophy (PhD)

#### Department

Chemistry

Nikolaus H. Fischer

#### Abstract

This dissertation consists of two parts. In part A, the isolation and structure elucidation of secondary metabolites from the genus Rudbeckia are described. A comprehensive review of newly reported sesquiterpene lactones published during 1986 and 1987 is presented in part B. Part A. As part of a biochemical systematic study within the family Asteraceae, seven species of the genus Rudbeckia were investigated for secondary terpenoid metabolites. This study resulted in the isolation of 42 compounds, of which 10 are new natural products. The compounds include sesquiterpene esters, pseudoguaianolides, germacrolides, eudesmanolides, lignanes and flavonols among others. The new compounds are 6$\alpha$-hydroxycostic acid, methyl ester, arbusculin E, methyl ester, desacetylligulatine C, rudbeckin A, tamaulipin A angelate, 11$\alpha$H, 13-dihydrorudmollin, 15-acetyl-11$\alpha$H, 13-dihydrorudmollin, 4-acetyl-11$\alpha$H, 13-dihydrorudmollin, 15-acetylconfertin and 11$\alpha$H, 13-dihydrorudmollin diacetate. Their structures were established by means of chemical and spectroscopic methods. These methods included MS, IR, UV, CD, $\sp1$H NMR and $\sp{13}$C NMR. Single crystal X-ray diffraction analysis of the following compounds confirmed the proposed structures: (+)-pinoresinol methyl ether, tamaulipin A angelate, 15-acetylrudmollin, rudmollin diacetate and 11$\alpha$H, 13-dihydrorudmollin. Part B. The comprehensive bibliographic review provides information about 522 new sesquiterpene lactones reported in the literature from the beginning of 1986 through the end of 1987. New plant sources (174) for sesquiterpene lactones are listed in this review which consists of a primary table which is arranged on the basis of structural types and substitution patterns.

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