Lakshmi N. Dutta

Neue sesquiterpenlactone aus Aster umbellatus

Abstract The investigation of Aster umbellatus afforded six new eudesmanolides and a new selina-triene and from Aster exilis a new tremetone derivative was isolated. The structures were elucidated by spectroscopic methods and by some chemical transformations. The chemotaxonomic situation is discussed briefly.

Neue germacranolide aus Liatris cylindracea

Abstract The investigation of Liatris cylindracea afforded in addition to known compounds a new geranyl derivative, an elemanolide, which may be identical with igalan, and five germacranolides, three belonging to the heliangolides. All are closely related to lactones isolated previously from Liatris species or other members of the tribe Eupatorieae.

Weitere hirsutinolide aus Vernonia-arten

Abstract The investigation of two Bolivian Vernonia species afforded, in addition to known compounds, five further enollactones of the hirsutinolide type and a new hydroxyzaluzanine. The structures were elucidated by intensive 1 H NMR studies and some chemical transformations. The results show again that the hirsutinolides are probably of chemotaxonomic importance in the large genus Vernonia .

Neue labdan-derivate aus Chrysothamnus nauseusus

Abstract The South American Chrysothamnus species afforded in addition to known compounds six new labdanetype acids, a bisabolene and a germacrene derivative as well as a new flavanone. The structures were elucidated by spectroscopic methods.

Neue acetylenverbindungen aus Leucanthemum-arten und revision der struktur eines germacranolids

Abstract The investigation of three Leucanthemum species afforded, in addition to known compounds, two new C 17 -acetylenes, a new isovalerate, two phenolic acetylenes, a C 12 -isobutylamide and a new farnesol derivative. Chrysanthemum ferulaceum contains deacetyllaurenobiolide (spiciformin) which is identical with a lactone from Inula britannica previously assumed to be a cis, cis -germacranolide.

Neue, abgewandelte pseudoguajanolide aus Psilostrophe villosa

Abstract Investigation of the North American species Psilostrophe villosa afforded, in addition to known compounds, five new sesquiterpene lactones, which all turn out to be modified pseudoguaianolides, most of them closely related to hymenolide. However, one of the lactones is a new type of nor-pseudoguaianolide. Furthermore a new monoacetylated borneol-β- D -glucoside is present. The chemotaxonomic situation is discussed briefly.