Karl-Heinz Knoll

Terpen-derivate aus Senecio-arten

Zusammenfassung Uberblickt man das jetzt vorliegende Material uber die Gattung Senecio , so bestatigt sich die schon eingangs erwahnte Festellung, das in Eine klare Differenzierung der Gattung Senecio von den Nachbargruppen von der Seite der Inhaltsstoffe her, ist nach wie vor problematisch. Wahrsche

Neuartige sesquiterpenlactone und neue acetylenverbingen aus Athanasia-arten☆

Abstract The investigation of two further South African Athanasia -species afforded, in addition to known compounds, sixteen new ones, ten guaianolides, an eudesmanolide, three sesquiterpenes, a new enediynene and a phenylpropane derivative. The structures were elucidated by extensive NMR-studies. Three of the lactones are very unusual in having an endoperoxide bridge; their structures, however, were elucidated only indirectly. These further chemical results on Athanasia again add support to the idea that these species might be better placed in the genus Pentzia .

Neuartige sesquiterpenlactone aus Pulicaria crispa

Zusammenfassung The investigation of Pulicaria crispa afforded, in addition to known xanthanolides, three new ones, a new pseudoguaianolide epoxide and a new type of seco-sesquiterpene lactone. The structures were elucidated by spectroscopic methods.

Weitere furanoeremophilane aus Othonna-arten☆

Abstract The investigation of further Othonna species affords 23 new furanoeremophilanes and a new benzofuran-derivative. All these compounds are closely related to those isolated before from other Othonna species. Highly oxidized furanoeremophilanes seem to be typical of this genus.

Neue guaianolide aus Cacosmia rugosa

Abstract The roots of C. rugosa afforded, in addition to known compounds, a C 17 -acetylenic epoxide and five new guaianolides, four of them being hydroperoxides. The structures were elucidated by extensive NMR studies. The aerial parts only contain triterpene mixtures, as those of C. hieronymi . The compounds isolated confirm that Cacosmia is unrelated chemically to true members of the tribe Senecioneae.

Neue α-santalen- und labdan-derivate aus Ayapana amygdalina

Abstract While the roots of Ayapana amygdalina contain typical euparine derivatives, the aerial parts afforded in addition to known compounds two new α-santalene derivatives as well as twelve new labdane derivatives with a partly unusual oxidation pattern, two being norditerpenes. Furthermore, a new bisabolene isomer is present. The structures were elucidated by spectroscopic methods and a few chemical transformations. The chemotaxonomy is discussed briefly.