Jürgen Ziesche

Eudesmanolides and diterpenes from Wedelia trilobata and an ent-kaurenic acid derivative from Aspilia parvifolia

Abstract The reinvestigation of the aerial parts of Wedelia trilobata afforded, in addition to known compounds, six new eudesmanolides, two ent-kaurenic acid derivatives as well as a degraded one. A corresponding hydroxy compound was present in Gnaphalium undulatum. From Aspilia parvifolia new ent-kaurenic acid epoxides were isolated. The structures were elucidated by spectroscopic methods. The chemotaxonomic situation is discussed briefly.

Sesquiterpenes from three Senecio species

Abstract Three succulent Senecio species afforded, in addition to known compounds, two further bisabolene derivatives, a norsesquiterpene and a diol related to β-caryophyllene alcohol, which, however, has a different stereochemistry. Structures were elucidated by spectroscopic methods and some chemical transformations. The chemotaxonomic relevance of the results is discussed briefly.

Neue flavone und phloroglucin-derivate aus Helichrysum herbaceum und Helichrysum chrysargyrum

The investigation of two further South African Helichrysum species afforded five new flavones and six new phloroglucinol derivatives. The structures were elucidated by spectroscopic methods and some chemical transformations. The chemotaxonomic situation is discussed briefly.

Neue germacren-derivate aus Senecio-arten☆

Abstract From the succulent Senecio species, S. cylindricus , eight new germacrene derivatives were isolated, while S. erosus afforded two new furanoeremophilones. Six further species only contain known compounds. The chemotaxonomic importance of these findings are briefly discussed.

Neue diterpene aus Gnaphalium-arten

Abstract The investigation of Gnaphalium undulatum afforded two new labdane derivatives, one having a new carbon skeleton, and a new flavonol. Furthermore, an unknown diterpene lactose is present; its structure, however, could not be elucidated. The only American species investigated contains the trans -isomer of the precursor of the acetylenic chloroenol ether, which is widespread in Gnaphalium and in related genera. The chemotaxonomic situation is discussed briefly.

Diterpenes and sesquiterpenes from Osteospermum species

Abstract The investigation of several Osteospermum species afforded in addition to known compounds three diterpenes from the rare cassane type, two further sandaracopimarene derivatives, two 6-desoxyglucosides of cubebol and 13-hydroxycaryophyllene, respectively, an isomer of 7-hydroxycalamenene, two p-hydroxyacetophenone derivatives derived from toxol, a thymol derivative and the palmitates of lupeol, taraxasterol and 3β,20-dihydroxydammarene. The structures were elucidated by spectroscopic methods. The chemotaxonomy of the genus is discussed briefly.

Neue chalkon-derivate und humulon-ähnliche verbindungen aus Helichrysum-arten

Abstract The investigation of two further Helichrysum species afforded in addition to known compounds three new prenylated chalcones and two humulone-like compounds. The structures were elucidated by spectroscopic methods and some chemical transformations. The chemotaxonomic situation is discussed briefly.

Melampolides and other germacranolides from Blainvillea dichotoma

The aerial parts of Blainvillea dichotoma afforded, in addition to known compounds, seven new sesquiterpene lactones, four related to elephantin, two melampolides and a further cis,cis-germacranolide. The chemotaxonomic situation is discussed briefly.

An unusual nerolidol derivative from Artemisia inculta

Abstract The aerial parts of Artemisia inculta afforded a new nerolidol derivative named arteincultone.

Eremophilane derivatives from Senecio species

Abstract The investigation of two further Senecio species afforded two new furanoeremophilanes, four eremophilanolides and a new hydroxyeremophilane. The structures of two furanoeremophilane, isolated before, have been revised.