A daucanolide further farnesene derivatives from Ageratum fastigiatum

A reinvestigation of Ageratum fastigiatum afforded, in addition to known compounds, several new farnesene derivatives including some tetrahydropyrane derivatives. Furthermore a sesquiterpene lactone derived from daucane and a minor derivative of the ent-labdanes isolated previously were isolated. The structures were elucidated by spectroscopic methods.     

A rearranged eudesmane and further verbesindiol derivatives from Verbesina eggersii

A reinvestigation of Verbesina eggersii gave in addition to compounds isolated previously two further verbesindiol derivatives, a rearranged eudesmane and a benzofuran related to tremetone.     

Neue sesquiterpene aus Verbesina occidentalis

The investigation of the aerial parts of V. occidentalis affords six new sesquiterpenes their structures being elucidated by spectroscopic methods. All compounds are derived from muurolene. V. enceloides contains simple compounds, only one being new, which is closely related to a diacetate from Amphiachyris amoenum.     

A further sesquiterpene lactone esterified with a sesquiterpenic acid

The roots of Hypochoeris oligocephala afforded in addition to known compounds a further sesquiterpene lactone esterified with a sesquiterpenic acid as well as the corresponding free acid.     

Sesquiterpenes and norsesquiterpenes from Pechuel-Loeschea leibnitziae

The aerial parts of Pechuel-Loeschea leibnitziae afforded, in addition to thymohydroquinone dimethyl ether, sitosterol and stigmasterol, xerantholide and its probable precursor, the 11,13-dihydro derivative methyl pechueloate and two norsequiterpenes, probably formed by degradation of the corresponding sesquiterpene acid. Two eudesmane derivatives were also isolated. The chemotaxonomy of Pechuel-Loeschea is discussed briefly.     

Four oplopanone and bisabolone derivatives from Rugelia nudicaulis

Rugelia nudicaulis afforded, in addition to known compounds, three new highly oxygenated oplopanone derivatives and a bisabolone derivative. The structures were elucidated by high field ¹H NMR spectroscopy. The chemotaxonomic situation is discussed briefly.     

New labdane derivatives and further constituents of Brickellia species

The investigation of several Brickellia species and two further related species afford besides known compounds four new labdane derivatives, a new acetylenic carbinol and a new dihydrobenzofuran derivative. The structures have been elucidated by spectroscopic methods. The chemotaxonomic aspects are discussed briefly.     

Neue sesquiterpene aus Liabum-arten

The reinvestigation of the roots of Liabum eggersii afforded, in addition to compounds reported before, several sesquiterpene hydrocarbons with unusual carbon skeletons and the first derivative of the propellane modhephene which itself is also present. The roots of L. floribundum contain a tricyclic sesquiterpene with three five-membered rings. This ketone most probably is a derivative of the sesquiterpene silphiperfolene. The structures of the new compounds were elucidated by extensive NMR studies and by some chemical transformations. Two further species only afforded known compounds. The chemotaxonomic situation is discussed briefly.     

Sesquiterpene and diterpene derivatives from Solidago species

The investigation of four Solidago species afforded, in addition to known compounds, four new caryophyllene derivatives, two eudesmanes, two abietanes, a clerodane, two labdanes, three kauranes and an anol angelate. The structures were elucidated by spectroscopic methods and by some chemical transformations. While the diterpenes isolated are widespread in the genus Solidago, the sesquiterpenes have not been obtained before from any species. The overall picture of the large genus, however, is relatively uniform.     

A diterpene,a sesquiterpene quinone and flavanones from Wyethia helenioides

The aerial parts of Wyethia helenioides afforded a new geranyl nerol derivative (a 16-hydroxy-18-oic acid), two isomeric prenylated lavanones and a quinone derived from bisabolene. The structures were elucidated by spectroscopic methods and some chemical transformations. The chemotaxonomic situation is discussed briefly.     

Cacalol derivatives from Senecio lydenburgensis

An investigation of Senecio lydenburgensis afforded eight new cacalol and cacalohastin derivatives. Their structures were deduced from the molecular formulae and ¹H NMR spectra.     

Further cadinene derivatives from Heterotheca latifolia

A reinvestigation of the aerial parts of Heterotheca latifolia afforded four new cadinene derivatives.     

Trixikingolides and germacrene derivatives from Trixis species

The investigation of two further Trixis species afforded five new sesquiterpenes related to trixikingolide, six new germacrene derivatives and a sesquiterpene derived from rotundene. Some further known compounds were isolated too, which in part may be of chemotaxonomic significance. The structures were elucidated by spectroscopic methods and a few chemical transformations. The relative position of the ester groups in eight of the new sesquiterpenoids however, could not be established with certainty as partial saponifications were not successful.     

Further silphinene derivatives from Cineraria geifolia var. glabra

A reinvestigation of the sesquiterpenes from the aerial parts of Cineraria geifolia var. glabra afforded eight new silphinene derivatives. One of these compounds had been isolated previously but its structure had not been elucidated with certainty. The stereochemistry of a corresponding isovalerate from Callilepis salicifolia has to be revised.     

Humulene derivatives from Acritopappus prunifolius

The investigation of Acritopappus prunifolius afforded in addition to known compounds two new derivatives of γ-humulene, a rearranged α-humulen     

Labdane and dehydronerolidol derivatives from Brickellia diffusa

An investigation of Brickellia diffusa afforded three new dehydronerolidol derivatives and five new labdane derivatives, all highly oxygenated. The structures were elucidated by spectroscopic methods and a few chemical transformations. The compounds isolated showed close relationships to those isolated from Brickellia sp.     

Caryophyllane derivatives from Pulicaria scabra

The investigation of Pulicaria scabra afforded in addition to known compounds seven new caryophyllane derivatives, three of them etherified with a caryophyllane derivative and one esterified with a caryophyllane derived alcohol. The structures were elucidated by high field ¹H NMR spectroscopy. The chemistry of this species is similar to that of P. dysenterica but differs from that of the other genera of the subtribe Inulinae.     

New sesquiterpene lactones,geranyllinalol derivatives and other constituents from Geigeria species

The investigation of three Geigeria species and five subspecies afforded, in addition to known compounds, the following 32 new compounds: two geigeranolides with a new carbon skeleton, two xanthanolides, five guaianolides, three pseudoguaianolides, a sesquiterpene related to ivaxillarin, a nerolidol derivative, 15 geranyllinalol derivatives, two thiophene acetylenes and a dimeric coniferyl isobutyrate. The structures and the stereochemistry of the new compounds were elucidated by spectroscopic methods and a few chemical transformation. Chemotaxonomic aspect and relationship of the comnounds are discussed.     

Sesquiterpenes from three Senecio species

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.