Sesquiterpenes,guaianolides and diterpenes from Stevia myriadenia

The investigation of Stevia myriadenia afforded in addition to known compounds a new clerodane and a labdane derivative, two guaianolides, a bisabolene and a germacrene derivative. The structures were elucidated by spectroscopic methods. The chemotaxonomic situation is discussed briefly.     

Sesquiterpenes from Kleinia species

The investigation of four Kleinia species afforded, in addition to known compounds, seven new germacrane and three oplopane derivatives, all highly oxygenated. This kind of sesquiterpene seems to be characteristic of the genus Kleinia and related succulent species, and its tentative grouping is 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.     

Sesquiterpenes from Perezia carpholepis

The previously unknown curcuquinol monoisovalerate and the known sesquiterpenes cyperene, cyperone, parvifoline, perezone, and α- and β-pipitzol were found in the roots of Perezia carpholepis. The structure of the new sesquiterpene was deduced from spectral data and by transformation into curcuquinone. Parvifoline and its derived acetate, previously thought to be oily materials, were characterized as crystalline compounds.     

A tetracyclic sesquiterpene,further isocedrene and guaiene derivatives from Jungia stuebelii

The aerial parts of Jungia stuebelii afforded, in addition to known compounds, two guaiene derivatives, a pseudoguaiane derivative, nine isocedrene     

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.     

Sesquiterpenes and acetylenes from Argyranthemum adauctum ssp. jacobaeifolium

The roots of Argyranthemum adauctum ssp. jacobaeifolium, a rare endemic from Gran Canaria, afforded two new derivatives of the aromatic acetylene frutescin and 8-isovaleryloxymyrcene, while the aerial parts gave a new bisabolol derivative. Furthermore several known compounds were isolated. The structures were elucidated by high field ¹H NMR spectroscopy and a few chemical reactions.     

Some sesqui- and diterpenes from the tribe eupatorieae

The aerial parts of Trichogonia salviaefolia afforded a new ent-kaurenic acid derivative and a germacranolide which, most likely, is the precursor of the trichosalviolides. The aerial parts of Liatris spicata gave 1α-hydroxybacchotricuneatin A and a guaianolide, which may be the precursor of spicatin. From Brickellia vernicosa some further dehydronerolidol derivatives were isolated.     

A guaian-5,12-olide from Hypochoeris cretensis

Hypochoeris cretensis afforded, in addition to triterpenes and isoalantolactone, a new guaian-5, 12-olide and the corresponding precursor.     

Cuauthemone sesquiterpenoids from Blumea alata

The investigation of five Blumea species afforded, in addition to known compounds, several cuauthemone derivatives, most of them being 7,11-epoxides, some thymol derivatives, an eremophilane epoxide and a himachalane diol. From Pterocaulon virgatum a further himachalane derivative was isolated. The structures were elucidated by spectroscopic methods and in part by partial synthesis.     

Eudesmane derivatives from Epaltes brasiliensis

The first investigation of an Epaltes species afforded two thiophene acetylenes and several eudesmane derivatives, all closely related to cuauhtemone, its esters being typical for Pluchea species. The structures were elucidated by spectroscopic methods.     

Five tricyclic sesquiterpenes from Callilepis salicifolia

The roots of Callilepis salicifolia afforded in addition to known compounds four derivatives of isocomene, one dihydroxysilphinene isovalerate, two     

Two sesquiterpenes from Senecio species

The investigation of further Senecio species gave, in addition to known compounds, two new sesquiterpenes, an eremophilane and a eudesmane derivative.     

New norsesquiterpenes from Senecio digitalifolius

The South African Senecio digitalifolius contain besides several known furanoeremophilanes three new norsesquiterpenes all related to bisabolene. The structures are elucidated by spectroscopic methods.     

Cadina-4,11-diene from Viguiera oblongifolia

Viguiera oblongifolia afforded two known furanoheliangolides and a new cadinane derivative whose structure was established by spectroscopic methods. From V. lanceolata 17,18-dihydrobudlein A was isolated.     

Eremophilene and germacrene derivatives from Senecio glanduloso-pilosus

Senecio glanduloso-pilosus afforded in addition to known compounds a new eremophilene deriva- tive and a hydroperoxide derived from germacrene D.     

New flavonoids from Inula cappa

Extraction of Inula cappa DC. yielded three new flavonoids with an unusual ring B substitution pattern, namely (2R,3R)-5′-methoxy-3,5,7,2′-tetrahydroxyflavone, (2S)-5,7,2′,5′-tetrahydroxyflavanone and 7.5′-dimethoxy- 3,5,2′-trihydroxyflavone. Structures were established by chemical correlation, spectroscopic studies and degradation.