Labdane derivatives from hemizonia species

The investigation of three Hemizonia species afforded in addition to known compounds seven new labdane derivatives, all derived from labd-13-en-15-ol. The absolute configuration of these diterpenes was determined by degradation of the triol by periodate cleavage, which afforded a known norditerpene ketone. From H. fitchii two new chromene esters and the cis-isomer of a known coumarate were isolated. H. congesta afforded in addition to labdane derivatives a hydroxycubebol.     

Thymol derivatives from Porophyllum riedelii

In addition to known compounds, Porophyllum riedelii attorded three new 2-methoxythymol derivatives.     

Neue ent-atisiren- und ent-kaurensäure-derivate aus Helianthus-arten

The investigation of four Helianthus species afforded, in addition to known compounds, four new atisirenic acid derivatives, a new ent-kaurenic acid derivative, three new labdane derivatives and an unknown C₁₅-acetylenic compound. The structures of the diterpenes were elucidated by intensive NMR studies and some chemical transformations. An unusual fragmentation in the mass spectra of the atisirenes is discussed briefly.     

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The investigation of one representative of the genus Morithamnus afforded, in addition to several known compounds, a new ent-labdane derivative, a new hydroxy-ent-kauranol and three tremetone derivatives. The structures were elucidated by spectroscopic methods. The chemotaxonomic situation is discussed briefly.     

Neue diterpene und neue dihydrochalkon-derivate sowie weitere inhaltsstoffe aus Helichrysum-arten

The investigation of 25 further Helichrysum species afforded in addition to known compounds a new diterpene, an oxo-geranyllinalol, a second one, most probably a cembrene derivative, and three dihydrochalkone derivatives. The distribution of the constituents in South African Helichrysum species is discussed briefly.     

Neue labdan-derivate aus Aristeguietia buddleaefolia

The aerial parts of Aristeguietia buddleaefolia afforded, in addition to known compounds, three new diterpenes, all being 12, 13-E-abienol derivatives. A further diterpene turned out to be jhanidiol-18-O-acetate, isolated earlier from an Ageratina species. Furthermore two derivatives of hydroxy dihydroconiferyl alcohol are present. The structures were elucidated by spectroscopic methods and by some chemical transformations.     

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.     

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.     

Neue phloroglucin-derivate aus Leontonyx-arten sowie weitere verbindungen aus vertretern der tribus inuleae

The investigation of several South African species of the tribe Inuleae afforded in addition to known compounds 16 new constituents. From Leontonyx a group of 9 new phloroglucinol derivatives, from Stoebe species two new p-hydroxyacetophenone, two thymol and two coumaric acid derivatives and from Relhania a new euparine-derivative were isolated. The structures are elucidated mainly by spectroscopic methods. The chemotaxonomic aspects are discussed briefly. The phloroglucinol derivatives, which in part are derived from geraniol, seem to be especially characteristic.     

Diterpenes from Heteropappus altaicus

The aerial parts of Heteropappus altaicus afforded, in addition to more widespread compounds and known clerodane derivatives, three new ones and a seco-clerodane acid. Furthermore, a neryl geraniol derivative was present. The structures were elucidated by spectroscopic methods. The stereochemistry was solved by NOE difference spectroscopy and by the Horeau method.     

Three diterpenes from Conyza podocephala

The investigation of Conyza podocephala afforded, in addition to known compounds, two clerodane derivatives and a dihydroxyfarnesyl methylfuran. Furthermore two new resorcinol derivatives were isolated. The structures were elucidated by spectroscopic methods and by chemical transformations. The chemotaxonomic situation within the genus is discussed briefly.     

Neue labdan-derivate und andere inhaltsstoffe aus Relhania acerosa

The investigation of Relhania acerosa afforded, in addition to known compounds, three new labdane derivatives, two of which are esterified with succinic acid and one which has an anomalous carbon skeleton. Furthermore, several new aromatic compounds are isolated, which are most probably degradated thymol derivatives. The structures are elucidated by spectroscopic methods and by some chemical transformations. The stereochemistry of one of the new labdanes has been established by a partial synthesis. The chemotaxonomic situation is briefly discussed.     

Types of sesquiterpenes from Artemisia douglasiana

Artemisia douglasiana afforded, in addition to known compounds, two new C₁₄-acetylenes, five longipinene derivatives, three nerolidol derivatives, a lactone and a ketone with a new carbon skeleton and lavendulol-2-methylbutyrate. The structures were elucidated by spectroscopic methods and some chemical transformations. The configurations of several oxo longipinene-7, 9-di- and 7, 8, 9-triesters isolated previously were corrected. The biogenesis of the new lactones is discussed briefly.     

New sesquiterpene lactones and other constituents from Fitchia speciosa

The investigation of Fitchia speciosa afforded, in addition to known compounds, three new sesquiterpene lactones, iso-β-costal, two p-hydroxyacetophenone derivatives and an isoeugenol derivative. The structures were elucidated by spectroscopic methods. The chemotaxonomic situation in this complicated genus is discussed.     

Neue pyron-derivate aus Helichrysum-arten

The investigation of five further Helichrysum species afforded in addition to known compounds nine α-pyrone derivatives all also being phloroglucinol derivatives. Furthermore, a new toxol derivative has been isolated. The structures were elucidated by extensive NMR studies and by some chemical transformations. The chemotaxonomic situation is discussed briefly.     

Eudesmane derivatives from Verbesina species

The investigation of seven Verbesina species afforded, in addition to known compounds, several new eudesmane and germacrane derivatives, all bearing a cinnamate or derivatives as residue. Furthermore, a new bisabolene aldehyde and two acetophenone derivatives were isolated. The structures were elucidated mainly by spectroscopic methods and some chemical transformations. The chemotaxonomic situation is discussed briefly.     

Pseudoguaianolides carabrone derivatives from Loxothysanus sinuatus

The aerial parts of Loxothysanus sinuatus afforded in addition to known compounds nine new pseudoguaianolides, three guaianolides and five carabrone derivatives. The structures were elucidated by spectroscopic methods. The chemotaxonomy is discussed briefly. The configurations of two guaianolides were corrected.     

Cytotoxic and anti-oxidant biphenyl derivatives from the leaves and twigs of Garcinia multiflora

Three new biphenyl derivatives (1–3), together with five known compounds, were isolated from the leaves and twigs of Garcinia multiflora. Their structures were determined by extensive spectroscopic techniques including NMR spectroscopy and mass spectrometry. All eight isolates showed weak cytotoxicity on five human tumor cell lines. In addition, the three biphenyl derivatives showed moderate anti-oxidant activity with IC₅₀ values ranging from 7.78 to 8.78 μM.     

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.     

New labdane derivatives from Madia sativa

The aerial parts of Madia sativa afforded, in addition to known compounds, two labdane derivatives whose structures were elucidated by spectroscopic methods. The absolute configuration was determined by chemical transformations. From the roots a new tremetone derivative was isolated. The constituents indicated close relationships of Madia to Hemizonia.