Labdane derivatives from Planaltoa lychnophoroides

The investigation of a representative of the small Brazilian genus Planaltoa afforded, in addition to known compounds, a new toxol derivative and two ent-labdane derivatives, closely related to austrofolin. The structures were elucidated by high field ¹H NMR spectroscopy. The chemotaxonomic situation is discussed briefly.     

Labdane derivatives and a himachalanolide from Acritopappus longifolius

The investigation of Acritopappus longifolius afforded, in addition to known compounds, further labdane derivatives and a new type of himachalanolide sesquiterpene lactone. The results support the chemotaxonomy of the genus and its relationship to Radlkoferotoma placed in the same group.     

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.     

Thirteen kolavane derivatives from Symphyopappus species

The aerial parts of Symphyopappus compressus afrorded three new kolavane derivatives and those of S. reticulatus ten diterpenes of this type, two of them esterified with long chain fatty acids. Furthermore, a dihydroxyphenylpropanol, also esterified with long chain fatty acids, was present in both species. The roots of S. reticulatus afforded a new tremetone derivative. The structures were elucidated by spectroscopic methods and some chemical transformations.     

Labdane and eudesmane derivatives from Ageratum fastigiatum

Several diterpenes, triterpenes, ent-labdanes, and eudesmane derivatives have been isolated from Ageratum fastigiatum. A previously unknown eud     

Eudesmanolides and kaurene derivatives from Wedelia hookeriana

From the aerial parts of Wedelia hookeriana eight new eudesmanolides, all derivatives of ivangustin, and a new ent-kaurenic acid derivative togethe     

Clerodane and labdane diterpenoids from Baccharis species

The investigation of eight Baccharis species afforded, in addition to known compounds, five new clerodanes, three labdane derivatives and a nor-diterpene as well as one hydroperoxide derived from 4α-hydroxygermacra-1(10), 5-diene. The structures were elucidated by spectroscopic methods. The structures of esters isolated previously from B. cassinaefolia have to be revised. Chemotaxonomic aspects are discussed briefly.     

Labdane derivatives and flavones from Gutierrezia dracunculoides

An investigation of the aerial parts of Gutierrezia dracunculoides afforded, in addition to known compounds, three new labdane derivatives, all related to lambertianic acid, 17-hydroxy- and 17-acetoxylambertianic acid and 7α- hydroxylambertianic acid, two esterified and three highly oxygenated flavones, 5,7,4′-trihydroxy-3,3′-dimethoxy- flavone-4′-O- [2-methylbutyrate] and isovalerate, 3′,5′-dihydroxy-3,5,6,7,8,4′-hexamethoxyflavone, 5,3′,5′-trihydroxy- 3,6,7,8,4′-pentamethoxyflavone and 5,7,3′,5′-tetrahydroxy-3,6,8,4′-tetramethoxyflavone. The structures were elucidated by spectroscopic methods and a few chemical transformations.     

Thymol derivatives from Eupatorium glechonophyllum

The known 10-acetoxy-8,9-epoxythymolisobutyrate and the new 8,9-dihydroxy-10-acetoxythymolisobutyrate and 8,9,10-trihydroxythymol have been isolated from the thallus of Eupatorium glechonophyllum. The acetonide of the last compound was also obtained. The possibility that the new compounds are artefacts is discussed.     

Fourteen heliangolides from Calea species

The investigation of two further Calea species afforded, in addition to known compounds, fourteen new heliangolides, most of them being 11,13-epoxides. One lactone is a new type, a heliangolide substituted with a monoterpene residue. Furthermore, a new chromene and a new dithienyl derivative were isolated. The structures were elucidated by spectroscopic methods. The chemotaxonomic situation is discussed briefly.     

Sandaracopimarene derivatives from Senecio subrubriflorus

Several new sandaracopimarene derivatives were isolated from Senecio subrubriflorus. A triphenyl acetate of shikimic acid and a 4, 7-oxide of bisabolene were also present. The structures were elucidated by high field ¹H NMR spectroscopy. The chemistry of this species differs considerably from that of other Senecio species.     

Homogeranyl nerol derivatives and a melampolide from Smallanthus glabratus

The investigation of the aerial parts of Smallanthus glabratus from two locations afforded the same known compounds but some additional new compounds which were not present in both collections. From the first location typical melampolides, one of them not isolated previously, and two homoditerpenes were isolated. The material from the second location gave four closely related homoditerpenes and two geranyl nerol derivatives from which the homoditerpenes were derived. The structures were elucidated by high field ¹H NMR spectroscopy. Chemotaxonomic aspects are discussed briefly.     

Heliangolides,and nerolidol and p-hydroxyacetophenone derivatives from Calea species

A new Calea species afforded a heliangolide, closely related to niveusin C, while from Calea teucrifolia two new nerolidol derivatives and eight p-hydroxyacetophenone derivatives were isolated. The structures were elucidated by spectroscopic methods and a few chemical transformations. The spectral data of 8β-angeloylatripliciolide, the main constituent of C. teucrifolia, are also included. The chemotaxonomic situation is discussed briefly.     

Kolavenol derivatives from goyazianthus tetrastichus

From the new monotypic genus Goyazianthus several kolavenol derivatives were isolated. Their structures were elucidated by spectroscopic methods.     

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.     

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.     

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.     

Heliangolides and other constituents from Bejaranoa semistriata

The investigation of Bejaranoa semistriata, a new genus in the tribe Eupatorieae, afforded in addition to known compounds a new furanoheliangolide, two epimeric 1-keto-heliangolides, two germacranolides, two nerolidol derivatives and a geranylnerol derivative. The structures were elucidated by spectroscopic methods and a few chemical transformations.     

Five labdane derivatives from Koanophyllon conglobatum

A re-investigation of the aerial parts of Koanophyllon conglobatum afforded six new diterpenes, five labdanes and one seco-labdane, as well as two hydroperoxides which may be artefacts.     

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.