Eudesman-12,8β-olides and other terpenes from Artemisia species

The aerial parts of Artemisia iwayomogi afforded, in addition to already known terpenes, eleven new cudesmanolides whereas four new guaianolides were found in A. gmelinii. No sesquiterpene lactones were detected in the aerial parts of A. santolinifolia which afforded two new nerolidol derivatives besides several other already known compounds. From A. caerulescens var. cretacea six eudesmanolides were isolated, one of which has not been reported previously. The structures were elucidated by high field ¹H NMR spectroscopy and chemical transformations. The chemotaxonomic significance of sesquiterpene lactones within the section Abrotanum and the subgenus Seriphidium is briefly discussed.     

Dimeric guaianolides and other constituents from Gochnatia species

The roots of Gochnatia polymorpha afforded two new bisabolene derivatives and four dimeric guaianolides, two of them being isolated previously from G. paniculata. The aerial parts gave two further dimeric guaianolides. The aerial parts of G. hypoleuca afforded three new germacran-8,12-olides, a germacranolide acid and four additional dimeric guaianolides, which may be characteristic for this genus, while the presence of oxygenated germacranolides seems to be typical for the whole subtribe.     

Sesquiterpene lactones from Mikania species

The aerial parts of Mikania guaco afforded in addition to a known eudesmanolide three new ones. The aerial parts of M. vitifolia gave two guaianolides, both being 3-chlorodehydroleudocin derivatives and a seco-germacranolide related to pycnolide. The structures were elucidated by highfield NMR techniques. The proposed position of the hydroxyl group in a chloroguaianolide from a Lasiolaena species has to be revised.     

Neue guaianolide aus Cacosmia rugosa

The roots of C. rugosa afforded, in addition to known compounds, a C₁₇-acetylenic epoxide and five new guaianolides, four of them being hydroperoxides. The structures were elucidated by extensive NMR studies. The aerial parts only contain triterpene mixtures, as those of C. hieronymi. The compounds isolated confirm that Cacosmia is unrelated chemically to true members of the tribe Senecioneae.     

Helenanolides from Gaillardia powellii

The chloroform extract of the aerial parts of Gaillardia powellii afforded four known and four new helenanolides, the latter all oxygenated on C-15, as well as the flavones hispidulin and eupafolin.     

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.     

Dimeric guaianolides from Artemisia sieversiana

The aerial parts of Artemisia sieversiana afforded in addition to known compounds five new guaianolides and four dimeric guaianolides, three of them closely related to absinthin and one derived from estafiatin as a monomer. The structures were elucidated by extensive NMR studies, which allowed the assignment of the 14 chiral centres. Artemisia frigida afforded several known compounds and one new guaianolide, 8-desoxy-cumambrin B, the most likely precursor of many guaianolides.     

Seven germacranolides and four eudesmanolides from Tithonia rotundifolia

The aerial parts of Tithionia rotundifolia afforded, in addition to two known sesquiterpene lactones, eleven new ones, seven germacranolides and four eudesmanolides. The structures were determined by ¹H NMR spectroscopy.     

Pseudoguaianolides related to confertin from Stevia isomeca

The aerial parts of Stevia isomeca afforded, in addition to known compounds, four new sesquiterpene lactones, three pseudoguaianolides related to stevin and a xanthanolide. The structures were elucidated by spectroscopic methods and a few chemical transformations.     

Diterpenes and sesquiterpene lactones from Mikania congesta

The chloroform extract of the aerial parts of Mikania congesta, afforded four new geranylnerol derivatives, new analogs of deoxyelephantopin, a new melampolide and several known compounds. Structures were elucidated by spectroscopic methods and chemical transformations.     

Four new cis,cis-germacranolides from cytotoxic fractions of Melampodium cinereum

The aerial parts of Melampodium cinereum afforded an antineoplastic crude extract from which, besides the known dilactones cinerenin and melampodin B, four new cis-1(10)-cis-4,5- germacranolides, melcanthins DG, were isolated from cytotoxic fractions.     

11β,13-Dihydroguaianolides from Artemisia douglasiana and a thiophene acetylene from A. schmidtiana

The aerial parts of Artemisia douglasiana afforded, in addition to some known sesquiterpene lactones, 22 new closely related guaianolides. A new thiophene acetylene was isolated from the aerial parts of A. schmidtiana together with some known sesquiterpene lactones. The structures were elucidated by high field ¹H NMR spectroscopy.     

Neue cadinen- und norcadinen-derivate aus Heterotheca grandiflora

The aerial parts of Heterotheca grandiflora afforded, in addition to known compounds, nine new cadinene and four norcadinene derivatives, which probably are formed by decarboxylation of 2-methoxycalamenen-14-acid or related acids. The structures were elucidated by spectroscopic methods and a few chemical transformations.     

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

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.     

Diterpenes related to grindelic acid and further constituents from Grindelia species

The aerial parts of Grindelia stricta afforded in addition to known compounds 21 diterpenes, all closely related to grindelic acid. The aerial part     

Germacranolides from Eupatoriastrum nelsonii

The aerial parts of Eupatoriastrum nelsonii afforded, in addition to known sesquiterpene lactones, four new lactones all closely related to the germacranolides isolated previously from other genera of the tribe Eupatorieae. The structures were elucidated by spectroscopic methods. Chemotaxonomic aspects are discussed briefly.     

Germacranolides from Piptolepis Ericoides and Vanillosmopsis species

The aerial parts of Piptolepis ericoides afforded in addition to known compounds two new germacranolides, a zexbrevanolide and piptolepolide, tentatively characterized as a germacranolide with a trans-disubstituted double bond. From the aerial parts of two Vanillosmopis species in addition to goyazensolide, a new isomer with an exocyclic double bond was isolated.     

On the pungent principle of Matricaria pubescens

The pungent principle of the aerial parts and roots of Matricaria pubescens has shown to be the known thienyl-hexadien-isobutylamide. The structure was confirmed by ¹³C NMR analysis. In addition, the roots afforded small amounts of decadien-isobutylamide, and the aerial parts afforded large amounts of herniarin. The chemosystematic significance of amide accumulation within the tribe Anthemideae is briefly discussed.     

Inositol angelates from Inula cappa

The aerial parts of Inula cappa afforded four inositol tetra angelates.     

Hirsutinolides and other sesquiterpene lactones from Vernonia species

The investigation of Vernonia compactiflora afforded in addition to known compounds a hirsutinolide and a glaucolide; the latter is most probably the direct precursor of the former. The aerial parts of V. monocephala contain the same hirsutinolide as well as the corresponding acetate, while those of V. chalybaea afforded glaucolide B. A reinvestigation of the aerial parts of V. cotoneaster gave in addition to the allenic lactone isolated before two further known ones as well as a new glaucolide. The structures of the lactones were elucidated by spectroscopic methods and some chemical transformations. The erroneously assigned stereochemistry at C-10 in the hirsutinolides has been revised. The biogenetic relationship of the Vernonia lactones is discussed briefly.