Goyazensolide,a schistosomicidal heliangolide from Eremanthus goyazensis

Isolation and structure determination of goyazensolide, a new heliangolide responsible for the schistosomicidal properties of Eremanthus goyazensis Sch.-Bip., is reported.     

Diterpene carboxylic acids and a heliangolide from Helianthus angustifolius

Two diterpene carboxylic acids, one a new kaurenoid derivative and one the previously characterized labdane, ()-cis-ozic acid, as well as a     

Eudesmanolides,trichomatolides B–E,and A heliangolide from Calea trichomata

Calea trichomata gave in addition to four known 1β-hydroxy-8β-tigloyloxy-11(13)-eudesmen-6α, 12-olide derivatives a new heliangolide, 3-deoxy     

A heliangolide from Schkuhria pinnata

Re-investigation of the aerial parts of Schkuhria pinnata afforded in addition to the heliangolides isolated previously a new one, the structure of     

A heliangolide from Chromolaena glaberrima

The investigation of Chromolaena glaberrima afforded, besides the known heliangolide chromolaenide, a new 4-dehydrochromolaenide. The structure of the new compound was elucidated by spectroscopic methods.     

An elemanolide from Zinnia grandiflora

Zinnia grandiflora afforded a new elemanolide with a δ-lactone ring.     

Six new melampolides from Tetragonotheca helianthoides

Chemical analysis of Tetragonotheca helianthoides L. yielded six new melampolide-type sesquiterpene lactones, tetrahelins A–F. All new compounds have the same medium ring skeleton and differ by the ester moieties at C-8 and C-9. Tetrahelin A and B contain the side chain 2-methyl-2,3-diacetoxybutanoate and tetrahelin E 3-hydroxy-3-methylbutanoate. Both ester side chains have previously not been found in sesquiterpene lactones.     

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.     

Eudesmanolides from Calea trichomata

Chemical analysis of Calea trichomata yielded, besides four known eudesmanolides, a new eudesmanolide, trichomatolide A. The structure of the new compound was established by chemical and spectral methods.     

Caryophyllene derivatives and a heliangolide from Lychnophora species

The investigation of three Lychnophora species afforded three new caryophyllenic acids and a new heliangolide closely related to 15-desoxygoyazensiolide. All three species contain lupeol, lupeyl acetate and eremanthine. The chemotaxonomic situation is 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.     

Furanoheliangolides and farnesol derivatives from Calea hispida

From Calea hispida, in addition to known compounds, two new furanoheliangolides, one substituted with a myrtenyl residue, two further farnesol deri     

Sesquiterpene lactones of Calea zacatechichi and C. urticifolia

Calea zacatechichi yielded the sesquiterpene lactone zexbrevin and a new analog, several analogs of neurolenin B including calein A, two analogs of budlein A and the flavones acacetin and O-methylacacetin. Calea urticifolia contained additional analogs of neurolenin B as well as a series of epoxidation products. Structures were established by spectrometric techniques. The results are contrasted with previous findings.