Michael Grenz

Terpen-derivate aus Senecio-arten

Zusammenfassung Uberblickt man das jetzt vorliegende Material uber die Gattung Senecio , so bestatigt sich die schon eingangs erwahnte Festellung, das in Eine klare Differenzierung der Gattung Senecio von den Nachbargruppen von der Seite der Inhaltsstoffe her, ist nach wie vor problematisch. Wahrsche

Neue sesquiterpenlactone und andere inhaltsstoffe aus vertretern der Eupatorium-gruppe☆

Abstract The investigation of twelve further species of the Eupatorium complex affords four new germacrolides and seven guaianolides together with new thymol and p-hydroxyacetophenone derivatives. The structures of these compounds have been elucidated by spectroscopic methods. Chemotaxonomic aspects of these findings are briefly discussed.

Twenty-one acylphloroglucinol derivatives and further constituents from south african Helichrysum species

Abstract The investigation of 27 South African Helichrysum species gave in addition to known compounds, 21 new acylphloroglucinol derivatives, five flavanoids, an unusual pyrone derivative, five diterpenes, a bicyclogermacrene and three cadinene derivatives, three guaianolides, a xanthanolide, a dimeric sesquiterpene lactone, an aliphatic lactone and seven glycerol angelate derivatives. The structures were elucidated by high field NMR techniques. The chemotaxonomic aspects are discussed in connection with previous investigations.

Eremophilane, germacrane and shikimic acid derivatives from chilean Senecio species

Abstract From 11 Chilean Senecio species eight new furoeremophilanes and eremophilanolides, eight eremophilane, one cadinane, five germacrane, one oplopanone and five shikimic acid derivatives were isolated in addition to known compounds. The structures were elucidated by high field NMR techniques and the chemotaxonomic aspects are discussed briefly.

Eudesmane derivatives from Verbesina species

Abstract 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.

Further pyrrolizidine alkaloids and furoeremophilanes from Senecio species

Abstract The investigation of 17 Senecio species afforded in addition to 14 known pyrrolizidine alkaloids 20 new ones, including some compounds of a novel type with an additional lactone moiety. Furthermore seven known and 11 new furoeremophilanes, two known and a new eremophilone, a further shikimic acid derivative and an acetylenic compound, most likely formed by intramolecular Diels-Alder reaction were isolated. The structures were elucidated by spectroscopic methods, especially high field 1H and 13C NMR and NOE difference spectroscopy. The configuration of the seneremophilondiol esters has been corrected.

Five diterpenes and other constituents from nine Baccharis species

Abstract The investigation of nine Baccharis species afforded, in addition to known compounds, three new clerodane derivatives related to bacchotricuneatin B, two ent -labdane derivatives, two 3-acetoxyflavanones, a benzofuran derivative and a chromene. The overall picture of the chemistry of this large genus is still not very clear.

Germacranolides and diterpenes from Viguiera species

Abstract The investigation of six Viguiera species afforded in addition to known compounds two new diterpenes, the 9,11-dehydro derivatives of trachylobanic and stachenic acid, two new heliangolides closely related to viguiestenin, and the acetate of falcarinol. The chemotaxonomic situation is discussed briefly.

A sesquiterpene lactone from Artemisia diffusa

Abstract The extract of the aerial parts of Artemisia diffusa afforded, in addition to several known eudesmanolides, two new eudesmanolides and a new type of sesquiterpene lactone with an eight-membered ring. The structures were elucidated by high field NMR techniques and some chemical transformations.

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

Abstract 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.