Antoinette Suwita

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.

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

Abstract 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.

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.

Trixikingolides and germacrene derivatives from Trixis species

Abstract The investigation of two further Trixis species afforded five new sesquiterpenes related to trixikingolide, six new germacrene derivatives and a sesquiterpene derived from rotundene. Some further known compounds were isolated too, which in part may be of chemotaxonomic significance. The structures were elucidated by spectroscopic methods and a few chemical transformations. The relative position of the ester groups in eight of the new sesquiterpenoids however, could not be established with certainty as partial saponifications were not successful.

New labdane derivatives and further constituents of Brickellia species

Abstract The investigation of several Brickellia species and two further related species afford besides known compounds four new labdane derivatives, a new acetylenic carbinol and a new dihydrobenzofuran derivative. The structures have been elucidated by spectroscopic methods. The chemotaxonomic aspects are discussed briefly.

Neue ent-labdan-derivate aus Austroeupatorium chaparense☆

Abstract The aerial parts of A. chaparense afforded, in addition to known compounds, five new ent-labdane derivatives, while Campovassouria bupleurifolia contains mainly kaurene derivatives. The chemotaxonomic situation is briefly discussed.

Weitere phloroglucin-derivate aus Helichrysum-arten

Zusammenfassung The investigation of five further South African Helichrysum species afforded, in addition to known compounds, several new phloroglucinol derivatives, their structures being elucidated by spectroscopic methods and some chemical transformations. These results confirm the existence of several different chemical groups within this large genus.

Six guaianolides from Stylotrichium rotundifolium

Abstract The investigation of Stylotrichium rotundifolium afforded the epoxide of β-sesquiphellandrene, a new derivative of geranylnerol and six guaianolides not isolated previously. Furthermore, two germacranolides also present in a Lasiolaena species and several known compounds were isolated. The structures were elucidated by detailed 1 H NMR investigations. The chemotaxonomic situation is discussed briefly.