A. Schuster

Hirsutinolides, glaucolides and sesquiterpene lactone from Vernonia species

Abstract The investigation of nine Vernonia species afforded in addition to known sesquiterpenes 28 new ones. The structures were elucidated by high field 1 H NMR spectroscopy and the configurations were determined by NOE difference spectroscopy and, in one case, by X-ray analysis. The results indicated that configurations of several previously reported sesquiterpene lactones have had to be revised. In addition to known types two new ones, the jalcaguaianolides and the vernojalcanolides, are described. Furthermore some unusual reaction products are presented which, in part, led to some natural occurring lactones.

Phloroglucinol derivatives and other constituents from south african helichrysum species

Abstract The investigation of 11 South African Helichrysum species afforded in addition to known compounds 26 further phloroglucinol derivatives, nine diterpenes, a derivative of isocomene and an α-pyrone derivative. The structures were elucidated by highfield NMR spectroscopy and a few chemical transformations. Furthermore the structures of several phloroglucinol derivatives were established by synthesis. The chemotaxonomy is discussed.

Sesquiterpene lactones from two Tithonia species

Abstract From two Tithonia species, in addition to known compounds, nine new sesquiterpene lactones were isolated: eight germacranolides and one eudesmanolide. The structures were elucidated by means of spectroscopic methods.

Further eudesmanolides and xanthanolides from Telekia speciosa

Abstract The re-investigation of the aerial parts of Telekia speciosa afforded five new sesquiterpene lactones, two eudesmanolides and three xanthanolides, all closely related to those isolated before from this species or from related genera. The structures were elucidated by 1 H NMR spectroscopy.

Sesqui- and diterpenes from Baccharis species

Abstract The extracts of the aerial parts of 10 Baccharis species gave in addition to several known compounds, also isolated from other species of the genus, seven new ent -clerodanes, seven labdanes, three of them being glycosides, a kaurane and a lactone derived from geranyllinalol. The structures were elucidated by high field NMR techniques.

New melampolides, kaurene derivatives and other constituents from Ichthyothere species

Abstract The reinvestigation of Ichthyothere terminalis afforded, in addition to known compounds, two new melampolides, a hydroxy borneol, a pinene derivati

Poskeanolide, a seco-germacranolide and other sesquiterpene lactones from Vernonia species

Abstract The aerial parts of Vernonia cinerea , collected in Costa Rica, gave four new hirsutinolides while a sample from Malawi afforded glaucolide E and two related lactones. From V. poskeana a seco-germacranolide biogenetically closely related to a new glaucolide was isolated. The investigation of two Critoniopsis species gave in addition to known lactones a further glaucolide and a vernopatensolide. A related species, V. flexipappa , only gave glaucolide B. The structures were elucidated by highfield NMR spectroscopy.

Guaianolides and homoditerpenes from Lasiolaena morii

The investigation of Lasiolaena morii afforded in addition to known compounds four new guaianolides, three diterpenes derived from geranyl nerol in

Sesquiterpene lactones from Vladimiria souliei

Abstract Chemical investigation of the underground parts of Vladimiria souliei from Sichuan province, southwest China, afforded nine new sesquiterpene lactones as well as 11 known ones. The structure and stereochemistry of the new compounds were elucidated by high field NMR techniques and a few chemical transformations.

Guaianolides and other constituents from Liabum floribundum

Abstract The reinvestigation of the aerial parts of Liabum floribundum afforded seven new guaianolides, all with a 9β-hydroxy group, a related eudesmanoli