Further glaucolides from south african Vernonia species

The investigation of three South African Vernonia species afforded minute amounts of five new glaucolides, two monoepoxides and three diepoxides. The structures were elucidated by ¹H NMR spectroscopy. The roots of Vernonia sutherlandii contain, in addition to vernonataloide, bergamotene and santalene, minute amounts of the corresponding acetoxy derivatives.     

Terpenoids and a flavan-3-ol from viguiera quinqueradiata

The isolation is reported of the new natural products from Viguiera quinqueradiata, acetylleptocarpin and (2R,3S-4′-hydroxy-3′,5,7-tri-O-methyl-flavan-3-ol. The diterpenes 15α-angeloyloxy-ent-kaur-16-en-19-oic acid, 15α-tigloyloxy-ent-kaur-16-en-19-oic acid and the sesquiterpene lactones leptocarpin and budlein A were also found.     

Guaianolides from Centaurea kotschyi

The aerial parts of Centaurea kotschyi (var. kotschyi) afforded, besides three known sesquiterpene lactones, a new derivative of linichlorin B.     

Xanthanolides from Xanthium indicum

From the aerial parts of Xanthium indicum, in addition to known compounds, two new xanthanolides were isolated and the stereochemistry of xanthumin     

Germacra-1(10),4-dien-cis-6,12-olides and elemanolides from Montanoa atriplicifolia

The investigation of the aerial parts of Montanoa atriplicifolia afforded, in addition to known compounds, two pairs of isomeric cis-6,12-germa     

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     

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.     

Sesquiterpene lactones from Ambrosia maritima (Damssissa)

Six sesquiterpene lactones were isolated from the aerial parts of Ambrosia maritima. Four pseudoguaianolides were isolated for the first time in addition to parthenin and neoambrosin.     

Xanthanolides from Xanthium spinosum

The aerial parts of Xanthium spinosum afforded in addition to known xanthanolides three new ones. The structures were elucidated by spectroscopic methods and by partial synthesis. Furthermore one lactone was transformed to a known derivative.     

2-Acetoxy-3α,4α-epoxy-3,4-dihydrokauniolide from grosvenoria coelocaulis

The aerial parts of Grosvenoria coelocaulis gave the known guaianolides dehydroleucodin, desacetoxymatricarin, kauniolide and a new one, 2β-acetoxy-3α,4α-epoxy-3,4-dihydrokauniolide.     

Guaianolides from Tricholepis glaberrima

Cynaropicrin and 11,13-dihydrodesacylcynaropicrin were isolated from Tricholepis glaberrima.     

Three eudesmanolides from Pluchea rosea

Three eudesmanolides of Pluchea rosea were found to be structurally related to the eudesmane, cuauthemone, earlier reported from plants of the same genus.