An acyclic diterpene from Viguiera deltoidea

A new geranylgeraniol type diterpene, named viguieric acid, was isolated from the dichloromethane extracts of V. deltoidea. Its structure was assigned to be (2Z,6Z,10E)-3,15-dimethyl-7-carboxy-11-formyl-2,6,10,14-hexadecatetraen-1-ol.     

Tetrachyrin,a new rearranged kaurenoid lactone,and diterpene acids from Tetrachyron orizabaensis and Helianthus debilis

(?)-Kaur-16-en-19-oic acid and tetrachyrin, a new rearranged kaurenoid lactone, were isolated from Tetrachyron orizabaensis var. websteri and Helianthus debilis ssp. debilis. The latter species also afforded angeloylgrandifloric acid.     

Tomexanthin,an oxepane diterpene from montanoa tomentosa

Chemical analysis of Montanoa tomentosa yielded an oxepane diterpene, tomexanthin, which was characterized by spectral comparison with the previously established zoapatanol.     

Sesquiterpene lactones from Viguiera species

Viguiera eriophora yielded the sesquiterpene lactones erioflorin, acetylerioflorin and 17,18-dehydroviguiepinin, which was correlated with tetrahyd     

15-Hydroxy-acetylerioflorin and other constituents from Viguiera linearis

Aerial parts of Viguiera linearis afforded 16α-hydroxy-ent-kauranoic acid, viguiestenin, leptocarpin, acetylleptocarpin, budlein B, clovandiol and the new heliangolide 15-hydroxy-acetylerioflorin.     

A diterpene with a new carbon skeleton from Solidago altissima

An Indian sample of Solidago altissima afforded in addition to several clerodanes already isolated from other Solidago species, a diterpene with a new carbon skeleton. Furthermore a ketone and a new anethole derivative were present.     

2α-iso-Valeroyloxyeperuic acid,a diterpene from Eupatorium petiolare

The diterpene acid 2α-iso-valeroyloxyeperuic acid was isolated from the aerial parts of Eupatorium petiolare. Its structure and stereochemist     

Isolation and structure of stephalic acid,a new clerodane diterpene from Stevia polycephala

From the methanolic extract of Stevia polycephala a new clerodane-type diterpene, stephalic acid, was isolated. The structure and stereochemistry were determined by a combination of spectral data and single-crystal X-ray analysis.     

Ent-pimaranes, ent-kauranes,Heliangolides and other Constituents of three Helianthus species

Aerial parts of Helianthus strumosus gave the C-2′ epimer of the heliangolide 2′,3′-dihydrobudlein A as well as the flavones nevadensin, hyme     

Sesquiterpene lactones from Viguiera hypargyrea

The new sesquiterpene lactones 8β-[epoxyangeloyloxy]-14-hydroxytithifolin and 8-[epoxyangeloyl]-14-acetoxy-eupatolide, were isolated from Viguiera hypargyrea. The structures were established by chemical and spectroscopic means. The chemotaxonomic implications of the chemical constituents of Viguiera are briefly discussed.     

Two sesquiterpene and three diterpene lactones from Acanthospermum australe

The aerial parts of Acanthospermum australe afforded two new sesquiterpene lactones, an acid and a cis,cis-germacranolide, as well as three diterpene lactones of a new type, most probably formed by intermolecular nucleophilic attack of the carboxyl group of an acid epoxide derived from geranylgeraniol. The structures were proposed on the basis of spectroscopic studies.     

Germacranolides and diterpenes from Viguiera species

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.     

Viguilenin,a germacranolide from Viguiera linearis

The new germacranolide, viguilenin, was isolated from Viguiera linearis and its structure was established by chemical and spectroscopic means.