Terpen-glycoside aus Melampodium divaricatum

The roots and the aerial parts of M. divaricatum contain a large variety of esterified glycosides of hydroxythymol. Their structures were elucidated mainly by spectroscopic methods.     

New coumarins from Coleonema album

Six coumarins have been isolated from the aerial parts of Coleonema album and identified as ulopterol, 7-(3′, 3′-dimethylallyloxy)-coumarin, (R)-(+)-2′,3′-epoxy-suberosin, and the novel coumarins (R)-(+)-7-(2′, 3′-epoxy-3′-methylbutoxy)-coumarin, (R)-(+)-7-(2′,3′-dihydroxy-3′-dihydroxy-3′-methylbutoxy)-coumarin and (R)-(+)-7-methoxy-8-(2′,3′-epoxy-3′-methylbutoxy)-coumarin.     

Coumarins from Musineon divaricatum

A chemical investigation of Musineon divaricatum has resulted in the isolation of 19 coumarins, five of which are novel compounds; 18 are khellactone derivatives. The coumarins were isolated from the crude extracts by a combination of adsorption chromatography, gel permeation and HPLC; the more successful HPLC separations utilized a nitrile bonded phase column. The structures were determined by ¹H NMR and mass spectral studies and by comparisons with literature data. The relative configuration for the entire series was secured from ¹H NMR data, while the absolute configuration could be assigned with any certainty only in the cases of two of the compounds.     

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.     

Zoapatanolide A and B,two new heliangolides from Montanoa tomentosa

The re-investigation of Montanoa tomentosa afforded, in addition to known diterpenoids of the kaurene class, two new sesquiterpene lactones, zoapatanolide A and B, of the heliangolide type.     

Rotundin and (Z)-18-methylsphaerocephalin,two new germacranolides from Tithonia rotundifolia

The aerial part of Tithonia rotundifolia afforded the heliangolide rotundin and the germacrolide (Z)-18-methylsphaerocephalin.     

Tricyclic sesquiterpenes and further diterpenes from Espeletiopsis species

The investigation of five Espeletiopsis and two Coespeletia species afforded, in addition to numerous known compounds, two new kaurene derivatives 19-acetoxy-ent-kaurene and 17-oxo-ent-kaur- 15-en-19-oic acid, as well as two new tricyclic sesquiterpenes, one being the previously reported oxidation product of copaborneol and the second one the 5-oxo derivative of silphiperfol-6-ene. The structures were elucidated by NMR studies and by chemical transformations. The chemotaxonomic situation is discussed briefly.     

Toddanol and toddanone,two coumarins from Toddalia asiatica

Two new constituents isolated from the roots of Toddalia asiatica and designated as toddanol and toddanone have been characterized as 5,7-dimethoxy-6-(2-hydroxy-3-methylbut-3-enyl)coumarin (1) and 5,7-dimethoxy-6-(3-methyl-2-oxobutanyl)coumarin (3), respectively, by spectral analysis and interconversion experiments.     

Simple coumarins from two populations of Diosma acmaeophylla

Investigation of two collections of Diosma acmaeophylla afforded seven simple coumarins, three of which were common to both samples. The chemotaxon     

The structure of two new coumarins from the roots of Lomatium columbianum

Two new coumarins, obtained from the roots of Lomatium columbianum are shown to be trans-p-coumaroyllomatin and cis-p-coumaroyllomatin. Furthermore, the roots afforded columbianadin, selinidin, lomatin, (+)-dihydrooroselol, and a mixture of monoesters of khellactone.     

Methylated flavonols from Wyethia bolanderi and Balsamorhiza macrophylla

A leaf wash of Wyethia bolanderi afforded eight known methylated flavonols: santin, ermanin, jaceidin, 3,6-dimethoxyapigenin, kaempferide, isokaempferide, axillarin and quercetin 3-methyl ether. A leaf wash of Balsamorhiza macrophylla afforded six known methylated flavonols: centaureidin, quercetin 3,4′-dimethyl ether, axillarin, spinacetin, tamarexetin and quercetin 3-methyl ether. The chemotaxonomy of the two genera is discussed briefly.     

Neue melampolide und cis,cis-germacranolide aus vertretern der subtribus melampodiinae

The investigation of four South American species of the tribe Heliantheae afforded in addition to known compounds 14 new sesquiterpene lactones, mostly belonging to the melampolides, but four being further examples of cis,cis-germacranolides. The stereochemistry is established by intensive ¹H-NMR studies and some chemical transformations. Some of the new lactones were only obtainable as inseparable mixtures of 2-methylbutyric and isovaleric esters. Furthermore a new acetylenic aldehyde was isolated. The chemotaxonomic situation is discussed especially with regard to the position of the genus Smallanthus.     

Montafrusin,a new germacrolide from Montanoa frutescens

The investigation of Montanoa frutescens afforded a new sesquiterpene lactone of the germacrolide type, montafrusin, besides the known diterpenes kaurenic acid and its 15α-isovalerate.     

Structural clarification of germacranolides from Calea species

The aerial parts of Calea pinnatifida contain a 4-glycosyloxybenzoic acid, anisic acid, tetradeca-4E,6E,12E-trien-8,10-diyn-1-ol and arucanolide. The structural elucidation of this germacranolide included comparison with neurolenin B whose stereochemistry had been defined by X-ray crystallographic analysis. The data suggest that the structures of all other known germacranolides of the genus Calea should be revised.     

Three new melampolide sesquiterpenes,polymatin A,B and C,from Polymnia maculata Cav. var. maculata

Three new melampolide type sesquiterpene lactones were isolated from Polymnia maculata Cav. var. maculata. Their structures were determined by spectroscopic and chemical means. Based on the presently available chemical data, the chemotaxonomic position of Polymnia within the subtribe is discussed.     

Helipyrone from Anaphalis araneosa and its synthesis

The dimeric 4-hydroxy-2-pyrone, heliopyrone, was isolated from Anaphalis araneosa and its structure confirmed by spectral analysis and synthesis.     

Ent-beyerene and ent-atisene diterpenes from viguiera insignis

The new diterpenes, ent-beyer-15-ene-12α,19-diol and ent-atis-13-en-3β,16α-diol, were isolated as minor constituents from the aerial part of Viguiera insignis. The structures were established by biomimetic transformation, spectroscopic means and comparison with closely related compounds.     

Neue sesquiterpene aus Verbesina occidentalis

The investigation of the aerial parts of V. occidentalis affords six new sesquiterpenes their structures being elucidated by spectroscopic methods. All compounds are derived from muurolene. V. enceloides contains simple compounds, only one being new, which is closely related to a diacetate from Amphiachyris amoenum.