Guaianolides and heliangolides from Hymenopappus newberryi

The aerial parts of Hymenopappus newberryi afforded two heliangolides, two thymol derivatives, as well as two new guaianolides and a trans, trans-germacranolide closely related to hiyodorilactone A. Furthermore, the ent-kaurene derivative abbeokutone was present. These results are of chemotaxonomic interest.     

Three biologically active heliangolides from Helianthus annuus

Growth inhibiting substances in Helianthus annuus have been investigated. From the ethanolic extract a new germacranolide with an α-methylene-γ-lactone moiety, the heliangolide niveusin B and its ethoxy derivative were isolated and their structures elucidated by spectroscopic methods. The biological activity of each was determined by inhibition in Avena coleoptile tests and antimicrobial tests.     

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.     

Guaianolides,heliangolides, diterpenes and cycloartenol derivatives from Balsamorhiza sagittata

Investigation of the aerial parts of Balsamorhiza sagittata afforded 12 new sesquiterpene lactones, five guaianolides, three heliangolides, three germacranolides and two geranylnerol derivatives. From the roots eight cycloartane derivatives, a hydroxylanosterone and hexacos-1-ene were isolated. Structures were elucidated mainly by spectroscopic methods, especially high field NMR. The chemotaxonomic situation is discussed briefly.     

Heliangolides from Leucanthemopsis pulverulenta

The structure of hispanolide (4,5-cis-3-oxogermacranolide) and three other related germacranolides, isolated from Leucanthemopsis pulverulenta, have been established by a series of chemical transformations and spectral data.     

Eudesmanolides and heliangolides from Calea rotundifolia

The aerial parts of Calea rotundifolia afforded, in addition to known compounds, heliangin and two further closely related lactones as well as three new eudesmanolides and a norterpene ketone. The structures were elucidated by spectroscopic methods. The chemotaxonomic situation is discussed briefly.     

New heliangolides from Calea oxylepis

An investigation of the roots and aerial parts of Calea oxylepis afforded, in addition to known compounds, three new heliangolides and an unusual monoterpene triacetate.     

Fourteen heliangolides from Calea species

The investigation of two further Calea species afforded, in addition to known compounds, fourteen new heliangolides, most of them being 11,13-epoxides. One lactone is a new type, a heliangolide substituted with a monoterpene residue. Furthermore, a new chromene and a new dithienyl derivative were isolated. The structures were elucidated by spectroscopic methods. The chemotaxonomic situation is discussed briefly.     

Further sesquiterpene lactones from Calea and Viguiera species

The aerial parts of Calea clematidea gave three new germacranolides, those of Viguiera procumbens two orizabin derivatives and those of V. linearis dihydrobudlein A. In addition to these lactones, several known ones were isolated.     

Heliangolides and germacrolides from Disynaphia multicrenulata

Investigation of Disynaphia multicrenulata afforded, in addition to known ent-kaurene derivatives and some widespread sesquiterpenes, several s     

Four heliangolides and other sesquiterpenes from Brasilia sickii

The investigation of Brasilia sickii afforded, in addition to known compounds, two new bisabolene derivatives, an acetate closely related to damsin     

Rivularinin,a new saponin from Anemone rivularis

A new saponin, rivularinin, has been isolated from the ethanolic extract of Anemone rivularis (Ranunculaceae). The saponin was shown to be [α-l-arabinofuranosyl(1→2)-α-l-rhamnopyranosyl (1→4)-β-d-glucopyranosyl(1→4)-β-d-glucuronopyranosyl(1→3)]-3β-hydroxy-olean-12-en-28-oic acid.     

Sesquiterpene lactones from Helianthus niveus subsp. niveus

Six germacranolides, tirotundin, tagitinin A. orizabin, 8β,14-dihydroxycostunolide and its 14-isobutyrate, and 4β,5-dihydrotagitinin C, were isolated from aboveground parts of Helianthus niveus subsp. niveus. The last two compounds are new.     

Furanoheliangolides and flavonoids from Lourteigia ballotaefolia

The aerial parts of Lourteigia ballotaefolia afforded, in addition to three known flavonoids, two furanoheliangolides. The structures and stereochemistries were determined by chemical and spectroscopic means and were established as the 8- and 9-acetylsarracinoyl esters of 1-keto-8β-9β-dihydroxygermacra-2,4,11(13)-trien-3, (10β)-oxo-6α,12-olide. The chemotaxonomic situation is discussed briefly.     

Sesquiterpene lactones from Liatris acidota, L. Aspera and L. Mucronata

Examination of Liatris mucronata gave the known 15-hydroxylated heliangolides liscundin, liscunditrin, punctaliatrin and two new closely related heliangolides. Liatris acidota furnished six new similar but 15-deoxygenated heliangolides as well as euparin and 3β-acetoxytaraxaster-20-en-30-aldehyde. Liatris aspera gave a known glycosidic germacradienolide and a new germacradienolide as well as several known flavones and a known benzofuran. Structures were established by spectroscopic methods and chemical transformations.     

Trichoclin,a new furocoumarin from trichocline incana

The structure for trichoclin, (E)-8-(3-methyl-4-hydroxy-2-butenyloxy)-psoralen, a new furocoumarin isolated from Trichocline incana, has been established. Phellopterin and isopimpinellin were also obtained. The new side chain of trichoclin was confirmed by synthesis.     

Mikanokryptin,a new guianolide from Mikania

The isolation and structure determination of mikanokryptin, a stereoisomer of 11,13-dehydrogeigerin, from what appears to be a previously undescribed Mikania species is reported. Mikania micrantha HBK. yielded mikanolide and dihydromikanolide.     

Marginatin,a new germacranolide from Vernonia species

A new germacranolide, marginatin, has been isolated from three species of Vernonia from the central United States, V. marginata, V. fasciculata and V. arkansana, and its structure has been determined.     

Two new flavones from Eupatorium coelestinum

Besides coumarin, nobiletin, lucidin dimethyl ether and 5,6,7,3′,4′-pentamethoxyflavone, two new highly oxygenated flavones were isolated from Eupatorium coelestinum. Their structures were determined by spectroscopic methods and alkaline degradations as 5,6,7,8,3′,4′,5′ -heptamethoxyflavone and 5,6,7,8,5′-pentamethoxy-3′,4′-methylenedioxyflavone.