New 6-hydroxyflavonoids and their methyl ethers and glycosides from Neurolaena oaxacana

Six new and nine known flavonoids were obtained from Neurolaena oaxacana. The known flavonoids are 6-hydroxykaempferol 3,7-dimethyl ether, quercetagetin 3,7-dimethyl ether, quercetin 3-methyl ether, axillarin, nodifloretin, 6-hydroxyluteolin 7-glucoside, kaempferol 3-glucoside, quercetagetin 7-glucoside and patulitrin. The new compounds are 6-hydroxykaempferol 3-methyl ether, quercetagetin 3,7-dimethyl ether 6-galactoside, quercetagetin 3-methyl ether 7-glucoside, the 6- and 7-glucosides of 6-hydroxykaempferol 3-methyl ether and quercetagetin 3-methyl ether 7-sulfate.     

6-methoxyflavonoids from Brickellia laciniata (compositae)

One new and fourteen known flavonoids, including thirteen containing 6-methoxy groups, were isolated from Brickellia laciniata. The new flavonol is quercetagetin 6,4′-dimethyl ether. Among the known compounds identified were the 4′-methyl and 7,4′-dimethyl ethers of eupafolin and luteolin 4′-methyl ether, and the flavonols: patuletin, spinacetin, eupatolitin, eupatin, centaureidin, casticin, patuletin 3-glucoside and 3-galactoside, eupatolitin 3-galactoside, patuletin 3-SO₃K and eupatin 3-SO₃Ca_1/2.     

Flavonoids of four species of Parthenium (compositae)

Kaempferol and quercetin 3-O-glycosides were found in the closely related species, Parthenium hysterophorus, P. bipinnatifidum and P. glomeratum; the major aglycone flavonols in P. hypterophorus are quercetagetin 3,7-dimethyl ether and a new flavonoid, 6-hydroxykaempferol 3,7-dimethyl ether. The North-South American species-pair P. glomeratum (Argentina) and P. bipinnatifidum (Mexico) yielded quercetagetin 3,7,3′-trimethyl ether as the major aglycone. The desert species P. rollinsianum yielded five methylated flavonols: quercetin 3,3′-dimethyl ether, penduletin, quercetagetin 3,6,7-trimethyl ether, polycladin and artemetin.     

Sulfated and 6-methoxyflavonoids from Brickellia baccharidea (compositae)

Thirteen known flavonoids, all containing 6-methoxyl substitution, were identified from leaves of Brickellia baccharidea.     

6-Hydroxyflavonoids from Pulicaria dysenterica (compositae)

Methyl ethers of 6-hydroxykaempferol and quercetagetin, together with scutellarein, were isolated from the leaves of Pulicaria dysenterica. The pattern of compounds is different from that previously recorded in the flowers.     

6-Methoxyflavonoids from Brickellia californica

Two new and eleven known 6-methoxyflavonoids were identified in leaf tissue of Brickellia californica. The new flavonols are eupatin 3-SO₃ Ca_1/2 and patuletin 3-SO₃K. The known compounds include the flavones hispidulin and eupafolin and their respective 7- and 4′-monomethyl ethers and the flavonols; spinacetin, eupatin, patuletin 3-glucoside and 3-galactoside, and eupatolitin 3-galactoside.     

Flavonoids from Artemisia frigida

Twelve flavonoids including a new flavone were isolated from Artemisia frigida. The structure of the new highly oxygenated flavone was determined b     

Sesquiterpene lactones from Viguiera deltoidea

Three sesquiterpene lactones, 2′,3′-dihydroniveusin-A, 2′,3′-dihydroniveusin-B and 3-acetylchamissonin, were isolated from the dichloromethane extract of leaves of Viguiera deltoidea. The structures were established on the basis of physical and spectroscopic data and that of 3-acetylchamissonin was also confirmed by X-ray analysis.     

Flavonoids from Brickellia chlorolepis and B. dentata

Eleven flavonoids including three new glycosides were isolated from Brickellia chlorolepis and one new and nine known flavonoids were obtained from B. dentata. The new glycosides from B. chlorolepis are 6-methoxykaempferol 3-rhamnoglucoside, spinacetin 3-rhamnogalactoside and veronicafolin 3-rhamnoglucoside. The known compounds identified from B. chlorolepis are patuletin, casticin, artemetin, eupatolitin 3-galactoside, quercetin 3-rhamnogalactoside, rutin, isorhamnetin 3-galactoside and eupatin 3-SO₃Ca_{$\text{1}\text{2}$}. B. dentata contains the new glycoside eupalitin 3-galactoside and nine known compounds: pectolinarigenin, salvigenin, eupafolin, cirsiliol, eupatorin, eupatolitin, eupatolitin 3-glucoside, eupatolitin 3-galactoside and eupatin.     

6-Methoxyflavonols from Brickellia veronicaefolia (compositae)

Three new and eight known flavonols, all containing 6-methoxyl groups, were isolated from Brickellia veronicaefolia. The new compounds were eupatolitin 3-sulfate, 6-methoxyquercetin 7,3′-dimethyl ether (veronicafolin) 3-digalactoside and veronicafolin 3-sulfate. The known flavonoids were eupatolitin, quer-cetagetin 3,6,7-trimethyl ether, eupatin, casticin, artemetin, eupatolitin 3-galactoside, patuletin 3-sulfate and eupatin 3-sulfate.     

Two oxepane-type diterpene lactones from melampodium diffusum

The isolation and structure elucidation of two new oxepane diterpene lactones, 1,10,17-trihydroxymelfusanolide and 1,10-dihydroxy-17-acetoxymelfusanolide, from Melampodium diffusum are reported. The structure determination involved chemical and spectral methods.     

Germacranolides,calbertolides A,B and C,from Calea berteriana

The isolation and structure elucidation of two germacranolides, calbertolides A and B, and a heliangolide, calbertolide C, from Calea berteriana are reported. The structures of the new compounds were established by spectroscopic methods.     

Eudesmanolides,trichomatolides B–E,and A heliangolide from Calea trichomata

Calea trichomata gave in addition to four known 1β-hydroxy-8β-tigloyloxy-11(13)-eudesmen-6α, 12-olide derivatives a new heliangolide, 3-deoxy     

Guaianolides and chromenes from Calea species

Chemical analysis of Calea berteriana yielded, besides the known flavonoid acacetin and the sesquiterpene lactone calbertolide C, three new guaianolides, desacyl-8-tiglylsubcordatolide A and 8-epi-8-tiglylrupicolins A and B. C. prunifolia provided acacetin, calbertolide C, desacyl-8-tiglylsubcordatolide A, and two new chromenes, prunichromenes A and B. From C. solidaginea acacetin, heliangine, calbertolide C, 8-epi-8-tiglylrupicolin A and desacyl-8-tiglylsubcordatolide A were isolated. The structures of the new compounds were established by chemical and spectral methods.     

Sesquiterpene and diterpene lactones from melampodium longipilum

the aerial parts of Melampodium longipilum afforded two new diterpene lactones, 17-hydroxy- and 17-acetoxyacanthoaustralide, and a new sesquiterpene lactone, repandin E, besides the known melampolides enhydrin and fluctuanin.     

Flavonoid methyl ethers on the external leaf surface of Larrea tridentata and L. Divaricata

The external phenolic resin on the leaves of Larrea tridentata contains eighteen flavone and flavonol aglycones (mostly as methyl ethers), one dihydroflavonol and two lignans (including nordihydroguaiaretic acid). Except for a few isolated 2n populations which exhibited minor differences, a single chemical type was observed for all three ploidy levels (2n, 4n and 6n) in the North American L. tridentata suggesting an autoploid origin for the tetraploid and hexaploid races. The resin chemistry of the North American taxon was most similar to that of the Argentinian diploid L. divaricata, although the resin of the latter taxon did not contain the three 8-hydroxyflavonols; however, 8-hydroxyflavonol aglycones were detected in Peruvian populations of L. divaricata.     

6-Methoxyflavonols from disjunct populations of Brickellia cylindracea (compositae)

Eight identical 6-methylated flavonols including aglycones and glycosides were isolated from two geographically disjunction population of Brickellia cylindracea from Mount Livermore and Austin, Texas, suggesting that they are best treated as a single taxon. Among the flavonol aglycones identified were patuletin, centaureidin, quercetagetin 3,6,3′,4′-tetramethyl ether and artemetin. The flavonol glycosides were patuletin and its 3-galactoside, 3-galactogalactoside, 3-rhamnogalactoside and a 3-rhamnogalactoside derivative.     

Germacra-12,6β-olides from Montanoa revealii and M. mollissima

Montanoa revealii and M. mollissima yielded a series of germacra-12,6β-olides similar to those previously reported from M. hibiscifolia and M. pteropoda.     

Three sesquiterpene lactones from Helianthus niveus subsp. canescens and H. argophyllus

Further investigation of the minor terpenoids in Helianthus niveus subsp. canescens and H. argophyllus afforded two known 12,8-fused sesquiterpene lactones, 3-acetylchamissonin and simsiolide as well as one new germacranolide, argophyllin C. Identification and structure elucidation of these lactones by ¹H NMR and chemical transformations are described.