RESUMO
The new homogentisic acid derivatives miliusol (1b) and miliusolide (2) from Miliusa balansae were isolated and structurally determined by spectroscopic means. The relative configurations of the new 1b and its known acetate 1a were established. Furthermore, the symmetric ether bis(2-hydroxyphenyl)methyl ether 3, which was isolated for the first time from a natural source, the known flavonoids pachypodol and chrysosplenol C, and sodium benzoate were identified.
Assuntos
Annonaceae/química , Benzofuranos/isolamento & purificação , Ácido Homogentísico/isolamento & purificação , Plantas Medicinais/química , Quercetina/análogos & derivados , Benzofuranos/química , Flavonoides/química , Flavonoides/isolamento & purificação , Ácido Homogentísico/análogos & derivados , Ácido Homogentísico/química , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Quercetina/química , Quercetina/isolamento & purificação , Estereoisomerismo , VietnãRESUMO
From the leaves of Xylopia vielana (Annonaceae) two dimeric guaianes named vielanins D and E were isolated and structurally elucidated by mass and NMR spectroscopy. Vielanin D and E consist of bridged ring systems formally representing the Diels-Alder products from the hypothetical guaiane-type monomers. Due to a hemiketal function at C-8' both compounds occurred as epimeric mixtures.
Assuntos
Annonaceae/química , Cicloeptanos/química , Cicloeptanos/isolamento & purificação , Sesquiterpenos de Guaiano/química , Sesquiterpenos de Guaiano/isolamento & purificação , Dimerização , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Folhas de Planta/química , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
The leaves of Luvunga sarmentosa yielded two new apotirucallane triterpenoids, 3-epi-skimmiarepin A (1) and 21,23-epoxy-7alpha,21-dihydroxyapotirucalla-14,24-dien-3-one (2), and a new tirucallane triterpene, 3-epi-flindissol (3). Because of a hemiacetal functionality at C-21, all compounds occurred as mixtures of 21-epimers. 3-epi-Skimmiarepin A (1) and 3-epi-flindissol (3) were oxidized to the corresponding gamma-lactones. The structures have been elucidated on the basis of mass and NMR spectroscopic methods.
Assuntos
Plantas Medicinais/química , Rutaceae/química , Triterpenos/isolamento & purificação , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Oxirredução , Estereoisomerismo , Triterpenos/química , VietnãRESUMO
The styryl derivatives 3,4-dimethoxy-6-styryl-pyran-2-one and (2E,5E)-2-methoxy-4-oxo-6-phenyl-hexa-2,5-dienoic acid methyl ester were isolated from leaves and branches of Miliusa balansae (Annonaceae). In addition, the geranylated homogentisic acid derivative miliusate, four flavanones and two dihydrochalcones were identified. Their structures were elucidated by spectroscopic means.
Assuntos
Annonaceae/química , Furanos/química , Furanos/isolamento & purificação , Estirenos/química , Estirenos/isolamento & purificação , Chalcona/análogos & derivados , Chalcona/química , Chalcona/isolamento & purificação , Flavonoides/química , Flavonoides/isolamento & purificação , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Estrutura Molecular , Componentes Aéreos da Planta/químicaRESUMO
The leaves of Luvunga sarmentosa (Bl.) Kurz. yielded eight apotirucallane triterpenoids named luvungins A-G, and 1alpha-acetoxyluvungin A. Characteristic of the structure are the seven-membered lactone-ring A, the alpha-hydroxyl or alpha-acetoxyl group at C-7 and an oxygen bridge in the side chain giving five-, six- or seven-membered rings, respectively. Because of a hemiacetal function at C-21, luvungin C occurred as a mixture of 21-epimers. The structures have been elucidated on the basis of MS and NMR spectral data. In addition, two known coumarins ostruthin (6-geranyl-7-hydroxycoumarin) and 8-geranyl-7-hydroxycoumarin as well as five known triterpenes friedelin, flindissone, melianone, niloticin and limonin were isolated.
Assuntos
Rutaceae/química , Triterpenos/isolamento & purificação , Estrutura Molecular , Folhas de Planta/química , Análise Espectral , Triterpenos/químicaRESUMO
Besides the known indole alkaloid, isovoacristine, the new bis-indole alkaloids, tabernaebovine and methylenebismehranine, have been isolated from the leaves and stems of Tabernaemontana bovina. Their structures have been assigned by NMR investigations.