RESUMO
The amorphane sesquiterpenes, deoxyarteannuin B and dihydro-deoxyarteannuin B, were isolated from Artemisia annua and their structures mainly determined by two-dimensional NMR spectoscopic analyses. The irregular monoterpene, trans-5-hydroxy-2-isopropenyl-5-methylhex-3-en-1-ol, was also characterized in the same way, and its structure was confirmed by synthesis from lavandulol. All of these natural products are suggested to be formed by autoxidation reactions. Full assignments of the 1H and 13C resonances for the known natural products epi-deoxyarteannuin B and isoannulide, determined by the same methodology, are also reported.
Assuntos
Artemisia/química , Artemisininas , Monoterpenos , Sesquiterpenos/química , Terpenos/química , Sesquiterpenos/isolamento & purificação , Terpenos/isolamento & purificaçãoRESUMO
Nine new phenylpropanoids (2-7, 10, 12, and 14) and two compounds representing novel structural classes of 7-O-8' and 7-O-8'.8-O-7' lignans (8 and 9, respectively) have been isolated from Illicium verum and their structures established by two-dimensional NMR. Most of these compounds appear to be biogenetically derived from threo-anethole glycol: relative stereochemistries for some members of this series were established by NOESY; absolute stereochemistries of others were determined by formation of Mosher esters.
Assuntos
Lignanas/isolamento & purificação , Fenilpropionatos/isolamento & purificação , Plantas Medicinais/química , Sequência de Carboidratos , China , Lignanas/química , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Dados de Sequência Molecular , Fenilpropionatos/química , Espectrofotometria Infravermelho , Espectrofotometria UltravioletaRESUMO
Twelve novel (1, 2, 4, 5, 7-14) and two known (3, 6) abietane diterpenes and have been isolated from the aerial parts of Illicium angustisepalum. These diterpenes are unusual in that they are oxygenated at the axial C-19 position of the gem-dimethyl group rather than the equatorial C-18 position.