A new isoprenylated flavonol, named broussonol A (1) was isolated from the leaves of Broussonetia kazinoki Sieb. The structure of broussonol A was characterized by chemical and spectral methods.
Gnetuhainin S, a new resveratrol dimer, was isolated from the lianas of Gnetum hainanense C. Y. Cheng. Its structure and relative configuration were established on the basis of spectroscopic evidence.
Gnetupendin C, a new dimer coupled by a resveratrol and an oxyresveratrol unit, was isolated from the lianas of Gnetum pendulum C.Y. Cheng (Gnetaceae). Its structure was established on the basis of spectroscopic evide...Gnetupendin C, a new dimer coupled by a resveratrol and an oxyresveratrol unit, was isolated from the lianas of Gnetum pendulum C.Y. Cheng (Gnetaceae). Its structure was established on the basis of spectroscopic evidence, especially 2D techniques.展开更多
A new dihydroflavone (1), named macrophyllol A, was isolated from the roots of Uvaria macrophylla. Its structure was elucidated on the basis of spectroscopic evidence.
By means of variable temperature NMR spectra, conformation of 8-C-glucosyl prunetin, isolated from the leaves of Dalbergia hainanensis (Leguminosae), was studied. The restricted rotation around the C (sp3)-C (sp2) bo...By means of variable temperature NMR spectra, conformation of 8-C-glucosyl prunetin, isolated from the leaves of Dalbergia hainanensis (Leguminosae), was studied. The restricted rotation around the C (sp3)-C (sp2) bond in the C-glucosides isoflavonoid results in two main conformers (syn and anti). With the help of MM calculation, the preferred conformation A has H-1 gauche to the 7-OCH3. The barrier to rotation was 18.1 kcal/mol. This result agrees with the calculated value 16.2 kcal/mol of free energy of activation for the interconversion between the conformers.展开更多
文摘A new isoprenylated flavonol, named broussonol A (1) was isolated from the leaves of Broussonetia kazinoki Sieb. The structure of broussonol A was characterized by chemical and spectral methods.
文摘Gnetuhainin S, a new resveratrol dimer, was isolated from the lianas of Gnetum hainanense C. Y. Cheng. Its structure and relative configuration were established on the basis of spectroscopic evidence.
文摘Gnetupendin C, a new dimer coupled by a resveratrol and an oxyresveratrol unit, was isolated from the lianas of Gnetum pendulum C.Y. Cheng (Gnetaceae). Its structure was established on the basis of spectroscopic evidence, especially 2D techniques.
文摘A new dihydroflavone (1), named macrophyllol A, was isolated from the roots of Uvaria macrophylla. Its structure was elucidated on the basis of spectroscopic evidence.
文摘By means of variable temperature NMR spectra, conformation of 8-C-glucosyl prunetin, isolated from the leaves of Dalbergia hainanensis (Leguminosae), was studied. The restricted rotation around the C (sp3)-C (sp2) bond in the C-glucosides isoflavonoid results in two main conformers (syn and anti). With the help of MM calculation, the preferred conformation A has H-1 gauche to the 7-OCH3. The barrier to rotation was 18.1 kcal/mol. This result agrees with the calculated value 16.2 kcal/mol of free energy of activation for the interconversion between the conformers.
