Triterpenoid glycosides from Stauntonia chinensis
A new bidesmoside triterpenoid saponin, named stauntoside C1 (1), along with three known saponins (2–4) was isolated from Stauntonia chinensis DC. (Lardizabalaceae). Their structures were established by means of spectral and chemical methods as 3-O-β-d-xylopyranosyl-(1 → 2)-O-β-d-xylopyranosyl-(1 → 3)-O-α-l-rhamnopyranosyl-(1 → 2)-α-l-arabinopyranosyl oleanolic acid 28-O-α-l-rhamnopyranosyl-(1 → 4)-β-d-glucopyranosyl-(1 → 6)-β-d-glucopyranosyl ester (1), scabiosaponin E (2), sieboldianoside B (3), and kizutasaponin K12 (4).
Five new bidesmoside triterpenoid saponins from Stauntonia chinensis
Eleven triterpenoid saponins (1–11) were isolated from Stauntonia chinensis DC. (Lardizabalaceae), including five new compounds, yemuoside YM21–25 (1–3, 6, 7) structures of which were elucidated by chemical methods and a combination of MS, 1D‐ and 2D‐ NMR experiments including DEPT, 1H1H COSY, HSQC, HMBC, TOCSY, and NOESY as 3‐O‐α‐L‐arabinopyranosyl‐(1 → 3)‐[α‐L‐rhamnopyranosyl‐(1 → 2)‐]α‐L‐arabinopyranosyl‐akebonicacid‐28‐O‐α‐L‐rhamnopyranosyl‐(1 → 4)‐β‐D‐glucopyranosyl‐(1 → 6)‐β‐D‐glucopyranosyl ester (1), 3‐O‐β‐D‐xylopyranosyl‐(1 → 3)‐α‐L‐rhamnopyranosyl‐(1 → 2)‐α‐L‐arabinopyranosyl‐akebonic acid‐28‐O‐α‐L‐rhamnopyranosyl‐(1 → 4)‐β‐D‐glucopyranosyl‐(1 → 6)‐β‐D‐glucopyranosyl ester (2), 3‐O‐β‐D‐glucopyranosyl‐(1 → 3)‐α‐L‐arabinopyranosyl‐akebonic acid‐28‐O‐α‐L‐rhamnopyranosyl‐(1 → 4)‐β‐D‐glucopyranosyl‐(1 → 6)‐β‐D‐glucopyranosyl ester (3), 3‐O‐α‐L‐arabinopyranosyl‐(1 → 3)‐[α‐L‐rhamnopyranosyl‐(1 → 2)‐]α‐L‐arabinopyranosyl‐akebonic acid‐28‐O‐β‐D‐glucopyranosyl‐(1 → 6)‐β‐D‐glucopyranosyl ester (6), 3‐O‐α‐L‐arabinopyranosyl‐(1 → 3)‐[α‐L‐arabinopyranosyl‐(1 → 2)‐]α‐L‐arabinopyranosyl‐akebonic acid‐28‐O‐β‐D‐glucopyranosyl‐(1 → 6)‐β‐D‐glucopyranosyl ester (7). Copyright © 2008 John Wiley & Sons, Ltd.
Fragment Rotational State Distributions From The Dissociation Of NeIBr: Experimental And Theoretical Results
The IBr fragment rotational state distributions that result when the NeIBr van der Waals molecule undergoes vibrational predissociation have been measured in a pump–probe laser‐induced fluorescence experiment. Independent of initial vibrational state and the number of quanta of vibrational energy lost from the I–Br coordinate, the rotational distributions extend over the full range of energetically accessible states. From the observation of energetic constraints on the rotational distribution, the dissociation energy (D0) is calculated to be 65.5±1.2 cm−1 for the A electronic state, v=16. For the X electronic state, v=0, D0=71.8±1.2 cm−1. Quantum mechanical bound state calculations carried out on a model A electronic state potential energy surface are in quantitative agreement with this result. The rotational distributions are broader than that predicted by either a Franck–Condon or classical impulsive model for the dissociation. The distributions are qualitatively in accord with classical trajectory calc...