Secoiridoid Constituents from the Fruits of Ligustrum lucidum

Four new secoiridiod glucosides, p‐hydroxyphenethyl 7‐β‐D ‐glucosideelenolic acid ester ( 1 ), 6′‐elenolylnicotiflorine ( 2 ), 6′′′‐acetylnicotiflorine ( 3 ), and oleoside 7‐ethyl 11‐methyl ester ( 4 ), as well as six known glucosides, nuezhenide ( 5 ), Gl‐3 ( 6 ), nicotiflorine ( 7 ), isonuezhenide ( 8 ), neonuezhenide ( 9 ), and oleoside 11‐methyl ester ( 10 ) were isolated from the fruits of Ligustrum lucidum. Their structures were elucidated by spectroscopic methods. Compound 4 was an artifact produced during extraction.     

Structure determination of chamaedryosides A—C,three novel nor‐neo‐clerodane glucosides from Teucrium chamaedrys,by NMR spectroscopy

Three new nor‐neo‐clerodane diterpenes, named chamaedryoside A (1), B (2) and C (3), have been isolated from the organic extracts of Teucrium chamaedrys (L.) and their structural characterization has been accomplished by ¹H and ¹³C‐NMR spectra, and DEPT, by COSY, TOCSY, HSQC, HSQC‐TOSCY and HMBC experiments, as well as by ESI‐MS/MS techniques. The stereostructures have been elucidated by NOESY and computational calculations. Copyright © 2009 John Wiley & Sons, Ltd.     

Enhanced degradation of cellulose acetate film containing diphenyliodonium salt–benzophenone

Cellulose acetate (degree of substitution 2.45) films containing diphenyliodonium salt and benzophenone were prepared and their degradative behavior was examined under simulated solar exposure. Acetic acid generation from the films under irradiation was greater in the co-presence of diphenyliodonium salt and benzophenone than in the sole presence of diphenyliodonium salt. Photosensitization and free-radical oxidization, which are followed by Brønsted acid generation, were postulated as the mechanism for the observed increase of deacetylation. The patterns of decreased molecular weight were different between the films with the diphenyliodonium salt and those with benzophenone; while the films with the diphenyliodonium salt kept a relatively constant molecular-weight distribution, the polydispersity increased in the films with benzophenone during the degradation. Since the synthesized characteristics of those two different patterns of change in molecular-weight distribution were observed in the co-presence of the diphenyliodonium salt and benzophenone, each additive appeared to act independently to lead to main-chain cleavage of cellulose acetate. Therefore, decrease in the molecular weight of cellulose acetate by diphenyliodonium salt did not seem to be enhanced in the co-presence with benzophenone.     

液相色谱/电喷雾质谱测定柑桔中的柠檬苦素类似物配糖体

 利用液相色谱 /电喷雾质谱联用技术对柚皮中的柠檬苦素类似物配糖体进行了定向分析 ,在柚皮的乙醇提取物中检测出奥巴叩酮配糖体和诺米林配糖体。利用制备液相色谱对这两种柠檬苦素类似物配糖体进行纯化 ,并用核磁共振对其结构进行鉴定。测定结果表明 ,液质联用法不需标样即可对柑桔中的柠檬苦素类似物配糖体进行定性分析。方法准确、快速、简便。     

Interaction of triplet-excited benzophenone with hindered amines and amino ethers A laser flash photolysis study employing photoconductivity and light emission measurements

Hindered amines such as 2,2,6,6-tetramethyl piperidines and N-methyl-2,2,6,6-tetramethyl piperidines and hindered amino ethers such as N-methoxy-2,2,6,6-tetramethyl piperidines were examined with respect to their reactivity towards triplet-excited benzophenone (³BP^*) in Ar-saturated acetonitrile solution at room temperature. Upon measuring phosphorescence decay rates in the absence and presence of quencher it was found that the amines are two to three orders of magnitude more reactive than the amino ethers. For all amine/BP systems examined the generation of free ions was inferred from an increase in the electrical conductivity. This indicates that a charge transfer (CT) mechanism is operative in these cases. Notably, tertiary amines were found to be more reactive towards ³BP^* and give higher free ion yields than secondary amines. In the case of amino ether/BP systems evidence for a CT mechanism was not obtained in spite of an increase in the electrical conductivity indicating the generation of free ions. The latter are formed much faster than the phosphorescence decays and very likely originate from triplet–triplet annihilation (³BP^*+³BP^*→BP√⁺+BP√⁻).     

New cucurbitane-type triterpenoid glucosides from the tubers of Hemsleya amabilis with anti-tumor activity

Abstract

Two new cucurbitane-type triterpenoid glucosides, 3β,11α-dihydroxycucurbita-5,24(E)-diene-3,26-glucosides (1) and 3β,11α-dihydroxycucurbita-5,24(Z)-diene-3,27-glucosides were isolated from the tubers of Hemsleya amabilis. Their structures were elucidated by various spectroscopic techniques including IR, HRESIMS, 1D and 2D NMR. The two compounds were evaluated for their anti-tumor activity against HeLa and HepG-2 cell lines, and both displayed moderate anti-tumor activity towards HeLa cell lines with IC₅₀ values of 9.8 and 15.7?μM, respectively.     

光引发丙烯酰胺在聚醚氨酯膜上的接枝聚合反应

本文研究了以二苯酮为光敏剂,在365nm光照下丙烯酰胺在聚醚氨酯表面的接枝聚合。研究了光照时间、单体浓度、二苯酮浓度对接枝率的影响。对产物作吸水性测定和扫描电镜观察,均证实是接枝共聚物。通过模型化合物的研究,认为激发三线态的二苯酮提取了聚醚氨酯中聚醚软段叔碳原子的氢和氨酯基氮原子上的氢,使这些部位产生自由基,引发单体接枝聚合。     

Unsymmetrical Diarylketones from Electron-rich Heterocyclic Arenes

Summary.  AlCl₃-mediated chlorocarbonylation of a first arene by oxalyl chloride followed by in situ Friedel-Crafts acylation of a second electron-rich arene expeditiously provides, in a one-pot procedure, either symmetrical or unsymmetrical benzophenones with yields ranging from 17–52%. Best results are obtained when the more activated substrate is used as the second arene. Another advantage is that the resultant benzophenone precipitates from the reaction mixture allowing facile workup. Corresponding author. E-mail: Poupaert@cmfa.ucl.ac.be Received October 4, 2002; accepted October 15, 2002 Published online March 6, 2003     

Unusual sesquiterpene glucosides from Amaranthus retroflexus

Implementing the phytochemical study of the weed Amaranthus retroflexus, four new sesquiterpene glucosides were isolated from the methanolic extract of the plant. The structures of these metabolites are determined on the basis of the mass spectrometry, and 1D and 2D NMR spectroscopies (DQ-COSY, TOCSY, HSQC, HSQC-TOCSY, HMBC, and NOESY). Two compounds are characterized by a new aglycone and differed from the site of glucosylation. The other two compounds are dimeric diastereoisomers.All the glucoside sesquiterpenes were tested on the wild species Taraxacum officinale to evaluate the role of this weed in the habitat and on the seed of A. retroflexus to verify the potential autotoxic effect of the plant.     

水溶性二苯酮类光敏剂中的羟基对光谱和光聚合的影响

有许多公司和研究所在从事光聚合的研究.本文报导两种不同分子结构的水溶性光敏剂的紫外光谱、磷光光谱和在不同溶剂中的量子产率,比较它们在水溶性预聚体中的光聚合效应. 两种水溶性光敏剂为: