Gnetuhainin P, a New Isorhapontigenin Dimer from the Lianas of Gnetum hainanense

Continuous investigation on oligostilbenes from the lianas of Gnetum hainanense resulted in the isolation of a new rhapontigenin dimer, Gnetuhainin P (1), in addition to the dimers of resveratrol and oxyresveratrol reported previously1. Gnetuhainin P (1) was obtained as a yellowish amorphous powder, [(]25D +6.6 (c 0.092, MeOH). The high resolution FABMS m/z 533.1866 [M+H]+ gave a molecular formula of C30H28O9 (C30H29O9 requires 533.1812), which corresponds to a isorhapontigenin dimer. …     

Characterization of Formation Kinetics of Self-Assembled Thiol Monolayers on Gold by Electrochemical Impedance Spectroscopy

Interest in the properties of organized monolayers has grown enormously in recent years because these monolayers can provide a means to control the interface at a molecular level1. The self-assemblies of alkanethiols and their derivatives were probably the most intensively studied due to their stability, well-packed structure, ease in preparation, and flexibility in designing the tail group2. The adsorption kinetics of thiol monolayer has been studied by using several techniques, including con…     

SYNTHESIS OF A SERIES OF NOVEL ORGANIC COMPOUNDS WITH TWO-PHOTON ABSORPTION AND TWO-PHOTON PUMPED LASING

Two-photon absorption (TPA) occurs through the simultaneous absorption of two photons via virtual states in a medium. Materials with large TPA cross section are gaining increasing attention recently due to their potential applications in optical data storage, two-photon up-converted lasing, two-photon-laser scanning fluorescence microscopy, optical power limiting and photodynamic therapy1-3. Numerous organic compounds have been investigated both experimentally and theoretically in order to u…     

Novel Stereoselective Synthesis of 1,3-Dienyl Tellurides by Palladium Catalyzed Cross-coupling Reaction of (E)-β-Bromovinyl Tellurides

Conjugated dienes are valuable intermediates in organic chemistry. Many biologically active compounds occurring in nature possess the structural skeleton of conjugated dienes such as chillea amide1 and pelltoine2. Besides, the synthesis of conjugated dienes for use in the Diels-Alder reaction is still an important challenge in organic synthesis. One particularly attractive approach has been the incorporation of heteroatom substituents that can activate the diene3.Recently, we found that β-br…     

A Molecular Modeling for the Complexation of Cyclobis(paraquat-p-phenylene) with Substituted Benzenes and Biphenyls

The molecular recognition of cyclobis(paraquat-p-phenylene), 14+, has drawn great attention recently, due to its important applications in the design and synthesis of electrochemically and chemically switchable rotaxanes, photoactive rotaxanes, and other molecular devices1. Usually, this type of molecular recognition was investigated with the methods including X-ray, NMR, UV, and IR. However, since these methods usually have difficulties in providing a detailed understanding of the energeti…     

One new bufadienolide biotransformed from cinobufagin by Cunninghamella elegans

Cunninghamella elegans has been employed for the biotransformation of cinobufagin （1） to afford one metabolites. The structure of the transformation product has been characterized as 7β,12β-dihydroxylcinobufagin （2）. Product 2 is a new compound. In vitro cytotoxic activities of the biotransformation product and the substrate-cinobufagin have been assayed against HeLa; they all showed cytotoxic activities.     

四氯四溴荧光素-Cl￣-Ag+沉淀吸附反应-光吸收比差法测定痕量氯离子

四氟四溴荧光素(TBTCF)能够与氯化银胶体在pH 4.33时发生灵敏的沉淀吸附反应,根据该反应颜色变化,应用光吸收比差法建立了痕量氯离子测定的新方法.实验表明盐度和温度对反应体系影响不明显.Cl￣浓度在0.09～9.0 mg/L范围与光吸收比差(△Ar)呈线性关系,方法检出限为0.03μg/mL.通过对三种地面水体Cl￣的分析,加标回收率为96.2%～104%,测定结果与离子色谱法相吻合.该方法具有成本低、选择性好、灵敏度高等特点,适用于现场在线检测以及海水、高温水体中氯离子的直接定量测定.     

Solid State Synthesis and Structural Characterizationof Binuclear Cu( I)-Sb Ph_3 Co m plex 〔 Cu( Sb Ph_3)_2 I〕

１　ＩＮＴＲＯＤＵＣＴＩＯＮＣｕ（Ｉ）ｃｏｍｐｌｅｘｅｓｗｉｔｈｐｈｏｓｐｈｉｎｅａｎｄａｒｓｉｎｅｌｉｇａｎｄｓａｒｅｗｅｌｌｋｎｏｗｎ〔１〕．ＦｏｒＣｕｐｈｏｓｐｈｉｎｅｃｏｍｐｌｅｘｅｓ，ｔｈｅＣｕ∶ｌｉｇａｎｄｒａｔｉｏｖａｒｉｅｓｆｒｏｍ１∶１ｔｏ１∶４ａｎｄｃｏｏｒｄｉｎａｔｉｏｎｇｅｏｍｅｔｒｙｏｆＣｕ（Ｉ）ｒａｎｇｅｓｆｒｏｍｌｉｎｅａｒｔｏｔｒｉｇｏｎａｌ，ｔｈｅｎｔｏｔｅｔｒａｈｅｄｒａｌｅｘｔｒｅｍｅｓ；ｆｏｒｅｘａｍｐｌｅ，ｔｈｅ１∶２ａｄｄｕｃｔｓＣｕ（ＰＰｈ３）…     

Direct amination of benzene to aniline with several typical vanadium complexes

The liquid-phase direct catalytic amination of benzene to aniline was performed in acetic acid water solvent using a series of vanadium(Ⅲ,Ⅳ,Ⅴ)complexes with N,O-or O,O-ligands as catalysts and hydroxylamine hydrochloride as the aminating agent. The vanadium complexes exhibited much higher selectivity towards the production of aniline than NaVO_3 or VOSO_4.Under the optimized conditions,an aniline yield of 42.5%and a TON of 48 with a high selectivity of above 99.9%was obtained using 0.2 mmol of[VO(OAc)_2]...     

The Synthesis of 7-[1-Aza-2-(dimethylamino)vinyl]-4-methylhydroquinolin-2-ones and their Isomerism in Different Solvents

Interesting biological activities have been reported recently for 4-methylhydro-2H-pyrano [6,5-h]-chromen-2-ones and 4-methylhydro-2H-pyrano[6,5-h]quinolin-2-ones, including excellent anti-HIV activity with DCK derivatives1 and significant cytotoxic activity with 4,8,8-trimethylhydro-2H-pyrano[6,5-h]quinolin-2-one2. These results prompted us to synthesize two series of corresponding diaza three-ring heterocyclic analogs, trihydro- pyridino[2,3-h]quinolin-2-ones and hydropyridino[2,3-h]quino…