A New Phenylpropanoid Glycoside: Serratumoside A from Clerodendrum serratum

In the previous papers"', we have reported some chemical constituents fromClerodendrum serratum var. amplerghlium Moldenke. A continuation of our studies onthe same plant led to the isolation of a new phenylpropanoid, serratumoside A (l), whichis reported in this paper.Serratumoside A (l) with three known phenylpropanoid glycosides identified asacteoside', mwtinoside' and myricoside', respectively, were isolated from the Cserratum. Compound I was isolated as a brown amorphous powder, laly …     

A New Triterpenoid Saponin: Se-saponin A

In continuation of our studies on the constituents of Clerodendrum serratum var.amplexghlium Moldenke'-"', a new triterpenoid saponin, sc-saponin A (l), was isolated.To the best of our knowledge, it is the second instance oftriterpenoid saponin from theClerodendrum genus. This paper deals with the structural elucidation of the newcompound.Se-saponin A (l) an amorphous powder, gave positive Liebermann-Burchardreaction. It was deduced to have a molecular formula of C58H,,O,, by high resoluti…     

Two New Iridoid Glucosides from Clerodendrum serratum

Clerodendrumserratumcalledas"SanDuiJie"inChinese,isasmallshrubwithfragrantflowersfoundwidelyintheforestsofthesouthofChina.IthasbeenusedasafolkmedicineinYunnanfortreatmentofmanydiseasessuchashepatitisandmalaria.Inordertofindthebioactivecomponents,studiesonthechemicalconstituentsoftheleavesofClerodendrumserratum,collectedatLongLingofYunnanprovince,werecarriedout.Wehavereportedtwonewglycosidespreviously'.NoW,furtherinvestigationofglycosidesofthisplantresultedintwonewiridoidglucosides76coumar…     

Two New Diterpenoid Glucosides from Clerodendrum serratum

WereportedsomeconstituentsfromtheplantofC.serrartumvar.amplexghliumMoldenkel.Furtherstudyontheaerialpadsoftheplainresultedintheisolationoftwonewlabdanetypediterpenoidglucosides,cleroserraosideA(l)andcleroserraosideB(2).InthispaperwedescribethestructIJralelucidationofthecompounds.CleroserrosideA(l),[a]:'-97.22(c0.289,MeOH),wasobtainedaswhiteamorphouspowders.Itexhibitedan[M-l],ionpeakatm/z481inthenegativeionFABMSindicatingitsmolecularweighttobe482.ThemolecularformulawasdeterminedasC,,H.,…     

三对节中两个新环烯醚萜甙的研究

从三对节的叶子中分离得到４个化合物,经化学和光谱方法鉴定其为７－Ｏ－ｐ－Ｃｏｕｍａｒｏｙｌｏｘｙｕｇａｎｄｏｓｉｄｅ（１）,７－Ｏ－ｃｉｎｎａｍｏｙｌｏｘｙｕｇａｎｄｏｓｉｄｅ（２）,ａｃｔｅｏｓｉｄｅ（３）和ｍａｒｔｙｎｏｓｉｄｅ（４）,其中前两者是新环烯醚萜甙化合物,后两者为首次从该植物中获得的苯丙素甙类化合物。     

Two New Iridoid Glucosides from Clerodendrum serratum

In our previous paper"', we have reported some constituents' from the extract of C.Serralum var. amplexghlium Moldenke. Further investigation on the same plant led tothe isolation of two new iridoid glucosides, serratoside A (l) and serratoside B (2). Inthis communication, we describe the structural elucidation of the two new compounds.Serratoside A (l) (Figure l) was obtained as brown gum. The positive FABMSestablished a molecular formula of C,,H,,O,. for I (m/z 505 IM l] ), which was…     

Structure elucidation and synthesis of lycoposerramine-B, a novel oxime-containing Lycopodium alkaloid from Lycopodium serratum Thunb

A new alkaloid, lycoposerramine-B (1), containing an oxime function, was isolated from the club moss Lycopodium serratum Thunb. The structure of 1 was elucidated by spectroscopic analysis, including J-resolved HMBC spectroscopy, and confirmed by its synthesis from the known alkaloid, serratinine (3).     

Asymmetric total syntheses of two phlegmarine-type alkaloids, lycoposerramines-V and -W, newly isolated from Lycopodium serratum

Two new Phlegmarine-type alkaloids, lycoposerramines-V and -W, were isolated from Lycopodium serratum, and their structures including the absolute configuration were established by asymmetric total synthesis involving such key steps as Johnson-Claisen rearrangement, asymmetric allylation, and ring-closing metathesis (RCM)- or SmI(2)-mediated stereoselective piperidine ring construction.     

Ten new Lycopodium alkaloids having the lycopodane skeleton isolated from Lycopodium serratum Thunb

Ten new alkaloids, lycoposerramines-F (1), -G (2), -H (3), -I (4), -J (5), -K (6), -L (7), -M (8), -N (9), and -O (10), having lycopodine-related structures, were isolated from the club moss Lycopodium serratum THUNB. and their structures were elucidated on the basis of spectroscopic analysis and/or chemical transformation.     

基于聚亚甲基蓝-碳纳米管复合膜固载血红蛋白的H2O2生物传感器

采用吸附和电化学聚合修饰方法,制得了聚亚甲基蓝-碳纳米管聚合膜玻碳电极(PMB-MWNTs/GCE),再将血红蛋白(Hb)固定在PMB-MwNTs/GCE表面,制备了稳定的Hb/PMB-MwNTs//GCE的H2O2生物传感器,并用循环伏安法对修饰电极的生物电催化行为进行了表征.研究结果表明,固定在PMB-MWNTs/...     

三维有序石墨烯掺杂纳米二氧化钛酶生物传感器

采用模板法在氧化铟锡电极上制备了三维有序多孔结构的石墨烯掺杂纳米二氧化钛修饰电极,并在此修饰电极上成功固定了过氧化氢酶,从而构建了一种新型的H2O2生物传感器。 通过循环伏安、交流阻抗及计时电流等方法研究了该修饰电极的电化学特性,实验结果表明,该修饰电极对H2O2有良好的电催化作用,对H2O2的检测线性范围为3.0×10-6~3.6×10-3 mol/L,检测限为4.2×10-7 mol/L(S/N=3);且传感器响应迅速、灵敏度高、重现性和稳定性好。     

A novel Surface Plasmon Resonance enhanced Total Internal Reflection Ellipsometric application: electrochemically grafted isophthalic acid nanofilm on gold surface

The scope of this study is to modify a Surface Plasmon Resonance (SPR) sensor slide with isophthalic acid to evaluate the possible application on the detection of copper(II) ions in aqueous media by total internal reflection ellipsometry. A gold sensor surface was modified by an electrochemical diazonium reduction modification method. The modified surfaces are characterized with cyclic voltammetry (CV) and ellipsometry. Isophthalic acid monolayer modified gold slides were used for in situ detection of aqueous Cu(2+) solution with the SPR enhanced total internal reflection ellipsometry (SPRe-TIRE) technique. Layer formation, pH dependency of adsorption, sensor response of the SPRe-TIRE and isothermal kinetic parameters were examined. A high dependency on the number of CV cycles in the monolayer-multiple layer transition was observed. The suggested sensor gave a linear response over a wide range of Cu(2+) concentrations. It was also reported that adsorption on the SPRe-TIRE sensor gave Langmuir adsorption model behavior.     

A colorimetric sensor based on catechol-terminated mixed self-assembled monolayers modified gold nanoparticles for ultrasensitive detections of copper ions

A colorimetric sensor for Cu(II) ions has been developed based on mixed self-assembled monolayers (SAMs) modified gold nanoparticles (AuNPs). The AuNPs were modified with mixed SAMs consisting of mercaptosuccinic acid and the product of electrochemically triggered Michael addition reaction of 4-thiouracil and catechol. In the presence of Cu(II) ions, the coordination of Cu(2+) to catechol-terminated AuNPs leads to aggregation-induced changes of surface plasmon resonance. The cost-effective chemical sensor allows rapid, sensitive and selective detection of Cu(2+) ions, indicating its potential application in environmental field.     

A Novel Electrochemical Sensor Based on Reduced Graphene Oxide–TiO2 Nanocomposites with High Selectivity for the Determination of Hydroxychloroquine

Russian Journal of Electrochemistry - A simply sensitive sensor based on a reduced graphene oxide–TiO2 nanocomposite modified glassy carbon electrode (RGO–TiO2/GCE) was developed for...     

POMs as Active Center for Sensitively Electrochemical Detection of Bisphenol A and Acetaminophen

A new type of electrochemical sensor based on multi-walled carbon nanotubes(MWCNTs), K2H4SiW11CuO39-6H2O(SiW11Cu) and gold nanoparticles(AuNPs) was prepared for the simultaneous detection of bisphenol A and acetaminophen. Differential pulse voltammetry(DPV), cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) were used for electrochemical characterization, and Fourier transfonn infrared spectroscopy(FTIR) was used to characterize the structure of polyoxometalates. Electrochemical experimental results show that the composite modified electrodes have good electrochemical activity as well as current response values of bisphenol A and acetaminophen when pH=7.0. At the same time, the modified electrode exhibits good stability and reproduction, and has good anti-interference ability to other substances. In practical application, the sensor obtained satisfactory results.     

Enantioselective total synthesis of cyathin A3

The total synthesis of (-)-cyathin A3 is described. The key step involves an unusual enantioselective Diels-Alder reaction of 2,5-dimethyl-1,4-benzoquinone with 2,4-bis(trimethylsilyloxy)-1,3-pentadiene, using Mikami's catalyst [(R)-BINOL + Cl2Ti(OiPr)2 + 4 A mol sieves] modified by addition of Mg and SiO2. Because cyathin A3 is easily transformed into allocyathin B3, cyathin B3, cyathin C3, and neoallocyathin A4, this route also constitutes formal syntheses of these natural products.     

A Low Temperature Vulcanized Transparent Silane Modified Epoxy Resins for LED Filament Bulb Package

In this work, low-temperature vulcanized, transparent silane modified epoxy resins for LED filament bulb package were prepared. Firstly, transparent silane modified epoxy resins were produced through a controllable sol-gel method using γ-(2,3-epoxypropoxy)propytrimethoxysilane and dimethyldiethoxylsilane. The features of the reaction were investigated and the products were characterized in detail. Subsequently, various curing agents were explored to prepare transparent silane modified epoxy resins. The silane modified epoxy resins cured by PEA-230 at a fairly low temperature(40 °C/2 h then 60 °C/1 h) exhibited excellent thermal stability with a thermal degradation temperature as high as 316.5 °C and adjustable hardness between 40-60 shore A. The application tests showed the materials obtained were good candidates for LED filament bulb package.     

有机硅改性双酚A型环氧树脂研究

采用二氯二甲基硅烷 (DMS) ,或DMS与α ,ω 二氯聚二甲基硅氧烷 (DPS)的混合物来改性双酚A型环氧树脂 ,通过对固化物的冲击强度、拉伸强度、断裂伸长率和玻璃化转变温度 (Tg)的测定 ,探讨了改性方法、有机硅组成与含量等对材料性能的影响 .结果表明 ,用 5 7phr的DMS改性时 ,树脂固化物的冲击强度达2 0 2kJ m2 ,拉伸强度达 6 7 0MPa ,断裂伸长率达 11 2 9% ,Tg 达 16 8 0℃ ;分别比未改性时提高了 9 4kJ m2 ,2 1 1MPa ,5 4 %以及 32 6℃ .而用 0 7phrDMS +10phrDPS共同改性时 ,除Tg 和拉伸强度略有上升外 ,冲击强度达到了 31 6kJ m2 ,断裂伸长率达到 81 6 % ,分别比纯环氧提高了 2 0 8kJ m2 和 75 7% .     

Electrochemical sensor based on f-SWCNT and carboxylic group functionalized PEDOT for the sensitive determination of bisphenol A

A simple,sensitive,and reliable method for the voltammetric determination of bisphenol A(BPA) by using carboxylic group functionalized single-walled carbon nanotubes(f-SWCNT)/carboxylic-functionalized poly(3,4-ethylenedioxythiophene)(PC4) complex modified glassy carbon electrode(GCE) has been successfully developed.The electrochemical behavior of BPA at the surface of the modified electrode is investigated by electrochemical techniques.The cyclic voltammetry results show that the as-prepared electrode exhibits strong catalytic activity toward the oxidation of BPA with a well-defined anodic peak at 0.623 V in PBS(0.1 mol/L,pH 7.0).The surface morphology of the 3D network of composite film is beneficial for the adsorption of analytes.Under the optimized conditions,the oxidation peak current is proportional to BPA concentration in the range between 0.099 and 5.794 μmol/L(R~2 = 0.9989),with a limit of detection of 0.032 μmol/L(S/N = 3).The enhanced performance of the sensor can be attributed to the excellent electrocatalytic property of/-SWCNT and the extraordinary conductivity of PC4.Furthermore,the proposed modified electrode displays high stability and good reproducibility.The good result on the voltammetric determination of BPA also indicates that the asfabricated modified electrode will be a good candidate for the electrochemical determination and analysis of BPA.     

A modified Mannich-type reaction catalyzed by VO(acac)(2)

A facile VO(acac)(2)-catalyzed in situ generation of iminium ions from amine N-oxides and their participation in a modified Mannich-type reaction is described.