bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrochemical Properties of Th(IV)‐Hexacyanoferrate Sol‐Gel Carbon Composite Electrode: Electrocatalytic Oxidation of Dopamine and Ascorbic Acid
Authors: Farhadi Khalil , Kheiri Farshad , Golzan Mir Maqsood
Published: May 2015

A new sol‐gel carbon composite electrode using hexacyanoferrate (HCF)‐Th(IV) ion pair as a suitable modifier is fabricated in the present study. The Th(IV)‐HCF‐sol‐gel carbon composite electrode (THCF‐CCE) has been prepared by mixing methyl trimethoxysilan (MTMOS) sol‐gel precursor and carbon powder with ion pair and then to fix in a plastic tube. Cyclic voltammetry and chronoamperometry were employed to study the electrochemical and electrocatalytic properties of proposed electrode. The apparent charge transfer rate constant, ks, and transfer coefficient, α, for electron transfer between ion‐pair and sol‐gel CPE were calculated as 3.10 ± 0.10 s−1 and 0.52, respectively. The THCF‐CCE showed a significant electrocatalytic activity towards oxidation of ascorbic acid (AA) and dopamine (DA) in 0.1 M acidic phosphate buffer solutions (pH 3) containing KCl as a supporting electrolyte. The mean value of the diffusion coefficients for ascorbic acid and dopamine were found 4.12 × 10−5 and 4.43 × 10−5 (cm2s−1), respectively. High stability, good reproducibility, rapid response, easy surface regeneration and fabrication are the important characteristics of the proposed sensor. The resulting peaks from the electrocatalytic oxidation of AA and DA were well resolved with good sensitivity. A linear response was observed for AA and DA in the concentration range of 1 × 10−5 to 3 × 10−3 M and 4 × 10−6 to 2.2 × 10−4 M, respectively.
Simple and Sensitive Extractive Spectrophotometeric Method for the Assay of Mebeverine Hydrochloride in Pure and Pharmaceutical Formulations
Authors: Siddappa K. , Mallikarjun M. , Reddy Tukaram , Tambe Mahesh
Published: May 2015

Simple, sensitive, rapid and cost effective extraction spectrophotometric methods are described for the assay of mebeverine hydrochloride (MBH) in bulk samples and pharmaceutical formulations. These two methods (Bromophenol blue and Erichrome Black‐T) are based on the formation of chloroform soluble ion‐pair complexes of MBH with Bromophenol blue (BPB) and with Erichrome Black‐T (EBT), to form yellow and pink colored chromogen in a Glycine‐HCl buffer of pH 2.4 (BPB) and in a KCl‐HCl buffer of pH 1.4 (EBT) with absorbance maximum at 416 nm and at 524 nm for BPB and EBT respectively. The calibration graph is found to linear over 0.2–20 μg/mL (BPB) and 0.2–20 μg/mL (EBT), with molar absorptivity values of 1.8295 × 104 1 moL−1 cm−1 and 1.5896 × 104 1 moL−1 cm−1, respectively. The LOD (Limit of Detection) were found to be 0.090 μg/mL and 0.084 μg/mL and LOQ (Limit of Quantification) were 0.2997 μg/mL and 0.2730 μg/mL for the BPB and EBT method, respectively. The results of analysis for the two methods have been validated statistically and by recovery studies. The results are compared with those obtained with reported method. The proposed methods are simple, sensitive, accurate and suitable for quality control applications.
Application of Luminescent BSA‐Capped CdS Quantum Dots as a Fluorescence Probe for the Detection of Cu2+
Authors: Han Su‐Qin , Liu Jian‐Li , Gan Zhi‐Gang , Liang Jian‐Gong , Zhao Shou‐Miao
Published: May 2015

CdS Quantum dots (QDs) are synthesized in aqueous solution with bovine serum albumin (BSA) as the stabilizing agents using a stepwise procedure at room temperature. They can be used as a new fluorescence probe in the determination of Cu2+, which is proved to be a simple, rapid and specific method. Approximate concentrations of other physiologically important cations, such as Zn2+, K+ etc, have no effect on the fluorescence. Under the optimum condition, the response is linear to the concentration of Cu2+ in the range of 0‐80.0 μol/L, and the detection limit is 50.0 nmol/L. This method is used to the determination of Cu2+ in human hair, the recovery is 98‐104%. And the possible detection mechanism is also discussed.
Cold Deposition as a Novel Procedure for the Preparation of Titania Sol‐Gel: A Development of a High Sensitive Electrochemical Method for Determination of Cu(II) in the Presence of Arsenic(III)
Authors: Farhadi Khalil , Kheiri Farshad , Golzan Mir Maqsoud
Published: May 2015

Titania sol‐gel modified gold electrode (TSGMGE) was prepared with the usage of a new proposed cold deposition method at −10 °C. Scanning electron microscope (SEM) operating at 30 kV was used to obtain micrographs of unmodified and modified electrodes. The obtained results showed that this procedure yields a sol‐gel with high porosity in comparison to conventional methods. The modified Au electrode was fabricated by trapping the L‐glutamine in titania sol‐gel at low temperatures to preparation of a new titania sol‐gel glutamine modified gold electrode (TSGGMGE). The possibility determination of traces of Cu(II) in the presence of As(III) was investigated using proposed electrode. Under the optimized conditions, copper was accumulated at −0.35 V (vs. Ag/AgCl) for 40 s in 0.1 M acetate buffer (pH 4.0) in the presence of different amounts of arsenic. Two dynamic linear responses with good reproducibility were observed for copper ions in the concentration range of 1 × 10−6 −4 × 10−4 M and 4 × 10−8 −6 × 10−7 M.
Condensation of 1‐(Dicyanomethylene)acenaphthene‐2‐one with Aromatic Diamines
Authors: El‐Shaieb Kamal M.
Published: May 2015

1‐(Dicyanomethylene)acenaphthene‐2‐one (1) reacts with 1,8‐diaminonaphthalene (2) to yield two products, identified as acenaphtho[1,2‐b]naphtho[1,8‐ef][1,4]diazepine (3) and (Z)‐2‐(8‐aminonaphthalen‐1‐ylamino)‐2‐(2‐oxoacenaphthylen‐1(2H)‐ylidene)acetonitrile (4). On the other hand, (2Z,2′Z)‐2,2′‐(hydrazine‐1,2‐diylidene)diacenaphthylen‐1(2H)‐one (6) was obtained during the condensation process of 1 with hydrazine hydrate (5). Reaction of 1 with 3,4‐diaminotoluene (8b) produces 9‐methylacenaphtho[1,2‐b]quinoxaline (9b) and (Z)‐2‐(2‐amino‐5‐methylphenyl‐amino)‐2‐(2‐oxoacenaphthylen‐1(2H)‐ylidene)acetonitrile (10b). However, treatment of 5,6‐diamino‐pyrimidine‐2,4‐diol hemisulphate (11) with 1 affords acenaphtho[1,2‐g]pteridine‐9,11‐diol (12).
TH‐11, a Streptomyces sp. Strain that Degrades Poly(3‐Hydroxybutyrate) and Poly(Ethylene Succinate)
Authors: Hoang Kim‐Chi , Lee Chung‐Yi , Lai Yi‐Chi , Liau Chun‐Yi
Published: May 2015

TH‐11, a bacterial strain with strong depolymerase activity that breaks down aliphatic esters such as poly(3‐hydroxybutyrate) (PHB) and poly(ethylene succinate) (PES) was isolated from a soil sample collected from the sediment of Tou‐Chain River, Taiwan, R.O.C. It was phenotypically and genetically characterized to be a Streptomyces strain. The degradation of PHB and PES were tested both using emulsified polymers in solid agar and thin polymer films in liquid culture media. The degradations were measured by clear‐zone formation on solid agar plates, or direct weight measurements and electromicroscope inspection of the incubated polymer films in the liquid culture. The depolymerase activities can be detected in the cell‐free preparation of the culture medium, and can be enhanced by gelatin.
Synthesis of Morphlinotetrahydrothieno[2,3‐c]Isoquinolines
Authors: El‐Dean Adel M. Kamal , Radwan Shaban M. , Zaki Remon M.
Published: May 2015

1‐Morpholin‐4‐yl‐5,6,7,8‐tetrahydroisoquinoline‐4‐carbonitrile (2) was synthesized from 3‐amino‐1‐thioxo‐5,6,7,8‐tetrahydro‐1H‐isothiochromene‐4‐carbonitrile (1) and used as starting material to synthesize many thienotetrahydroisoquinolines (4), which in turn were used in the synthesis of many pyrimidothienotetrahydroisoquinolines.
Analysis Laboratory on a Chip
Authors: Lin Bing‐Cheng , Gao Yan , Qin Jian‐Hua
Published: May 2015

Microfluidic chip offers a promising platform for chemical or biological analysis on the basis of flexible integration of various functional operation units. This article provides an overview of the recent achievements of microfluidic chip and its applications based on the works mainly carried out in the authors' lab, especially for the purpose of constructing analytical laboratory on a microfluidic chip. Different operation units and some representative applications in molecules, cell and organism analysis are described.
Ligand‐Tuning of the Excitation Wavelength of a Solid state E/Z Isomerization: [Zn(TA)2(2,2′‐Bipyridyl)] in a Supramolecular Framework
Authors: Zheng Shao‐Liang , Gembicky Milan , Messerschmidt Marc , Coppens Philip
Published: May 2015

The single‐crystal‐to‐single‐crystal (SCSC) EŕZ photoisomerization of TA in the supramolecular solid CECR‐[Zn(TA)2(bpy)]·H2O (CECR = C‐ethylcalixresorcinarene, HTA = tiglic acid, and bpy = 2,2′‐bipyridine, is induced by 458 nm light, indicating a red‐shift of the photo‐active wavelength on introduction of the aromatic bpy ligand compared with the previously studied reaction of CECR‐[Zn(TA)2(H2O)2] 4H2O. Theoretical calculations show that the initial excitation involves the bipyridyl ligand, which acts as an intramolecular photosensitizer for the isomerization process. The reaction is topotactic and illustrated by photodifference maps.
DFT Modelling of the Magnetic Coupling in a Di‐ and in a Trinuclear Robson‐Type Complexes of CuII
Authors: Labéguerie Pierre , Rohmer Marie‐Madeleine , Bénard Marc
Published: May 2015

DFT/B3LYP calculations are able to reproduce the magnetic behaviour of dinuclear complexes of CuII within the framework of the Heisenberg Hamiltonian. The trinuclear complexes recently characterized by Glaser et al from trinucleating Robson‐type ligands provide an opportunity to extend the application of the broken symmetry formalism to a nonsymmetric CuIICuIICuII framework. At variance with the tentative fit deduced from experiment, the calculations suggest that the coupling along the three magnetic centers could be weak.
Synthesis and Biological Activity Evaluation of Novel Imidazolidinedione Derivatives, as Potent Antidiabetic Agent
Authors: Wang Run‐Ling , Li Wen‐Ming , Liu Meng‐Yuan , Xu Wei‐Ren
Published: May 2015

A set of novel imidazolidinedione derivatives were synthesized and evaluated as potential antidiabetic agents. Imidazolidinedione scaffold‐based molecules were synthesized and validated on a mice hyperglycemia model caused by alloxan. As a result, three of them showed antihyperglycemic activities. This research provides useful clues for further design and discovery of antidiabetic agents.
Ultrasound‐Assisted Wittig Reaction: A Short, Efficient Synthesis of 2‐Methoxy‐6‐Alkyl‐1,4‐Benzoquinones
Authors: Wu Li‐Qiang , Yang Chun‐Guang , Yang Li‐Ming , Yang Li‐Juan
Published: May 2015

A short, efficient synthesis of 2‐methoxy‐6‐alkyl‐1,4‐benzoquinones is described. Ultrasound‐assisted Wittig reaction of alkyltriphenyl phosphonium bromides with o‐vanillin in basic aqueous conditions followed by reduction with Na/n‐BuOH gave 2‐methoxy‐6‐alkylphenols. Oxidation of 2‐methoxy‐6‐alkylphenols with Fremy's salt produced the title compounds.
A Multi‐Center Energy Analysis of the Tunable Proton Affinity of Hydrogen Bonded Cluster Ions
Authors: Lankau Timm , Yu Chin‐Hui
Published: May 2015

The proton affinity (PA) of the [Tca–HβMim]− ion (Tca−: trichloroacetate ion, HMim: 4‐Methyl‐1H‐imidazole) is a nearly linear function of the position (r3) of Hβ using the rigid framework approximation. This useful property of the ion is caused by an unusually large four‐center interaction term revealed by the multi‐center energy (MCE) analysis of PA(r3). The MCE analysis shows further that despite the general stabilization of the [Tca–HMim–HAc]− ion by cooperative effects, the individual hydrogen bonds carry a strong anti‐cooperative element caused by the rivalry of the two bases for the proton linking them.
Crystal Structures, Magnetic Properties and Catecholase‐Like Activities of μ‐Alkoxo‐μ‐Carboxylato Double Bridged Dinuclear and Tetranuclear Copper(II) Complexes
Authors: Chen Chih‐Yu , Lu Jian‐Wei , Wei Ho‐Hsiang
Published: May 2015

One μ‐alkoxo‐μ‐carboxylato bridged dinuclear copper(II) complex, [Cu2(L1)(μ‐C6H5CO2)] (1)(H3L1 = 1,3‐bis(salicylideneamino)‐2‐propanol)), and two μ‐alkoxo‐μ‐dicarboxylato doubly‐bridged tetranuclear copper(II) complexes, [Cu4(L1)2(μ‐C8H10O4)(DMF)2]·H2O (2) and [Cu4(L2)2(μ‐C5H6O4]·2H2O·2CH3CN (3) (H3L2 = 1,3‐bis(5‐bromo‐salicylideneamino)‐2‐propanol)) have been prepared and characterized. The single crystal X‐ray analysis shows that the structure of complex 1 is dimeric with two adjacent copper(II) atoms bridged by μ‐alkoxo‐μ‐carboxylato ligands where the Cu···Cu distances and Cu‐O(alkoxo)‐Cu angles are 3.5 11 Å and 132.8°, respectively. Complexes 2 and 3 consist of a μ‐alkoxo‐μ‐dicarboxylato doubly‐bridged tetranuclear Cu(II) complex with mean Cu‐Cu distances and Cu‐O‐Cu angles of 3.092 Å and 104.2° for 2 and 3.486 Å and 129.9° for 3, respectively. Magnetic measurements reveal that 1 is strong antiferromagnetically coupled with 2J =‐210 cm−1 while 2 and 3 exhibit ferromagnetic coupling with 2J = 126 cm−1 and 82 cm−1 (averaged), respectively. The 2J values of 1–3 are correlated to dihedral angles and the Cu‐O‐Cu angles. Dependence of the pH at 25 °C on the reaction rate of oxidation of 3,5‐di‐tert‐butylcatechol (3,5‐DTBC) to the corresponding quinone (3,5‐DTBQ) catalyzed by 1–3 was studied. Complexes 1–3 exhibit catecholase‐like active at above pH 8 and 25 °C for oxidation of 3,5‐di‐tert‐butylcatechol.
A New Low‐Molecular‐Weight Gelator: 2,4,6‐Tris(N′‐Laurylureido‐Phenoxy)Triazine in Different Solvents
Authors: Lu Cheng‐Chi , Su Shuenn‐Kung
Published: May 2015

A new gelator of urea‐containing triazine derivatives was synthesized, and its gelation potential was examined in different organic solvents. The compound was found to form organogels with a variety of organic solvents such as decalin and other solvents. The resulting thermo‐reversible gel was characterized by using the dropping ball method and a number of other instruments. The melting temperature of the gels in decalin and DMSO increased with the gelator concentrations. Intermolecular hydrogen bonding of gelation was observed with a FT‐IR spectrometer. Temperature‐dependent UV‐Vis and fluorescence analysis revealed that the organogels displayed the H‐type aggregation in decalin and the J‐type aggregation in DMSO. The morphological features of the gels in decalin and DMSO were studied by applying atomic force microscopy (AFM), and the morphological features demonstrated that there were different aggregations in different solvents.
On‐Surface Cyclization of Tetrapeptides Using Molecularly Imprinted Polymers as Non‐Covalent Auxiliaries
Authors: Lin Yee‐Fung , Lee Shih‐Ming , Chen Chi‐Tai , Lu Kao‐Haw , Tai Dar‐Fu
Published: May 2015

Based on the fabrication of molecularly imprinted polymeric film on cellulose paper (MIFC), we have developed a robotic system for homodetic tetrapeptide cyclization. We constructed molecularly imprinted polymeric film (MIPF) on cellulose paper as the non‐covalent auxiliary to assist cyclic tetrapeptide (CTP) formation. Tetrapeptides were bound by their hydrophobic interaction with MIFC. With the help of MIFC and a coupling reagent, quantitative synthesis of CTPs was achieved conveniently for various tetrapeptides. The syntheses of cyclic tetrapeptide (CTP) could also be facilitated using the MIFC induced from CTP or other tetrapeptides with partially matched sequences.
Simultaneous Spectrophotometric Determination of Paracetamol and P‐Aminophenol by Using Mean Centering of Ratio Kinetic Profiles
Authors: Kamyabi Mohammad Ali
Published: May 2015

A specific spectrophotometric method was developed for simultaneous determination of paracetamol (PCT) and p‐aminophenol (PAP) in water samples without prior separation steps. The method is based on the mean centering of ratio kinetic profiles. Paracetamol and P‐aminophenol react with Fe(III)/hexacyanoferrate(III) complex and result in the formation of colored complex, i.e. Prussian Blue. The differences in the rate of reaction of PCT and PAP with reagents make their simultaneous determination feasible by using mean centering of ratio kinetic profiles.

The experimental parameters, such as reagent concentrations and pH were optimized for getting results with minimum errors. The analytical characteristics of the method such as detection limit, accuracy, precision, relative standard deviation (R.S.D.) and relative standard error (R.S.E.) for the simultaneous determination of binary mixtures of p‐aminophenol and acetaminophen were calculated. The results show that the method was capable of simultaneous determination of 0.5–21.0 μg mL−1 and 0.1–15.0 μg mL−1 of PCT and PAP, respectively. The proposed method was successfully applied to the simultaneous determination of paracetamol and p‐aminophenol in several pharmaceutical products and synthetics mixtures.
Chemiluminescence Determination of Sulpiride in Pharmaceutical Preparations and Biological Fluids Based on KMnO4‐Tween 80 Reaction
Authors: Li Yin‐Huan
Published: May 2015

Chemiluminescence (CL) of an acidic KMnO4 system in the presence of Tween 80 was investigated for the determination of sulpiride. Strong CL was recorded when a mixture of sulpiride and Tween 80 was injected into acidic KMnO4 solution. The experimental parameters affecting the CL intensity were carefully studied using flow injection mode. Under the optimum conditions, the CL intensity was proportional to the concentration of sulpiride in the range of 5.0 × 10−7 ∼ 1.0 × 10−4 g mL−1. The detection limit is 1.6 × 10−7 g mL−1 sulpiride, and the relative standard deviation for 1.0 × 10−6 g mL−1 sulpiride solution is 1.5% (n = 11). The proposed method has been successfully applied to the determination of sulpiride in tablets and in spiked human plasma and urine samples.
Simultaneous Determination of Paracetamol and Orphenadrine Citrate in Dosage Formulations and in Human Serum by RP‐HPLC
Authors: Arayne M. Saeed , Sultana Najma , Siddiqui Farhan Ahmed
Published: May 2015

Rapid liquid chromatographic procedures are proposed for analysis of paracetamol and orphenadrine citrate in pharmaceutical preparations and human serum using acetonitrile: water (50:50) as a mobile phase, adjusting pH to 2.6, UV detection at 215 nm and propylparaben sodium as internal standard. The advantages of this method include good and rapid separation, well resolved peaks, and only a small amount of sample is required for assay and adequate precision. The method showed good linearity in the range of 6 to 10000 ng/mL for paracetamol serum concentrations with a correlation coefficient 0.9999 (inter and intra day CV < 3.15) and in the range 3–10000 ng/mL for orphenadrine citrate serum concentrations with a correlation coefficient of 0.9999 (inter and intra day CV < 3.58). The recovery of paracetamol and orphenadrine citrate was > 96.9% and > 96.7%, respectively. The proposed method may be used for the quantitative analysis of paracetamol and orphenadrine citrate alone or in combination from raw materials, in bulk drugs, dosage formulations and in serum.
Cyclic Voltammetrically‐Prepared MnO2 Coated on an ITO Glass Substrate
Authors: Ding Ke‐Qiang
Published: May 2015

For the first time, nanostructured manganese dioxide was successfully electrodeposited onto an ITO (indium tin oxide) glass substrate by cyclic voltammetry (CV) method from an aqueous solution of 0.1 M Na2SO4 containing 5 × 10−3 M MnSO4. The obtained manganese dioxide‐modified ITO glass substrates were characterized by energy dispersive spectrometry (EDS), Fourier transform infrared spectrometry (FTIR) and scanning electron microscopy (SEM), respectively. All results not only proved the existence of MnO2 on an ITO glass substrate but also demonstrated that the morphology of the obtained MnO2 was greatly affected by the electrodeposition conditions. Also, this MnO2‐modified ITO electrode was systematically investigated by cyclic voltammetry (CV), chronopotentiometry and electrochemical impedance spectroscopy (EIS) in an aqueous electrolyte of 0.1 M Na2SO4. The results obtained from electrochemical measurement indicated that this developed MnO2‐modified ITO electrode has a satisfied specific capacitance value of 264 F·g−1 and exhibits excellent electrochemical stability and reversibility.
Sulfamic Acid as a Cost‐Effective and Recyclable Catalyst for β‐Amino Carbonyl Compounds Synthesis
Authors: Luo Hai‐Tang , Kang Yu‐Ru , Nie Hong‐Yun , Yang Li‐Ming
Published: May 2015

Sulfamic acid was used as a catalyst in the synthesis of β‐amino carbonyl compounds from amines, acetophenone and aldehyde. The reaction was carried out at room temperature. High selectivity, mild reaction temperature, cost‐effective catalyst, simple product separation and catalyst recycle were notable achievements in the reaction. Another feature was that the reaction could be performed on a relatively larger scale to the model reaction (50 times), which also gave good yields. In particular, the first preparation of β, β'‐diamino diketone derivatives via the direct coupling of amines, acetophenone and isophthalic aldehyde promoted by sulfamic acid has been developed.
An Efficient Catalytic Procedure for the Selective Oxidation of Sulfides to Sulfoxides by Citric Acid/Al(NO3)3.9H2O/MBr Under Mild and Heterogeneous Conditions
Authors: Ghorbani‐Choghamarani Arash , Rezaei Somaieh
Published: May 2015

A wide range of aliphatic or aromatic sulfides are selectively oxidized to the corresponding sulfoxides using Al(NO3)3.9H2O, citric acid and a catalytic amount of KBr or NaBr in the presence of wet SiO2 (50% w/w)in CH2Cl2 under mild and heterogeneous conditions in good to high yields.
A Simple Method to Prepare On‐Capillary Frits for Micro‐Column Separation
Authors: Zhang Yi‐Jun , Chen Na , Wang Ai‐Rong , Wei Xin‐Jun , Zhang Yu‐Ping , Qu Ling‐Bo
Published: May 2015

Sintering stainless steel powders was initially used to prepare the inlet frit in fused silica capillaries. The use of such inlet frits and outlet frits sintered by the stationary phase itself in the capillary to retain C18 particles was demonstrated to withstand the long exposure, up to a high pressure of 60 MPa, for packing and the prepare column was stable and robust enough to do the continuous chromatographic operations. Characterization of the inlet and outlet frits by scanning electron micrography showed the fused metal particles formed a porous network in the capillary inlet and the homogenous separation beddings were obtained by slurry packing.
Nanocrystals of Co2+‐Doped MgGa2O4: Preparation by a Low‐Temperature Combustion Method and Optical Properties
Authors: Lu Hai‐Liang , Du Ji‐Yong , Tang Zi‐Qiang , Liu Chang‐Ning
Published: May 2015

Co2+‐doped MgGa2O4 nanocrystals were prepared at 500°C by a low‐temperature combustion method without any further calcination. Powder X‐ray diffraction (XRD) indicated that the only crystalline phase in the product was MgGa2O4 with a grain size of 33–36 nm. Scanning electron microscopy (SEM) showed that the products contained pores formed by the gases evolved during the combustion reaction. The excitation and emission spectra of the nanocrystalline powders in the visible and near infrared regions were characteristic of tetrahedral Co2+ ions, suggesting that Co2+ ions replaced tetrahedral Mg2+ ions in the MgGa2O4 crystals. We assigned the visible and near infrared luminescent bands to the spin‐allowed 4T1(4P) → and 4A2(4F) and 4T1(4P) → 4T2(4F) transitions.
Preconcentration of Rare Earth Elements in Seawater with Chelating Resin Having Fluorinated β‐Diketone Immobilized on Styrene Divinyl Benzene for their Determination by ICP‐OES
Authors: Waqar Farhat , Jan Saida , Mohammad Bashir , Hakim Muhammad , Alam Shah , Yawar Wasim
Published: May 2015

An analytical method has been developed for the preconcentration of rare earth elements (REEs) in seawater for their determination by inductively coupled plasma optical emission spectrometry (ICP‐OES). An indigenously synthesized chelating resin was used for the preconcentration of (REEs) which was based on immobilization of fluorinated β‐diketone group on solid support styrene divinyl benzene. Sample solutions (adjusted to optimized pH) were passed through a polyethylene column packed with 250 mg of the resin. Experimental conditions consisting of pH, sample flow rate, sample volume and eluent concentration were optimized. The established method has been applied for the preconcentration of light, medium and heavy REEs in coastal sea water samples for their subsequent determination by (ICP‐OES). Percentage recoveries of La, Ce, Nd, Sm, Eu, Gd, Dy, Er, Yb and Lu were ≥ 95%, a preconcentration factor of 200 times, and relative standard deviations < 5% were achieved.
Determination of Total Polyphenol Glycosides in Polygoni Cuspidati Rhizoma and Rumecis Radix
Authors: Chiang Hsiu‐Mei , Tsai Shang‐Yuan , Hsiao Pei‐Ling , Chiu Chen‐Yuan , Hsiu Su‐Lan , Wen Kuo‐Ching
Published: May 2015

Polyphenol glycosides are reported to be hydrolyzed to lower polar aglycones and then become absorbable in the intestine. It would be more reasonable if the total glycosides of active ingredients could be assayed. In this study, the contents of polyphenol glycosides in Chinese herbs—Polygoni cuspidati rhizoma and Rumecis radix—were studied. The contents of aglycones were determined in decoctions of the herbs before and after hydrolysis. The aglycones assayed were emodin and resveratrol for Polygoni cuspidati rhizoma, and emodin and chrysophanol for Rumecis radix. The results showed that the contents of aglycones in Rumecis radix and Polygoni cuspidati rhizoma increased by 9227% and 4930%, respectively, after hydrolysis. In addition, the content of emodin in Polygoni cuspidati rhizoma increased after hydrolysis (9187%), whereas the amount of resveratrol was decreased (40%) as heating time increased. The method in this study can be applied to the determinations of the contents of aglycones and their glycosides in these Chinese herbs for quality control.
Development and Validation of HPLC, TLC and Derivative Spectrophotometric Methods for the Analysis of Ezetimibe in the Presence of Alkaline Induced Degradation Products
Authors: El‐Moghazy Samir Mohamed , Mohamed Mohamed Abd El‐Azem , Mohamed Marwa Fadel , Youssef Nadia Fayek
Published: May 2015

Reversed phase‐high performance liquid chromatography (RP‐HPLC), thin layer chromatography (TLC) densitometry and first derivative spectrophotometry (1D) techniques are developed and validated as a stability‐indicating assay of ezetimibe in the presence of alkaline induced degradation products. RP‐HPLC method involves an isocratic elution on a Phenomenex Luna 5μ C18 column using acetonitrile: water: glacial acetic acid (50:50:0.1 v/v/v) as a mobile phase at a flow rate of 1.5 mL/min. and a UV detector at 235 nm. TLC densitometric method is based on the difference in Rf‐values between the intact drug and its degradation products on aluminum‐packed silica gel 60 F254 TLC plates as stationary phase with isopropanol: ammonia 33% (9:1 v/v) as a developing mobile phase. On the fluorescent plates, the spots were located by fluorescence quenching and the densitometric analysis was carried out at 250 nm. Derivative spectrophotometry, the zero‐crossing method, ezetimibe was determined using first derivative at 261 nm in the presence of its degradation products. Calibration graphs of the three suggested methods are linear in the concentration ranges 1–10 mcg/mL, 0.1–1 mg/mL and 1–16 mcg/mL with a mean percentage accuracy of 99.05 ± 0.54%, 99.46 ± 0.63% and 99.24 ± 0.82% of bulk powder, respectively. The three proposed methods were successfully applied for the determination of ezetimibe in raw material and pharmaceutical dosage form; the results were statistically analyzed and compared with those obtained by the reported method. Validation parameters were determined for linearity, accuracy and precision; selectivity and robustness and were assessed by applying the standard addition technique.
Synthesis and Antimycobacterial Evaluation on Arylsulfonyl and Arylcarbonyl Derivatives of Ofloxacin
Authors: Chen Yeh‐Long , Chen Yu‐Wen , Lo We‐Fen , Kao Chai‐Lin , Liu Yu‐Shuan , Yao Chen‐Wen , Tzeng Chemg‐Chyi
Published: May 2015

Four ofloxacin derivatives 3, 5, 6, and 11 were found to exhibit > 90% inhibition on the growth of M. tuberculosis at a concentration of 6.25 μg/mL. Compounds 3, 5 and 11 have also exhibited a broad spectrum of antibacterial activities while 8‐fluoro‐3‐methyl‐9‐[4‐(4‐nitrophenylsulfonyl)piperazin‐1‐yl)‐6‐oxo‐2,3‐dihydro‐6H‐1‐oxo‐3a‐azaphenalene‐5‐carboxylic acid (6), which exhibited potent activity against the growth of TB with the MIC of 2.23 μg/mL and a selectivity index (SI) of > 14.80, was inactive against the growth of G(+)‐ and G(‐)‐bacteria. Selective anti‐TB activity was achieved by the introduction of an arylsulfonyl group at C‐7 piperazin‐4‐yl of N‐demethyl ofloxacin. Compound 6 is species‐specific, exhibiting no significant activity against the growth of bacterial species other than M. tuberculosis, which implied the possibility of developing new specific anti‐TB drug candidates without inducing cross resistance with other currently used antibacterial drugs. Structural optimization of 6 is on‐going.
Regio‐ and Stereoselective Reaction of α‐Epoxyketones with AlCl3: An Efficient Approach for the Synthesis of Functionalized β‐Chlorohydrines
Authors: Nikpour Farzad , Mozafari Roya , Mogaddam Baran Mohammadi
Published: May 2015

A simple and efficient synthesis of functionalized β‐chlorohydrins is described from the regio‐ and stereoselective reaction of α‐epoxyketones with AlCl3 in acetonitrile at room temperature.
Synthesis of Novel Thioglycoside Derivatives Containing Quinazolinone
Authors: Huang Hui , Gao Jian‐Fang , Cao Ling‐Hua , Wang Duo‐Zhi , Zhang Jian‐Bin , Zhou Shu‐Bao , Zhou Yu‐Qiang
Published: May 2015

A series of novel thioglycoside derivatives containing 4(3H)‐quinazolinone was designed and synthesized from 2‐chloromethyl‐quinazolin‐4(3H)‐ones and 1‐thioglycose. Several 2‐chloromethyl‐quinazolin‐4(3H)‐ones were synthesized on refluxing with 2‐(chloroacetylamino)‐benzoic acid and arylamines in acetonitrile. All of the novel compounds were characterized by IR, 1H NMR spectra and elemental analysis. The structures of compounds 7b, 8b and 8c have been determined by X‐ray diffraction analysis.
Synthesis and Characterization of Nickel(II) Complex Containing 2‐(t‐Butylaminomethyl)pyrrole
Authors: Hsieh Chang‐Chih , Chao Wan‐Jung , Horng Yih‐Chern , Lee Hon Man
Published: May 2015

Two aminopyrroles, 2‐(t‐butylaminomethyl)pyrrole (HL1) and 2, 5‐di(t‐butylaminomethyl)pyrrole (HL2), were synthesized and the hydrogen‐bond interactions were observed in the single‐crystal X‐ray structures of HL1·HCl and HL2. Bis[2‐(t‐butylaminomethyl)pyrrole]nickel(II) [Ni(L1)2] was prepared by treatment of the NiCl2 with 2 equiv. of mono‐deprotonated HL1 in THF solvent. The solid‐state structure of Ni(L1)2 shows the N4‐coordinated nickel atom, with a geometry corresponding to a square‐planar structure, in which two intramolecular C‐H···Ni interactions are present at the axial positions with contact distances of 2.77 Å. The complex displays an irreversible reduction response at −0.66 V (vs. Fc+/Fc) in CH3CN. Furthermore, 1H, 13C‐HSQC NMR experiments performed at room temperature revealed that the two methylene protons of the chelating L1−1 are chemically nonequivalent and one of them is coupled to the amino proton. The coupling constants (JHH') observed are close to the values predicted from the vicinal Karplus correlation diagram.
AFM‐Correlated CSM‐Coupled Raman/Fluorescence Studies on Selective Interactions of Water Soluble Porphyrins with DNA
Authors: Yoon Min‐Joong
Published: May 2015

The Raman and fluorescence spectroscopic properties of water‐soluble oxo‐titanium(IV) mesotetrakis (1‐methyl pyridium‐4‐yl) porphyrin (O=Ti(TMPyP)4+) bound with calf thymus DNA and artificial DNAs such as double stranded poly[d(A‐T)2] and poly[d(G‐C)2] have been investigated on the single DNA molecule basis by AFM‐correlated confocal scanning microscope (CSM)‐coupled Raman and fluorescence spectroscopic techniques as well as the ensemble‐averaged spectroscopy. The ensemble‐averaged spectroscopic studies imply that the porphyrin interacts with DNA in different groove binding patterns depending on the base pairs. AFM‐images of the different DNAs bound with O=Ti(TMPyP)4+ were measured, and their morphologies are found to depend on kind of base pairs interacting with O=Ti(TMPyP)4+. Being correlated with the AFM images, the CSM‐coupled Raman and fluorescence spectral properties of the three different single O=Ti(TMPyP)4+‐DNA complexes were observed to be highly resolved and sensitive to base pair‐dependent axial ligation of Ti‐O bond as compared to the corresponding ensemble‐averaged spectral properties, which affect the groove binding and its strength of the O=Ti(TMPyP)4+ with DNA. The axial ligation was found to be accompanied by vibration structural change of the porphyrin ring, leading to keep the shape of double stranded poly[d(A‐T)2] rigid while poly‐[d(G‐C)2] and calf thymus DNA flexible after binding with the oxo‐titanyl porphyrin. The base pair dependence of the fluorescence decay times of the DNA‐bound porphyrins was also observed, implying that an excited‐state charge transfer takes place in the G‐C rich major groove in calf thymus DNA. These results suggest that binding of O=Ti(TMPyP)4+ is more preferential with the G‐C rich major groove than with the A‐T rich minor groove in calf thymus DNA so that the morphology of DNA is changed.
Syntheses and Crystal Structures of Copper(II) and Silver Complexes with 5‐Methyl‐1‐(4‐Methylphenyl)‐1,2,3‐Triazol‐4‐Carboxylic Acid
Authors: Wu Yuan‐Gao , Wang Duo‐Zhi , Zhang Jian‐Bin , Cao Ling‐Hua
Published: May 2015

Two novel complexes [CuL2(MeOH)] (1)and [Ag2L(HL)2(MeOH)] (2) (L = 5‐methyl‐1‐(4‐methylphenyl)‐1,2,3‐triazol‐4‐carboxylic acid) were synthesized and characterized by elemental analysis, IR and X‐ray diffraction. Complex 1 is a mononuclear structure; the molecules were assembled into an infinite 2–D supramolecular by the C–H···O weak interactions. Complex 2 is a centrosymmetric dinuclear structure with bis(unidentate) carboxylato co‐ordination mode, and the molecules were assembled into 2–D layers by C–H···O and O–H···O weak interactions.
Interpretation on Band‐Broadening in Chromatography with Spatial Peak Profiles Obtained Using Whole‐Column Detection
Authors: Lin Shu‐Hui , Yu Tiing , Pai Su‐Cheng
Published: May 2015

Fifteen liquid chromatographic experiments were investigated using a whole‐column detection (WCD) system and a conventional post‐column UV/Vis detector. The peak widths obtained from chromatograms were found dependent on the retention factor; the larger the retention factor was the greater the peak width. However, the on‐column spatial peak widths were dependent on the locations where they were measured in the column. The peak widths monitored at 17 cm from the column inlet were found essentially the same no matter what their retention factors were. In addition, a linear relationship was found between the chromatographic peak width and the reciprocal of the average linear rate of the solute migration. The peak widths on chromatograms did not reflect how they appeared in the column; instead, the widths were determined by the solute speed passing the detector.
Non‐Isothermal Decomposition Kinetics, Specific Heat Capacity and Adiabatic Time‐to‐explosion of a Novel High Energy Material: 1‐Amino‐1‐Methylamino‐2,2‐Dinitroethylene (AMFOX‐7)
Authors: Xu Kang‐Zhen , Song Ji‐Rong , Zhao Feng‐Qi , Heng Shu‐Yun , Ding Li , Wang Yao‐Yu , Hu Rong‐Zu
Published: May 2015

A novel high energy material, 1‐amino‐1‐methylamino‐2,2‐dinitroethlyene (AMFOX‐7), was synthesized by the reaction of 1,1‐diamino‐2,2‐dinitroethylene (FOX‐7) and methylamine aqueous solution in N‐methyl pyrrolidone at 80°C. The thermal behavior and non‐isothermal decomposition kinetics of AMFOX‐7 were studied with DSC and TG/DTG methods. The kinetic equation of thermal decomposition reaction can be expressed as: \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm d\alpha /d}T = \frac{{10^{21.03}}}{{\rm \beta}}\frac{3}{2}\left({1 - {\rm \alpha}} \right)\left[{- 1{\rm n}\left({{\rm 1} - {\rm \alpha}} \right)} \right]^{\frac{1}{3}} \exp \left({- 2.292 \times 10^5 {\rm /}RT} \right) $\end{document}. The critical temperature of thermal explosion of AMFOX‐7 is 244.89°C. The specific heat capacity of AMFOX‐7 was determined with micro‐DSC method and theoretical calculation method, and the standard molar specific heat capacity is 199.39 J·mol−1·K−1 at 298.15 K. Adiabatic time‐to‐explosion of AMFOX‐7 was also calculated to be 215.41 s. AMFOX‐7 has higher thermal stability than FOX‐7.
Liquid‐Liquid Microextraction Coupled with High Performance Liquid Chromatography for Determination of Platinum
Authors: Dong Yan‐Jie
Published: May 2015

Liquid‐liquid microextraction (LLME) coupled with high performance liquid chromatography (HPLC) for the analysis of platinum is described. The analyte were extracted from 10.0 mL aqueous sample into organic phase. The extraction time was 20 min. Factors such as pH in aqueous phase, extraction times, and stirring rate were optimised. The method was applied for determination of platinum in mixture samples. The linearity range was from 1.0 to 100 nM and the detection limits was 0.1 nM. Relative standard deviations (%, n = 5) was 0.44 to 0.81. All experiments were carried out at room temperature, 35 ± 0.2°C.
Direct Electrochemistry of Hemoglobin and its Electrocatalysis Based on a Carbon Nanotube Paste Electrode
Authors: Zhai Zi‐Qin , Wu Jie , Sun Wei , Jiao Kui
Published: May 2015

A new hemoglobin (Hb) and carbon nanotube (CNT) modified carbon paste electrode was fabricated by simply mixing the Hb, CNT with carbon powder and liquid paraffin homogeneously. To prevent the leakage of Hb from the electrode surface, a Nafion film was further applied on the surface of the Hb‐CNT composite paste electrode. The modified electrode was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). Direct electrochemistry of hemoglobin in this paste electrode was easily achieved and a pair of well‐defined quasi‐reversible redox peaks of a heme Fe(III)/Fe(II) couple appeared with a formal potential (E0′) of −0.441 V (vs. SCE) in pH 7.0 phosphate buffer solution (PBS). The electrochemical behaviors of Hb in the composite electrode were carefully studied. The fabricated modified bioelectrode showed good electrocatalytic ability for reduction of H2O2 and trichloroacetic acid (TCA), which shows potential applications in third generation biosensors.
Determination of Trace Methyl Tert‐Butyl Ether in Water Samples Using Dispersive Liquid‐Liquid Microextraction Coupled with GC‐FID
Authors: Farhadi Khalil , Maleki Ramin , Nezhad Nasim Mohammad
Published: May 2015

A rapid and sensitive analytical method has been developed for trace analysis of methyl tert‐butyl ether (MTBE) in water samples using dispersive liquid‐liquid microextraction and gas chromatography with flame ionization detection. Factors relevant to the microextraction efficiency, such as the kind of extraction solvent, the disperser solvent and their volumes, the effect of salt, sample solution temperature and the extraction time were investigated and optimized. Under the optimal conditions the linear dynamic range of MTBE was from 0.2 to 25.0 μg L−1 with a correlation coefficient of 0.9981 and a detection limit of 0.1 μg L−1. The relative standard deviation (RSD%) was less than 5.1% (n = 3) and the recovery values were in the range of 97.8 ± 0.9%. Finally, the proposed method was successfully applied for the analysis of MTBE in aqueous samples.
Heteropolyacid as a New, Green and Recyclable Catalyst for the Synthesis of 2‐Aryl Benzoxazole under Solvent‐Free Conditions
Authors: Heravi Majid M. , Javanmardi Najme , Oskooie Hossein A. , Baghernejad Bita , Heidari Maryam , Bamoharram Fatemeh F.
Published: May 2015

A simple, convenient and general method has been developed for the synthesis of 2‐arylbenzoxazole via condensation of o‐aminophenols and benzoyl chloride derivatives under solvent‐free conditions in the presence of a catalytic amount of heteropolyacids in good yields.
Synthesis of 6‐Bromocoumarins Using Tetrabutylammonium Tribromide as a Selective Brominating Agent and an Efficient Generator of HBr
Authors: Wu Li‐Qiang , Yang Chun‐Guang , Wu Yan‐Fang , Yang Li‐Min
Published: May 2015

A simple and efficient one‐pot synthesis of 6‐bromocoumarins was achieved in good yields via the three‐component reaction of phenols, 4‐substituted acetoacetate and tetrabutylammonium tribromide (TBATB) in CH2Cl2‐MeOH.
Novel Flame‐Retardant and Thermally Stable Poly(Amide‐imide)s Based on Bicyclo[2,2,2]oct‐7‐Ene‐2,3,5,6‐Tetracarboxylic Diimide and Phosphine Oxide in the Main Chain: Synthesis and Characterization
Authors: Faghihi Khalil , Hajibeygi Mohsen , Shabanian Meisam
Published: May 2015

Six novel poly(amide‐imide)s PAIs 5a‐f were synthesized through the direct polycondensation reaction of six chiral N,N′‐(bicyclo[2,2,2]oct‐7‐ene‐tetracarboxylic)‐bis‐L‐amino acids 3a‐f with bis(3‐amino phenyl) phenyl phosphine oxide 4 in a medium consisting of N‐methyl‐2‐pyrrolidone (NMP), triphenyl phosphite (TPP), calcium chloride (CaCl2) and pyridine. The polymerization reaction produced a series of flame‐retardant and thermally stable poly(amide‐imide)s 5a‐f with high yield and good inherent viscosity of 0.39–0.83 dLg−1. The resultant polymers were fully characterized by means of FTIR, 1H NMR spectroscopy, elemental analyses, inherent viscosity, specific rotation and solubility tests. Thermal properties and flame retardant behavior of the PAIs 5a‐f were investigated using thermal gravimetric analysis (TGA and DTG) and limited oxygen index (LOI). Data obtained by thermal analysis (TGA and DTG) revealed that these polymers show good thermal stability. Furthermore, high char yields in TGA and good LOI values indicated that resultant polymers exhibited good flame retardant properties. N,N′‐(bicyclo[2,2,2]oct‐7‐ene‐tetracarboxylic)‐bis‐L‐amino acids 3a‐f were prepared in quantitative yields by the condensation reaction of bicyclo[2,2,2]oct‐7‐ene‐2,3,5,6‐tetracarboxylic dianhydride 1 with L‐alanine 2a, L‐valine 2b, L‐leucine 2c, L‐isoleucine 2d, L‐phenyl alanine 2e and L‐2‐aminobutyric acid 2f in acetic acid solution. These polymers can be potentially utilized in flame retardant thermoplastic materials.
Hypervalent Iodine(III) Sulfonate Mediated Synthesis of 2‐Arylimidazo[1,2‐a]Pyrimidines in Liquid PEG‐400
Authors: Cheng Hui‐Ting , Hou Rei‐Sheu , Wang Huey‐Min , Kang Iou‐Jiun , Lin Pei‐Ying , Chen Ling‐Ching
Published: May 2015

PEG‐400[poly(ethylene glycol‐400)] is used as a “green” recyclable solvent in the one‐pot synthesis of 2‐arylimidazo[1,2‐a]pyrimidines by reaction with ketones, [hydroxyl(2,4‐dinitrobenzenesulfonyloxy)‐iodo]benzene (HDNIB), and 2‐aminopyrimidine. Significant rate enhancements and improved yields have been observed.
Synthesis and Properties of Mixed Ligand Complexes of Diorganotin(IV): Part(VII) – Synthesis and Characterisation of Some Antibacterial Dibenzoylmethane Diorganotin(IV)‐O‐alkyl Trithiophosphates
Authors: Chordia Leena , Chaturvedi Alok
Published: May 2015

A series of some new mixed ligand complexes have been synthesized with an objective for evaluation as antimicrobials. Reactions of diorganotin(IV) dichloride with dibenzoyl methane and O‐alkyl trithiophosphates in a 1:1:1 molar ratio in refluxing benzene yield products of the type [PhCOCHCOPh]R2Sn‐[SSH(S)POR'] [where R = Me, Bu, Ph; R' = Me, Et, Pri, Bui, Ph]. The newly synthesized complexes are light yellow colored crystalline solids, non‐volatile, soluble in common organic solvents, monomeric in nature and highly sensitive towards atmospheric moisture. These complexes are characterized by elemental analysis, IR and multinuclear NMR (1H, 31P and 119Sn) spectral studies. Spectral studies of these complexes indicate that dibenzoyl methane and O‐alkyl trithiophosphate moieties are bidentate and the central tin atom is hexacoordinated in nature. A few of these compounds were tested for their antibacterial activity using standard drugs.
Potentiometric Membrane Electrode for Cr(III) Ion Based on a New Aryl Amide Bifunctional Bridging Ligand as a Neutral Carrier
Authors: Ma Yu‐Hua , Yuan Ruo , Chai Ya‐Qin , Liu Xin‐Lu
Published: May 2015

A novel Cr(III) ion‐selective electrode is constructed by incorporating a new aryl amide bifunctional bridging ligand, 2,2′‐bis{[(2″‐benzylaminoformyl)phenxoyl]methyl}‐diethylether (BBPMD) as a neutral carrier into the PVC matrix. The proposed electrode, with optimum membrane composition, exhibits an excellent near‐Nernstian response for Cr3+ ion ranging from 2.8 × 10−6 to 1.0 × 10−1 mol/L with a detection limit of 8.6 × 10−7 mol/L and a slope of 19.5 ± 0.2 mV/dec in pH 3.0 nitrate buffer solution at 25 °C. It has an appropriate response time, suitable reproducibility, and good selectivity towards Cr3+ ion. The operational pH range of the proposed electrode is 2.5–6.5. The response mechanism was discussed in view of UV‐vis spectroscopy and the A. C. impedance technique. The excellent analytical features of the proposed electrode could lead to its successful application as an indicator electrode in potentiometric titration of Cr3+ ion and in the direct determination of Cr3+ ion in tea leaves and coffee samples.
Photocatalytic Degradation of Michler's Ketone in Water by UV Light Illumination Using TiO2 Photocatalyst: Identification of Intermediates and the Reaction Pathway
Authors: Lu Chung‐Shin , Mai Fu‐Der , Wu Yi‐Chin , Yao I‐Chun , Hsu Peng‐Yueh , Chen Chiing‐Chang
Published: May 2015

The TiO2/UV photocatalytic degradation of Michler's Ketone (MK) has been investigated in aqueous heterogeneous suspensions. Results obtained show rapid and complete oxidation of MK after 24‐h, and more than 97.5% of MK was mineralized after a 32‐h exposure to UV‐365 nm irradiation. Establishment of the reaction pathway was made possible by a thorough analysis of the reaction mixture identifying the main intermediate products generated. Nine intermediates have been detected by HPLC/ESI‐MS and GC/MS techniques. The photocatalytic degradation of MK proceeds through competitive reactions such as N‐de‐methylation and destruction of the bis‐aminobenzophenone structure. The former reaction took place in a stepwise manner to yield mono‐, di‐, tri‐, tetra‐demethylated species, while the latter reaction yielded N‐methylaminobenzene and aminobenzene. The reaction mechanisms of TiO2/UV proposed in this study should shed some light on future applications of the technology to the destruction of organic pollutants.
New Polyphenols and Triterpene from the Pseudobulbs of Pleione Formosana
Authors: Shiao Young‐Ji , Chen Wan‐Ping , Lin Yun‐Lian
Published: May 2015

Three new polyphenolic compounds including a dihydrophenanthrene, pleioanthrenin (1), two bibenzyls, pleiobibenzynin A (2) and B (3), and a new cycloartane triterpenoid, (24R)‐cyclomargenyl p‐coumarate (4), together with eight known compounds, were isolated from the pseudobulbs of Pleione formosana. The structures of the new compounds were elucidated by extensively spectroscopic analysis.
Bipyridine‐Modulated Palladium‐Catalyzed Oxidative Heck‐Type Reactions of Arylboronic Acids with Olefins
Authors: Hsu Chien‐Ming , Li Chih‐Bin , Sun Chia‐Hsing
Published: May 2015

We have demonstrated that 4,4′‐dimethyl 2,2′‐bipyridine as ligand for Pd(II) catalysts was very efficient for oxidative Heck‐type coupling reaction of arylboronic acids with olefins in DMA or CH3CN under atm air at 80 °C. The presence of chelated bipyridine ligand isindispensable to achieve high reaction yields and to suppress the formation of biphenyl as homocoupled byproduct.
A New Oligostilbenoid from Rhizomes of Curculigo Sinensis
Authors: Wang Tian‐Ming , Wang Kai‐Jin , Tang Jun , Li Ning
Published: May 2015

Curcusinol (1), a new resveratrol trimer, was isolated and identified from the rhizomes of Curculigo sinensis (Hypoxidaceae), together with five known phenolic compounds: curcapital (2), pilosidine (3), crassifoside A (4), curculigoside I (5) and phegopolin (6). The new compound 1 was determined as an oligostilbenoid on the basis of various spectroscopic methods, especially intensive 2D‐NMR (COSY, HMQC, HMBC and NOESY) techniques.