bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three‐Component One‐Pot Synthesis of Indeno[2′,1′:5,6]Pyrido[2,3‐d]Pyrazole Derivatives in Aqueous Media
Authors: Shi Da‐Qing , Shi Jing‐Wen , Yao Hao 
Published: May 2015

AbstractA series of indeno[2′,1′:5,6]pyrido[2,3‐d]pyrazoles was synthesized by the three‐component reaction of aldehyde, 5‐amino‐3‐methyl‐1‐phenylpyrazole and 1,3‐indenedione in the presence of SDS in aqueous media. The structures were characterized by IR, 1H NMR, high resolution mass spectra and were further confirmed by X‐ray diffraction analysis.
Metal Trifluoromethanesulfonate‐Catalyzed Regioselective Reductive Ring Opening of Benzylidene Acetals
Authors: Shie Chi‐Rung , Tzeng Zheng‐Hao , Wang Cheng‐Chung , Hung Shang‐Cheng 
Published: May 2015

AbstractA systematic study of various metal trifluoromethanesulfonates as efficient catalysts in the regioselective reductive ring opening of benzylidene acetals is described, including the effects of solvents, reducing agents, and temperature. These catalysts are found to be effective in cleaving the 4,6‐O‐acetal rings of hexopyranosides at either O4 or O6, respectively. When used in conjunction with a 1 M solution of BH3·THF in THF without extra addition of any solvent, it affects the ring fission at the O6 position to generate the corresponding primary alcohols, whereas O4‐opening takes place in acetonitrile in the presence of dimethylethylsilane as the reductant leading to the secondary hydroxyl derivatives in high selectivity and yields. These methodologies can be applied to a wide range of substrates containing various functional groups.
Transition Metal Complexes of N‐(4,6‐Dimethoxypyrimidin‐2‐Ylcarbamothioyl)Benzamide: Design, Synthesis and Herbicidal Activity
Authors: Wu Ai‐Bin , Duan Li‐Ping 
Published: May 2015

AbstractTransition metal (Cu(II), Zn(II), Co(II)) complexes of N‐(4,6‐dimethoxypyrimidin‐2‐ylcarbamothioyl)benzamide were prepared. The structures of all the newly synthesized complexes were identified by elemental analyses, IR, 1H NMR, XPS, MS and TG. Their herbicidal activities were evaluated against a variety of weeds. The preliminary results showed that the target complexes had moderate biological activities against both broad leaf weeds and monocotyledon plants. More importantly, the complexes exhibited some improved herbicidal activities over their non‐complexed counterparts. The present work provides a novel class of transition metal‐based derivatives with potent herbicidal activities for further optimization.
Kinetic Study of the Electro‐Catalytic Oxidation of Acetaldehyde on Copper Electrode
Authors: Karim‐Nezhad Ghasem , Hasanzadeh Mohammad , Saghatforoush Lotfali , Ershad Sohrab , Shadjou Nasrin 
Published: May 2015

AbstractElectrocatalytic oxidation of acetaldehyde was investigated on a copper electrode in alkaline solution. The process of oxidation involved and its kinetics were established by using cyclic voltammetry and chronoamperometry techniques as well as steady state polarization measurements. It has been found that in the course of an anodic potential sweep the electro‐oxidation of acetaldehyde follows the formation of Cu(III) and is catalysed by this species through a mediated electron transfer mechanism. A mechanism based on the electrochemical generation of Cu(III) active sites and their subsequent consumption by the acetaldehyde in question was also investigated.
A Novel Spectrophotometric Method for the Determination of Levodopa with the Detection System of Potassium Ferricyanide‐Fe(III)
Authors: Guo Li , Zhang Yan , Li Quan‐Min 
Published: May 2015

AbstractIn this paper, a novel method has been established to determine levodopa with the detection system of potassium ferricyanide‐Fe(III). In the presence of potassium ferricyanide, it has been demonstrated that Fe(III) is reduced to Fe(II) by levodopa at pH 4.0. In addition, the in situ formed Fe(II) reacts with potassium ferricyanide to form soluble prussian blue (KFeIII[FeII(CN)6]). Beer's law is obeyed in the range of levodopa concentrations of 0.01–4.00 μg mL−1 at the maximal absorption wavelength of 735 nm. The linear regression equation is A = 0.0082 + 0.61365 C (μg mL−1) with a correlation coefficient of 0.9996. The detection limit (3σ/k) is 9 ng mL−1, and R.S.D. is 0.73% (n = 11). Moreover, the apparent molar absorption coefficient of indirect determination of levodopa is 1.2 × 105 Lmol−1cm−1. The parameters with regard to determination are optimized, and the reaction mechanism is discussed. This method has been successfully applied to determine levodopa in pharmaceutical, serum and urine samples. Analytical results obtained with this novel assay are satisfactory.
Green Regioselective Azidolysis of Epoxides Catalyzed by Multi‐Site Phase‐Transfer Catalyst
Authors: Kiasat Ali Reza , Mirzajani Roya , Shalbaf Haji , Tabatabaei Tahereh , Fallah‐Mehrjardi Mehdi 
Published: May 2015

AbstractA facile synthesis of 1,2‐azidoalcohols from their epoxides using α,α',α”‐N‐hexakis(triethylammoniummethylene chloride)‐melamine as a multi‐site phase‐transfer catalyst in water was developed. By this eco‐friendly and highly atom‐economic method, a variety of 1,2‐azidoalcohols was obtained in high yields with excellent regioselectivity and in short reaction times. Application of this six‐site PTC in the ring opening of epoxides by cyanide, acetate and chloride anions was also studied. The catalyst can be recovered after completion of the reaction and can be recycled without affecting the catalytic property.
The Antimicrobial Activity, Mosquito Larvicidal Activity, Antioxidant Property and Tyrosinase Inhibition of Piper Betle
Authors: Row Li‐Ching Morgan , Ho Jiau‐Ching 
Published: May 2015

AbstractThe essential oil and methanolic and aqueous extracts of Piper betle L. were assayed for their antimicrobial activity, mosquito larvicidal activity, antioxidant property and mushroom tyrosinase inhibition. The methanolic and aquaous extracts showed strong activity against the yeasts: C. albicans, and M. pachydermatis. The crude essential oil exhibited a broad‐spectrum strong antimicrobial activity against all test organisms. The strongest activity was observed against C. albicans, followed by S. aureus and M. pachydermatis. The chemical composition of the essential oil and its fractions was analyzed by GC/MS analysis. Eugenol (36.2%), chavibetol acetate (16.9%), 4‐allylphenyl acetate (9.4%) and 4‐allylphenol (7.2%) were the main components, comprising 69.7% of the oil. The fractionation of the essential oil gave two fractions. Fraction I was rich in eugenol (71.3%) and fraction II in eugenol (46.4%), chavibetol acetate (19.4%) and 4‐allylphenyl acetate (11.8%). The essential oil exhibited the mosquito larvicidal activity with 2 h and 24 h LD50 value of 86 and 48 ppm, respectively. The methanolic extract of P. betle showed larvicidal activity with 2 h and 24 h LD50 value of 153 and 125 ppm, respectively, whereas the aqueous extract showed slight active. The individual antioxidant assays such as DPPH scavenging activity, chelating effect of ferrous ions and reducing power have been used. P. betle showed remarkable antioxidant activity in DPPH and reducing power assays. The activity observed can be attributed to the presence of the phenolic compounds. The essential oil exhibited concentration‐dependent inhibition of mushroom tyrosinase, giving an IC50 value of 126 ppm. The fraction I showed a strong inhibition of tyrosinase activity, giving an IC50 value of 115 ppm. The presence of 4‐allylphenolic components in the essential oil may play an important role in the inhibition of tyrosinase. In conclusion, the results presented here show that Piper betle essential oil could be considered as a natural antimicrobial, mosquito larvicidal, antioxidant and tyrosinase inhibition source.
Cloning and Expression of Chitinase A from Serratia Marcescens for Large‐Scale Preparation of N,N‐Diacetyl Chitobiose
Authors: Wu Yue‐Jin , Cheng Chih‐Yu , Li Yaw‐Kuen 
Published: May 2015

AbstractThe gene of Serratia marcescens chitinase A (chiA) was cloned by PCR. The complete gene was constructed into a pRSET vector and expressed in Escherichia coli. The recombinant enzyme was purified to > 90% homogeneity by hydrophobic interaction chromatography followed by ion‐exchange separation. Measured with an electrospray‐ionization mass spectrometer, the molecular mass of the protein was 58,607 Da, consistent with a theoretical calculation of the deduced protein without the signal peptide. The recombinant enzyme was characterized and tested for the preparation of chitobiose. In general, the recombinant Chtinase A exhibited an exo‐type catalytic activity toward colloidal chitin and released both N‐acetylglucosamine and N,N‐diacetyl chitobiose as products. After extensive testing, we produced N,N‐diacetyl chitobiose as the predominant product when the enzymatic reaction was performed in sodium acetate buffer at pH 5.5; under such conditions, an enzymatic process is established for the production of the disaccharide on a 100‐g scale.
Interactions of Human Serum Albumin with Phenothiazine Drugs: Insights from Fluorescence Spectroscopic Studies
Authors: Bai Hai‐Xin , Liu Xiao‐Hua , Yang Fan , Yang Xiu‐Rong 
Published: May 2015

AbstractThis study was based on the use of fluorescence quenching and differentiation between static and dynamic quenching, as well as energy transfer for distance measurements. The interactions of human serum albumin with phenothiazine drugs, i.e. phenothiazine, chlorpromazine, perphenazine and promethazine, were studied and extrapolated important information on quenching mechanism, types of interaction force, binding‐site number and distance between Trp214 in HSA and the bound drugs. This study has great significance in methodology and understanding the protein‐drug interaction mechanism.
Synthesis, Structural Characterization and Thermal Stability of [Mn(3‐bpd)2(NCS)2(H2O)2]·2H2O (1) and {[Mn(bpe)(NCS)2(H2O)2]·(3‐bpd)·(bpe)·H2O}n (2) from One‐Pot Crystallization
Authors: Liu Chuan‐Yien , Lee Gene‐Hsiang , Wang Hsin‐Ta 
Published: May 2015

AbstractTwo supramolecular architectures, [Mn(3‐bpd)2(NCS)2(H2O)2]·2H2O (1) and {[Mn(bpe)(NCS)2(H2O)2]·(3‐bpd)·(bpe)·H2O}n (2) [bpe = 1,2‐bis(4‐pyridyl)ethylene and 3‐bpd = 1,4‐bis(3‐pyridyl)‐2,3‐diaza‐1,3‐butadiene] have been synthesized and characterized by spectroscopic, elemental and single crystal X‐ray diffraction analyses. Compound 1 crystallizes in the monoclinic system, space group P21/c, with chemical formula C26H28Mn N10O4S2, a = 9.1360(6), b = 9.7490(6), c = 17.776(1) Å, β = 93.212(1)°, and Z = 2 while compound 2 crystallizes in the orthorhombic system, space group P212121, with chemical formula C38H36Mn1N10O3S2, a = 14.1902(6), b = 15.4569(7), c = 18.2838(8) Å, α = β = γ = 90°, and Z = 4. Structural determination reveals that the coordination geometry at Mn(II) in compound 1 or 2 is a distorted octahedral which consists of two nitrogen donors of two NCS−ligands, two oxygen donors of two water molecules, and two nitrogen donors of two 3‐bpd ligands for 1 and two dpe ligands for 2, respectively. The two 3‐bpd ligands in 1 adopt a monodentate binding mode and the dpe in 2 adopts a bismonodentate bridging mode to connect the Mn(II) ions forming a 1D chain‐like coordination polymer. Both the π‐π stacking interactions between the coordinated and the free pyridyl‐based ligands and intermolecular hydrogen bonds among the coordinated and the crystallized water molecules and the free pyridyl‐based ligands play an important role in construction of these 3D supramolecular architectures.
The Nitrogen‐Assisted Triphenylphosphine Displacement of 3‐Hydroxypyridine and 3‐Aminopyridine Ligands in Palladium(II) Complexes: Crystal Structures of [Pd(PPh3)Br]2{μ,η2‐C5H3N(OH)}2 and [Pd(PPh3)Br]2{μ,η2‐C5H3N(NH2)}2
Authors: Yih Kuang‐Hway , Wang Hsiao‐Fen , Huang Keh‐Feng , Kwan Chang‐Chi , Lee Gene‐Hsiang 
Published: May 2015

AbstractTreatment of Pd(PPh3)4 with 2‐bromo‐3‐hydroxypyridine [C5H3N(OH)Br] and 3‐amino‐2‐bromopyridine [C5H3N(NH2)Br] in dichloromethane at ambient temperature cause the oxidative addition reaction to produce the palladium complex [Pd(PPh3)2{η1‐C5H3N(OH)}(Br)], 2 and [Pd(PPh3)2{η1‐C5H3N(NH2)}(Br)], 3, by substituting two triphenylphosphine ligands, respectively. In dichloromethane solution of complexes 2 and 3 at ambient temperature for 3 days, it undergo displacement of the triphenylphosphine ligand to form the dipalladium complexes [Pd(PPh3)Br]2{μ,η2‐C5H3N(OH)}2, 4 and [Pd(PPh3)Br]2{μ,η2‐C5H3N(NH2)}2, 5, in which the two 3‐hydroxypyridine and 3‐aminopyridine ligands coordinated through carbon to one metal center and bridging the other metal through nitrogen atom, respectively. Complexes 4 and 5 are characterized by X‐ray diffraction analyses.
Investigation of Electrochemical Copolymerization of 1‐Naphthylamineaniline in the Presence of Various Organic Sulfonic Acids
Authors: Massoumi Bakhshali , Aghili Hakimeh , Entezami Aliakbar 
Published: May 2015

AbstractThe electrochemical and electro activity properties of poly(aniline‐co‐1‐naphthylamine) thin films have been investigated in the presence of various organic sulfonic acids. Homo and copolymer thin films are synthesized electrochemically, under cyclic voltammetric conditions in aqueous solution of organic sulfonic acids (1 M), viz p‐toluene‐sulfonic acid (P‐TSA), methane‐sulfonic acid (MSA), 5‐sulfosalicylic acid (5‐SSA), camphor‐sulfonic acid (CSA) and dodecylbenzene‐sulfonic acid (DBSA) (0.25 M) on glass carbon (GC) electrode at room temperature. The cyclic voltammograms (CVs) show that the current densities are strongly influenced by the size and acidity of the organic acids which are present in electrolyte. Electocopolymerization was carried out at different ratios of NPA to ANI (0.07, 0.05, 0.03, 0.02, 0.014). The formation of copolymer was proved by cyclic voltammogram study.
Effects of pH and Concentration on Cs Ions Sorption and Diffusion in Crushed Granite by Using Batch and Modified Capillary Method
Authors: Wang Tsing‐Hai , Li Ming‐Hsu , Wei Yuan‐Yaw , Teng Shi‐Ping 
Published: May 2015

AbstractA comprehensive evaluation of Cs ions sorption to and diffusion in crushed granite was conducted in this study. The sorption capacity of crushed granite suggested by the Langmuir model was 5.48 × 10−6 mol‐Cs/g‐granite. The distribution coefficient (Kd) was around 7.5 mL/g and pH independent. By using an in‐diffusion method with a modified capillary column, some diffusion relevant parameters of Cs ions in crushed granite were derived. The apparent diffusion coefficient (Da) seemed unaffected by Cs concentration (1.15 × 10−10 to 2.82 × 10−10 m2/s, at 10−7 and 10−3 M, respectively). The determined effective diffusion coefficients (De) were located in the window from 8.59 × 10−10 (10−7 M) to 1.69 × 10−9 (10−3 M) m2/s. Under various pH environments, pH independent Da (9.0 × 10−9 m2/s) and De (1.0 × 10−9 m2/s) values were observed. Under current systems, consistently higher De than Da implied the diffusion of Cs ions was governed by surface diffusion phenomenon. Whereas the pH insensitive feature indicated the Cs sorption to crushed granite was mainly through ion‐exchange reaction. Moreover, further SEM/EDS mapping clearly showed the adsorbed Cs ions were highly concentrated on the fracture surface of biotite.
Spectrofluorimetric Determination of the Hypertensive Drug Captopril Based on Its Oxidation with Cerium(IV)
Authors: El‐Didamony Akram Mohamed 
Published: May 2015

AbstractA highly sensitive and specific spectrofluorimetric method for the analysis of captopril (CAP) in the pure form and in the tablet dosage forms has been described. The method was based on the oxidation of captopril by cerium(IV) in the presence of sulphuric acid and subsequent monitoring the fluorescence of the induced Ce(III) ion produced at λex= 256 nm and λem= 354 nm. All variables affecting the reaction conditions such as cerium(IV) concentration, type and concentration of acid medium, reaction time, diluting solvents, temperature and heating time were carefully studied and optimized. Under the experimental conditions used, an excellent linear relationship was obtained between fluorescence intensity and the concentration of CAP. A linear range of determination was verified for captopril concentrations between 0.1–1.3 μg mL−1and the correlation coefficient of determination was 0.9997. Quantitation and detection limits were calculated. The precision of the method was satisfactory; the values of relative standard deviations did not exceed 1.14%. No interference could be observed from the excipients and additives are commonly presented in dosage forms. The proposed method was applied successfully for the assay of the studied drug in pure form and in pharmaceutical dosage forms. Recovery experiments revealed recovery of 99.82–100.21%. The results of the analysis show a good agreement with those obtained by official method stated in the United State Pharmacopoeia.
Flotation‐Spectrophotometric Determination of Trace Amounts of Thorium
Authors: Pourreza N. , Parham H. , Mirzavand P. 
Published: May 2015

AbstractA simple, sensitive and reproducible flotation‐spectrophotometric method for the determination of thorium is reported. The method is based on the ion‐associate formation between thorium, xylenol orange (XO) and cethyltrimethyl ammonium bromide (CTAB) which is floated in the interface of the aqueous phase and n‐hexane by vigorous shaking. By discarding the aqueous solution and n‐hexane, the adsorbed ion‐associate (Th‐XO‐CTAB) on the wall of a separating funnel was dissolved in a small volume of ethanol solvent, and its absorbance was measured at 568 nm. The effects of different parameters such as pH, concentrations of HCl, XO, and CTAB, volume of n‐hexane, and standing and shaking time were studied. The calibration graph was linear in the concentration range of 2–200 ng mL−1 of thorium(r = 0.9994). The limit of detection (LOD) is 1.4 ng mL−1. The relative standard deviations (RSD) at 50 and 175 ng mL−1 of thorium were 2.5% and 1.0% (n = 7), respectively. The method was successfully applied to the determination of thorium in gas mantel samples.
Photoinduced Polymerization for Entrapping of Octadecylsilane Microsphere for Capillary Liquid Chromatography
Authors: Zhang Yu‐Ping , Deng Pu‐Hong , Xu Ming‐Lu , Wei Xin‐Jun , Tang Bo 
Published: May 2015

AbstractA short length of a sol‐gel monolith was initially prepared as the temporary frit in a 100 μm inner diameter fused‐silica capillary by an in situ photopolymerization. The packed 4 μm octadecylsilane particles were then immobilized within the identical sol‐gel solution through the same photopolymerization process. The prepared fritless capillary column was examined for the chromatographic performance by the self‐developed capillary liquid chromatography system. Baseline separation of the model analytes was achieved including thiourea, benzene, toluene and ethylbenzene with the lowest theoretical plate height about 66 μm for the retained component. A scanning electron micrograph was used to characterize the temporary frit and entrapped microspheres. The inorganic polymer matrix in the microsphere‐packed column functioned to link microspheres at specific sphere‐sphere and sphere‐capillary contact points. Furthermore, the stability and porosity of the fritless column were systematically investigated by a simple flow method.
Construction of a New Uranyl‐Selective Electrode Based on a New Ionophore: Comparison of the Effect Additive on Electrode Responses
Authors: Shokrollahi A. , Ghaedi M. , Montazerozohori M. , Khanjari N. , Najibzadeh M. 
Published: May 2015

AbstractA new plasticized PVC uranyl‐selective electrode based on a bis(2‐hydroxyacetophenone)ethylenediimine (BHAED) carrier by the direct coating of the membrane ingredients on the surface of a graphite disk electrode is reported. The electrode displayed high selectivity for uranyl ion toward a number of inorganic ions. The influence of the membrane compositions and pH, the effect of lipophilic cationic and anionic additives and plasticizer on the response properties of the electrode were investigated. The electrode exhibited a Nernstian slope of + 29.3 ± 1.2 for the uranyl ion concentration in the range of 5.0 × 10−6 −0.05 M with detection limits of approx. 2.0 μM. The potentiometric responses of the electrode are independent of pH over the range of 3.0–4.5 with satisfactory reproducibility. The sensor has response times of <5 s and can be used for at least 2 months without considerable divergence in potential.
An Efficient Protocol for the Synthesis of N‐Alkyl‐ and N‐Arylimides Using the Lewis Acidic Ionic Liquid Choline Chloride·2ZnCl2
Authors: Xie You‐Teng , Hou Rei‐Sheu , Wang Huey‐Min , Kang Iou‐Jiun , Chen Ling‐Ching 
Published: May 2015

AbstractLewis acidic ionic liquid choline chloride·2ZnCl2 is shown to be for the first time an excellent medium and efficient catalyst for the synthesis of N‐alkyl‐ and N‐arylimides in good yields under mild conditions.
Preparation, Antibacterial Activity and Absorption Spectra of Pyrazolo‐Oxadiazine Cyanine Dyes
Authors: Eissa Fayez M. 
Published: May 2015

AbstractA new pyrazolo[4,3‐e]‐1,3,4‐oxadiazine heterocyclic ring system was prepared and employed to synthesize cyanine dyes of different methine types, including monomethine (simple cyanine) and trimethine (carbocyanine). The antibacterial activity of all the newly synthesized compounds was investigated against some bacterial strains. The electronic absorption spectra of the dyes were studied in absolute ethanol. The structure of all the synthesized compounds was identified via elemental and spectroscopic analysis.
Gd(OTf)3‐[Bmim][PF6]: A Novel and Recyclable Catalytic System for the Synthesis of Quinolines
Authors: Wu Jian‐Long , Hou Rei‐Sheu , Wang Huey‐Min , Kang Iou‐Jiun , Chen Ling‐Ching 
Published: May 2015

AbstractA mild and efficient route for the synthesis of quinolines and polycyclic quinolines utilizing Gadolinium triflate (Gd(OTf)3) as a novel catalyst via Friedländer annulation in ionic liquid 1‐n‐butyl‐3‐methyl‐imidazolium hexafluorophosphate [Bmim][PF6] under mild conditions was described.
Theoretical and Experimental 27Al NMR Chemical Shift Studies on End‐Group Aluminates Linked to Different Silicate Species
Authors: Azizi S. Naser , Ehsani‐Tilami S. 
Published: May 2015

AbstractAluminium‐27 nuclear magnetic resonance spectroscopy (27Al NMR) does not yield fully resolved spectra for end‐group aluminates attached to different silicate species. For example, the chemical shifts of all q1 (end‐group aluminates) lying in the range δ ≈ 72.2–77 ppm are observed on average at δ ≈ 74.6 ppm in an NMR spectrum. With the aim of better characterisation of different q1 linked units, we first made some attempts to resolve the signals that might arise from different q1 linkages through the application of suitable experimental methods and then followed up this work by applying some calculation methods. Some of the observed differences and evidence have not been previously detected experimentally, but were clearly apparent from our calculations (Table 1) as well as in our experimental data. Therefore, in such a situation, theoretical calculations of NMR chemical shifts can be very helpful and can provide some missing information.