bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bis‐Bromine‐1,4‐Diazabicyclo[2.2.2]Octane (Br2‐DABCO) as an Efficient Promoter for One‐Pot Conversion of N‐Arylglycines to N‐Arylsydnones in the Presence of NaNO2/Ac2O Under Neutral Conditions
Authors: Ghasemnejad‐Bosra Hassan , Haghdadi Mina , Khanmohammade Omid , Gholipour Abdoreza M. , Asghari Gharibreza 
Published: May 2015

AbstractBis‐Bromin‐1,4‐diazabicyclo[2.2.2]octane (Br2‐DABCO)‐promoted one‐pot conversion of various N‐arylglycines to sydnones using a combination of NaNO2 and Ac2O has been achieved efficiently through N‐nitrosation followed by cyclization in high yields (90‐96%) under mild and neutral conditions.
Increased Conversion to 2,4,6‐Triarylpyrylium Salt: Aldol Cyclotrimerization of Acetophenone in BMImPF6 Ionic Liquid
Authors: Chuang Po‐Neng , Wu Tsao‐Dong , Liu Ling‐Kang 
Published: May 2015

AbstractSubstituted acetophenone 1 in BMImPF6 ionic liquid, heated at 120 °C for 24 h, produces β‐methylchalcone 2, triarylbenzene 3, and triarylpyrylium salt 4. BMImPF6 catalyzes the self‐aldol condensation of 1, whose cyclotrimerization gives an increased conversion to 4 at the expense of 3 normally obtained from the cyclotrimerization of 1 in common organic solvent.
Magnolol Encapsulated by Liposome in Inhibiting Smooth Muscle Cell Proliferation
Authors: Chen Calvin Yu‐Chian , Wu Chieh‐Hsi 
Published: May 2015

AbstractMagnolol, a pure compound extracted from Magnolia officinalis, encapsulated by liposome was investigated for inhibiting vascular smooth muscle cell (VSMC) proliferation leading to restenosis by Percutaneous Transluminal Coronary Angioplasty (PTCA). 1,2‐Diacyl‐Sn‐glycero‐3‐phosphocholine (EPC) and 1,2‐dipalmitoyl‐Sn‐glycero‐3‐phosphocholine (DPPC) liposomes were utilized to encapsulate the magnolol in this study. The inhibitory efficiency of the liposome encapsulated magnolol on cell viability was higher than the pure magnolol. EPC liposome was found to have higher efficiency in inhibiting VSMCs than DPPC. The diameters of EPC and DPPC liposome which encapsulated magnolol became larger than pure EPC and DPPC liposomes. The photos from transmission electron microscopy (TEM) were demonstrated that the EPC and DPPC liposomes could be interfered by magnolol to form a homogeneous liposome. Addition of cholesterol to EPC and DPPC liposome could reduce the liposome diameter.
Computational Study of Hydrogen Bonding in Substituted Phenol‐Acetonitrile‐Water Clusters
Authors: José Cotuá V. , Sandra Cotes O. , Fernando Castro G. , Pedro Castro P. , Liadys Mora L. 
Published: May 2015

AbstractThe calculations for a water‐acetonitrile‐substituted phenols system and the comparison with the experimental parameters will be given. Here we study change in the nature of the interactions into the system with donor and acceptor electron substituents on the phenolic ring, the structures, relative energies and harmonic frequencies. The conformers showed a significant difference in the OH and CN band shift depending on the type of the hydrogen bond formed and the position of the substituent on the phenolic ring. The cyclical hydrogen bonds between water‐acetonitrile and substituted phenol OH are important evidence of the relative stability in the system under study.
Preparation and Application of Cholesteryl‐Benzo‐15‐Crown‐5/Cholesteryl Mixed Liquid Crystals
Authors: Shen Ya‐Chi , Shih Jeng‐Shong 
Published: May 2015

AbstractVarious mixed liquid crystals containing crown ether‐cholesteryl liquid crystal, benzo‐15‐crown‐5‐COO‐C27H45 (B15C5‐COOCh), with various common cholesteric liquid crystals, e.g., cholesteryl chloride, cholesteryl benzoate and cholesteryl palmitate, were prepared and studied using polarizing microscopy and differential scanning calorimetry. Investigating the concentration effect of B15C5‐COOCh in mixed liquid crystals revealed that the addition of B15C5‐COOCh resulted in wider phase transition temperature ranges of these cholesteryl liquid crystals. The stability of these B15C5‐COOCh/cholesteryl mixed liquid crystals was studied using comprehensive graphic molecular modeling computer programs (Insight II and Discover) to calculate their molecular energy and stability energy. The effect of salts, e.g. Na+, Co3+, Y3+ and La3+, on the transition temperature range of the mixed liquid crystals was also investigated. The crown ether cholesteric liquid crystal B15C5‐COOCh was applied both as a surfactant and an ion transport carrier to transport metal ions through liquid membranes. Cholesteryl benzo‐15‐crown‐5 exhibited distinctive characteristics of a surfactant and the critical micellar concentration (CMC) of the surfactant was investigated by the pyrene fluorescence probe method. Cholesteryl benzo‐15‐crown‐5 was successfully applied as a good ion transport carrier (Ionophore) to transport various metal ions, e.g. Li+, Na+, La3+, Fe3+ and Co3+, through organic liquid membranes. The transport ability of the cholesteryl benzo‐15‐crown‐5 surfactant for these metal ions was in the order: Co3+ ≥ Li+ > Fe3+ > Na+ > La3+.
Study on the Binding Characteristic of Methamidophos‐Specific Molecularly Imprinted Polymer and the Interactions between Template and Monomers
Authors: Shen Zhong‐Lan , Zhu Xiao‐Lan , Yang Jun , Cai Ji‐Bao , Su Qing‐De 
Published: May 2015

AbstractA new molecularly imprinted polymer (MIP) was prepared using methamidophos (MAP) as the template molecule based on non‐covalent interaction. The complexes formed between template and monomers before polymerization were characterized by 1H NMR titration test, FT‐IR and UV spectrometry study. These studies indicated that a 1:2 molecular complex formed dominantly between MAP and functional monomers. A model mainly involving cooperative hydrogen interaction was proposed by exact placement of functional groups. Association constant was estimated to be 2.894 × 106 L2/mol2. When the initial concentration of MAP was 1.0 mmol L−1, the affinity capacity of MIP was 4.23 times that of NIP. The binding performance of MIP was modeled with the Freundlich isotherm (FI) and the total number of binding sites was calculated to be 33.97 μmol/g. The MIP showed great homogeneity with a heterogeneity index of m = 0.7356. The specificity of MIP was investigated by single‐analyte binding and molecularly imprinted solid‐phase extraction (MISPE) assays using MAP and other structurally related organophorous pesticides (OPPs). The results indicated that the MIP had a marked preference for MAP.
The Method for Analysis of Hydrocarbon Mixtures C1‐C5 by Capillary Column Gas Chromatography
Authors: Yang Feng‐Ke , Zhang Zhan‐Tao , Chen Fang 
Published: May 2015

AbstractThis study was carried out to determine low‐boiling point hydrocarbon mixtures C1‐C5 using gas chromatography supplied with a flame ionization detector (FID) and a low‐pole capillary column. The temperature of the column reached −30 centigrade and all components eluted within 4 minutes. Sufficient resolution was available for the components with low retentions. The limits of the relative standard deviations (RSD) were from 0.19% to 2.40%. The method was found to be suitable for the determination of natural gas, petroleum, environmental quality, etc.
H3PW12O40/SiO2: An Eco‐Friendly Alternative for the Stereo‐, Regio‐ and Chemoselective Claisen‐Schmidt Condensation
Authors: Mirjalili Bibi Fatemeh , Zaghaghi Zahra 
Published: May 2015

AbstractH3PW12O40/SiO2 or (PW/SiO2) promotes the regio‐, stereo‐ and chemoselective Claisen‐Schmidt condensation with improved yields.
Synthesis and ABTS Radical, MMP‐1 Inhibitory Activity of CAPE Analogues
Authors: Chiang Chih‐Chia , Hsu Ling‐Yih , Chang Tsu‐Chung , Tsai Hou‐Jen 
Published: May 2015

AbstractIn the photoaging process of skin, the ultraviolet (UV)‐induced reactive oxygen species (ROS) is the key regulator of matrix metalloproteinase (MMPs) expression. In this study, a series of Caffeic acid phenethyl ester (CAPE) analogues were synthesized by conjugating the group VI elements (selenium, sulfur, oxygen)‐containing aliphatic alcohols to polyphenolic acids. Their biological activities were evaluated by in vitro testing of their radical scavenging activity the of ABTS [2,2′‐azinobis‐(3‐ethyl‐benzothiazoline‐6‐sulfonic acid)] radical and inhibitory effect against the matrix metalloproteinase‐1 (MMP‐1) activity of collagen degradation and cytotoxicity of a human dermal fibroblast skin cell. Our results suggest these compounds displayed moderate anti‐free radical, potent MMP‐1 inhibitory, and low cytotoxic activities.
PEG‐N2O4 System as an Efficient Reagent both for the Rapid Oxidation of Urazoles and 1,4‐Dihydropyridines under Nonaqueous Conditions
Authors: Zolfigol Mohammad Ali , Ghaemi Ezat , Madrakian Elaheh , Niknam Khodabakhsh 
Published: May 2015

AbstractN2O4 was easily impregnated on polyethyleneglycol to give a stable reagent. Polyethyleneglycol‐N2O4 (PEG‐N2O4) system was used as an effective oxidizing agent for the oxidation of urazoles and bis‐urazoles to their corresponding triazolinediones and also for the aromatization of 1,4‐dihydropyridines into the corresponding pyridine derivatives under mild conditions at room temperature with good to excellent yields.
Monte Carlo Simulation of Microemulsion Phase Transitions by Solvent Accessible Surface Area
Authors: Behjatmanesh‐Ardakani Reza , Karimi Mohammad Ali , Nikfetrat Mehdi 
Published: May 2015

AbstractResults of lattice Monte Carlo simulation are presented for the behavior of a mixture of oil‐water‐amphiphile in different conditions. For the first time, the phase transitions between different types of microemulsion are modeled, in a qualitative manner, using the concept of solvent accessible surface area. All of the simulations are run in canonical (N, V, T) ensemble. Simple cubic lattices with the dimension of 50 have been used to avoid any size or surface effects of the boxes. Periodic boundary conditions and excluded volumes are used to mimic the box of simulation as a bulk of solution. All of the results are in good qualitative agreement with previous theoretical and experimental results.
Prediction of GC Retention Indexes for Insect‐Produced Methyl‐Substituted Alkanes Using a Wavelet Neural Network
Authors: Atabati Morteza , Zarei Kobra 
Published: May 2015

AbstractA quantitative structure‐property relationship (QSPR) study based on the wavelet neural network (WNN) technique was performed for the prediction of gas chromatography retention indexes of methyl‐substituted alkanes produced by insects. In addition to the simple structural descriptors, semi‐empirical quantum chemical calculations at the AM1 (Austin Model 1) level were used to find the optimum 3D geometry of the studied molecules and a numbers of descriptors were calculated with HyperChem and Dragon software. A stepwise MLR (Multiple Linear Regression) method was used to select the best descriptors, and the selected descriptors were used as input neurons in a wavelet neural network model. The average relative error was 2.2%.
Synthesis of (3,5‐Aryl/methyl‐1H‐Pyrazol‐1‐yl)‐(5‐Arylamino‐2H‐1,2,3‐Triazol‐4‐yl)Methanone
Authors: Cao Zi‐Ping , Quan Bin , Dong Heng‐Shan 
Published: May 2015

AbstractSome new (3,5‐aryl/methyl‐1H‐pyrazol‐1‐yl)‐(5‐arylamino‐2H‐1,2,3‐triazol‐4‐yl)methanones were synthesized and characterized by 1HNMR, 13C NMR, MS, IR spectra data and elemental analyses or high resolution mass spectra (HRMS). During the procedure, Dimroth rearrangement was used in this synthesis.
Contributions of a Surface Hydrophobic Cluster to the Folding and Structural Stability of Ubiquitin
Authors: Chen Rita P.‐Y. , Liang Fu‐Cheng , Lee Chung‐Tien , Zerella Rosa , Chan Sunney I. 
Published: May 2015

AbstractThe role of the small exterior hydrophobic cluster (SEHC) in the strand region of the N‐terminal β‐hairpin of ubiquitin on the structural stability and the folding/unfolding kinetics of the protein have been examined. We introduce a Phe→Ala substitution at residue 4 in the strand region of the N‐terminal β‐hairpin of the ubiquitin. A peptide with the same amino acid sequence as the first 21 residues of the mutated ubiquitin has also been synthesized. The F4A mutation unfolds the hairpin structure of the peptide segment without disruption of the turn. The same mutation does not seem to affect the overall structure, but the stability of the mutated full‐length protein decreases by approx. 2 kcal/mol. Kinetically, the entire hairpin structure is implicated in the transition state during folding of the wild type protein. The rate of refolding is retarded by the F4A mutation in ∼80% of the protein molecules. The F4A substitution also increases the unfolding rate of the protein by 10 fold. Thus the hydrophobic side‐chain of Phe‐4 not only contributes to the stability of the hairpin, but also to the stability of the entire protein by forming a cluster together with the hydrophobic residues on the C‐terminal strand.
Synthesis and Structural Characterization of One‐Dimensional Cadmium(II) Coordination Polymers Containing Polydentate Nitrogen Ligands
Authors: Suen Maw‐Cherng , Wang Ju‐Chun 
Published: May 2015

AbstractThe reactions of Cd(NO3)2·4H2O with NH4SCN and 2,4‐dpa (2,4‐dpa = 2,4‐dipyridineamine) in CH3OH afforded the one‐dimensional coordination polymer [Cd(NCS)2(2,4‐dpa)2]n, 1, while reaction of Cd(NO3)2·4H2O with NH4SCN and PmPa (PmPa = 2‐(1‐piperazinyl)pyrimidine) in CH3OH gave complex of the type [Cd(NCS)2(PmPa)2]n, 2. Each of the 2,4‐dpa ligand in complex 1 is coordinated to the Cd2+ metal center through pyridyl nitrogen atoms to form the one‐dimensional chain structures. The distorted {CdN4S2} octahedral coordination geometry around Cd2+ center is completed by pairs of bidentate thiocyanato ligands. Complex 2 has the 1‐D arrangement constructed through one‐dimensional double μ(N,S) end‐to‐end bridging thiocyanato groups bridged Cd(II) chains interconnected through PmPa ligands.
AC Impedance Studies on the Relationship between the Fractal Characteristics and Electrochemical Properties of Poly(Para‐Phenylene) Film
Authors: Chen Wan , Liang Cheng‐Hao , Yie Yang , Wu Bo 
Published: May 2015

AbstractThe effects of experimental conditions on the fractal structure of electrosynthetic polyparaphenylene films were studied by electrochemical impedance spectroscopy. The results indicate that, at the potential range (0‐0.6 V), the film surface fractal dimension rises while the corresponding charge transfer resistances Rct decrease as charge increases. This is consistent with the oxidized behavior of the conducting polymer. As for the degradation of electrolytes, scanning electron microscopy observations of poly(para‐pheneylene) (PPP) film provide evidence of the close relationship between the degradation of electrolytes and the film morphology, also in good agreement with the electrochemical impedance results interpretation. The X‐ray photoelectron spectroscopic analysis results present that the relative oxygen content ratio (O/C) of the films increases with the times the electrolyte is used, which reveals that the degradation of the electrolyte may result in a compact and passivation PPP film.
Synthesis and Molecular Structure of New S‐Nucleosides of 5‐(4‐Pyridyl)‐4‐Aryl‐4H‐1,2,4‐Triazole‐3‐Thiols
Authors: Zhang Huan‐Huan , Hu Xiu‐Qin , Fan Gui‐Fang , Xu Peng‐Fei 
Published: May 2015

AbstractThe synthesis of some new S‐nucleosides of 5‐(4‐pyridyl)‐4‐aryl‐4H‐1,2,4‐triazole‐3‐thiols (4a‐n) is described. Direct glycosylation of (4a‐n) with tetra‐O‐acetyl‐α‐D‐glucopyranosyl bromide in the presence of potassium hydroxide followed by deacetylation using dry ammonia in methanol gave the corresponding 3‐S‐(ñ‐D‐glucopyranosyl)‐5‐(4‐pyridyl)‐4‐aryl‐4H‐1,2,4‐triazoles (6a‐n) in good yields. All the compounds were fully characterized by means of 1HNMR, 13C NMR spectra and elemental analyses. To assist in the interpretation of the spectroscopic data, the crystal structure of 3‐S‐(2′,3′,4′,6′‐tetra‐O‐acetyl‐β‐D‐glucopyranosyl)‐5‐(4‐pyridyl)‐4‐phenyl‐4H‐1,2,4‐triazole (5a) was determined by X‐ray diffraction.
Synthesis of 2‐[4‐(Imidazolin‐2‐Ylideneamino)Benzyl]‐Indan‐1‐Ones as Novel Potent Prostacyclin Antagonists
Authors: Chern Ching‐Yuh , Yek Yung‐Lee , Chen Yu‐Lin , Kan Wai‐Ming 
Published: May 2015

AbstractProstacyclin is involved in many pathological conditions, such as sensitization of inflammation induced pain and isovolumetic distention. Therefore, antagonism of prostacyclin action may be useful in the alleviation of these conditions. In this study, novel potent prostacyclin antagonists, 2‐[4‐(imidazolin‐2‐ylideneamino)benzyl]‐indan‐1‐ones were synthesized from their respective substituted indanones in three steps. The construction of the amino‐imidazole moiety of these derivatives is achieved by using in situ generation of chloro‐imidazole and reaction with their respective anilines. Thus, these N‐substituted 2‐imidazolines can be prepared safely and efficiently. Moreover, these compounds show potent prostacyclin antagonistic activity by inhibition of prostacyclin agonist induced ERK1/2 phosphorylation in human erythroleukemia cells. Moreover, we observed an increase in activity with the increase in electro‐donating property of the substitution on the indanone aromatic ring. Prostacyclin antagonists with increased potency may be designed based on these findings. These compounds may also be invaluable tools for the study of the physiological functions of prostacyclin.
Silica Sulfuric Acid and Al(HSO4)3: As Efficient Catalysts for the Formylation of Alcohols by Using Ethyl Formate under Heterogeneous Conditions
Authors: Zolfigol Mohammad Ali , Chehardoli Gholamabbas , Dehghanian Mina , Niknam Khodabakhsh , Shirini Farhad , Khoramabadi‐Zad Ahmad 
Published: May 2015

AbstractA mixture of ethyl formate and a catalytic amount of silica sulfuric acid or Al(HSO4)3 as suitable formylating systems can formylate various alcohols to their corresponding formate ester derivatives under mild, nearly neutral and heterogeneous conditions at room temperature with good to excellent yields.
A Convenient and Versatile Method for the Preparation of α‐Hydroxymethyl Ketone Derivatives from the Corresponding Allyl Silyl Ethers or Allyl Carboxylates
Authors: Hon Yung‐Son , Wong Ying‐Chieh , Wu Kuo‐Jui 
Published: May 2015

AbstractThe ozonolysis of 1‐substituted allyl silyl ethers or 1‐substituted allyl carboxylates followed by treatment with bases gave the corresponding α‐silyloxymethyl‐ or α‐acyloxymethyl‐ketones in good yields. It is proposed to proceed via the corresponding α‐silyloxy‐ or α‐acyloxyaldehydes intermediates followed by 1,4‐group migration. The results of theoretical calculations are applicable to explain the experimental results.
Ethyl Xanthate and Propyl Xanthate as Activators and Inhibitors of Mushroom Tyrosinase in Different Concentrations
Authors: Saboury A. A. , Alijanianzadeh M. 
Published: May 2015

AbstractThe effect of ethyl xanthate(I) and propyl xanthate(II) on the kinetics of hydroxylation by mushroom tyrosinase (MT) has been investigated at 20°C in 10 mM phosphate buffer solution, pH 6.8. 4‐[(4‐Methyl‐phenyl)azo]‐phenol (MePAPh) was used as a synthetic substrate for the enzyme for cresolase reaction. The results show that ethyl xanthate and propyl xanthate can activate or inhibit the cresolase activity of mushroom tyrosinase depending on the concentration of these effectors. Both I and II act uncompetitive at relatively high concentrations (20‐50 μM). The inhibition constant (Ki) values for I and II are 13.8 and 11 μM, respectively. However, both I and II act as activators at relatively low concentrations (0‐11.5 μM). Activation of the enzyme in low concentrations of xanthates arises from increasing the affinity of binding for the substrate as well as increasing the enzyme catalytic constant. The activation constant (Ka) values for I and II are 1.88 and 2.68 μM, respectively. The enzyme has two distinct sites for both effectors. The first one is a high‐affinity activation site and the other is a low‐affinity inhibition site.
Synthesis of Polysubstituted Quinolines Using Cyanuric Chloride as a Catalyst Under Aqueous Conditions
Authors: Bandgar Babasaheb P. , More Parmeshwar. E. , Kamble Vinod T. 
Published: May 2015

AbstractA mild, eco‐friendly and efficient route for the synthesis of quinolines and polycyclic quinolines via Friedländer annulation using cyanuric chloride as a catalyst under aqueous conditions is described.
Computational Study of the Dissolution of Some Atomic and Diatomic Species in the Square and Hexagonal 2‐D Helium Lattices
Authors: Zanjanchi Farzaneh , Sabzyan Hassan 
Published: May 2015

AbstractDissolution of some industrially relevant atomic and diatomic species (Ar, Ne, H, O, H2, N2 and O2) in the 5 × 5 2‐D hexagonal and square helium lattices, as the model of the liquid helium cryogen, has been studied using ab initio MP2/6‐31++G computations. Structural, electronic and thermochemical properties have been calculated and analyzed for these solution lattices. Results of these calculations show that dissolution of Ar, Ne, H and H2 species is more favored at higher temperatures. A reverse trend is observed for the dissolution of O, N2 and O2 species. A staggered orientation is preferred by all diatomic species in both lattices. Results of this study also show that breakage of the O2 molecule becomes slightly easier in the 2‐D helium lattices as compared with that of the H2 molecule. Effect of the cavity geometry and size, and position of the solute in the lattice have also been studied. Analysis of the results shows that the range of the interaction between the solute and solvent atoms is only one helium layer.
Simple and Sensitive Electrochemiluminescence Method for Determination of Bisphenol a Based on its Inhibitory Effect on the Electrochemiluminescence of Luminol
Authors: Zhuang Ya‐Feng , Zhang Jin‐Tao , Cao Gui‐Ping 
Published: May 2015

AbstractAn electrochemiluminescence inhibition method has been developed for the determination of bisphenol A based on studying the inhibition phenomena of bisphenol A to the electrochemiluminescence of luminol. There is a linear relationship between the inhibitive intensity of electrochemiluminescence and the concentration of bisphenol A in the range of 4.4 × 10−7 to 2.2 × 10−5 mol/l. The method was successfully applied to the determination of bisphenol A in hot water in contact with commercially available table‐water bottle samples.
Reaction HFCO + 2H2O — Calculated Mechanisms
Authors: Tsai Wu‐Hung , Ho Jia‐Jen 
Published: May 2015

AbstractThree possible reaction mechanisms of methanoyl fluoride with 2H2O include a concerted and a stepwise hydrolysis of HFCO into HCOOH + HF, and a pure catalytic decomposition of HFCO into HF + CO. Among these, the two H2O molecules acting as catalyst to decompose HFCO has the lowest calculated barrier, 25.1 kcal/mol with respect to the reactant‐adduct complex, whereas the barriers for the concerted and stepwise hydrolytic reactions in which one H2O acts as a reactant and the other H2O as catalyst are similar, 30.8 kcal/mol for concerted and 29.9 kcal/mol for stepwise. The formation of transoid HCOOH in the hydrolysis of HFCO is more favorable than cisoid HCOOH.