共查询到20条相似文献,搜索用时 15 毫秒
1.
Mi?osz Mi?tkiewski Beata Powa?a Bartosz Staniszewski Maciej Kubicki W?odzimierz Urbaniak Cezary Pietraszuk 《Central European Journal of Chemistry》2011,9(4):728-736
Selected β-diketones bearing unsaturated derivatives have been demonstrated to undergo homo-metathesis and cross-metathesis with selected
olefins in the presence of Grubbs catalysts. The reactions led to respective homo- and cross-metathesis products mainly with
good yields and selectivities.
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2.
(Z/E)-1-(2-Methoxyaryl)-1-phenylpropenes have been prepared in good yields by heating a mixture of a phenolic substrate, cinnamyl
chloride, tetramethylammonium chloride and K2CO3 in polyethyleneglycol at 180°C. The one-pot synthesis proceeds through four discrete reaction steps: alkylation of the
phenol with cinnamyl chloride, Claisen rearrangement, O-methylation and double-bond migration. The configuration of one crystalline product was determined using a single-crystal
X-ray diffraction analysis. The thermodynamic and structural features of the products were evaluated using computational chemistry
techniques.
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3.
This article describes the simple hydrodehalogenation of halogenated anilines and their derivatives by the action of Raney
aluminium-nickel alloy in aqueous alkaline solution at room temperature. The reaction course was monitored by means of 1H
nuclear magnetic resonance (NMR) spectroscopy and GC-MS spectra.
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4.
Rayna Bryaskova Nelly Georgieva Dimitar Peshev 《Central European Journal of Chemistry》2010,8(5):1053-1058
Polyvinyl alcohol (PVA) and tetraethoxysilane (TEOS) hybrid materials were prepared by sol-gel methods and tested as matrices
for immobilization of Trichosporon cutaneum R57, capable of removing cadmium and copper ions from aqueous solutions. A kinetic model was applied and the effects of matrix
TEOS content on the copper and cadmium uptake equilibria and rate constants were investigated.
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5.
Anuţa Câmpean Mihaela Tertiş Robert Săndulescu 《Central European Journal of Chemistry》2011,9(4):688-700
Electrochemical behaviour of some alkaloids, namely: caffeine, aminophylline, theophylline, codeine phosphate and papaverine
hydrochloride, that are in solution in various combinations or in the presence of other compounds contained in pharmaceuticals
or in real samples (urine) was investigated using cyclic voltammetry (CV), square-wave voltammetry (SWV) and differential
pulse voltammetry (DPV) on electrochemically activated glassy carbon electrode.
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6.
Fluorescence spectroscopy and circular dichroism (CD) spectroscopy were used to investigate the interaction of coumarin-3-carboxylic
acid with human serum albumin (HSA) and bovine serum albumin (BSA) under physiological conditions in a buffer solution of
pH 7.4.
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7.
Nikolai N. Kolesnikov Elena B. Borisenko Dmitrii N. Borisenko Boris A. Gnesin 《Central European Journal of Chemistry》2011,9(4):619-623
In the present study newly produced semiconductor ceramic nanopowder materials made of CdTe and Cd1−xZnxTe (CZT) are considered. Common features and differences in microstructures, phase transformations, grain growth and properties
of the ceramic materials of the binary and ternary compositions are studied.
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8.
Aleksandra Č. Mišan Neda M. Mimica-Dukić Anamarija I. Mandić Marijana B. Sakač Ivan Lj. Milovanović Ivana J. Sedej 《Central European Journal of Chemistry》2011,9(1):133-142
Rapid Resolution HPLC/DAD method, on a 1.8 μm, 4.6×50 mm column, was developed to enable a rapid separation of a mixture of
17 compounds, which consisted of hydroxybenzoic acids, hydroxycinnamic acids, flavones, flavonols, flavanone, flavonol-glycoside
and antraquinone, in a single run, within 22 minutes. The developed method is precise, accurate and sensitive enough for simultaneous
quantitative evaluation of major compounds in crude and hydrolyzed extracts of parsley, buckthorn, mint, caraway and birch.
In order to overcome the inability to quantify all the phenolic compounds present in the samples caused by lack of external
standards, HPLC approaches for the total phenolic content estimation based on sum of all integrated peak areas were made.
These results were compared with the total phenolic content determined by Folin-Cioacalteu method. Although the correlation
between the series of data was not significant (p<0.05), the difference between the results of total phenolic content obtained spectrophotometrically and by HPLC was not high
in the case of parsley, buckthorn and mint extract. Regarding the obtained results, the HPLC approach could serve as an excellent
tool for total phenolic content estimation, without the need for complete identification of the individual compounds.
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9.
Irena Baranowska Sylwia Magiera Jacek Baranowski 《Central European Journal of Chemistry》2011,9(6):972-981
The aim of this paper is to optimize and validate a high performance liquid chromatography (HPLC) method for separation and
quantification of five isoflavones. A statistical central composite design was used to separate all peaks. These multivariate
procedures were efficient in determining the optimal separation condition using resolution, capacity factor, asymmetry and
number of theoretical plates.
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10.
Bingcheng Yang Feifang Zhang Xinmiao Liang 《Central European Journal of Chemistry》2012,10(3):472-479
This review summarizes the development of capillary ion chromatography (CIC) over approximately the last 5 years. It mainly
focuses on the technologic aspects of several key components associated with CIC, including micropump, microscale electrodialytic
eluent generator, microscale suppressor and the detector.
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11.
Mehdi Ghandi Parham Asgari Abuzar Taheri Alireza Abbasi 《Central European Journal of Chemistry》2010,8(4):899-905
One-pot, three-component condensation of 2-hydroxybenzaldehyde derivatives, primary amines with alkyl isocyanides is reported.
N-alkyl-2-(2-hydroxyphenyl)-2-iminoacetamide derivatives are generated presumably via the preliminary formation of N, N′-disubstituted benzo[b]furan-2,3-diamines and subsequent oxidation with molecular oxygen.
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12.
Jurgita Dabulyt?-Bagdonavi?ien? Feliksas Ivanauskas Valdemaras Razumas 《Central European Journal of Chemistry》2011,9(4):712-719
This paper presents mathematical and computational modelling of kinetics of a bioelectroanalytical system based on the interfacial
action of hydrolytic enzyme. A system of non-linear differential equations with diffusion is used to describe the kinetics
of Termomyces lanuginosa lipase (TLL) catalyzed hydrolysis of L-ascorbic acid palmitate (AAP). The system was solved numerically, and the kinetic
prameters of AAP hydrolysis by the enzyme were determined. The experimental and modelling results show linear dependence of
the rate of AAP hydrolysis on the TLL concentration. Complex dependence of the initial rate of bioelectrocatalytic current
increase on the thickness of total diffusion layer (hydrodynamic diffusion layer plus thickness of dialysis membrane on the
electrode surface) is also demonstrated and explained.
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13.
14.
New chiral enantiopure ureas and thioureas with (R,R)-TADDOL backbone were synthesized. Bis-(thio)ureas with C2 symmetry were obtained from TADDOL iso(thio)cyanates and bifunctional
amino-(thio)ureas from TADDAMINE, respectively. These were tested for carboxylate recognition capacity and the association
constant was determined for the most stable complex.
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15.
U. Ceren Başköse Sevgi Haman Bayarı Semran Sağlam Hacı Özışık 《Central European Journal of Chemistry》2012,10(2):395-406
The conformational analysis of rasagiline [N-propargyl-1(R)-aminoindan] was performed by the density functional theory (DFT) B3LYP method using the 6–31++G (d,p) basis set. A single
point energy calculations based on the B3LYP optimized geometries were also performed at MP2/6-31++G (d, p) level. The vibrational
frequencies of the most stable conformer of rasagiline was calculated at the B3LYP level and vibrational assignments were
made for normal modes on the basis of scaled quantum mechanical force field (SQM) method. The influence of mesylate and ethanedisulfonate
salts on the geometry of rasagiline free base and its normal modes are also discussed.
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16.
Rodion Yu. Iliashenko Olexiy S. Zozulia Andrey O. Doroshenko 《Central European Journal of Chemistry》2011,9(6):962-971
A series of novel nitro-substituted ortho-analogs of POPOP was synthesized. Like the most of the other known compounds of this class, the synthesized molecules demonstrate
high Stokes shift fluorescence emission owing to the planarization of their molecules at electronic excitation. Significant
fluorescence quenching in polar solvents was described as the “energy gap law” action rather than the specific effect of the
dialkylamino group excited state twisting.
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17.
Sushilkumar A. Jadhav 《Central European Journal of Chemistry》2012,10(2):295-299
New symmetrical disulfides together with the corresponding thiols bearing fluorescent end-groups have been synthesized as
building-blocks for self-assembled monolayers (SAMs). The synthesis has been accomplished starting from aromatic nitrogen
heterocycles in three steps. The conversion of the tosylated intermediate into the final disulfide is accomplished by use
of sodium hydrogen sulfide (NaSH). Both products (thiols and disulfides) were isolated and characterized.
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18.
Dariusz Wyrzykowski Michał Wera Artur Sikorski Dagmara Jacewicz Lech Chmurzyński 《Central European Journal of Chemistry》2011,9(6):1096-1101
The crystal structure of 2-methylpyridinium tetrachloroferrate(III) was determined. The iron cation is tetracoordinated by
chloride anions, and it adopts a slightly distorted tetrahedral coordination with three angles smaller, two almost equal and
one larger than the tetrahedral. The compound is isostructural with its 3-, and 4-methylpyridinium analogues. The thermal
properties of 2-, 3- and 4-methylpyridinium tetrachloroferrates(III) have been studied using TG and DSC techniques. The compounds
exhibit a high stability in the melt.
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19.
Jerzy Stanek 《Central European Journal of Chemistry》2011,9(4):737-742
An approximate analytical solution of the radial Schr?dinger equation for the generalized Hulthén potential is obtained by
applying an improved approximation of the centrifugal term. The bound state energy eigenvalues and the normalized eigenfunctions
are given in terms of hypergeometric polynomials. The results for arbitrary quantum numbers n
r
and l with different values of the screening parameter δ are compared with those obtained by the numerical method, asymptotic iteration,
the Nikiforov-Uvarov method, the exact quantization rule, and variational methods. The results obtained by the method proposed
in this work are in a good agreement with those obtained by other approximate methods.
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20.
Dominique R. Duguay Matthew T. Zamora Johanna M. Blacquiere Francis E. Appoh Christopher M. Vogels Susan L. Wheaton Felix J. Baerlocher Andreas Decken Stephen A. Westcott 《Central European Journal of Chemistry》2008,6(4):562-568
The addition of formylphenylboronic acid derivatives to thiourea and ethyl acetoacetate proceeds in the presence of an additional
Lewis acid catalyst to give the corresponding 3,4-dihydropyrimidin-2(1H)-(thio)ones (Biginelli products) in moderate yield.
Compounds were tested for antifungal activity against pure cultures of Aspergillus niger, Aspergillus flavus, Candida albicans and Saccharomyces cerevisiae but, unfortunately, none showed any appreciable activity.
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