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901.
Mohammad Anary-Abbasinejad Hossein Anaraki-Ardakani Fatemeh Ghanea 《Monatshefte für Chemie / Chemical Monthly》2009,140(4):397-400
Abstract The reactive intermediate generated by the reaction of alkyl isocyanides and dialkyl acetylenedicarboxylates was trapped by
ethyl carbazones to produce stable ketenimine derivatives in good yield. The reaction is characterized by mild conditions,
high selectivity, and tolerance to various functional groups.
Graphical abstract
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902.
Robabeh Baharfar Seyed M. Vahdat Fatemeh G. Hakimabadi 《Monatshefte für Chemie / Chemical Monthly》2009,140(5):489-493
Abstract An efficient one-pot reaction of dialkyl acetylenedicarboxylates with 2,4-dihydroxybenzo(or aceto)phenones in the presence
of triphenylphosphine produces 5-hydroxy- and 7-hydroxycoumarin derivatives. The novel procedure features short reaction time,
fairly good yields, and simple workup.
Graphical abstract
相似文献
903.
The protective antigen (PA) of Bacillus anthracis is a potent immunogen and an important candidate vaccine. In addition, it is used in monitoring systems like enzyme-linked
immunosorbent assay to assess antibodies against PA in immunized subjects. The low level of PA production in B. anthracis and the difficulty of separating it from other bacterial components have made the researchers do different studies with the
aim of producing recombinant PA (rPA). In this study, to produce rPA as a recombinant protein vaccine, the partial sequence
of protective antigen of B. anthracis, amino acids 175–764, as a potent immunogenic target was inserted in pET21b(+). This is a prokaryotic plasmid that carries
an N-terminal T7.tag sequence. The integrity of constructed plasmid was confirmed using restriction enzyme mapping. rPA was
expressed after induction with isopropyl β-d-1-thiogalactopyranoside in Escherichia coli BL21. Purification of rPA was done with an affinity system using anti T7.tag antibody. Electrophoresis and Western blotting
confirmed the specificity of the expressed protein. BALB/c mice were immunized with obtained PA protein and evaluation of
specific immunoglobulin G antibodies against PA in sera using Western blotting method and showed that rPA is immunogenic.
The challenge of immunized mice with virulent strain of B. anthracis showed that rPA is functional to protect against pathogenic strain. 相似文献
904.
Fatemeh Rajabi 《Tetrahedron letters》2009,50(52):7256-4418
Chemoselective deprotection of aryl acetates is successfully carried out in excellent yield using a mesoporous silica-supported (Salen) Co(II) catalyst. The catalyst shows high thermal stability and also can be recovered and reused at least 10 times without any significant loss of its catalytic activity. The present process is environmentally benign and economical. 相似文献
905.
The present work is motivated by the desire to obtain numerical solution to a quasilinear parabolic inverse problem. The solution
is presented by means of the method of lines. Method of lines is an alternative computational approach which involves making
an approximation to the space derivatives and reducing the problem to a system of ordinary differential equations in the variable
time, then a proper initial value problem solver can be used to solve this ordinary differential equations system. Some numerical
examples and also comparison with finite difference methods will be investigated to confirm the efficiency of this procedure. 相似文献
906.
Ultrasonic back-extraction of Triton X-100 reverse micelles by a water/chloroform binary system and gas chromatography with flame ionization detection (GC-FID) was developed for extraction and determination of β-sitosterol and cholesterol in soybean and sunflower oil samples. After the homogenization of the oil samples with Triton X-100, an aliquot of 200 μL of methanol was added to the samples to form two phases. The clear Triton X-100 extract obtained by centrifugation was treated with a mixture of water (1000 μL) and chloroform (300 μL) for back-extraction of the analytes into the chloroform phase by ultrasonication. After centrifugation, the sedimented chloroform layer was withdrawn easily by a microsyringe and directly injected into the GC-FID system. The influence of several important parameters on the extraction efficiencies of the analytes was evaluated. Under optimized experimental conditions, the calibration graphs were linear in the range of 1.0–30.0 mg L−1 with coefficient of determination more than 0.994 for both analytes. The method detection limit values were in the range of 0.2–0.7 mg L−1. The lower limit of quantification values were in the range of 0.7–2.4 mg L−1. Intra-day relative standard deviations were in the range of 1.0–2.7%. This procedure was successfully applied with satisfactory results to the determination of β-sitosterol and cholesterol in spiked oil samples. The relative mean recoveries of oil samples ranged from 93.6% to 105.0%. 相似文献
907.
Gold nanoparticles (AuNPs) were electrodeposited on the surface of pencil graphite (PG) by fast scan cyclic voltammetry without using any additives in acidic medium. The effect of deposition time on the size of electrodeposited AuNPs was investigated in sulfuric acid as a supporting electrolyte. The deposition time was varied by varying the scan rate, number of cycles and applied potential range. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X‐ray diffraction (XRD) were used for characterization of PG and electrodeposited AuNPs. The results confirmed that nanosized gold particles (20 ± 8 nm) were deposited on the PG substrate with almost spherical geometry. 相似文献
908.
We present families of tableaux which interpolate between the classical semi-standard Young tableaux and matching field tableaux. Algebraically, this corresponds to SAGBI bases of Plücker algebras. We show that each such family of tableaux leads to a toric ideal, that can be realized as initial of the Plücker ideal, hence a toric degeneration for the flag variety. 相似文献
909.
Nickel selenide (NiSe) nanoparticles were prepared from the reaction of a SeCl4 aqueous solution with a NiCl2·6H2O aqueous solution in the presence of polyvinyl alcohol (PVA) as a capping agent and hydrazine hydrate (N2H4·H2O) as a reductant through a hydrothermal method. The size, morphology, chemical composition and purity of these nanoparticles depend on the capping agent, reductant, reaction temperature and time. 相似文献
910.
Mehdi Taghdiri Reza Behjatmanesh-Ardakani Abbas Shockravi Fatemeh Taheri Hanif Fattahi 《Journal of inclusion phenomena and macrocyclic chemistry》2012,73(1-4):255-262
Complexation properties of dinaphthosulfide-substituted macrocyclic diamides 1 and 2 with some metal cations that have been obtained by conductometric method are described with quantum mechanics calculations. To do this, the most stable structures of ligands, Hg2+-ligand complexes, ligand-MeOH and ClO4 ?–MeOH are optimized at HF/Lanl2dz level of theory and the most important interactions are analyzed by atoms in molecules (AIM) theory. These calculations predict the existence of strong interaction between Hg2+ cation and ligands 1 and 2, particularly, S–Hg2+ interaction. The different conductometric behaviors of complexation of ligands 1 and 2 with metal ions are interpreted on the basis of the calculated intramolecular hydrogen bonds in ligands and intermolecular hydrogen bonds between ligands and methanol as a solvent and perchlorate as a counter ion. In addition, binding energies between Hg2+ and ligands are also calculated by HF/Lanl2dz level of theory. Results show that all theoretical predictions are in line agreement with the experimental data. 相似文献