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61.
The three-component condensation of benzaldehyde derivatives, alkyl propiolates, and primary amines catalyzed by silica gel, zeolite HY, montmorillonite K-10, and acidic alumina under microwave irradiation gave N-substituted 4-aryl-1,4-dihydropyridines in short reaction times and high yields. The best results were obtained with silica gel. 相似文献
62.
Faramarz Rostami-Charati Zinatossadat Hossaini Masoumeh Moghimi Elaheh Kowsari 《中国化学快报》2012,23(9):1007-1010
An efficient synthesis of thiazines from the three component reactions between dialkyl acetylenedicarboxylates,arylisothio-cyanates and iV-nucleophiles at room temperature in water as the solvent is described. 相似文献
63.
We have developed a simple and sensitive colorimetric procedure for the quantification of trace amounts of uric acid. It is based on the finding that uric acid in a medium containing ammonia and sodium hydroxide at 65?°C can reduce silver ions to form yellow silver nanoparticles (Ag NPs). These are stabilized in solution by using poly(vinyl alcohol) as a capping agent. The yellow color of the solution that results from the localized surface plasmon resonance of Ag NPs can be observed by the bare eye. The absorbance at 415?nm is proportional to the concentration of uric acid which therefore can be determined quantitatively. The calibration curve is linear in the concentration range from 10 to 200?nM, with a limit of detection of 3.3?nM. The method was successfully applied to the determination of uric acid in human plasma and urine samples. Figure
A colorimetric procedure has been developed for the determination of uric acid based on the formation of yellow Ag NPs by the reaction of uric acid with silver ions in a medium containing ammonia and sodium hydroxide at 65?°C. 相似文献
64.
Abstract
Palladium-catalyzed reactions are key steps for the formation of carbon–carbon bonds in modern synthetic chemistry and among these reactions few have influenced organic synthesis as greatly as the Suzuki–Miyaura reaction which was first reported in 1979. This review highlights recent and major developments of this approach in intramolecular cyclization and heterocyclization reactions. 相似文献65.
Chiral Bora[1]ferrocenophanes: Syntheses,Mechanistic Insights,and Ring‐Opening Polymerizations 下载免费PDF全文
Saeid Sadeh Hridaynath Bhattacharjee Elaheh Khozeimeh Sarbisheh Prof. Dr. J. Wilson Quail Prof. Dr. Jens Müller 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(49):16320-16330
A series of new boron‐bridged [1]ferrocenophanes ([1]FCPs) was prepared by salt‐metathesis reactions between enantiomerically pure dilithioferrocenes and amino(dichloro)boranes (Et2NBCl2, iPr2NBCl2, or tBu(Me3Si)NBCl2). The dilithioferrocenes were prepared in situ by lithium–bromine exchange from the respective planar‐chiral dibromides (Sp,Sp)‐[1‐Br‐2‐(HR2C)H3C5]2Fe (R=Me or Et). In most of the cases, mixtures of the targeted [1]FCPs 4 and the unwanted 1,1′‐bis(boryl)ferrocenes 5 were formed. The product ratio depends on the bulkiness of the amino group, the speed of addition of the amino(dichloro)borane, the alkyl group on Cp rings, and in particular on the reaction temperature. The formation of strained [1]FCPs is strongly favored by increased reaction temperatures. Secondly, CHEt2 groups at Cp rings favored the formation of the targeted [1]FCPs stronger than CHMe2 groups. These discoveries open up new possibilities to further suppress the formation of unwanted byproducts by a careful choice of the reaction temperature and through tailoring the bulkiness of CHR2 groups on ferrocene. Thermal ring‐opening polymerizations of selected boron‐bridged [1]FCPs gave metallopolymers with a Mw of 10 kDa (GPC). 相似文献
66.
67.
Nanoparticles of ZnO with the wurtzite structure have been successfully synthesized via a microwave through the decomposition of zinc acetate dihydrate in an ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, as a solvent. Fundamental characterizations including X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were conducted for the ZnO nanostructures.To explore the growth mechanism, the samples have been prepared in different irradiation time and also cetyltrimethylammonium bromide (CTAB) has been used as the capping reagent. 相似文献
68.
Razieh Sanavi Khoshnood Elaheh Hatami Donya Arefi Fatemeh Zahra Maknoni 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2016,90(2):308-317
In the present work the complexation process between Ag+ and Mg2+ cations and 4-hydroxyphenyl-2,5-bis(2-benzofuranyl)pyridine (HBFPY) ligand was studied in pure dimethylformamide (DMF), ethanol (EtOH), acetonitrile (AN) and in (DMF-EtOH), (AN-EtOH) and (DMF-AN) binary mixed solvent solutions at different temperatures using the conductometric method. Also in this work the complexation reaction between Ca2+, K+ cations and HBFPY ligand, was studied in pure dimethylformamide (DMF), propanol (PrOH), 1,4-dioxane (DOX), ethanol (EtOH) and in DMF-PrOH, DMF-DOX and DMF-EtOH binary mixed solvent solutions at different temperatures using the conductometric method. The conductance data show that the stoichiometry of the complexes formed between this ligand and the studied cations is 1 : 1 [ML]. In most cases, addition of HBFPY to solutions of these cations, causes a continuous increase in the molar conductivities which indicates that the mobility of complexed cations is more than the uncomplexed ones. The stability constants of the complexes were obtained from fitting of molar conductivity curves using a computer program, GENPLOT. The stability constant of [Mg(HBFPY)]2+ complex in various neat solvents at 15°C decreases in order: EtOH > DMF > AN and the stability constant of [Ag(HBFPY)]+ complex in various neat solvents at 35°C decreases in order: DMF > EtOH. The values of standard enthalpy changes (ΔH° c ) for complexation reactions were obtained from the slope of the Van’t Hoff plots and the changes in standard entropy (ΔS° c ) were calculated from the relationship ΔH° c,295.15= ΔH° c –298.15ΔS° c . 相似文献
69.
Mohammad Ali Zolfigol Gholamabbas Chehardoli Ezat Ghaemi Elaheh Madrakian Reza Zare Tahereh Azadbakht Khodabakhsh Niknam Shadpour Mallakpour 《Monatshefte für Chemie / Chemical Monthly》2008,139(3):261-265
Summary. Various N-bromo reagents [HMTAB, DABCO-bromine, DPTBE, and TBCA] were used as effective oxidizing agents for the oxidation of urazoles and bisurazoles to their corresponding triazolinediones
under mild and heterogeneous conditions at room temperature with good to excellent yields. Also the oxidation of some new
4-phenylurazole derivatives with these reagents is discussed. 相似文献
70.
An Efficient Method for Chemoselective Reduction of Nitro Compounds Using Bimetallic Fe‐Ni NPs/H3PW12O40.×H2O System 下载免费PDF全文
Soodabeh Rezazadeh Batool Akhlaghinia Elaheh K. Goharshadi Hossein Sarvari 《中国化学会会志》2014,61(10):1108-1114
The selective reduction of nitro compounds by treatment with bimetallic Fe‐Ni nanoparticles (NPs) and tungestophosphoric acid hydrate (H3PW12O40.×H2O) in H2O is reported. The method has been applied to a broad range of nitro compounds with different sensitive functionalities, including halides, carbonyl, hydroxyl, aldehyde, methyl, acetyl, nitrile, and ester substituents with excellent yields. The reaction yielded single product in all cases with very high yield. The simple experimental procedure and easy purification make the protocol advantageous. 相似文献