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41.
(BeDABCO)2Pd2Cl6 as an efficient homogeneous catalyst for copper‐free Sonogashira cross‐coupling reaction
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An efficient catalytic system using 1‐benzyl‐4‐aza‐1‐azoniabicyclo[2.2.2]octane chloride and palladium chloride ((BeDABCO)2Pd2Cl6) was developed for the Sonogashira reaction. In the presence of a catalytic amount of this efficient, stable homogeneous catalytic system that is non‐sensitive to air and moisture, various aryl halides were efficiently coupled with phenylacetylene in good yields in H2O at 50°C under copper‐free conditions. Benzyl dabco as an efficient ligand and also a quaternary ammonium salt had an efficient stabilizing effect on the Pd(0) species. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
42.
Iron zirconium phosphate (ZPFe) nanoparticles were found to function as an efficient catalyst for the acetylation of a wide range of alcohols and phenols using acetic anhydride, generating good to excellent yields under solvent‐free conditions. The steric and electronic properties of various sub‐strates had a significant influence on the reaction conditions required to achieve the acetylation. The catalyst used in the current study was characterized by inductively coupled plasma‐optical emission spectrometry, X‐ray diffraction, N2 adsorption‐desorption, scanning electron microscopy, and transmission electron microscopy. These analyses revealed that the interlayer distance in the catalyst increased from 7.5 to 9.3 ? when Fe3+was intercalated between the layers, whereas the crystallinity of the material was reduced. This nanocatalyst could also be recovered and reused at least six times without any discernible decrease in its catalytic activity. This new method for the acetylation of alcohols and phenols has several important advantages, including mild and environ‐mentally friendly reaction conditions, as well as good to excellent yields and a facile work‐up. 相似文献
43.
Thickness measurement is important in various engineering fields. The several methods have been used to measure the thickness. This work explains a novel method for measuring the thickness of translucent plastic materials using scanner. The plastic samples were scanned against a white and a black background and the RGB parameters of obtained images were used to measure the opacity. Then, the thickness was calculated using relationship between thickness and opacity of samples. The best thickness prediction was obtained using a 3rd polynomial regression with the XYZ parameter. 相似文献
44.
An efficient method for preparation of aryl nitriles—using [Pd{C6H2(CH2CH2 NH2)‐(OMe)2,3,4} (µ‐Br)]2 complex as an efficient catalyst and K4[Fe(CN)6] as a green cyanide source—from aryl bromides, aryl iodides and aryl chlorides under microwave irradiation has been reported. This complex has been demonstrated to be an active and efficient catalyst for this reaction. Using a catalytic amount of this synthesized palladium complex in DMF at 130 °C led to production of the cyanoarenes in excellent yields in short reaction times. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
45.
We have developed a chemoselective, simple and efficient method for the preparation of aldoximes using microwave irradiation in the presence of tribenzylamine or 1,4-diazabicyclo[2.2.2]octane or 1-benzyl-4-aza-1-azoniabicyclo[2.2.2]octane bromide as bases and useful precursors for in situ generation of ionic liquids. 相似文献
46.
Direct and chemoselective sulfonation of aromatic compounds with silica sulfuric acid in 1,2-dichloeoethane or under solvent-free conditions. 相似文献
47.
Shadpour Mallakpour Abdol Reza Hajipour Hedayat A. Taghizadeh 《Monatshefte für Chemie / Chemical Monthly》2003,134(7):1015-1017
Summary. A rapid and simple method for the preparation of 4-substituted 1-ethoxycarbonyl semicarbazide is reported. The reaction is
carried out under microwave irradiation by the reaction of five different isocyanates with ethyl carbazate.
Corresponding author. E-mail: mallak@cc.iut.ac.ir
Previous name. Shadpour E. Mallakpour
Received October 28, 2002; accepted October 31, 2002
Published online May 15, 2003 相似文献
48.
An efficient catalytic system using (BeDABCO)2Pd2Cl6 was developed for the Stille cross‐coupling reaction. The substituted biaryls were produced in excellent yields in short reaction times using a catalytic amount of this catalyst in DMF at 120 °C. The ionic character of homogeneous catalyst and microwave irradiation and also DMF as microwave‐active polar solvent gave higher yields and shorter reaction times than conventional heating. Benzyl DABCO as an efficient ligand and also a quaternary ammonium salt had an efficient stabilizing effect on the Pd(0) species. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
49.
Copper zirconium phosphate nanoparticles have been used as an efficient catalyst for the acetyla-tion of a wide range of alcohols and phenols with acetic anhydride in good to excellent yields under solvent-free conditions. The steric and electronic properties of the different substrates had a signif-icant influence on the reaction conditions required to achieve the acetylation. The catalyst used in the current study was characterized by inductively-coupled plasma optical emission spectroscopy,energy dispersive spectroscopy, X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, and transmission electron microscopy. These analyses revealed that the interlayer distance in the catalyst increased from 7.5 to 8.0 when Cu2+ was intercalated between the layers, whereas the crystallinity of the material was reduced. This nanocatalyst could also be recovered and reused at least six times without any discernible decrease in its catalytic activity. This new method for the acetylation of alcohols and phenols has several key advantages, including mild and environmentally friendly reaction conditions, as well as good to excellent yields and a facile work-up. 相似文献
50.
Cobalt nanoparticles supported on ionic liquid‐functionalized multiwall carbon nanotubes as an efficient and recyclable catalyst for Heck reaction
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A novel and environmentally friendly cobalt nanoparticle catalyst supported on ionic liquid‐functionalized multiwall carbon nanotubes was successfully prepared and evaluated as a heterogeneous catalyst for the Mizoroki–Heck reaction. Several reaction parameters, including type and amount of solvent and base, were evaluated. This nanocatalyst could also be recovered and reused at least six times without any discernible decrease in its catalytic activity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献