排序方式: 共有57条查询结果,搜索用时 31 毫秒
41.
Mn(Ⅲ)-四芳基卟啉与高碘酸四丁基铵催化羧酸的氧化脱羧:金属、取代基和轴向阴离子配体的影响 总被引:1,自引:0,他引:1
Gholam Reza KARIMIPOUR Bahador KARAMI Morteza MONTAZEROZOHORI Saeed ZAKAVI 《催化学报》2007,28(11):940-946
锰四芳基卟啉与高碘酸四丁基铵(n-Bu4NIO4)和咪唑(ImH)组合,为羧酸氧化脱羧提供了一个有效的催化剂体系.中位含有吸电子基团和/或大体积芳基的中位-四芳基卟啉使金属卟啉的活性降低.咪唑的存在和金属中心的选择对金属卟啉的催化性能起关键性作用,催化体系中的反离子也有重要影响.Mn(TPP)CN/n-Bu4NIO4/ImH体系的催化活性最好.二苯基乙酸的氧化脱羧可能涉及高价的含氧锰物种与反应物间的相互作用,提出了可能的反应机理. 相似文献
42.
Novel silica-supported molybdic acid (SSMA): an efficient catalyst for the synthesis of new azo dyes
Research on Chemical Intermediates - Silica-supported molybdic acid (SSMA) as a novel and highly efficient catalyst was prepared and characterized by X-ray fluorescence, X-ray diffraction, and... 相似文献
43.
In this work, new, efficient, and environmentally adapted synthesis of benzylpyrazolocoumarins in one‐pot is introduced. From tri‐component reaction of a wide range of aryl aldehydes, 4‐hydroxycoumarin, and 3‐methyl‐1‐phenyl‐2‐pyrazolin‐5‐one on water, benzylpyrazolocoumarins with good to excellent yields in a green procedure were synthesized. The highly efficient role of ferrous ammonium sulfate hexahydrate (Mohr’s salt) as a new green catalyst in this synthesis is obviously demonstrated. This novel procedure is an effective, cheap and environmentally adapted route to the synthesis of benzylpyrazolocoumarin derivatives. The crude products recrystallized to afford the crystalline pure product. This novel procedure has some advantages such as high efficiency, simplicity, high rate and environmental safety. 相似文献
44.
Magnetically recoverable Fe3O4 nanoparticles have been synthesized as a catalyst for the cyclocondensation of 1,2-phenylenediamines with orthoesters under solvent-free conditions.Catalyst loadings can be as low as 1 mol% to give high yields of the corresponding benzimidazole derivative at 80 °C.This green method offers significant advantages in terms of its simplicity,low catalyst loadings,high product yields,and non-toxic nature.The Fe3O4 nanoparticles were characterized by X-ray diffraction,transmission electron microscopy,and Fourier transform infrared spectroscopy. 相似文献
45.
Highly Functionalized and Potent Antiviral Cyclopentane Derivatives Formed by a Tandem Process Consisting of Organometallic,Transition‐Metal‐Catalyzed,and Radical Reaction Steps
下载免费PDF全文
![点击此处可从《Chemistry (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Pratap R. Jagtap Dr. Leigh Ford Dipl.‐Chem. Elmar Deister Dr. Radek Pohl Dr. Ivana Císařová Jan Hodek Dr. Jan Weber Dr. Richard Mackman Dr. Gina Bahador Dr. Ullrich Jahn 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(33):10298-10304
A simple modular tandem approach to multiply substituted cyclopentane derivatives is reported, which succeeds by joining organometallic addition, conjugate addition, radical cyclization, and oxygenation steps. The key steps enabling this tandem process are the thus far rarely used isomerization of allylic alkoxides to enolates and single‐electron transfer to merge the organometallic step with the radical and oxygenation chemistry. This controlled lineup of multiple electronically contrasting reactive intermediates provides versatile access to highly functionalized cyclopentane derivatives from very simple and readily available commodity precursors. The antiviral activity of the synthesized compounds was screened and a number of compounds showed potent activity against hepatitis C and dengue viruses. 相似文献
46.
A new library of pyrano[c]chromenes containing an aroyl group has been synthesized by a novel multicomponent process involving the reaction of various aryl glyoxals with 4-hydroxycoumarin and malononitrile. The reactions were catalyzed efficiently by ammonium dihydrogen phosphate to yield the desired products in good to excellent yields. 相似文献
47.
In(OTf)3 plays the role of a Lewis acid catalyst in the Pechmann condensation of phenols with β-ketoesters under solvent-free conditions to give coumarin derivatives. This novel and inexpensive method has advantages such as short reaction time, excellent product yields, and avoids the use of organic solvents in agreement with green chemistry principles. Catalyst loadings can be as low as 1 mol% to give high yields of the corresponding coumarins at 80 °C. The catalyst can be recovered after the reaction, and reused with only a slight decrease in the yield. 相似文献
48.
A green regioselective synthesis of some new and known 9-aryl-5,9-dihydropyrimido[4,5-d][1,2,4]triazolo[1,5-a]pyrimidine-6,8(4H,7H)-diones has been described via the microwave-assisted one-pot reaction of 3-amino-1H-1,2,4-triazoles, aromatic aldehydes and barbituric acids under solvent- and catalyst-free conditions. This operationally simple procedure is less laborious and provides a better scope than previously reported procedures. 相似文献
49.
Seyed Mohammad Javad Hosseini Ataallah Soltani Goharrizi Bahador Abolpour 《Particuology》2014,(2):100-105
The design of micro-devices involving aerosol transport requires the study of the deposition of aerosols in micro-channels. In this study, the slip and no-slip boundary conditions for the gas flow regime were applied to the Navier-Stokes equations to obtain the particle deposition in simple and converging-diverging micro-channels. The equation of particle motion included inertial, viscous, Brownian, and gravity terms. It was found that the ratio of gravity to inertial effects controls the deposition of particles with diameters of 0.1-1 μm, and the ratio of diffusion to inertial effects controls the deposition of particles with diameters of 0.01-0.001 i~m. Comparison between the no-slip and slip flow regimes showed that the deposition of 0.1- to 1-μm-diameter particles was less and the deposition of 0.01- to 0.001-1μm-diameter particles was greater for the slip flow regime. There was no significant difference between slip and no-slip flow regimes for the deposition of 0.01- to 0.1-μm-diameter particles. Finally, it was shown that the stagnated gas in the corners of the converging-diverging micro-channel produced similar gas velocity profiles under the slip and no-slip flow regimes. 相似文献
50.
Masoud Nasr‐Esfahani Bahador Karami Morteza Montazerozohori Karim Abdi 《Journal of heterocyclic chemistry》2008,45(4):1183-1185