Readily available copper powder with K2CO3 as the base was extremely effective catalyst for Suzuki-Miyaura coupling reaction performed in PEG-400, which afforded almost quantitative coupling products of aryl iodides. Using iodine as additive, coupling products of aryl bromides or chlorides could be obtained with moderate to good yields. 相似文献
PEG-400-H2O was found to be a green and recyclable reaction medium for asymmetric hydrogenations of aromatic ketones catalyzed by a ruthenium achiral monophosphine complex RuCl2(TPPTS)2 [TPPTS: P(m-C6H4SO3Na)3] modified by (S,S)-DPENDS [disodium salt of sulfonated (S,S)-1,2-diphenyl-1,2-ethylene-diamine]. The acetophenone product was obtained with 86.3% ee under the optimized conditions. The resulting products can be easily separated from the catalyst by extraction with n-hexane. The catalyst immobilized in PEG-400-H2O not only exhibits excellent activity and enantioselectivity, but also can be recycled and reused several times without a loss of activity or enantioselectivity. 相似文献
AbstractNiCl2(dppp) in PEG-400 is shown to be a highly efficient catalyst for Suzuki-Miyaura coupling of aryl chlorides with arylboronic acids. The reaction could be conducted at 100?°C using K3PO4 as base, yielding a variety of biaryls in good to excellent yields. The isolation of the products was readily performed by extraction with petroleum ether and NiCl2(dppp)/PEG-400 system could be easily recycled and reused up to five times without significant loss of activity. Our system not only avoids the use of easily volatile and toxic dioxane or toluene as a solvent but also solves the basic problem of nickel catalyst reuse. 相似文献
Copper(I)-catalyzed N-arylation of imidazole with iodobenzene, its derivatives, and bromobenzene in poly(ethylene glycol) under microwave irradiation was studied. The influence of the following factors on the yield of arylation product was investigated: the nature of the source of copper and ligand, type of poly(ethylene glycol) (PEG) used, and substituents in iodoarene. An optimal catalytic system was selected: CuO/l-Hys/Cs2CO3/PEG-400, a possibility of recycling of copper-containing catalyst was demonstrated. N-Arylation of eight natural amino acids using catalysis with Cu2O/Cs2CO3/PEG-400 and microwave irradiation was studied, the dependence of the reaction results on temperature, duration of the process, and the ratio of the starting reagents was found. The highest yields of the target products were reached in the case of leucine, valine, and phenylalanine. 相似文献
PEG-400 [poly(ethylene glycol-400)] was found to improve the Pd(OAc)2/DABCO-catalyzed aqueous Suzuki-Miyaura and Stille cross-coupling reactions. In the presence of Pd(OAc)2, DABCO, and PEG-400, a variety of aryl halides were coupled with arylboronic acids or organotin compounds efficiently to afford the corresponding cross-coupled products in moderate to excellent yields. The turnover numbers was up to 900,000 for the Suzuki-Miyaura reaction and up to 9800 for the Stille reaction. The catalyst system was also effective for Heck and Sonogashira cross-coupling reactions to some extent. 相似文献
Zinc doped tin oxide nanoparticles were synthesized by employing sol–gel method assisted with different surfactants namely cetyl trimethyl ammonium bromide (CTAB), hexamine and polyethylene glycol 400 (PEG-400). The synthesis of uniform distribution of spherical Zn-SnO2 nanoparticles in presence of PEG-400 was optimized. The synthesized Zn-SnO2 nanoparticles were characterized by employing standard characterization techniques. X-ray diffraction results confirmed the product high-quality crystalline formation. The photoluminescence peaks appeared at 360?nm revealed the recombination of electron and hole from band to band emission of SnO2 optical properties. The vibrational properties of Zn-SnO2 nanoparticles were confirmed by both Raman and infra red spectra. The spherical morphology and nano sized product was evident in 200?nm scale SEM images. The cyclic voltammetry result of the product Zn-SnO2 assisted PEG-400 exhibited the specific capacitance value of 312.7?F/g at scan rate of 10?mV/s and revealed the superior electrochemical properties. Moreover, the EIS and GCD studies also revealed the good supercapacitor nature with specific capacitance of 132.1?F/g at current density of 1?A/g for the product Zn-SnO2 (PEG-400).
Diagrammatic representation of Zn doped SnO2 synthesis by sol-gel method with enhanced specific capacitance of 132.1?F/g at 1?A/g for Zn-SnO2 (PEG-400).
PEG-400 and glycerol were successfully used as recyclable solvents for the synthesis of several organylthioenynes in good to excellent yields and high selectivity using solid supported catalyst (KF/Al2O3). This easy, general and improved method furnishes the corresponding alkenyl sulfides preferentially with Z configuration. The catalytic system and the glycerol or PEG-400 can be reused up to three times without previous treatment with comparable activity. 相似文献
A novel approach for chemoselective S- and N-arylation of 2-mercaptobenzothiazole was developed by copper/PEG-400 catalyst systems. Copper source and reaction temperature play an important role in this protocol, selective S-arylation of 2-mercaptobenzothiazole was achieved by using CuI/PEG-400/50 °C catalyst system, while selective N-arylation was achieved with CuO/PEG-400/140 °C catalyst system. Both are compatible with a variety of aryl halides and selectively give the desired S- and N-arylation products in good to excellent yields, respectively. 相似文献
A novel series of indeno-benzothiazepine derivatives was synthesised via a “green” route. Synthesis of these compounds involves the treatment of dinucleophiles such as 2-aminobenzenethiols with α,β-unsaturated ketones in poly(oxyethylene) (poly(ethylene glycol), PEG-400) catalysed by acetic acid. The synthone α,β-unsaturated ketones were obtained by Claisen-Schmidt condensation of indan-1-one with substituted pyrazole-2-carbaldehydes prompted by bleaching earth (pH 12.5) as catalyst and PEG-400 as “green” reaction solvent. Screening of all the synthesised compounds for antimicrobial activity revealed that most of these compounds exhibited moderate to significant antimicrobial activity. 相似文献
Boehmite (BO) nanoparticles (NPs) were prepared via the injection of aqueous NaOH solution to aqueous aluminum nitrate solution at room temperature. Afterwards, a new complex of copper was immobilized on BO-NPs (Cu-Guanidine@BO-NPs). This heterogeneous nanocatalyst was used as a practical, recyclable, chemo and homoselective nanocatalyst in the organic processes, i.e. the preparation of tetrazole five-membered heterocycles and chemoselective sulfoxidation of sulfides using H2O2 as oxidant. In this sense, the prepared nanocatalyst was characterized by AAS, N2 adsorption–desorption isotherms, WDX, EDS, SEM, and TGA techniques. The reusability of this catalyst was investigated in the described organic reactions for several runs without notable loss of its catalytic activity. Moreover, all of the tetrazole and sulfoxide derivatives were isolated in high Turn Over Number (TON) and Turn Over Frequency (TOF) numbers indicating the high activity and selectivity of Cu-Guanidine@BO-NPs in the described reactions. 相似文献
Within the problem of the synthesis of silver nanoclusters and nanoparticles in polyether media, systems containing silver nitrate AgNO3 and low-molecular-weight polyethers, poly(ethylene glycol) PEG-400 or oxyethylated glycerol OEG-5, were studied by fast atom bombardment (FAB) mass spectrometry. The formation of stable clusters of polyether oligomers (Mm) with silver cations Mm · Ag+ was shown, in agreement with the previous data of laser desorption/ionization. Quantum-chemical DFT calculations have shown that the Mm · Ag+ clusters are stabilized by wrapping of the polyether chain around the silver cation with the cation coordinating ether oxygen atoms. Silver nanoclusters were not found in the FAB mass spectra of liquid systems, but Agn+ clusters were detected for silver nanoparticles separated from the reaction medium. No products of chemical transformations of PEG-400 or OEG-5 were observed by FAB. A plausible mechanism of the reduction of silver cations involving nitrate anions is discussed. 相似文献
An efficient procedure based on arginine‐modified Fe3O4@carbon magnetic nanoparticles (FCA MNPs) with highly dispersed copper nanoparticles (Cu NPs) and 92.8 ppm of Pd is reported for room temperature Suzuki reaction. For enhancing the activity of this Cu‐based heterogeneous catalyst, special arginine amino acid as a ligand with high content of heteroatoms was immobilized onto the Fe3O4@carbon MNPs to increase the electron density. Cu(II) ions were then loaded on the surface of the FCA MNPs and reduced to achieve uniformly dispersed Cu NPs. An aqueous mixture of metal hydroxides such as KOH, Ba(OH)2, Ca(OH)2, Mg(OH)2 as a green, non‐toxic and basic medium was used for the Suzuki reaction at room temperature. This catalyst could also be recovered and reused with no loss of activity over six successful runs. 相似文献
Palladium nanoparticles supported on different shapes of nanocrystalline CuO are prepared by the treatment of Cu(NO3)2 and Pd(OAc)2 in polyethylene glycol (PEG-6000). The shapes of the CuO/Pd composite are dependent on the amount of PEG used. Suzuki coupling was catalyzed efficiently by the oval-shaped material, whereas the rod shape facilitates the cyanation reaction. The CuO/Pd catalyst is recovered and reused for subsequent Suzuki reactions; however, cyanation poisons the catalyst for further use. Both these reactions are very clean and high yielding. 相似文献
A simple and efficient one-pot method for the synthesis of new 2,4-diaryl-1,2,3,4-tetrahydroquinolines using a three-component imino Diels-Alder cycloaddition between trans-isoeugenol or trans-anethole, anilines, and benzaldehyde in the presence of BF3·OEt2 in PEG-400, a green and reusable solvent, has been developed. Also, BF3·OEt2-catalyzed formal [3+2] cycloaddition reaction of trans-isoeugenol or trans-anethole with 1,4-benzoquinone in PEG-400 to give dihydrobenzo[b]furan derivatives has been described. 相似文献
2-Phenylseleno aldehydes and ketones were selectively obtained using solid-supported catalyst (KF/Al2O3) and PEG-400 as clean, recyclable medium in good to excellent yields. The method was applied in the preparation of highly functionalized 2-phenylseleno citronellal and citronellol, potential bactericide agents. The catalytic system KF/Al2O3 and PEG-400 can be re-used for four times without previous treatment. 相似文献
A facile synthesis of hitherto unreported benzofuran-2-yl(9-methyl-9H-carbazol-3-yl)methanones (3a?Cl) is described. The synthesis mainly relies on the ultrasound-assisted Rap?CStoermer reaction of 3-chloroacetyl-9-methyl-9H-carbazole (1) with a variety of salicylaldehydes, as well as 2-hydroxy-1-naphthaldehyde (2) in CH3CN, with the presence of PEG-400 as a catalyst. This procedure offers easy access to benzofuran-2-yl(carbazolyl)methanone derivatives in a short reaction time and the products are achieved in good yields. 相似文献
A productive natural method has been produced for the synthesis of 2-aryl-2-methyl-4,5-diphenyl-2,3-dihydro-2H-imidazoles in great yields under catalyst free-conditions utilizing polyethylene glycol (PEG-400) as a green reaction medium. The highlights of this new method are shorter reaction times, good yields, room temperature, and use of nontoxic, inexpensive, and recyclable PEG-400. 相似文献
Microencapsulated copper(II) acetylacetonate was prepared and used in the aziridination of alkenes employing [N-(p-tolylsulfonyl)imino]phenyliodinane (PhINTs) as the nitrogen source. Microencapsulated copper(II) acetylacetonate [MC-Cu(acac)2] catalyst was reused for several cycles with consistent activity. 相似文献