CuI/Proline-catalyzed N-Arylation of Nitrogen Heterocycles

Ma＇s CuI/proline procedure for the catalytic cross coupling between nitrogen heterocycles and aryl halides was markedly improved. The key finding was that K3PO4 was a much better base than K2CO3 for the reaction. With this new reaction condition the cross coupling with aryl iodides could be accomplished in 1,4-dioxane instead of DMSO. This reactin also could be carried out in DMF. Furthermore, the coupling yields under the new conditions are usually higher than in Ma＇s original methods.

One-step synthesis of carbon-supported copper nanoparticles from biomass for N-arylation of pyrazole

Carbon-supported copper catalyst was prepared for the first time in one-step with copper nitrate and corn stalk through calcination under different temperatures. Uniformly dispersed nanoparticles were obtained and were identified to be Cu（0） and Cu（Ⅰ） in XRD patterns. Excellent catalytic activity and selectivity were achieved in the N-arylation of pyrazole under ligand and protection gas free conditions. About90.4% of product yield was achieved with only 0.5 mol% of copper catalyst（Cu-C-300）, which was considerably more efficient than previous reports. XPS results suggested that the N-arylation of pyrazole activity was closely related to the surface Cu（Ⅰ） species.

Practical copper-catalyzed N-arylation of amines with 20% aqueous solution of n-Bu_4NOH

N-Arylation of a wide variety of amines with phenylboronic acid catalyzed by copper acetate under 20%aqueous solution of n-Bu_4NOH was accomplished in good to excellent yields（up to 92%） and substrate conversions（up to 96%）.

A General and Efficient CuBr2-Catalyzed N-Arylation of Secondary Acyclic Amides

A general and efficient Cu（II）-catalyzed cross-coupling method is reported for the preparation of acyclic tertiary amides. Generally moderate to excellent yields and functional group tolerance were obtained with secondary acyclic amides and aryl halides as substrates in toluene.

Copper-catalyzed N-arylation of 2-arylindoles with aryl halides

10 mol% Cul combined with the DMEDA ligand can efficiently catalyze the N-arylation of 2-arylindoles with aryl iodides and aryl bromides in good to excellent yields. The aryl halides bearing electron-rich or electron-deficient functional groups can be well tolerated under this mild reaction conditions.

1,1′-Binaphthyl-2,2′-diamine Dihydrochloride：an Efficient Ligand for the N-Arylation of Imidazole with Aryl/heteroaryl Halides Catalyzed by CuI

Employing 1,1′-binaphthyl-2,2′-diamine（BINAM） dihydrochloride as an efficient and commerciallyavailable ligand, relatively mild and highly efficient copper-catalyzed coupling reactions of imidazole with aryl andheteroaryl halides have been developed. Various N-arylimidazoles could be synthesized in moderate to excellentyields.

Bifunctional Salen-Cu（II） Complex as Efficient Catalyst for N-Arylation of Imidazoles and Suzuki-Miyaura Coupling Reactions

Bifunctional Salen-Cu（II） complex catalyzed cross-coupling reactions of aryl halids with imidazoles or phenylboronic acid reagents have been developed as practical methods for C--N and C--C bond formation. The procedure tolerates aryl halides with various functional groups（such as methoxy, acetyl, nitrile, fluoro and nitro groups） and gives the corresponding coupling products in moderate to high yields. The catalyst remained active after fiye successive catalytic runs without loss in performance.

Tetrazole-1-acetic acid as a ligand for copper-catalyzed N-arylation of imidazoles with aryl iodides under mild conditions

Tetrazole-l-acetic acid was found to serve as a superior ligand for Cul-catalyzed N-arylation of imidazoles with aryl iodides under a low catalyst loading （5 mol% of Cul）. A variety of aryl iodides could he aminated to provide the N-arylated products in good to excellent yields without the need of an inert atmosphere.

Amorphous Cu^0 on Carbon Nanofiber as Recyclable Heterogeneous Catalyst for N-Arylation Reactions

A novel heterogeneous catalyst,amorphous Cu^0 on the carbon nanofibers was developed and characte-rized by means of several characterization techniques.The prepared Cu^0 was investigated as a heterogeneous catalyst for N-arylation reaction.The results show it is an excellent catalyst with recyclability,high consistency and catalytic activity.After the catalyst was used for 5 cycles in the N-arylation reaction,amorphous Cu^0 reunited into crystalline copper nanoparticles with different particle sizes and its good heterogeneity in the catalytic system was confirmed after the catalyst recovery.

Direct N-Arylation of Azaheterocycles with Aryl Halides under Ligand-free Condition

A simple and efficient C--N cross-coupling method of aryl halides with various heterocycles was reported, by using 10 tool% of CuI as catalyst and 1.2 equiv. Nail as base. Aryl iodides, aryl bromides and many substituted atyl chlorides could efficiently react with heterocycles, providing variety of N-arylated products in good to excellent yields. The ligand-free catalyst system was stable in air and could be readily reused.

3-(Diphenylphosphino)propanoic acid: An efficient ligand for the Cu-catalyzed N-arylation of imidazoles and 1H-pyrazole with aryl halides

3-（Diphenylphosphino）propanoic acid（L2） has proved to be an efficient ligand for the copper-catalyzed C–N coupling reactions.N-arylation of imidazoles with aryl iodides catalyzed by CuCl/L2 was smoothly carried out in DMSO at 100 8C with a yield up to 98%.N-arylation of 1H-pyrazole with aryl iodides and bromides catalyzed by Cu（OAc）2/L2 in 1 4-dioxane also gave the corresponding products with yields of40%–98%.

A bifunctional and recyclable catalyst:Amine and ionic liquid grafting on MOFs for the one-pot synthesis of N-aryl oxazolidin-2-ones

A bifunctional heterogeneous catalyst was designed and synthesized,denoted DMEDA/IL–NH2-MIL-101.The structure and physical-chemical characterization of DMEDA/IL–NH2-MIL-101 and its precursors were characterized by SEM,N2 adsorption-desorption,XPS,FT-IR,PXRD,elemental analysis,and TGA techniques.The date showed that the two catalytic components of N,N-dimethylethylenediamine(DMEDA)and 1-butyl-3-methylimidazolium bromide(BmimBr)were chemically immobilized in NH2-MIL-101 nanocages.The amine of DMEDA was grafted onto carrier NH2-MIL-101 by N–Cr coordinate covalent bonds and the ionic liquid of BmimBr(IL(Br-))was anchored in the NH2-MIL-101 nanocages by'ship-in-a-bottle'method,in which the amidogen of NH2-MIL-101 condensed with N,N-carbonyldiimidazole(CDI)firstly,and then alkylated with 1-bromo butane.This novel heterogeneous catalyst with two different active sites can efficiently catalyze the synthesis of N-aryl oxazolidin-2-ones from carbon dioxide(CO2),epoxides,and anilines in one-pot under mild solvent-free conditions.It not only showed good stability and recoverability after five cycles but also exhibited shape selectivity for the substrate due to the synergic catalysis of amine,ionic liquid,and NH2-MIL-101.This novel bifunctional material is a promising solid catalyst for the green synthesis of N-aryl oxazolidin-2-ones.

Popping of g-C_3N_4 mixed with cupric nitrate: Facile synthesis of Cu-based catalyst for construction of C-N bond

A novel strategy to synthesize copper-based nanoparticles supported on carbon nitride(C3 N4) was developed by popping of mixture containing C3 N4 and cupric nitrate. Characterizations such as X-ray photoelectron spectroscopy(XPS) and X-ray diffraction(XRD) indicate that the structure of g-C3 N4 maintained although a popping process occurred. High resolution transmission electronic microscopy(HRTEM) characterization illustrated that copper-based nanoparticles with diameter of < 1 nm were well distributed on g-C3 N4. This kind of copper catalyst exhibits high catalytic activity and selectivity in arylation of pyrazole, a simple and effect strategy to construct C-N bond in organic chemistry.According to the results of control experiments and characterizations, cuprous oxide should be the catalytic active phase in the supported coperbased catalyst.

Salen-Cu(II) Complex Catalyzed <i>N</i>-Arylation of Imidazoles under Mild Conditions

Three inexpensive and air-/moisture-stable Salen-Cu complexes 1-3 were evaluated to be a novel class of catalysts for the N-arylation of imidazoles with aryl halides. A variety of aryl iodides, bromides underwent the coupling with imida-zoles, promoted by the complex 3, in moderate to excellent yields without the protection by an inert gas.

Synthesis,Structural Characterization and Catalytic Activity of Copper(Ⅰ)Complexes with Triphenylphosphine and Pyridine Derivatives

Two new Cu（Ⅰ） complexes [CuCl（3-PyOH）（PPh_3）_2]（1） and [Cu_2（μ-Cl）_2（4-Stpy）（Ph_3P）_3]（2）（PyOH = hydroxypyridine; stpy = styrylpyridine） with triphenylphosphine and pyridine derivatives have been synthesized and characterized by elemental analysis and X-ray single-crystal diffraction. Compound 1 crystallizes in monoclinic, space group P2_1/c with a = 9.8945（7）, b = 37.266（2）, c = 10.9461（7） A, β = 116.0750（10）°, V = 3625.3（4） A^3, Z = 4, D_c = 1.350 Mg/cm^（-3）, μ = 0.801 mm^（-1）, F（000） = 1528, the final R = 0.0320 and w R = 0.0729 for 18568 observed reflections（I 〉 2σ（I））, R（all data） = 0.0413, wR（all data） = 0.0769, completeness to theta of 25.01 is 99.9% and GOF = 1.037. Compound 2 crystallizes in monoclinic, space group P2_1/c with a = 11.290（3）, b = 20.388（5）, c = 24.092（6） A, β = 102.028（4）°, V = 5424（2） A^3, Z = 4, D_c = 1.428 Mg/cm^（-3）, μ = 1.016 mm^（-1）, F（000） = 2408, the final R = 0.0568 and w R = 0.1486 for 27644 observed reflections（I 〉 2σ（I））, R（all data） = 0.0716, wR（all data） = 0.1592, completeness to theta of 25.01 is 99.9% and GOF = 1.056. Two new Cu（I） complexes have been utilized as catalysts for N-arylation of imidazole and both showed good catalytic activity.

N-Aryl diketopyrrolopyrrole derivatives towards organic optical and electronic materials

Diketopyrrolopyrrole(DPP)and related derivatives have drawn great attention due to their applications in organic optical/electronic materials.Progress in these materials is associated with developments in the syntheses of the DPP family.Chemical modification of DPP at nitrogen atom,including N-alkylation and N-arylation,is an effective strategy to improve its physical and chemical properties,such as solubility,optical and semiconducting properties.However,N-arylation of DPPs remains challenging compared to the easily accessible N-alkylation.Herein,the synthesis of N-aryl DPP derivatives and correlatedπ-expanded DPPs are summarized,and their optical/electronic properties are introduced.The future perspectives of N-aryl DPP derivatives are also discussed.

Electrochemical C-H/N-H cross-coupling of 2-phenylindolizines with phenothiazines to synthesize novel N-aryl phenothiazine derivatives

A facile and elegant method for synthesis of novel N-aryl phenothiazine derivatives from 2-phenylindolizines and phenothiazines through direct electrochemical oxidation has been developed.This approach was performed smoothly at room temperature without external oxidant and catalyst.Cyclic voltammetry and in situ FTIR techniques were applied to analyze the cross-coupling process of phenothiazines and 2-phenylindolizines,which helped to select the appropriate reaction potential.Under the optimized conditions,a broad range of substrates were well tolerated,affording the desired products in moderate to excellent isolated yields(up to 91%)with high regioselectivity.Meanwhile,a plausible mechanism involving a radical pathway has been proposed.

Synthesis and Characterization of Some N-Aryl-4-nitroimidazoles as Potential Insensitive Energy Materials

N-Aryl derivatives of 4-nitroimidazole have been synthesized under CuI/TBAB catalytic system in excellent yields, using KOH as base in DMF solvent.