cas 23309-16-2, Imidazole, 1-(o-nitrophenyl)- (8CI)

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A post-synthetically modified metal-organic framework for copper catalyzed denitrative C-N coupling of nitroarenes under heterogeneous conditions
Here we report, for the first time, the Ullmann C-N coupling reaction of nitroarenes which is achieved by using a copper containing metal-organic framework (MOF) catalyst under heterogenous conditions. The ready availability of nitroarenes and their low cost have made them ideal replacements for haloarenes as electrophilic coupling partners. Notably, the reaction protocol suppresses the by-product formation in the catalytic reaction. The catalyst has been designed and synthesized by two step post-synthesis functionalization of a MOF,viz.dabco MOF-1 with a -NH2functional group (DMOF-NH2). In the post-synthetic treatment, salicylaldehyde has been used for organic modification first and then copper(ii) was successfully incorporated onto the inner surface of the porous material. The hybrid porous solid thus obtained has been employed in the catalytic C-N coupling reaction of nitroarenes with a wide variety of amines under heterogeneous conditions, which displayed very high turnover frequencies (TOF) in catalytic reactions attesting its efficacy towards theN-arylation reaction.
Maity, Tanmoy,Ghosh, Pameli,Das, Soma,Saha, Debraj,Koner, Subratanath
p. 5568 - 5575
(2021/04/06)

N -Arylation of (hetero)arylamines using aryl sulfamates and carbamates via C-O bond activation enabled by a reusable and durable nickel(0) catalyst
An effective and general aryl amination protocol has been developed using a magnetically recoverable Ni(0) based nanocatalyst. This new stable catalyst was prepared on Fe3O4@SiO2 modified by EDTA and investigated by FT-IR, EDX, TEM, XRD, DLS, FE-SEM, XPS, NMR, TGA, VSM, ICP and elemental analysis techniques. The reaction proceeded via carbon-oxygen bond cleavage of (hetero)aryl carbamates and sulfamates under simple and mild conditions without the use of any external ligands. This method demonstrated functional group tolerance in the N-arylation of various nitrogen-containing compounds as well as aliphatic amines, anilines, pyrroles, pyrazoles, imidazoles, indoles, and indazoles with good to excellent yields. Furthermore, the catalyst could be easily recovered by using an external magnetic field and directly reused at least six times without notable reduction in its activity. This journal is
Dindarloo Inaloo, Iman,Majnooni, Sahar,Eslahi, Hassan,Esmaeilpour, Mohsen
p. 13266 - 13278
(2020/10/07)

A green and practical reduction of N-(4-chlorophenyl)-2-nitroaniline and its derivatives to corresponding N-substituted-benzene-1,2-diamines using thiourea dioxide
A new effective approach for synthesizing diverse N-substituted-benzene-1,2-diamines is reported. The treatment of N-substituted-2-nitroanilines with thiourea dioxide in the presence of sodium hydroxide efficiently formed the corresponding N-substituted-benzene-1,2-diamines, including N-(4-chlorophenyl)benzene-1,2-diamine with a good yield of 94%. The by-product is environmentally-friendly urea and is easy to separate from the product by filtration procedure that enhances the convenience of the approach.
Cui, Jian-Lan,Wang, Ning,Wang, Xiao,Yu, Si-Yuan,Zhong, Cong-Shan
supporting information

(2020/01/22)

Synthesis of indolo- And pyrrolo[1,2-: a] quinoxalinones through a palladium-catalyzed oxidative carbonylation of the C 2 position of indole
A methodology that involves the Pd-catalyzed direct C(sp2)-H bond carbonylation of the C2 position of indole has been introduced for the synthesis of indolo[1,2-a]quinoxalin-6(5H)-ones. The methodology developed herein was used for the synthesis of pyrrolo[1,2-a]quinoxalin-4(5H)-ones. The reaction of N-substituted 2-(1H-indol-1-yl)anilines or 2-(1H-pyrrol-1-yl)anilines and carbon monoxide in the presence of Pd(OCOCF3)2 as a catalyst and Cu(OAc)2 as an oxidant in toluene at 80 °C forms the corresponding quinoxalinones as exclusive products in good yields. The catalytically active C-H activated intermediate Pd complex was isolated and characterized for the first time which on exposure to CO gas in toluene at 80 °C gave the corresponding quinoxalinone derivative. On the basis of isolation of the intermediate, a possible mechanism has been proposed for the C-H activated direct carbonylative annulation of 2-(5-methoxy-1H-indol-1-yl)-N,4-dimethylaniline.
Chandrasekhar, Attoor,Sankararaman, Sethuraman
supporting information
p. 1612 - 1622
(2020/03/06)

Fragment-Based Discovery of a Qualified Hit Targeting the Latency-Associated Nuclear Antigen of the Oncogenic Kaposi's Sarcoma-Associated Herpesvirus/Human Herpesvirus 8
The latency-associated nuclear antigen (LANA) is required for latent replication and persistence of Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8. It acts via replicating and tethering the virus episome to the host chromatin and exerts other functions. We conceived a new approach for the discovery of antiviral drugs to inhibit the interaction between LANA and the viral genome. We applied a biophysical screening cascade and identified the first LANA binders from small, structurally diverse compound libraries. Starting from a fragment-sized scaffold, we generated optimized hits via fragment growing using a dedicated fluorescence-polarization-based assay as the structure-activity-relationship driver. We improved compound potency to the double-digit micromolar range. Importantly, we qualified the resulting hit through orthogonal methods employing EMSA, STD-NMR, and MST methodologies. This optimized hit provides an ideal starting point for subsequent hit-to-lead campaigns providing evident target-binding, suitable ligand efficiencies, and favorable physicochemical properties.
Kirsch, Philine,Jakob, Valentin,Oberhausen, Kevin,Stein, Saskia C.,Cucarro, Ivano,Schulz, Thomas F.,Empting, Martin
(2019/05/01)

Fragment-Based Discovery of a Qualified Hit Targeting the Latency-Associated Nuclear Antigen of the Oncogenic Kaposi's Sarcoma-Associated Herpesvirus/Human Herpesvirus 8
The latency-associated nuclear antigen (LANA) is required for latent replication and persistence of Kaposi's sarcoma-associated herpesvirus/human herpesvirus 8. It acts via replicating and tethering the virus episome to the host chromatin and exerts other functions. We conceived a new approach for the discovery of antiviral drugs to inhibit the interaction between LANA and the viral genome. We applied a biophysical screening cascade and identified the first LANA binders from small, structurally diverse compound libraries. Starting from a fragment-sized scaffold, we generated optimized hits via fragment growing using a dedicated fluorescence-polarization-based assay as the structure-activity-relationship driver. We improved compound potency to the double-digit micromolar range. Importantly, we qualified the resulting hit through orthogonal methods employing EMSA, STD-NMR, and MST methodologies. This optimized hit provides an ideal starting point for subsequent hit-to-lead campaigns providing evident target-binding, suitable ligand efficiencies, and favorable physicochemical properties.
Kirsch, Philine,Jakob, Valentin,Oberhausen, Kevin,Stein, Saskia C.,Cucarro, Ivano,Schulz, Thomas F.,Empting, Martin
p. 3924 - 3939
(2019/05/06)

Optimization of Drug Candidates That Inhibit the D-Loop Activity of RAD51
RAD51 is the central protein in homologous recombination (HR) repair, where it first binds ssDNA and then catalyzes strand invasion via a D-loop intermediate. Additionally, RAD51 plays a role in faithful DNA replication by protecting stalled replication forks; this requires RAD51 to bind DNA but may not require the strand invasion activity of RAD51. We previously described a small-molecule inhibitor of RAD51 named RI(dl)-2 (RAD51 inhibitor of D-loop formation #2, hereafter called 2 h), which inhibits D-loop activity while sparing ssDNA binding. However, 2 h is limited in its ability to inhibit HR in vivo, preventing only about 50 % of total HR events in cells. We sought to improve upon this by performing a structure–activity relationship (SAR) campaign for more potent analogues of 2 h. Most compounds were prepared from 1-(2-aminophenyl)pyrroles by forming the quinoxaline moiety either by condensation with aldehydes, then dehydrogenation of the resulting 4,5-dihydro intermediates, or by condensation with N,N′-carbonyldiimidazole, chlorination, and installation of the 4-substituent through Suzuki–Miyaura coupling. Many analogues exhibited enhanced activity against human RAD51, but in several of these compounds the increased inhibition was due to the introduction of dsDNA intercalation activity. We developed a sensitive assay to measure dsDNA intercalation, and identified two analogues of 2 h that promote complete HR inhibition in cells while exerting minimal intercalation activity.
Budke, Brian,Tueckmantel, Werner,Miles, Kelsey,Kozikowski, Alan P.,Connell, Philip P.
supporting information
p. 1031 - 1040
(2019/04/30)

Copper immobilized on magnetite nanoparticles coated with ascorbic acid: An efficient and reusable catalyst for C─N and C─O cross-coupling reactions
In a continuation of using magnetic nanoparticle (MNP)-supported catalysts, ascorbic acid (readily available, very safe and with strong affinity to MNPs) was used instead of the commonly used silica layer coating. This hybrid was used for immobilizing copper nanoparticles to produce Cu/ascorbic acid@MNPs catalyst. The catalyst was characterized and used in carbon–oxygen and carbon–nitrogen (various substrates) cross-coupling reactions in aqueous media and at room temperature with excellent product yields. Furthermore, the catalyst could be quickly and completely recovered using an external magnetic field and reused for six reaction cycles without significant change in catalytic activity.
Hajipour, Abdol R.,Check, Maryam,Khorsandi, Zahra
(2017/09/30)

A catalytic intramolecular nitrene insertion into a copper(i)-N-heterocyclic carbene bond yielding fused nitrogen heterocycles
N-(2-Azidophenyl)azolium salts were easily prepared and reacted with copper(i) under conditions allowing the formation of NHC complexes. Under these conditions, the formation of benzimidazo-fused heterocycles occurred under catalytic, efficient and very mild conditions. This reaction is proposed to proceed via dinitrogen elimination and imido/nitrene-NHC cyclization.
Fauché, Kévin,Nauton, Lionel,Jouffret, Laurent,Cisnetti, Federico,Gautier, Arnaud
supporting information
p. 2402 - 2405
(2017/02/23)

Heterogeneous sequential N-arylation of N-heterocycles over copper anchored mesoporous silica catalyst
N-Arylation reaction of N-heterocyclic compounds has been carried out in excellent yield using copper anchored SBA-15 catalyst. Sequential N-arylation reactions employing single catalyst under heterogeneous condition provides a straightforward access to a
Das, Soma,Maity, Tanmoy,Koner, Subratanath
p. 53 - 66
(2016/01/12)

Synthesis and characterization of 1,3-diamino-graphene as a heterogeneous ligand for a CuI-catalyzed C-N coupling reaction
1,3-Diamino-graphene (NH2-G-NH2) materials were synthesized using a simple chemical method. The as-prepared materials were characterized using FT-IR, TG, XRD, XPS, and SEM measurements. The results revealed that a 1,3-diamino group was successfully grafted on graphene and could immobilize CuI by coordination interactions. The NH2-G-NH2 materials can be used as heterogeneous ligands for CuI-catalyzed C-N coupling reactions, and the desired products were obtained with good yields. The reaction system is much smoother at lower temperature compared with others previously reported. Additionally, the new method can easily realize the purification of products and recycling of catalysts.
Zhou, Limei,Yin, Mengyun,Jiang, Xiaohui,Huang, Qiang,Lang, Wencheng
p. 1454 - 1459
(2016/02/19)

Copper(I) 3-methylsalicylate mediates the Chan-Lam N-arylation of heterocycles
Copper(I) 3-methylsalicylate (CuMeSal) mediates N-arylation reactions between aryl boronic acids and aromatic heterocycles (Chan-Lam coupling) under moderate reaction conditions (K2CO3, methanol, 65 °C, in air, 3-5 h). Both electron-rich and electron-deficient aryl boronic acids and a diverse set of N-heterocycles were allowed to react and gave N-arylation products in reasonable yields, which demonstrate the utility of this catalyst.
Farahat, Abdelbasset A.,Boykin, David W.
supporting information
p. 245 - 252
(2015/10/29)

N-Arylation of Heterocycles Promoted by Cyclen Derivatives
An efficient copper-catalyzed N-arylation reactions of imidazole, indole, and triazole with aryl or heteroaryl halides using cyclen derivatives as efficient organic base and ligand at moderate temperature have been investigated. The cross-couplings procee
Zhang, Bao-Hua,Shi, Lan-Xiang,Liu, Si-Jie,Guo, Rui-Xia
p. 1234 - 1239
(2015/08/06)

Cu(0)@Al2O3/SiO2 NPs: An efficient reusable catalyst for the cross coupling reactions of aryl chlorides with amines and anilines
The C-N cross coupling reaction of aryl chlorides with various alkyl/aryl amines catalyzed by copper nanoparticles impregnated on alumina/silica support (Cu(0)@Al2O3/SiO2) was investigated. The prepared catalyst was characterized for its intrinsic physico-chemical and textural properties using XRD, XPS, HR-TEM, BET surface area, SEM-EDAX, H2-TPR and ICP-AES techniques. The catalyst exhibits excellent reactivity and efficacy in the cross-coupling of a wide range of alkyl/aryl amines including challenging anilines with aryl chlorides. The catalyst offers significant advantages such as brevity, milder reaction conditions, excellent yields and high functional group tolerance for C-N cross coupling when compared with the other reported methods. Moreover, this atom-economical methodology does not require an additional ligand or co-catalyst/activator. The Cu(0)@Al2O3/SiO2 catalyst was efficiently applied to a gram scale synthesis of 7-chloro-4-(4-(2-nitrophenyl)piperazin-1-yl)quinolone (2k). The robustness of the catalyst was examined by reusing it for five consecutive runs.
Reddy, P. Linga,Arundhathi,Rawat, Diwan S.
p. 92121 - 92127
(2015/11/17)

A metal-organic framework Cu2(BDC)2(DABCO) as an efficient and reusable catalyst for Ullmann-type N-arylation of imidazoles
A highly porous metal-organic framework (Cu2(BDC)2(DABCO)) was synthesized and used as an efficient and recyclable heterogeneous catalyst for the Ullmann-type N-arylation of aryl halides with imidazoles. The Cu2(BDC)2(DABCO) was characterized by several techniques, including X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared, atomic absorption spectrophotometry, and nitrogen physisorption measurements. The catalyst offered high activity under mild conditions, confirming outstanding advantages when employing the Cu2(BDC)2(DABCO) as catalyst for Ullmann-type N-arylation reaction. The catalyst could be separated from the reaction mixture by simple filtration, and could be reused without a significant degradation in catalytic activity.
Nguyen, Tung T.,Phan, Nam T. S.
p. 1877 - 1883
(2015/02/19)

Aromatic N-arylations catalyzed by copper-anchored porous zinc-based metal-organic framework under heterogeneous conditions
A highly porous Zn-based metal-organic framework (MOF) IRMOF-3 was covalently decorated with pyridine-2-aldehyde. The free amine group of IRMOF-3 upon condensation with pyridine-2-aldehyde affords a bidentate Schiff-base moiety in the porous matrix. The Schiff base moieties are availed to anchor copper(II) ions to display the catalyst's utility towards catalytic reactions. The catalyst was characterized by UV/Vis and IR spectroscopy, powder XRD spectrometry, SEM energy-dispersive X-ray spectrometry, and nitrogen sorption measurements. The catalyst exhibits excellent activity in catalyzing the N-arylation reaction of nitrogen-containing heterocycles with aryl bromides in DMSO medium, under mild condition (90°C) in the presence of Cs 2CO3. The porous catalyst demonstrates size selectivity towards substrate as a result of the presence of active sites inside the pores of the MOF. The anchored complex seems to be not leached or decomposed during the catalytic reactions up to five successive catalytic cycles, demonstrating practical advantages over homogeneous catalysis.
Maity, Tanmoy,Saha, Debraj,Koner, Subratanath
p. 2373 - 2383
(2014/08/18)

Synthesis of N-aryl imidazoles catalyzed by copper nanoparticles on nanosized silica-coated maghemite
A magnetically recoverable catalyst consisting of copper nanoparticles (CuNPs) on nanosized silica-coated maghemite is presented. The catalyst has been prepared under mild conditions by mixing the magnetic support with a freshly prepared suspension of CuN
Nador, Fabiana,Volpe, María Alicia,Alonso, Francisco,Radivoy, Gabriel
p. 6082 - 6087
(2015/03/30)

Copper(I) 3-methylsalicylate, an efficient catalyst for N-arylation of heterocycles under moderate reaction conditions
Copper(I) 3-methylsalicylate mediates N-arylation reactions of both aliphatic and aromatic heterocycles under moderate reaction conditions. Both electron rich and electron poor aryl bromides and a diverse set of N-heterocycles were allowed to react and gave N-arylation products in high yields which demonstrated the efficiency and utility of this catalyst.
Farahat, Abdelbasset A.,Boykin, David W.
supporting information
p. 3049 - 3051
(2014/05/20)

Nano copper(i) oxide/zinc oxide catalyzed N-arylation of nitrogen-containing heterocycles with aryl halides and arylboronic acids in air
The synergistic effect of zinc and copper in Cu2O/ZnO nanoflake as a heterogeneous catalyst for the N-arylation of heterocycles with aryl halides and arylboronic acids in the absence of additional ligand in air were demonstrated. The catalyst was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), BET surface area measurement, and FT-IR spectroscopy. The Royal Society of Chemistry 2014.
Hosseini-Sarvari, Mona,Moeini, Fatemeh
p. 7321 - 7329
(2014/02/14)

Recyclable hydrophobic copper (II) phthalocyanine catalyzed N-arylation of imidazoles in dimethylsulfoxide
Copper (II) phthalocyanine (CuPc) was used as a catalyst for the N-arylation of imidazoles with aryl iodides or bromides. The catalyst showed high activity and could be reused 3 times without any significant loss in activity. The catalyst was characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and ultraviolet-visible spectroscopy.
Huang, Qiang,Zhou, Limei,Jiang, Xiaohui,Qi, Xiaolong,Wang, Zhonghua,Lang, Wencheng
p. 1818 - 1824
(2015/09/28)

Sequential decarboxylative azide-alkyne cycloaddition and dehydrogenative coupling reactions: One-pot synthesis of polycyclic fused triazoles
Herein, we describe a one-pot protocol for the synthesis of a novel series of polycyclic triazole derivatives. Transition metalcatalyzed decarboxylative CuAAC and dehydrogenative cross coupling reactions are combined in a single flask and achieved good yi
Bharathimohan, Kuppusamy,Ponpandian, Thanasekaran,Ahamed, A. Jafar,Bhuvanesh, Nattamai
p. 3031 - 3037
(2015/02/19)

Hg(II), Ag(I) and Au(I) complexes with aniline or pyridine-functionalized N-heterocyclic carbene
[Hg(La)2](PF6)2 (1), [Hg(L b)2](PF6)2 (2), [Hg(L c)2](PF6)2 (3), [Ag(L a)2]I (4) and Au(La)Cl (5) (La, Lb, and Lc are aniline or pyridine N-functionalized imidazol-2-ylidene) have been synthesized and characterized. Single crystals of 1·MeOH, 3 and 5 are obtained and their crystal structures are determined by X-ray diffraction analysis. The molecular structure of 1·MeOH shows that Hg(II) center is coordinated to two carbene ligands, one nitrogen atom from aniline group and one oxygen atom from methanol. The anions are embedded between two cations layers and linked the cations through the intermolecular hydrogen bonding. The Hg(II) center of 3 is coordinated to two carbene ligands and two nitrogen atoms from pyridine group. The PF6- anions of 3 hold two adjacent cations through Hg?F interactions and H?F hydrogen bonding and the crystal packing consists of alternating anion and cation layers. The Au atom of 5 is linearly coordinated with a carbenoic carbon and a chloro ligand, and the molecules are neatly arranged to a one-dimensional hole through weak hydrogen bonding interactions. For 1·MeOH and 5, the -NH2 group of aniline plays an important role in stabilizing the crystal structure through intramolecular and intermolecular hydrogen bonding interactions.
Zhuang, Ren-Tai,Lin, Wan-Jung,Zhuang, Rui Rui,Hwang, Wen-Shu
p. 132 - 141
(2013/04/10)

Ligand effects on the hydrogenation of biomass-inspired substrates with bifunctional Ru, Ir, and Rh complexes
We herein report on the application and structural investigation of a new set of complexes that contain bidentate N-heterocyclic carbenes (NHCs) and primary amine moieties of the type [M(arene)Cl(L)] [M=Ru, Ir, or Rh; arene=p-cymene or pentamethylcyclopentadienyl; L=1-(2-aminophenyl)-3-(n-alkyl) imidazol-2-ylidine]. These complexes were tested and compared in the hydrogenation of acetophenone with hydrogen. Structural variations in the chelate ring size of the heteroditopic ligand revealed that smaller chelate ring sizes in combination with ring conjugation in the ligand are beneficial for the activity of this type of catalyst, favoring an inner-sphere coordination pathway. Additionally, increasing the steric bulk of the alkyl substituent on the NHC aided the reaction, showing almost no induction period and formation of a more active catalyst for the n-butyl complex relative to complexes with smaller Me and Et substituents. As is common in hydrogenation reactions, the activity of the complexes decreases in the order Ru>Ir>Rh. The application of [Ru(p-cym)Cl(L)]PF6, which outperforms its reported analogues, has been successfully extended to the hydrogenation of more challenging biomass-inspired substrates. Adding value to biomass: The influence of structural variations of N-heterocyclic carbene-amine motif in half-sandwich Ru, Ir, and Rh complexes on the hydrogenation of biomass-inspired substrates is reported. Through this study insight is gained for the future rational design of hydrogenation catalysts for the conversion of biomass into useful/added-value compounds. Copyright
Jansen, Eveline,Jongbloed, Linda S.,Tromp, Dorette S.,Lutz, Martin,De Bruin, Bas,Elsevier, Cornelis J.
p. 1737 - 1744
(2013/10/21)

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet-Spengler reaction
An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a-g and imidazo[1,5-a]quinoxalines 7a-h by the reaction of 2-imidazolyl anilines 4a-c with aryl aldehydes 5a-k under mild reaction conditions is described.
Verma, Akhilesh Kumar,Jha, Rajeev Ranjan,Kasi Sankar,Singh, Raj Pal
supporting information
p. 5984 - 5990
(2013/10/22)

Efficient and reusable catalytic system of Cul-PEG for n-arylation of imidazoles
A simple, efficient, and recyclable catalytic system of CuI-poly(ethylene glycol) (PEG) was developed for the N-arylation of imidazoles with aryl halides to afford corresponding N-arylimidazoles in good to excellent yields under mild conditions and free of any additional ligands and solvents. The isolation of the products was readily performed by simple extraction with ether, and the catalytic system could be reused without remarkable loss of activity even after six runs.
Zhang, Qiang,Luo, Jun,Wei, Yunyang
experimental part
p. 114 - 121
(2011/11/01)

Direct N-arylation of azaheterocycles with aryl halides under ligand-free condition
A simple and efficient Ci￡N cross-coupling method of aryl halides with various heterocycles was reported, by using 10 mol% of CuI as catalyst and 1.2 equiv. NaH as base. Aryl iodides, aryl bromides and many substituted aryl 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. An efficient, convenient and applicable method was developed for the N-arylation of azaheterocycles catalyzed by CuI and NaH under ligand free condition. Copyright
Yang, Qichao,Wang, Yufang,Zhang, Baoji,Zhang, Mingjie
p. 2389 - 2393,5
(2020/09/16)

Copper-catalyzed aerobic oxidative intramolecular C-H amination leading to imidazobenzimidazole derivatives
A highly efficient copper-catalyzed aerobic oxidative intramolecular C-H amination has been developed using substituted 2-(1H-imidazol-1-yl)-N- alkylbenzenamines as the starting materials, and the corresponding imidazobenzimidazole derivatives were obtain
Wang, Xiaoqiang,Jin, Yunhe,Zhao, Yufen,Zhu, Lin,Fu, Hua
supporting information; experimental part
p. 452 - 455
(2012/02/16)

Ligands for copper-catalyzed C-N bond forming reactions with 1 Mol% CuBr as catalyst
Several new ligands were designed to promote copper-catalyzed Ullman C-N coupling reactions. In this group, 8-hydroxyquinolin-N-oxide was found to serve as a superior ligand for CuBr-catalyzed coupling reactions of aryl iodides, bromides, and chlorides with aliphatic amines and N-heterocycles under a low catalyst loading (1% [Cu] mol). Reactions with the inexpensive catalytic system display a high functional group tolerance as well as excellent chemoselectivity.
Yang, Kai,Qiu, Yatao,Li, Zheng,Wang, Zhaoyang,Jiang, Sheng
experimental part
p. 3151 - 3159
(2011/06/23)

Cross-coupling reactions of aryl halides with amines, phenols, and thiols catalyzed by an N,N′-dioxide-copper(I) catalytic system
The coupling reactions of various N, O, and S nucleophilic reagents with aryl halides have been successfully carried out under mild conditions by using a novel chiral N,N′-dioxide-copper(I) catalytic system as the catalyst. This versatile and efficient catalyst system has been demonstrated to facilitate the cross-coupling reactions of aryl halides with amines, phenols, and thiols to afford the corresponding desired products in good to excellent yields.
Yang, Haitao,Xi, Chao,Miao, Zhiwei,Chen, Ruyu
supporting information; experimental part
p. 3353 - 3360
(2011/08/03)

A versatile and efficient cu-catalyzed N-Arylation of aromatic cyclic secondary amines with aryl halides
A copper-catalyzed coupling reaction of aryl halides with various aromatic cyclic secondary amines in DMSO has been developed efficiently. The versatile and efficient copper catalyst system is of wide-spread and practical application in cross-coupling reactions.
Yang, Haitao,Miao, Zhiwei,Chen, Ruyu
experimental part
p. 325 - 331
(2012/05/31)

Lewis acid-catalyzed selective synthesis of diversely substituted indolo-and pyrrolo[1,2-a]quinoxalines and quinoxalinones by modified pictet-spengler reaction
An efficient tandem process for the selective synthesis of 1,2-annulated α-fused quinoxalines using benzotriazole methodology by a modified Pictet-Spengler reaction is described. The approach involves the reaction of arylamines 4 with aromatic aldehydes 5 to furnish 6-endo-dig-cyclized products. Dihydroquinoxalines 6 were selectively obtained by using AlCl3 in tetrahydrofuran (THF) at room temperature for two hours. However, after ten hours, quinoxalines 7 were obtained exclusively in excellent yields. A series of biologically important fluoro-and piperazenyl-substituted quinoxalines were also synthesized. This developed methodology also provides access to a novel tandem synthesis of quinoxalinones 9.
Verma, Akhilesh K.,Jha, Rajeev R.,Sankar, V. Kasi,Aggarwal, Trapti,Singh, Rajendra P.,Chandra, Ramesh
supporting information; scheme or table
p. 6998 - 7010
(2012/01/06)

C-N bond formation catalysed by CuI Bonded to polyaniline nanofiber
Polyaniline nanofiber as a macroligand for the supported cuprous iodide catalyst (CuI-PANInf) has been developed for the coupling of aryl halides (including aryl chlorides) with aliphatic, aromatic, and N(H)-heterocyclic amines under ambient conditions (80 °C for aryl chlorides) has been developed. This simple and efficient method for coupling reactions is highly versatile, convenient, and also the catalyst can be used for several cycles with good-to-excellent yields.
Arundhathi, Racha,Kumar, Desitti Chaitanya,Sreedhar, Bojja
supporting information; experimental part
p. 3621 - 3630
(2010/08/20)

Cu-Al hydrotalcite: An efficient and reusable ligand-free catalyst for the coupling of aryl chlorides with aliphatic, aromatic, and N(H)-heterocyclic amines
Copper-aluminum hydrotalcite catalysts were effectively used in the coupling of aryl chlorides with aliphatic, aromatic, and N(H)-heterocyclic amines to afford the corresponding N-alkylated/arylated amines in excellent yields. The catalyst was quantitatively recovered from the reaction by simple filtration and reused for a number of cycles with almost consistent activity. Georg Thieme Verlag Stuttgart.
Sreedhar,Arundhathi,Linga Reddy,Amarnath Reddy,Lakshmi Kantam
experimental part
p. 2517 - 2522
(2010/03/24)

CuI nanoparticles for C-N and C-O cross coupling of heterocyclic amines and phenols with chlorobenzenes
(Chemical Equation Presented) Employing CuI nanoparticles as an efficient catalyst for the cross-coupling reactions of various N/O nucleophilic reagents with aryl chlorides could be successfully carried out under mild conditions in the absence of both the ligands and strong bases. A variety of products including N-arylimidazoles and aryl ethers were synthesized in good to excellent yields. 2009 American Chemical Society.
Sreedhar,Arundhathi,Reddy, P. Linga,Kantam, M. Lakshmi
supporting information; experimental part
p. 7951 - 7954
(2010/01/16)

Copper(I) thiophene-2-carboxylate (CuTC): A versatile non-nitrogen ligand-based catalyst for direct N-arylation of imidazole and pyrazole using aryl iodides, aryl bromides, and aryl chlorides
A new protocol to prepare N-aryl heterocyclic adducts in excellent yields via cross-coupling of HN-heterocycles with aryl halides is reported using commercially available and easy-to-prepare copper(I) thiophene-2-carboxylate (CuTC) as catalyst.
Maheswaran, Hariharasarma,Krishna, Gaddamanugu Gopi,Srinivas, Vandanapu,Prasanth, Kurushunkal Leon,Rajasekhar, Chinamukthevi Venkata
supporting information; experimental part
p. 515 - 517
(2009/04/10)

Bis(μ-iodo)bis((-)-sparteine)dicopper(I): versatile catalyst for direct N-arylation of diverse nitrogen heterocycles with haloarenes
The easy-to-prepare dimeric bis(μ-iodo)bis((-)-sparteine)dicopper(I) complex is shown to be a versatile catalyst for N-arylation of number of NH-heterocycles with structurally divergent aryl halides including activated aryl chloride substrates under mild conditions. The DFT studies not only provide structural insights into square-pyramidal Cu(III) intermediate complexes derived from (-)-sparteine, but also highlight the important role of sterically demanding (-)-sparteine ligand framework in promoting activation of aryl-chlorine bonds for N-arylation of imidazoles.
Maheswaran,Krishna, G. Gopi,Prasanth, K. Leon,Srinivas,Chaitanya, G. Krishna,Bhanuprakash
p. 2471 - 2479
(2008/09/18)

N-arylation of heterocycles with chloro- and fluoroarenes using resin-supported sulfonato-Cu(salen) complex
Sulfonato-Cu(salen) complex immobilized onto a Merrifield's resin was found to be an efficient catalyst for the N-arylation of heterocycles with electron-withdrawing hloro- and fluoroarenes. The reactions were carried out in the presence of an inexpensive mild base, K2CO3, and N-arylated compounds were obtained in good to excellent yields. The catalyst was recovered by simple filtration and reused for three cycles with almost consistent activity. Copyright Taylor & Francis Group, LLC.
Kantam, M. Lakshmi,Ramani,Chakrapani
p. 626 - 636
(2008/04/12)

In vitro and in vivo anti-tumoral activities of imidazo[1,2-a]quinoxaline, imidazo[1,5-a]quinoxaline, and pyrazolo[1,5-a]quinoxaline derivatives
Imidazoquinoxaline and pyrazoloquinoxaline derivatives, analogues of imiquimod, were synthesized, and their in vitro cytotoxic and pharmacodynamic activities were evaluated. In vitro cytotoxicity studies were assessed against melanoma (A375, M4Be, RPMI-75
Moarbess, Georges,Deleuze-Masquefa, Carine,Bonnard, Vanessa,Gayraud-Paniagua, Stephanie,Vidal, Jean-Remi,Bressolle, Francoise,Pinguet, Frederic,Bonnet, Pierre-Antoine
p. 6601 - 6610
(2008/12/22)

N-arylation of heterocycles with activated chloro- and fluoroarenes using nanocrystalline copper(II) oxide
Nanocrystalline copper oxide was found to be an effective heterogeneous catalyst for the N-arylation of heterocycles with activated chloro- and fluoroarenes using potassium carbonate as base. N-Arylated products were isolated in good to excellent yields. The catalyst can be used for five cycles with almost consistent activity.
Kantam, M. Lakshmi,Yadav, Jagjit,Laha, Soumi,Sreedhar, Bojja,Jha, Shailendra
p. 1938 - 1942
(2008/09/16)

Benzotriazole: an excellent ligand for Cu-catalyzed N-arylation of imidazoles with aryl and heteroaryl halides
Benzotriazole (BtH) is an efficient ligand for the Cu-catalyzed N-arylation of imidazoles with aryl and heteroaryl halides. A combination of CuI/BtH was found to be an efficient and inexpensive catalyst system to carry out the N-arylation of imidazoles affording the corresponding products in good to excellent yields.
Verma, Akhilesh Kumar,Singh, Jaspal,Sankar, V. Kasi,Chaudhary, Ritu,Chandra, Ramesh
p. 4207 - 4210
(2008/02/05)

Design and evolution of copper apatite catalysts for N-arylation of heterocycles with chloro- and fluoroarenes
We report the preparation of recyclable heterogeneous catalysts, copper-exchanged fluorapatite, and copper-exchanged tert-butoxyapatite by incorporating basic species F-/tBuO- in apatite in situ by coprecipitation and subsequent exchange with Cu(II). These basic copper catalysts catalyzed N-arylation of imidazoles and other heterocycles with chloroarenes and electron-poor fluoroarenes in good to excellent yields. Synthesis and characterization of some of the intermediates of the catalytic cycle gave some insight into the mechanism of the very important organic transformation. The necessity of basic sites for the activation of C-Cl and C-F bonds in the N-arylation of heterocycles with haloarenes is well-established. Copyright
Choudary, Boyapati M.,Sridhar, Chidara,Kantam, Mannepalli L.,Venkanna, Gopaldasu T.,Sreedhar, Bojja
p. 9948 - 9949
(2007/10/03)

Method for arylating aza-heterocycles with activated aromatic compounds in the presence of caesium carbonate
The invention concerns a process for the preparation of N-aryl-aza-heterocycles of the general formula I by reaction of aza-heterocycles with activated aryl halides with use of caesium carbonate without addition of further catalysts at room temperature.
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(2008/06/13)

Imidazoquinoxaline protein tyrosine kinase inhibitors
Novel imidazoquinoxalines and salts thereof, pharmaceutical compositions containing such compounds, and methods of using such compounds in the treatment of protein tyrosine kinase-associated disorders such as immunologic disorders.
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(2008/06/13)

Gas-phase pyrolysis of 1-(2-azidophenyl)imidazole
Flash vacuum pyrolysis (FVP) of the azide 4 leads to imidazo[1,2-a]benzimidazole 8 exclusively, via highly regioselective insertion of the triplet nitrene intermediate 5 into the 2-CH bond of the imidazole ring. The X-ray crystal structure and NMR spectro
Blake, Alexander J.,Clark, Bernard A. J.,McNab, Hamish,Sommerville, Craig C.
p. 1605 - 1608
(2007/10/03)

The Reaction of Some N-(Nitrophenyl)azoles with Alkali: Preparation of the Corresponding Azoxybenzenes. X-Ray Structure of 2,2'-Bis(1'',2'',4''-triazol-1''-yl)azoxybenzene
The reactions of some representative N-(nitrophenyl)azoles with boiling aqueous ethanolic potassium hydroxide solution gave the corresponding bis(azolyl)azoxybenzenes.It is deduced that, in these reactions, the N-attached azolyl groups concerned are acting as weak electron-withdrawing groups.The structure of 2,2'-bis(1'',2'',4''-triazol-1''-yl)azoxybenzene was determined in the solid state by X-ray crystallography.The monoclinic crystals belong to the space group P21/c with a 8.815(1), b 7.863(1), c 11.836(1) Angstroem, β 109.96(1) deg and Z 2.The structure was refined to an R index of 0.041 for 1172 observed terms.The midpoint of the exocyclic N=N bond lies on an inversion centre so that the azoxy oxygen is statistically distributed between two sites.The benzene ring atoms are coplanar to within experimental error, as are the triazole ring atoms, and the dihedral angle between the perpendiculars to the two rings is 35.3(3) deg.
Mackay, Maureen F.,Trantino, Giuseppe J.,Wilshire, John F. K.
p. 417 - 425
(2007/10/02)

Novel compounds possessing potent cAMP and cGMP phosphodiesterase inhibitory activity. Synthesis and cardiovascular effects of a series of imidazo[1,2-a]quinoxalinones and imidazo[1,5-a]quinoxalinones and their aza analogues
A series of novel imidazoquinoxalinones and their aza analogues were prepared by the cyclization of o-amino(1H-imidazol-1-yl)aryls and heteroaryls with carbonyldiimidazole. The compounds were screened for inhibition of Type I and Type IV phosphodiesterase
Davey,Erhardt,Cantor,Greenberg,Ingebretsen,Wiggins
p. 2671 - 2677
(2007/10/02)