- Ruthenium Complex-catalyzed Novel and Facile Synthesis of Imidazopyridines from 2-Aminopyridines and vicinal-Diols
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Ruthenium complex-catalyzed N-heterocyclization of 2-aminopyridines with vicinal-diols offers a novel synthetic method for various imidazopyridines.For example, the reaction of 2-amino-4-methylpyridine with 1,2-cyclohexanediol in the presence of a catalytic amount of RuCl2(PPh3)3 under reflux in diglyme for 24 h afforded 2-methyl-6,7,8,9-tetrahydropyridobenzimidazole in 74percent yield.
- Kondo, Teruyuki,Kotachi, Shinji,Ogino, Shin-ichi,Watanabe, Yoshihisa
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- New Titanium Complexes and Their Use in Hydroamination and Hydroaminoalkylation Reactions
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The synthesis of three new sterically crowded titanium complexes which all possess an identical formamidinato ligand, two dimethylamido ligands and in addition, a 2-aminopyridinato ligand that contains either an N-methyl, an N-phenyl, or an N-cyclohexyl substituent is presented. All new complexes are easily accessible from a common titanium mono(formamidinate) precursor and correspondingly N-substituted 2-aminopyridines. Furthermore, the new complexes are used as catalysts for selected hydroamination and hydroaminoalkylation reactions and finally, the catalytic performance of the new catalysts is compared with the performance of the titanium mono(formamidinate) precursor.
- Bielefeld, Jens,Kurochkina, Ekaterina,Schmidtmann, Marc,Doye, Sven
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- Nucleophilic Difluoroalkylation of Isocyanates with Difluoromethyl 2-Pyridyl Sulfone
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The nucleophilic difluoroalkylation of isocyanates with difluoromethyl 2-pyridyl sulfone furnished 2,2-difluoro-2-pyridinylsulfonylacetamides with good to excellent yield. These products can be converted to 2,2-difluoroacetamide sulfinate, iododifluoroacetamide and 2-aminopyridine derivatives easily.
- Li, Shan,Peng, Peng,Wei, Jun,Hu, Yongzhou,Hu, Jinbo,Sheng, Rong
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- Directing Group Enables Electrochemical Selectively Meta-Bromination of Pyridines under Mild Conditions
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Without the use of catalysts and oxidants, a facile and sustainable electrochemical bromination protocol was developed. By introducing the directing groups, the regioselectivity of pyridine derivatives could be controlled at themeta-position utilizing the inexpensive and safe bromine salts at room temperature. A variety of brominated pyridine derivatives were obtained in 28-95% yields, and the reaction could be readily performed at a gram scale. By combining the installation and removing the directing group, the concept ofmeta-bromination of pyridines could be verified.
- Wu, Yanwei,Xu, Shanghui,Wang, Hong,Shao, Dongxu,Qi, Qiqi,Lu, Yi,Ma, Li,Zhou, Jianhua,Hu, Wei,Gao, Wei,Chen, Jianbin
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p. 16144 - 16150
(2021/07/19)
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- Copper-catalyzed direct amination of benzylic hydrocarbons and inactive aliphatic alkanes with arylamines
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A new synthetic method toward direct C-N bond formation through saturated C-H amination of benzylic hydrocarbons and inactive aliphatic alkanes with primary aromatic amines under an inexpensive catalyst/oxidant (Cu/DTBP) system has been developed. Both aminopyridines and anilines could react smoothly with primary and secondary benzylic C-H substrates or cyclohexane to form the corresponding aromatic secondary amines in moderate to good yields. This protocol has the advantages of wide functional group tolerance and use of readily available raw materials.
- Jin, Shengzhou,Lin, Sen,Xie, Bo,Yan, Zhaohua,Yao, Hua,Zhong, Xiaoyang
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supporting information
p. 3263 - 3268
(2020/05/14)
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- A catalyst system, copper/ N -methoxy-1 H -pyrrole-2-carboxamide, for the synthesis of phenothiazines in poly(ethylene glycol)
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A copper/N-methoxy-1H-pyrrole-2-carboxamide catalyst system has been established for the preparation of phenothiazines in good yields by two routes, starting from 2-iodoanilines and 2-bromobenzenethiol and from aryl ortho-dihalides and o-aminobenzenethiols, by conducting the reaction at 90 °C in poly(ethylene glycol)-100 (PEG-100). In addition, the catalyst system was useful for promoting direct arylation of various aryl amines, aliphatic amines, and aqueous ammonia. The simple experimental operation, low loading of catalyst system together with the use of green solvent, makes it attractive for the versatile syntheses of phenothiazines and various amines.
- Huang, Manna,Hou, Jianying,Yang, Ruiqiao,Zhang, Liting,Zhu, Xinhai,Wan, Yiqian
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supporting information
p. 3356 - 3364
(2015/02/02)
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- Copper(II) anilides in sp3 C-H amination
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We report a series of novel β-diketiminato copper(II) anilides [Cl2NN]Cu-NHAr that participate in C-H amination. Reaction of H 2NAr (Ar = 2,4,6-Cl3C6H2 (Ar Cl3), 3,5-(CF3)2C6H3 (ArF6), or 2-py) with the copper(II) t-butoxide complex [Cl 2NN]Cu-tOBu yields the corresponding copper(II) anilides [Cl2NN]Cu-NHAr. X-ray diffraction of these species reveal three different bonding modes for the anilido moiety: κ1-N in the trigonal [Cl2NN]Cu-NHArCl3 to dinuclear bridging in {[Cl2NN]Cu}2(μ-NHArF6)2 and κ2-N,N in the square planar [Cl2NN] Cu(κ2-NH-2-py). Magnetic data reveal a weak antiferromagnetic interaction through a π-stacking arrangement of [Cl2NN]Cu- NHArCl3; solution EPR data are consistent with monomeric species. Reaction of [Cl2NN]Cu-NHAr with hydrocarbons R-H (R-H = ethylbenzene and cyclohexane) reveals inefficient stoichiometric C-H amination with these copper(II) anilides. More rapid C-H amination takes place, however, when tBuOOtBu is used, which allows for HAA of R-H to occur from the tBuO? radical generated by reaction of [Cl 2NN]Cu and tBuOOtBu. The principal role of these copper(II) anilides [Cl2NN]Cu-NHAr is to capture the radical R? generated from HAA by tBuO? to give functionalized aniline R-NHAr, resulting in a novel amino variant of the Kharasch-Sosnovsky reaction.
- Jang, Eun Sil,McMullin, Claire L.,K??, Martina,Meyer, Karsten,Cundari, Thomas R.,Warren, Timothy H.
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supporting information
p. 10930 - 10940
(2014/08/18)
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- A recyclable Cu-catalyzed C-N coupling reaction in water and its application to synthesis of imidazo[1,2-a]quinoxaline
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Polystyrene-supported pyrrole-2-carbohydrazide (PSP) was synthesized and combined with CuI to make up a recyclable heterogeneous catalytic system for Ullmann-type C-N coupling reaction in water. In which, a variety of functionalized aryl halides animated efficiently with anilines, benzylamine, aliphatic amines, and imidazole. its preliminary application resulted in a more practical synthesis of imidazo[1,2-a]quinoxaline.
- Huang, Liye,Yu, Ruina,Zhu, Xinhai,Wan, Yiqian
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supporting information
p. 8974 - 8977
(2013/09/23)
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- Carbene adduct of cyclopalladated ferrocenylimine-assisted synthesis of aminopyridine derivatives by the amination of chloropyridines with primary and secondary amines
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An efficient, simple way to synthesize aminopyridine derivatives is presented, based on Buchwald-Hartwig aminations. Using 1 mol% N-heterocyclic carbene adduct of cyclopalladated ferrocenylimine in the presence of 1.5 equiv. tBuOK as base in dioxane at 110°C offered moderate to excellent yields in the reaction of chloropyridines with primary and secondary amines, including sterically hindered amines and alkyl amines. Copyright
- Mu, Bing,Li, Jingya,Wu, Yangjie
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p. 537 - 541
(2013/09/23)
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- Efficient catalytic aryl amination of bromoarenes using 3-iminophosphine palladium(II) chloride
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While pursuing the development of new hydroamination catalysts, a 3-iminophosphine palladium(II) chloride complex [(3IP)PdCl2] was synthesized that has subsequently proven to be an effective precatalyst for the aryl amination of bromoarenes. This (3IP)PdCl2 complex has been utilized in the catalytic aryl amination of both bromobenzene and bromopyridine derivatives, specifically yielding excellent activity in coupling reactions involving bromobenzene, 4-bromotoluene, and 2-bromopyridine. Using a standard set of catalytic conditions, many alkyl and aryl amines have been investigated as coupling partners in the aryl amination of bromoarenes. In general, secondary alkyl amines and ortho-substituted anilines proved to be the best substrates for this reaction, commonly giving quantitative conversion to products, while primary amines and other anilines gave only poor to moderate results. Catalytic screening data, product yields, and full characterization of isolated products are included.
- Samblanet, Danielle C.,Schmidt, Joseph A. R.
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supporting information
p. 7 - 18,12
(2012/12/12)
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- NOVEL CATALYSTS
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The present invention provides novel compounds and ligands that are useful in transition metal catalyzed cross-coupling reactions. For example, the compounds and ligands of the present invention are useful in palladium or gold catalyzed cross-coupling reactions.
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Page/Page column 66
(2012/06/01)
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- Sulfonato-Cu(salen) complex catalyzed N-arylation of aliphatic amines with aryl halides in water
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A water-soluble sulfonato-Cu(salen) complex catalyzed procedure for the N-arylation of simple aliphatic amines, amino alcohols and amino acids in pure water have been developed. A variety of substituted aryl iodides, bromides and electron-deficient chlorides were found to be applicable, and 1,2-disubstituted benzimidazoles could be prepared easily by a cascade amination/condensation process in this catalytic system.
- Wu, Zhiqing,Zhou, Li,Jiang, Zhaoqiong,Wu, Di,Li, Zhengkai,Zhou, Xiangge
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experimental part
p. 4971 - 4975
(2010/11/03)
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- General and mild preparation of 2-aminopyridines
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A general and facile one-pot amination procedure for the synthesis of 2-aminopyridines from the corresponding pyridine-N-oxides is presented as a mild alternative to SNAr chemistry. A variety of amines and heterocyclic-N-oxides participate effectively in this transformation which uses the phosphonium salt, PyBroP, as a means of substrate activation.
- Londregan, Allyn T.,Jennings, Sandra,Wei, Liuqing
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supporting information; experimental part
p. 5254 - 5257
(2011/02/24)
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- A highly versatile catalyst system for the cross-coupling of aryl chlorides and Amines
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The syntheses of 2-(di-tertbutylphosphino)-N,N-dimethylaniline (L1, 71%) and 2-(di-1-adamantylphosphino)-N,N-dimethylaniline (L2, 74%), and their application in BuchwaldHartwig amination, are reported. In combination with [Pd(allyl)Cl]2 or [Pd(cinnamyl)Cl]2, these structurally simple and air-stable P,N ligands enable the cross-coupling of aryl and heteroaryl chlorides, including those bearing as substituents enolizable ketones, ethers, esters, carboxylic acids, phenols, alcohols, olefins, amides, and halogens, to a diverse range of amine and related substrates that includes primary alkyl- and arylamines, cyclic and acyclic secondary amines, N-H imines, hydrazones, lithium amide, and ammonia. In many cases, the reactions can be performed at low catalyst loadings (0.5-0.02 mol % Pd) with excellent functional group tolerance and chemoselectivity. Examples of cross-coupling reactions involving 1,4-bromochlorobenzene and iodobenzene are also reported. Under similar conditions, inferior catalytic performance was achieved when using Pd(OAc)2, PdCl2, [PdCl2(cod)] (cod = 1,5-cyclooctadiene), [PdCl 2(MeCN)2], or [Pd2(dba)3] (dba = dibenzylideneacetone) in combination with L1 or L2, or by use of [Pd(allyl)Cl]2 or [Pd(cinnamyl)Cl]2 with variants of L1 and L2 bearing less basic or less sterically demanding substituents on phosphorus or lacking an ortto-dimethylamino fragment. Given current limitations associated with established ligand classes with regard to maintaining high activity across the diverse possible range of C-N coupling applications, L1 and L2 represent unusually versatile ligand systems for the cross-coupling of aryl chlorides and amines
- Lundgren, Rylan J.,Sappong-Kumankumah, Antonia,Stradiotto, Mark
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supporting information; experimental part
p. 1983 - 1991
(2010/07/03)
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- Highly reactive, general and long-lived catalysts for palladium-catalyzed amination of heteroaryl and aryl chlorides, bromides, and iodides: Scope and structure-activity relationships
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We describe a systematic study of the scope and relationship between ligand structure and activity for a highly efficient and selective class of catalysts containing sterically hindered chelating alkylphosphines for the amination of heteroaryl and aryl chlorides, bromides, and iodides. In the presence of this catalyst, aryl and heteroaryl chlorides, bromides, and iodides react with many primary amines in high yields with part-per-million quantities of palladium precursor and ligand. Many reactions of primary amines with both heteroaryl and aryl chlorides, bromides, and iodides occur to completion with 0.0005-0.05 mol % catalyst. A comparison of the reactivity of this catalyst for the coupling of primary amines at these loadings is made with catalysts generated from hindered monophosphines and carbenes, and these data illustrate the benefits of chelation. Studies on structural variants of the most active catalyst indicate that a rigid backbone in the bidentate structure, strong electron donation, and severe hindrance all contribute to its high reactivity. Thus, these complexes constitute a fourth-generation catalyst for the amination of aryl halides, whose activity complements catalysts based on monophosphines and carbenes.
- Shen, Qilong,Ogata, Tokutaro,Hartwig, John F.
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p. 6586 - 6596
(2008/12/22)
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- [(CyPF-Bu)PdCI2]: An air-stable, one-component, highly efficient catalyst for amination of heteroaryl and aryl halides
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(Chemical Equation Presented) An air- and moisture-stable palladium catalyst, [(CyPF-1Bu)PdCI2] (1), for coupling of heteroaryl chlorides, bromides, and iodides with a variety of primary amines is described. Most of these reactions occurred in high yield with 0.001-0.05 mol % catalyst loading. The reactions tolerated a wide range of functional groups.
- Shen, Qilong,Hartwig, John F.
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supporting information; experimental part
p. 4109 - 4112
(2009/05/27)
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- Highly efficient and practical phosphoramidite-copper catalysts for amination of aryl iodides and heteroaryl bromides with alkylamines and N(H)-heterocycles
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A highly efficient copper-catalyzed system using phosphoramidite as ligands was applied to N-arylation of alkylamines and N(H)-heterocycles with aryl iodides and heteroaryl bromides. The reactions were carried out in relative mild conditions and good to excellent yields were obtained.
- Zhang, Zhanjin,Mao, Jincheng,Zhu, Di,Wu, Fan,Chen, Huilin,Wan, Boshun
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p. 4435 - 4443
(2007/10/03)
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- Highly reactive, general, and long-lived catalysts for coupling heteroaryl and aryl chlorides with primary nitrogen nucleophiles
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Resisting pathways for decomposition followed by palladium complexes of monodentate ligands is one characteristic of the highly reactive but long-lived catalyst generated from the Josiphos ligand L and palladium. It catalyzes under mild conditions the coupling of primary amines with chloropyridines and chloroarenes in high yield with low catalyst loadings (see scheme).
- Shen, Qilong,Shekhar, Shashank,Stambuli, James P.,Hartwig, John F.
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p. 1371 - 1375
(2007/10/03)
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- Synthesis of aminopyridines from 2-fluoropyridine and lithium amides
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Lithium amides promote the amination of 2-fluoropyridine under mild reaction conditions, providing 2-aminopyridines in good yields and purity. Treatment of 2-fluoropyridine with 1 equiv of lithium amide at room temperature affords complete conversion afte
- Pasumansky, Lubov,Hernández, Armando R.,Gamsey, Soya,Goralski, Christian T.,Singaram, Bakthan
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p. 6417 - 6420
(2007/10/03)
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- Reactions of 2-(N-Cyclohexyl)aminopyridine with Electrophiles
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2-(N-Cyclohexyl)aminopyridine 1 was reported to form a 1,2-dihydropyridine derivative with carbonyl chloride.This implies that the pyridine nitrogen of 1 is a stronger nucleophile than the exocyclic nitrogen.Presently 1 is found to react with electrophiles, including carbonyl chloride, to form derivatives at the exocyclic nitrogen of 1.This is proven by relating the structures of these compounds to 2-(N-alkoxycarbonyl-N-cyclohexyl)aminopyridine 1-oxides 5.Compounds 5 were prepared by two independent routes, thus proving the structure of 5. 1H n.m.r. and 13C n.m.r. spectra also support the assigned structures.
- Morkved, Eva H.
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p. 401 - 406
(2007/10/02)
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