- Approach toward the understanding of coupling mechanism for EDC reagent in solvent-free mechanosynthesis
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A unique approach in mechanosynthesis, joining solid-state NMR spectroscopy, X-ray crystallography, and theoretical calculations, is employed for the first time to study the mechanism of the formation of the C- N amide bond using EDC?HCl as a coupling reagent. It has been proved that EDC?HCl, which in the crystal lattice exists exclusively in the cyclic form (X-ray data), easily undergoes transformation to a pseudocyclic stable intermediate in reaction with carboxylic acid forming a low-melt phase (differential scanning calorimetry, solid-state NMR). The obtained intermediate is reactive and can be further used for synthesis of amides in reaction with appropriate amines.
- Wróblewska, Aneta,Paluch, Piotr,Wielgus, Ewelina,Bujacz, Grzegorz,Dudek, Marta K.,Potrzebowski, Marek J.
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- Proton-Transfer Polymerization by N-Heterocyclic Carbenes: Monomer and Catalyst Scopes and Mechanism for Converting Dimethacrylates into Unsaturated Polyesters
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This contribution presents a full account of experimental and theoretical/computational investigations into the N-heterocyclic carbene (NHC)-catalyzed proton-transfer polymerization (HTP) that converts common dimethacrylates (DMAs) containing no protic gr
- Hong, Miao,Tang, Xiaoyan,Falivene, Laura,Caporaso, Lucia,Cavallo, Luigi,Chen, Eugene Y.-X.
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Read Online
- Photoinduced Annulation of N-Phenylbenzamides for the Synthesis of Phenanthridin-6(5H)-Ones
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A general concise method for the synthesis phenanthridin-6(5H)-ones via photoinduced intramolecular annulation of N-phenylbenzamides was developed. Under argon atmosphere and room temperature, phenanthridin-6(5H)-ones were obtained via irradiation N-phenylbenzamides with a 280 nm UV lamp in the presence of methanesulfonic acid in toluene. The mechanism is illustrated and believed to proceed in the order of amides tautomerization, 6π-electric cyclization, [1,5]-H shift, amide-imidine tautomerization, keto-enol tautomerism and evolution hydrogen. (Figure presented.).
- Wang, Nana,Wang, Ding,He, Yun,Xi, Jin,Wang, Tao,Liang, Yong,Zhang, Zunting
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supporting information
p. 1150 - 1155
(2022/02/25)
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- In Situ Formation of Cationic π-Allylpalladium Precatalysts in Alcoholic Solvents: Application to C-N Bond Formation
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We report an efficient Buchwald-Hartwig cross-coupling reaction in alcoholic solvent, in which a low catalyst loading showed excellent performance for coupling aryl halides (I, Br, and Cl) with a broad set of amines, amides, ureas, and carbamates under mild conditions. Mechanistically speaking, in a protic and polar medium, extremely bulky biarylphosphine ligands interact with the dimeric precatalyst [Pd(π-(R)-allyl)Cl]2 to form the corresponding cationic complexes [Pd(π-(R)-allyl)(L)]Cl in situ and spontaneously. The resulting precatalyst further evolves under basic conditions into the corresponding L-Pd(0) catalyst, which is commonly employed for cross-coupling reactions. This mechanistic study highlights the prominent role of alcoholic solvents for the formation of the active catalyst.
- Steinsoultz, Philippe,Bailly, Aurélien,Wagner, Patrick,Oliva, Estefania,Schmitt, Martine,Grimaud, Laurence,Bihel, Frédéric
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p. 560 - 567
(2022/01/03)
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- A practical and sustainable protocol for direct amidation of unactivated esters under transition-metal-free and solvent-free conditions
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In this paper, a NaOtBu-mediated synthesis approach was developed for direct amidation of unactivated esters with amines under transition-metal-free and solvent-free conditions, affording a series of amides in good to excellent yields at room temperature. In particular, an environmentally friendly and practical workup procedure, which circumvents the use of organic solvents and chromatography in most cases, was disclosed. Moreover, the gram-scale production of representative products3a,3wand3auwas efficiently realized by applying operationally simple, sustainable and practical procedures. Furthermore, this approach was also applicable to the synthesis of valuable molecules such as moclobemide (a powerful antidepressant), benodanil and fenfuram (two commercial agricultural fungicides). These results demonstrate that this protocol has the potential to streamline amide synthesis in industry. Meanwhile, quantitative green metrics of all the target products were evaluated, implying that the present protocol is advantageous over the reported ones in terms of environmental friendliness and sustainability. Finally, additional experiments and computational calculations were carried out to elucidate the mechanistic insight of this transformation, and one plausible mechanism was provided on the basis of these results and the related literature reports.
- Chen, Cheng,Cheng, Hua,Du, Min-Chen,Qian, Liang,Qin, Xin,Sang, Wei,Yao, Wei-Zhong,Yuan, Ye,Zhang, Rui
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supporting information
p. 3972 - 3982
(2021/06/17)
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- Fe-mediated synthesis of: N -aryl amides from nitroarenes and acyl chlorides
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Amides are prevalent in nature and valuable functional compounds in agrochemical, pharmaceutical, and materials industries. In this work, we developed a selective and mild method for the synthesis of N-aryl amides. Starting from commercially available nitroarenes and acyl halides, N-aryl amides with good yields can be obtained in water. Especially in the process of transformation, Fe dust is the only reductant and additive, and the reaction can be easily performed on a large scale.
- Wu, Yundong,Guo, Lei,Liu, Yuxuan,Xiang, Jiannan,Jiang, Jun
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p. 15290 - 15295
(2021/05/19)
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- Visible-light-induced direct construction of amide bond from carboxylic acids with amines in aqueous solution
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A novel visible-light-promoted N-acylation for the synthesis of amides from easily available carboxylic acids with amines in the presence of I2 within 2.5 h in aqueous solution has been developed. Using sunlight as the visible light source greatly reduces the cost of experiments and produces almost no toxic effects. Hence, this study provides an alternative catalytic system for the construction of a wide range of amides with readily available materials. Moreover, the strategy was successfully applied in the preparation of N-(3-(2,6-dimethoxyphenoxy)-7-nitroquinoxalin-2-yl)benzohydrazide, which displayed a signification anti-proliferation effect on A549, MCF-7 and HCT116 cell lines.
- Wang, Jin,Hou, Huiqing,Hu, Yongzhi,Lin, Jin,Wu, Min,Zheng, Zhiqiang,Xu, Xiuzhi
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supporting information
(2021/02/09)
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- Iron-catalyzed oxidative amidation of acylhydrazines with amines
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A new approach for amide bond formation via a mild and efficient Iron-catalyzed cross-coupling reaction of acylhydrazines and amines using TBHP as oxidant is described. This protocol is compatible with a wide range of amines and acylhydrazines. In addition, the synthetic application of the reaction is presented.
- Wang, Yi-Jie,Zhang, Guo-Yu,Shoberu, Adedamola,Zou, Jian-Ping
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supporting information
(2021/08/18)
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- Room-temperature copper-catalyzed electrophilic amination of arylcadmium iodides with ketoximes
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We started our study by preparation two ketoximes. Later, there were studies to reveal these ketoximes' effects in the electrophilic amination reaction with organocadmium reagents. Primarily, it was observed that arylcadmium iodides could not be reacted with ketoximes at room temperature in the absence of a catalyst. CuCN was a suitable catalyst for this electrophilic amination reaction of arylcadmium iodides and allowed the preparation of functionalized aniline derivatives in good yields under mild reaction conditions. We obtained the results indicated that the yield of primary arylamines was strongly dependent on the steric and electronic effects of organocadmium reagent and amination agent. In the case of both amination reagents, meta-substituted arylamines were obtained in higher yields than para-substituted arylamines. We observed that acetone O-(4-chlorophenylsulfonyl)oxime, 1, as an aminating agent, was more successful than acetone O-(2-Naphthylsulfonyl)oxime, 2, in the synthesis of functionalized arylamines by electrophilic amination of corresponding aryl cadmium iodides. In this method, there is no cadmium release to the environment.
- Korkmaz, Adem
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p. 3119 - 3125
(2021/05/10)
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- Visible-Light Carbon Nitride-Catalyzed Aerobic Cyclization of Thiobenzanilides under Ambient Air Conditions
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A metal-free heterogeneous photocatalysis has been developed for the synthesis of benzothiazoles via intramolecular C-H functionalization/C-S bond formation of thiobenzanilides by inexpensive graphitic carbon nitride (g-C3N4) under visible-light irradiation. This reaction provides access to a broad range of 2-substituted benzothiazoles in high yields under an air atmosphere at room temperature without addition of a strong base or organic oxidizing reagents. In addition, the catalyst was found to be stable and reusable after five reaction cycles.
- Bai, Jin,Yan, Sijia,Zhang, Zhuxia,Guo, Zhen,Zhou, Cong-Ying
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supporting information
p. 4843 - 4848
(2021/06/28)
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- High yielding electrophilic amination with lower order and?higher order organocuprates: Application of acetone O-(4-Chlorophenylsulfonyl)oxime in the construction of the C?N bond at room temperature
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Electrophilic amination reaction was performed with lower order and?higher order organocuprates using acetone O-(4-Chlorophenylsulfonyl)oxime (1). It was proceeded smoothly at room temperature in the presence of organocuprates to provide the corresponding primary amines in good yields with 10 and 60 min, respectively. The primary amine yields of the electrophilic amination of bromomagnesium organocyanocuprates and dibromomagnesium diorganocyanocuprates were obtained 52–72% and 58–83%, respectively. We observed that higher order organocuprates were more successful than lower order organocuprates in the synthesis of functionalized arylamines by electrophilic amination.
- Duran, Serdar,Korkmaz, Adem
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p. 2077 - 2087
(2021/05/27)
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- Studies towards the design and synthesis of novel 1,5-diaryl-1h-imidazole-4-carboxylic acids and 1,5-diaryl-1h-imidazole-4-carbohydrazides as host ledgf/p75 and hiv-1 integrase interaction inhibitors
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Two targeted sets of novel 1,5-diaryl-1H-imidazole-4-carboxylic acids 10 and carbohy-drazides 11 were designed and synthesized from their corresponding ester intermediates 17, which were prepared via cycloaddition of ethyl isocyanoacetate 16 and diarylimi
- Bode, Moira L.,Fish, Muhammad Q.,Mabel Coyanis, E.,Rashamuse, Thompho J.
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- Metal-free transamidation of benzoylpyrrolidin-2-one and amines under aqueous conditions
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N-Acyl lactam amides, such as benzoylpyrrolidin-2-one, benzoylpiperidin-2-one, and benzoylazepan-2-one reacted with amines in the presence of DTBP and TBAI to afford the transamidated products in good yields. The reactions were conducted under aqueous conditions and good functional group tolerance was achieved. Both aliphatic and aromatic primary amines displayed good activity under metal-free conditions. A radical reaction pathway is proposed.
- Joseph, Devaneyan,Lee, Sunwoo,Park, Myeong Seong
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supporting information
p. 6227 - 6232
(2021/07/28)
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- Chromium-catalyzed ligand-free amidation of esters with anilines
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Amides are important structural motifs in pharmaceutical and agrochemical chemistry because of the intriguing biological active properties. We report here the amidation of commercially available esters with anilines that was promoted by low-cost and air-stable chromium(III) pre-catalyst combined with magnesium, providing access to amides. This reaction occurs without the use of external ligands in a simple operation. Mechanistic studies indicate that a reactive aminated Cr species responsible for the amidation can be considered, which may be formed by reaction of low-valent Cr with aniline followed by reduction with hydrogen evolution.
- Chen, Changpeng,Ling, Liang,Luo, Meiming,Zeng, Xiaoming
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supporting information
p. 762 - 766
(2021/04/14)
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- Practical one-pot amidation of N -Alloc-, N -Boc-, and N -Cbz protected amines under mild conditions
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A facile one-pot synthesis of amides from N-Alloc-, N-Boc-, and N-Cbz-protected amines has been described. The reactions involve the use of isocyanate intermediates, which are generated in situ in the presence of 2-chloropyridine and trifluoromethanesulfonyl anhydride, to react with Grignard reagents to produce the corresponding amides. Using this reaction protocol, a variety of N-Alloc-, N-Boc-, and N-Cbz-protected aliphatic amines and aryl amines were efficiently converted to amides with high yields. This method is highly effective for the synthesis of amides and offers a promising approach for facile amidation.
- Hong, Wan Pyo,Tran, Van Hieu,Kim, Hee-Kwon
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p. 15890 - 15895
(2021/05/19)
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- Regioselective Synthesis of 2° Amides Using Visible-Light-Induced Photoredox-Catalyzed Nonaqueous Oxidative C-N Cleavage of N, N-Dibenzylanilines
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A visible-light-driven photoredox-catalyzed nonaqueous oxidative C-N cleavage of N,N-dibenzylanilines to 2° amides is reported. Further, we have applied this protocol on 2-(dibenzylamino)benzamide to afford quinazolinones with (NH4)2S2O8 as an additive. Mechanistic studies imply that the reaction might undergo in situ generation of α-amino radical to imine by C-N bond cleavage followed by the addition of superoxide ion to form amides.
- Neerathilingam, Nalladhambi,Bhargava Reddy, Mandapati,Anandhan, Ramasamy
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p. 15117 - 15127
(2021/10/25)
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- Method for synthesizing amide derivative under catalysis of vanadium
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The invention discloses a method for synthesizing an amide derivative under the catalysis of vanadium, which comprises the following step of: by using a nitro aromatic compound and an ester compound as raw materials, a vanadium compound as a catalyst and magnesium chips as a reducing agent, carrying out amidation reaction in an organic solvent to obtain the amide derivative. The method has the advantages that (1) the nitro aromatic compound which is good in stability, low in price and easy to obtain is used as a nitrogen source; (2) the used catalyst is cheap, easy to obtain and low in toxicity; and (3) the method has good substrate applicability, and is suitable for aromatic nitro compounds, fatty esters and aryl esters containing different substituents.
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Paragraph 0013-0015; 0049-0051
(2021/02/10)
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- Activator free, expeditious and eco-friendly chlorination of activated arenes by N-chloro-N-(phenylsulfonyl)benzene sulfonamide (NCBSI)
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N-Chloro-N-(phenylsulfonyl)benzene sulfonamide (NCBSI) has been explored for the first time as a chlorinating reagent for direct chlorination of various activated arenes and heterocycles without any activator. A comparative in-silico study was performed to determine the electrophilic character for NCBSI and commercially available N-chloro reagents to reveal the reactivity on a theoretical viewpoint. The reagent was prepared by an improved method avoiding the use of hazardous t-butyl hypochlorite. This reagent was proved to be very reactive compared to other N-chloro reagents. The precursor of the reagent N-(phenylsulfonyl)benzene sulfonamide was recovered from aqueous spent, which can be recycled to synthesize NCBSI. The eco-friendly protocol was equally applicable for the synthesis of industrially important chloroxylenol as an antibacterial agent.
- Misal, Balu,Palav, Amey,Ganwir, Prerna,Chaturbhuj, Ganesh
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supporting information
(2021/01/04)
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- Iron-catalyzed cross-coupling of N?methoxy amides and arylboronic acids for the synthesis of N-aryl amides
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An efficient iron-catalyzed synthesis of N-aryl amides from N?methoxy amides and arylboronic acids is developed. FeCl3 is used as the sole catalyst for the cross-coupling reaction between N?methoxy amides and arylboronic acids without any other
- Li, Jinhui,Liu, Jin-Biao,Luo, Nianhua,Qiu, Guanyinsheng,Ren, Shangfeng,Wang, Ying,Xie, Huilin
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- Visible-Light-Promoted Iron-Catalyzed N-Arylation of Dioxazolones with Arylboronic Acids
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A visible-light-promoted and simple iron salt-catalyzed N-arylation was achieved efficiently under external photosensitizer-free conditions. Arylboronic acids and bench-stable dioxazolones were used for this cross-coupling reaction. This reaction features high reactivity, wide substrate scope, good functional group tolerance, simple operation procedure, and mild reaction conditions. Preliminary mechanistic investigations were conducted to support a radical pathway. This method may contribute to shift the paradigm of iron-catalyzed C-N bond construction and nitrene transfer chemistry.
- Tang, Jing-Jing,Yu, Xiaoqiang,Yamamoto, Yoshinori,Bao, Ming
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p. 13955 - 13961
(2021/11/20)
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- An Environmentally Benign, Catalyst-Free N?C Bond Cleavage/Formation of Primary, Secondary, and Tertiary Unactivated Amides
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Herein, we report an operationally simple, cheap, and catalyst-free method for the transamidation of a diverse range of unactivated amides furnishing the desired products in excellent yields. This protocol is environmentally friendly and operates under extremely mild conditions without using any promoter or additives. Significantly, this strategy has been implied in the chemoselective synthesis of a pharmaceutical molecule, paracetamol, on a gram-scale with excellent yield. We anticipate that this universally applicable strategy will be of great interest in drug discovery, biochemistry, and organic synthesis.
- Kumar, Vishal,Dhawan, Sanjeev,Girase, Pankaj Sanjay,Singh, Parvesh,Karpoormath, Rajshekhar
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p. 5627 - 5639
(2021/11/11)
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- CuO-decorated magnetite-reduced graphene oxide: a robust and promising heterogeneous catalyst for the oxidative amidation of methylarenes in waterviabenzylic sp3C-H activation
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A magnetite-reduced graphene oxide-supported CuO nanocomposite (rGO/Fe3O4-CuO) was preparedviaa facile chemical method and characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), UV-vis spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), Brunauer-Emmett-Teller (BET) analysis, vibrating-sample magnetometry (VSM), and thermogravimetric (TG) analysis. The catalytic activity of the rGO/Fe3O4-CuO nanocomposite was probed in the direct oxidative amidation reaction of methylarenes with free amines. Various aromatic and aliphatic amides were prepared efficiently at room temperature from cheap raw chemicals usingtert-butyl hydroperoxide (TBHP) as a “green” oxidant and low-toxicity TBAI in water. This method combines the oxidation of methylarenes and amide bond formation into a single operation. Moreover, the synthesized nanocomposites can be separated from the reaction mixtures using an external magnet and reused in six consecutive runs without a noticeable decrease in the catalytic activity.
- Ebrahimi, Edris,Khalafi-Nezhad, Ali,Khalili, Dariush,Rousta, Marzieh
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p. 20007 - 20020
(2021/11/12)
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- Solar and visible-light active nano Ni/g-C3N4photocatalyst for carbon monoxide (CO) and ligand-free carbonylation reactions
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In this study, we investigate the amino and alkoxycarbonylation reaction between various substituted aryl halides, benzyl iodides, and iodocyclohexane with different types of amines and alcohols in the absence of carbon monoxide gas and ligands. Similar reactions are carried out at high temperatures, in the presence of appropriate ligands, stoichiometric amounts of bases, and gaseous carbon monoxide, which endanger the health of organic chemists. We present a novel method that does not utilize ligands, bases, gaseous CO, and special conditions. This procedure is a redox reaction carried out by new economic nano Ni/g-C3N4at room temperature and under visible light. Mo(CO)6was used toin situgenerate CO, to resolve the problems caused by the use of CO gas. This protocol has the ability to be used on a gram scale by using a continuous flow reactor.
- Hosseini-Sarvari, Mona,Akrami, Zahra
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p. 956 - 969
(2021/02/26)
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- Facile amidation of esters with aromatic amines promoted by lanthanide tris (amide) complexes
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The development of catalysts capable of catalyzing amidation of esters with amines to construct amides under mild conditions is of great importance. Compared to aliphatic amines, the direct catalytic amidation of esters with less nucleophilic aromatic amines is rather difficult. Employing simple lanthanide tris (amide) complexes Ln[N (SiMe3)2]3(μ-Cl)Li (THF)3 as the catalysts, it was found a broad range of aromatic amines and esters were efficiently converted into various amides in good yields under mild conditions. A plausible mechanism for this transformation was experimentally supported as starting from an amide exchange reaction between the lanthanide tris (amide) complex and the substrate amine.
- Li, Zhao,Guo, Chenjun,Chen, Jue,Yao, Yingming,Luo, Yunjie
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- Synthesis of 2-Amino-1,3-dienes from Propargyl Carbonates via Palladium-Catalyzed Carbon-Nitrogen Bond Formation
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A catalytic method to synthesize 1,3,-dienes from propargylic precursors is reported. This palladium-catalyzed carbon-nitrogen bond-forming reaction furnishes 2-amino-1,3-dienes in excellent yields (up to 98%) and shows a broad tolerance to functional group diversity. The reaction has been demonstrated for over 30 amine substrates, including anilines and indoles, and proceeds under mild neutral conditions. The resulting 1,3-dienes are of great synthetic interest because of their further reaction potential.
- O'Broin, Calvin Q.,Guiry, Patrick J.
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supporting information
p. 879 - 883
(2020/02/04)
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- α-Imino Iridium Carbenes from Imidoyl Sulfoxonium Ylides: Application in the One-Step Synthesis of Indoles
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Imidoyl sulfoxonium ylides are presented for the first time as potential precursors to generate α-imino metal-carbene intermediates and applied in direct C-H functionalization reactions catalyzed by [Ir(cod)Cl]2 (4 mol %) to provide 2-substituted indoles (up to 70% yield) in just one step. This class of sulfur ylide is successfully obtained from imidoyl chloride and dimethylsulfoxonium methylide (23 new examples in 45-85% yield) or by imino group formation from the corresponding β-keto sulfoxonium ylides and anilines in the presence of TiCl4 as a Lewis acid (9 examples in 33-94% yield).
- Burtoloso, Antonio C. B.,Caiuby, Clarice A. D.,De Jesus, Matheus P.
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p. 7433 - 7445
(2020/06/27)
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- Silver-Catalyzed Cascade Cyclization Reaction of Isocyanides with Sulfoxonium Ylides: Synthesis of 3-Aminofurans and 4-Aminoquinolines
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A silver-catalyzed cascade cyclization reaction of isocyanides with sulfoxonium ylides has been developed for the first time. This reaction provides a new and efficient method for the construction of highly functionalized 3-aminofurans and 4-aminoquinolines from readily available starting materials in a single step.
- Liang, Yong-Xin,Yang, Ming,He, Bo-Wen,Zhao, Yu-Long
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supporting information
p. 7640 - 7644
(2020/10/09)
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- Copper-Catalyzed Radical N-Demethylation of Amides Using N-Fluorobenzenesulfonimide as an Oxidant
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An unprecedented N-demethylation of N-methyl amides has been developed by use of N-fluorobenzenesulfonimide as an oxidant with the aid of a copper catalyst. The conversion of amides to carbinolamines involves successive single-electron transfer, hydrogen-atom transfer, and hydrolysis, and is accompanied by formation of N-(phenylsulfonyl)benzenesulfonamide. Carbinolamines spontaneously decompose to N-demethylated amides and formaldehyde, because of their inherent instability.
- Yi, Xuewen,Yi, Xuewen,Lei, Siyu,Liu, Wangsheng,Che, Fengrui,Yu, Chunzheng,Liu, Xuesong,Wang, Zonghua,Zhou, Xin,Zhang, Yuexia
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p. 4583 - 4587
(2020/05/05)
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- Switching from biaryl formation to amidation with convoluted polymeric nickel catalysis
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A stable, reusable, and insoluble poly(4-vinyl-pyridine) nickel catalyst (P4VP-NiCl2) was prepared through the molecular convolution of poly(4-vinylpyridine) (P4VP) and nickel chloride. We proposed a coordination structure of the Ni center in the precatalyst based on elemental analysis and Ni K-edge XANES, and we confirmed that it is consistent with Ni K-edge EXAFS. The Suzuki?Miyaura-type coupling of aryl halides and arylboronic esters proceeded using P4VP-NiCl2 (0.1 mol % Ni) to give the corresponding biaryl compounds in up to 94% yield. Surprisingly, when the same reaction of aryl halides and arylboronic acid/ester was carried out in the presence of amides, the amidation proceeded predominantly to give the corresponding arylamides in up to 99% yield. In contrast, the reaction of aryl halides and amides in the absence of arylboronic acid/ester did not proceed. P4VP-NiCl2 successfully catalyzed the lactamization for preparing phenanthridinone. P4VP-NiCl2 was reused five times without significant loss of catalytic activity. Pharmaceuticals, natural products, and biologically active compounds were synthesized efficiently using P4VPNiCl2 catalysis. Nickel contamination in the prepared pharmaceutical compounds was not detected by ICP-MS analysis. The reaction was scaled to multigrams without any loss of chemical yield. Mechanistic studies for both Suzuki?Miyaura and amidation were performed.
- Sen, Abhijit,Dhital, Raghu N.,Sato, Takuma,Ohno, Aya,Yamada, Yoichi M.A.
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p. 14410 - 14418
(2020/12/21)
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- A one pot protocol to convert nitro-arenes into: N-aryl amides
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A two-step one pot, experimentally simple protocol, based on readily available and inexpensive reagents allowed the conversion of nitro-arenes directly to N-aryl amides. A metal-free reduction of the nitro group, mediated by trichlorosilane, followed by the addition of an anhydride afforded the corresponding N-aryl carboxyamide, that was isolated after a simple aqueous work up in good-excellent yields. When the methodology was applied to the reaction with γ-butyrolactone, the desired N-aryl butanamide derivative was obtained, featuring a chlorine atom at the γ-position, a functionalized handle that can be used for further synthetic manipulation of the reaction product. Such an intermediate has already been employed as a key advanced precursor of pharmaceutically active compounds.
- Massolo, Elisabetta,Pirola, Margherita,Puglisi, Alessandra,Rossi, Sergio,Benaglia, Maurizio
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p. 4040 - 4044
(2020/02/04)
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- Oxidative Photochlorination of Electron-Rich Arenes via in situ Bromination
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Electron-rich arenes are oxidatively photochlorinated in the presence of catalytic amounts of bromide ions, visible light, and 4CzIPN as organic photoredox catalyst. The substrates are brominated in situ in a first photoredox-catalyzed oxidation step, followed by a photocatalyzed ipso-chlorination, yielding the target compounds in high ortho/para regioselectivity. Dioxygen serves as a green and convenient terminal oxidant. The use of aqueous hydrochloric acid as the chloride source reduces the amount of saline by-products.
- Düsel, Simon Josef Siegfried,K?nig, Burkhard
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supporting information
p. 1491 - 1495
(2019/04/30)
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- Copper-catalyzed aerobic oxidative C-C bond cleavage of simple ketones for the synthesis of amides
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A Cu-catalyzed oxidative amidation of simple ketones with amines via carbon-carbon (C-C) bond cleavage has been developed. A number of aryl and alkyl ketones could be easily converted to amides using cheap copper salt as the catalyst and O2 as the oxidant with a wide range of amines, including primary and secondary amines. This method shows a notable advantage of the broad scope for the substrate, thus providing a practical approach to amides. A plausible mechanism is proposed based on the preliminary experiments.
- Li, Ke,Liu, Wei,Liu, Yu-Feng,Yang, Guo-Ping,Zeng, Kai
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p. 6958 - 6964
(2020/10/02)
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- Green synthetic method of N-arylamides using recyclable cheap metal catalyst
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Magnetically separable and reusable Fe/Cu oxide (Fe3O4-Cu2O) nanoparticles were employed as an efficient catalyst for the arylation of benzamide, which was carried out with a range of both arylboronic acid and benzamide to afford N-arylamide in good to excellent yield.
- Wang, Xingyang,Liu, Jianhui,An, Guanghui
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supporting information
(2020/10/05)
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- Direct Amidation of Carboxylic Acids with Nitroarenes
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N-Aryl amides are an important class of compounds in pharmaceutical and agrochemical chemistry. Rapid and low-cost synthesis of N-aryl amides remains in high demand. Herein, we disclose an operationally simple process to access N-aryl amides directly from readily available nitroarenes and carboxylic acids as coupling substrates. This method involves the in situ activation of carboxylic acids to acyloxyphosphonium salt for one-pot amidation, without the need for isolation of the corresponding synthetic intermediates. Furthermore, the ease of preparation and workup allow the quick and efficient synthesis of a wide range of N-aryl amides, including several amide-based druglike and agrochemical molecules.
- Wang, Shao-Peng,Cheung, Chi Wai,Ma, Jun-An
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p. 13922 - 13934
(2019/11/03)
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- Electrochemical: N-acylation synthesis of amides under aqueous conditions
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An electrochemical N-acylation of carboxylic acids with amines was reported. The sustainable TBAB electrocatalysis proceeded with excellent chemoselectivity and positional selectivity, and with ample scope, allowing electrochemical N-acylation under mild reaction conditions at room temperature in water. Moreover, the synthetic utility of the current method is demonstrated by the synthesis of melatonin.
- Ke, Fang,Xu, Yiwen,Zhu, Suning,Lin, Xiaoyan,Lin, Chen,Zhou, Sunying,Su, Huimin
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supporting information
p. 4329 - 4333
(2019/08/21)
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- Exogenous Photosensitizer-, Metal-, and Base-Free Visible-Light-Promoted C-H Thiolation via Reverse Hydrogen Atom Transfer
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Visible-light-driven, intramolecular C(sp2)-H thiolation has been achieved without addition of a photosensitizer, metal catalyst, or base. This reaction induces the cyclization of thiobenzanilides to benzothiazoles. The substrate absorbs visible light, and its excited state undergoes a reverse hydrogen-atom transfer (RHAT) with 2,2,6,6-tetramethylpiperidine N-oxyl to form a sulfur radical. The addition of the sulfur radical to the benzene ring gives an aryl radical, which then rearomatizes to benzothiazole via RHAT.
- Xu, Ze-Ming,Li, Hong-Xi,Young, David James,Zhu, Da-Liang,Li, Hai-Yan,Lang, Jian-Ping
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supporting information
p. 237 - 241
(2019/01/10)
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- Catalytic Hydrogenation of Carboxamides with a Bifunctional Cp Ru Catalyst Bearing an Imidazol-2-ylidene with a Protic Aminoethyl Side Chain
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Synthesis of a Cp Ru complex bearing an NH 2 -functionalized N -heterocyclic carbene (C-N H) was achieved by treatment of CpRuBr(isoprene) with an equimolar amount of a silver complex, which was generated from Ag 2 O and 1-(2-aminoethyl)-3-methylimidazolium bromide, in CH 3 CN at room temperature. The new CpRuBr(C-N H) complex showed a higher catalytic performance than the related CpRuCl(P-N H) and CpRuCl(N-N H) complexes. In the reaction of N -arylcarboxamides, the amine products were obtained in satisfactory yields under mild temperature conditions.
- Ikariya, Takao,Kawano, Teruhiro,Kayaki, Yoshihito,Watari, Ryo
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supporting information
p. 2542 - 2547
(2019/06/08)
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- Solvent- and transition metal-free amide synthesis from phenyl esters and aryl amines
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A general, economical, and environmentally friendly method of amide synthesis from phenyl esters and aryl amines was developed. This new method has significant advantages compared to previously reported palladium-catalyzed approaches. The reaction is performed transition metal- and solvent-free, using a cheap and environmentally benign base, NaH. This approach enabled us to obtain target amides in high yields with high atom economy.
- Rzhevskiy, Sergey A.,Ageshina, Alexandra A.,Chesnokov, Gleb A.,Gribanov, Pavel S.,Topchiy, Maxim A.,Nechaev, Mikhail S.,Asachenko, Andrey F.
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p. 1536 - 1540
(2019/01/24)
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- Vilsmeier-Haack reagent mediated synthetic transformations with an immobilized iridium complex photoredox catalyst
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An immobilized iridium complex photocatalyst Ir(ppy)2(PDVB-py) was synthesized by immobilization of the iridium complex onto the nanoporous vinylpyridine-divinylbenzene copolymer (PDVB-py). Its application for the synthesis of amides, nitriles, and anhydrides was reported via reactions under the action of the visible-light-driven in situ generated Vilsmeier-Haack reagent from CBr4 in DMF. The results showed that this heterogeneous photocatalyst has extremely high activity and excellent stability to be recycled five times.
- Zhi, Peng,Xi, Zi-Wei,Wang, Dan-Yan,Wang, Wei,Liang, Xue-Zheng,Tao, Fei-Fei,Shen, Run-Pu,Shen, Yong-Miao
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p. 709 - 717
(2019/01/10)
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- Modular Continuous Flow Synthesis of Imatinib and Analogues
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A modular continuous flow synthesis of imatinib and analogues is reported. Structurally diverse imatinib analogues are rapidly generated using three readily available building blocks via a flow hydration/chemoselective C-N coupling sequence. The newly developed continuous flow hydration and amidation modules each exhibit a broad scope with good to excellent yields. Overall, the method described does not require solvent switches, in-line purifications, or packed-bed apparatuses due to the judicious manipulation of flow setups and solvent mixtures.
- Fu, Wai Chung,Jamison, Timothy F.
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supporting information
p. 6112 - 6116
(2019/08/26)
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- Photocatalytic tandem reaction of primary alcohols with arylamines in the synthesis of amides and alkylquinolines in the presence of a heterogeneous Fe(CrO2)2–TiO2/X system under aerobic conditions
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A heterogeneous system Fe(CrO2)2–TiO2/X (where X is promoter NiO, CuO, ZnO, Cr2O3, Fe2O3, PrOCl, TbOCl, LaOCl, or EuOCl) was prepared. The photocatalytic activity of the system was tested in the tandem reaction of primary alcohols (BnOH, EtOH) with arylamines aimed at synthesizing benzamides and substituted 2-methylquinolines under aerobic conditions at room temperature.
- Makhmutov
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- Chromium-Catalyzed Activation of Acyl C-O Bonds with Magnesium for Amidation of Esters with Nitroarenes
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Here, we report a chromium-catalyzed activation of acyl C-O bonds with magnesium for amidation of esters with nitroarenes. Low-cost chromium(III) chloride shows high reactivity in promoting amidation by using magnesium as reductant and chlorotrimethylsilane as additive. It provides a step-economic strategy to the synthesis of centrally important amide motifs using inexpensive and air-stable nitroarenes as amino sources.
- Ling, Liang,Chen, Changpeng,Luo, Meiming,Zeng, Xiaoming
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supporting information
(2019/03/19)
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- Method for preparing derivatives of benzamide under microwave condition in aqueous phase
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The invention discloses a method for preparing derivatives of benzamide under a microwave condition in an aqueous phase. A coupling reaction is carried out between substituted benzoic acid and amine under the microwave condition in the aqueous phase. The method for preparing the derivatives of benzamide is environmentally friendly, easy and convenient to operate, safe, low in cost and efficient. Compared with the prior art, the method can be applicable to a large number of functional groups, is high in yield, produces fewer by-products, and further is easy to operate, safe, low in cost and environmentally friendly. A formula is shown in the description.
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Paragraph 0019; 0059
(2019/03/28)
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- Amidation of Aryl Chlorides Using a Microwave-Assisted, Copper-Catalyzed Concurrent Tandem Catalytic Methodology
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A concurrent tandem catalytic (CTC) methodology has been developed for the amidation of aryl chlorides where the aryl chloride is first converted to an aryl iodide via halogen exchange and the aryl iodide is subsequently transformed into the aryl amide. A variety of aryl chlorides were converted to aryl amides in up to 85% isolated yield using 20 mol % CuI, 60 mol % N,N′-cyclohexane-1,2-diamine, 2.2 equiv of K2CO3, and 1.05-1.5 equiv of amide in acetonitrile at 200 °C after 0.75-1 h. The same copper/ligand system served as multifunctional catalyst for both steps of the concurrent catalytic process with iodide present in substoichiometric amounts. Mechanistic studies were consistent with CTC amidation occurring via a nonradical mechanism. Kinetic modeling was conducted to investigate the effect of competitive direct amidation of an aryl chloride or aryl bromide on the formation of product over time during a CTC amidation reaction.
- Chang, Raymond K.,Clairmont, Brice P.,Lin, Shirley,MacArthur, Amy H. Roy
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supporting information
p. 4448 - 4454
(2019/11/13)
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- A metal-free approach for the synthesis of amides/esters with pyridinium salts of phenacyl bromides via oxidative C–C bond cleavage
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An efficient, simple, and metal-free synthetic approach for the N- and O-benzoylation of various amines/benzyl alcohols with pyridinium salts of phenacyl bromides is demonstrated to generate the corresponding amides and esters. This protocol facilitates the oxidative cleavage of a C–C bond followed by formation of a new C–N/C–O bond in the presence of K2CO3. Various pyridinium salts of phenacyl bromides can be readily transformed into a variety of amides and esters which is an alternative method for the conventional amidation and esterification in organic synthesis. High functional group tolerance, broad substrate scope and operational simplicity are the prominent advantages of the current protocol.
- Manasa, Kesari Lakshmi,Tangella, Yellaiah,Krishna, Namballa Hari,Alvala, Mallika
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p. 1864 - 1871
(2019/08/12)
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- The use of Cr (CO)6 as an alternative CO source in Pd-catalyzed C-N bond formation: Synthesis of benzamides
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An efficient strategy for the synthesis of benzamides from acetamides and aryl iodides using 1?mol% Pd (OAc)2 as catalyst and Cr (CO)6 as CO-precursor is described. This new synthetic methodology displays high functional group tolerance on both substrates and avoids the need for ligands, reducing agents, or other additives. The corresponding products were obtained in good to excellent yields at atmospheric pressure under mild reaction conditions.
- Mozaffari, Mozhdeh,Nowrouzi, Najmeh,Abbasi, Mohammad
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- Amide Synthesis from Thiocarboxylic Acids and Amines by Spontaneous Reaction and Electrosynthesis
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Amide bond formation is one of the most important basic reactions in chemistry. A catalyst-free approach for constructing amide bonds from thiocarboxylic acids and amines was developed. The mechanistic studies showed that the disulfide was the key intermediate for this amide synthesis. Thiobenzoic acids could be automatically oxidized to disulfides in air, thioaliphatic acids could be electro-oxidized to disulfides, and the resulting disulfides reacted with amines to give the corresponding amides. By this method, various amides could be easily synthesized in excellent yields without using any catalyst or activator. The successful synthesis of bioactive compounds also highlights the synthetic utility of this strategy in medicinal chemistry.
- Tang, Li,Matuska, Jack H.,Huang, Yu-Han,He, Yan-Hong,Guan, Zhi
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p. 2570 - 2575
(2019/06/13)
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- Synthesis of Amides by Mild Palladium-Catalyzed Aminocarbonylation of Arylsilanes with Amines Enabled by Copper(II) Fluoride
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A general Pd-catalyzed synthesis of amides by oxidative aminocarbonylation of arylsilanes under mild conditions was accomplished for the first time. The reaction is promoted by a commercially available copper(II) fluoride, which acts as a dual silane activator and mild oxidant, enabling highly efficient aminocarbonylation of versatile arylsilanes at atmospheric CO pressure. The reaction is tolerant of a wide range of arylsilanes and various sensitive halide functional groups as well as a broad scope of amines are compatible with this oxidative process using cheap CO. A significant aspect involves the increased efficiency by the catalyst system. The reaction represents a segue into the powerful Pd-catalyzed oxidative transformations of organosilanes.
- Zhang, Jin,Hou, Yanyan,Ma, Yangmin,Szostak, Michal
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p. 338 - 345
(2019/01/10)
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- Synthesis of benzamides through direct condensation of carboxylic acids and amines in the presence of diatomite earth@IL/ZrCl4 under ultrasonic irradiation
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A green, rapid, mild and highly efficient pathway for the preparation of benzamide derivatives is reported. The reaction was performed through direct condensation of benzoic acids and amines under ultrasonic irradiation in the presence of Lewis acidic ionic liquid immobilized on diatomite earth (diatomite earth@IL/ZrCl4). A new, highly efficient and green solid acid catalyst was easily prepared via a two-step procedure and used as an effective reusable catalyst. The prepared catalyst provides active sites for the synthesis of benzamides. The advantages of this method are the use of a superior and recoverable catalyst, low reaction times, simple procedure, high-yielding and eco-friendly process and use of ultrasonic irradiation as a green and powerful technology. Since benzamides are used widely in the pharmaceutical, paper and plastic industries, and also as an intermediate product in the synthesis of therapeutic agents, the presented new synthetic methods for this type of compounds can be of considerable importance.
- Ahmadi, Masoumeh,Moradi, Leila,Sadeghzadeh, Masoud
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p. 7873 - 7889
(2018/09/27)
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- Towards a Sequential One-Pot Preparation of 1,2,3-Benzotriazin-4(3H)-ones Employing a Key Cp*Co(III)-catalyzed C?H Amidation Step
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1,2,3-benzotriazin-4(3H)-one derivatives have been recognised for their potential application as pesticides and pharmaceuticals and new methodologies for their preparation, starting from readily accessible reagents would therefore be an attractive proposition. A wide range of differently substituted benzamides are readily available, which provide an excellent substrate scaffold for the application of direct C?H functionalization protocols. In this context, herein we report the use of a Cp*Co(III) catalyst for the amidation of these benzamides, using 1,4,2-dioxazol-5-ones as amidating agent. The isolable intermediate 2-acetamido benzamide products can thereafter be converted to the desired 1,2,3-benzotriazin-4(3H)-one derivatives through the use of tert-butyl nitrite under mild conditions. It was found to be possible to perform the second step with the crude reaction mixture obtained from the initial C?H amidation step, leading to the overall development of a facile one-pot procedure for the preparation of a range of substituted 1,2,3-benzotriazin-4(3H)-one derivatives, requiring only 5 hours of reaction time, which is also applicable on a gram scale. In addition, the key Cp*Co(III)-catalyzed C?H amidation step has been studied by DFT calculations in order to fully elucidate the mechanism. (Figure presented.).
- Chirila, Paula G.,Skibinski, Lauren,Miller, Keith,Hamilton, Alex,Whiteoak, Christopher J.
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supporting information
p. 2324 - 2332
(2018/04/30)
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- Selective cleavage of the N-propargyl group from sulfonamides and amides under ruthenium catalysis
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The selective cleavage of the N-propargyl group from sulfonamides and amides under ruthenium catalysis is described. The reaction tolerates a broad range of functional groups, and the desired products were obtained in 10–95% yield.
- Wang, Jingjing,Li, Feng,Pei, Wenlong,Yang, Mixue,Wu, Yidan,Ma, Danyang,Zhang, Furong,Wang, Jianhui
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supporting information
p. 1902 - 1905
(2018/04/19)
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- Potassium Carbonate Promoted C-N Coupling Reaction between Benzamides and Aryl Iodides
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A practical and efficient method for N-arylation of benz-amides promoted by potassium carbonate in the presence of DMEDA was developed. The reaction was carried out without addition of any transition-metal catalyst to afford a variety of N-arylated products in moderate to good yields (up to 97%).
- Huang, Fei,Wu, San,Hu, Weiye,Zhang, Songlin
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supporting information
p. 1090 - 1096
(2017/11/29)
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