- Remarkably Efficient Iridium Catalysts for Directed C(sp2)-H and C(sp3)-H Borylation of Diverse Classes of Substrates
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Here we describe the discovery of a new class of C-H borylation catalysts and their use for regioselective C-H borylation of aromatic, heteroaromatic, and aliphatic systems. The new catalysts have Ir-C(thienyl) or Ir-C(furyl) anionic ligands instead of the diamine-type neutral chelating ligands used in the standard C-H borylation conditions. It is reported that the employment of these newly discovered catalysts show excellent reactivity and ortho-selectivity for diverse classes of aromatic substrates with high isolated yields. Moreover, the catalysts proved to be efficient for a wide number of aliphatic substrates for selective C(sp3)-H bond borylations. Heterocyclic molecules are selectively borylated using the inherently elevated reactivity of the C-H bonds. A number of late-stage C-H functionalization have been described using the same catalysts. Furthermore, we show that one of the catalysts could be used even in open air for the C(sp2)-H and C(sp3)-H borylations enabling the method more general. Preliminary mechanistic studies suggest that the active catalytic intermediate is the Ir(bis)boryl complex, and the attached ligand acts as bidentate ligand. Collectively, this study underlines the discovery of new class of C-H borylation catalysts that should find wide application in the context of C-H functionalization chemistry.
- Chattopadhyay, Buddhadeb,Hassan, Mirja Md Mahamudul,Hoque, Md Emdadul
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supporting information
p. 5022 - 5037
(2021/05/04)
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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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- Direct amidation of non-activated carboxylic acid and amine derivatives catalyzed by TiCp2Cl2
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This paper described a mild and efficient direct amidation of non-activated carboxylic acid and amine derivatives catalyzed by TiCp2Cl2. Arylacetic acid derivatives reacted with different amines to afford the corresponding amides in good to excellent yield except of aniline. Aryl formic acids failed to react with aniline but smoothly reacted with aliphatic amines and benzylamine in moderate to good yield, fatty acids reacting with benzyl and aliphatic amines give amides in good to excellent yield. Chiral amino acids derivatives were transformed into amides without racemization in moderate yield. The possible mechanism of direct amidation catalyzed by TiCp2Cl2 was discussed. This catalytic method is very suitable for the amidation of low sterically hindered arylacetic acid, fatty acids with different low sterically hindered amines except aniline, as well as the amidation of aryl formic acid with benzyl and aliphatic amines.
- Wang, Hui,Dong, Wei,Hou, Zhipeng,Cheng, Lidan,Li, Xiufen,Huang, Longjiang
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- Catalyst-Free, Metal-Free, and Chemoselective Transamidation of Activated Secondary Amides
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A simple protocol, which is catalyst-free, metal-free, and chemoselective, for transamidation of activated secondary amides in ethanol as solvent under mild conditions is reported. A wide range of amines, amino acids, amino alcohols, and the substituents, which are problematic in catalyzed transamidation, are tolerated in this methodology. The transamidation reaction was successfully extended to water as the medium as well. The present methodology appears to be better than the other catalyzed transamidations reported recently.
- Ramkumar, Rajagopal,Chandrasekaran, Srinivasan
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p. 921 - 932
(2019/02/10)
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- Transamidation of: N -acyl-glutarimides with amines
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The development of new transamidation reactions for the synthesis of amides is an important and active area of research due to the central role of amide linkage in various fields of chemistry. Herein, we report a new method for transamidation of N-acyl-glutarimides with amines under mild, metal-free conditions that relies on amide bond twist to weaken amidic resonance. A wide range of amines and functional groups, including electrophilic substituents that would be problematic in metal-catalyzed protocols, are tolerated under the reaction conditions. Mechanistic experiments implicate the amide bond twist, thermodynamic stability of the tetrahedral intermediate and leaving group ability of glutarimide as factors controlling the reactivity of this process. The method further establishes the synthetic utility of N-acyl-glutarimides as bench-stable, twist-perpendicular, amide-based reagents in acyl-transfer reactions by a metal-free pathway. The origin of reactivity of N-acyl-glutarimides in metal-free and metal-catalyzed processes is discussed and compared.
- Liu, Yongmei,Achtenhagen, Marcel,Liu, Ruzhang,Szostak, Michal
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p. 1322 - 1329
(2018/03/06)
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- An Efficient Heterobimetallic Lanthanide Alkoxide Catalyst for Transamidation of Amides under Solvent-Free Conditions
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A practical heterobimetallic lanthanide-catalyzed transamidation of primary, secondary and tertiary amides with aliphatic and aromatic amines has been developed. The methodology was also applied to the weakly reactive thioamides to demonstrate its versatility and wide substrate scope. The heterobimetallic lanthanide catalysts showed high catalytic activity and a wide scope of substrates with good to excellent yields under solvent-free conditions. Efficient activation of the transamidation can be realized by the above complexes acting as cooperative acid–base bifunctional catalysts, which are proposed to be responsible for the higher reactivity in comparison with simple monometallic catalysts. (Figure presented.).
- Sheng, Hongting,Zeng, Ruijie,Wang, Wenjuan,Luo, Shuwen,Feng, Yan,Liu, Jing,Chen, Weijian,Zhu, Manzhou,Guo, Qingxiang
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p. 302 - 313
(2017/02/05)
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- Metal-Free Transamidation of Secondary Amides via Selective N-C Cleavage under Mild Conditions
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Nonplanar, electronically destabilized amides have emerged as powerful intermediates in organic synthesis. We report a highly selective method for transamidation of common secondary amides under mild, metal-free conditions that relies on transient N-selective functionalization to weaken amidic resonance. The combination of rational modification of the amide bond with nucleophilic addition mechanism, and the thermodynamic collapse of the resultant tetrahedral intermediate constitutes a two-step procedure to accomplish a challenging transamidation of secondary amides under mild conditions.
- Liu, Yongmei,Shi, Shicheng,Achtenhagen, Marcel,Liu, Ruzhang,Szostak, Michal
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p. 1614 - 1617
(2017/04/11)
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- Transamidation catalysed by a magnetically separable Fe3O4 nano catalyst under solvent-free conditions
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An environmentally benign protocol for transamidation of carboxamides with different amines under solvent free conditions using magnetically separable nano Fe3O4 as a heterogeneous catalyst is developed. The series of aryl and alkyl amines with long chain alkyl substituents have been selectively converted into transamide products. The current protocol offers a diverse substrate scope with good yield of the product. The Fe3O4 nano catalyst has also been used for formylation of amines via transamidation of dimethyl formamide. Efficient transamidation, ease of work up, simple separation and reusability of the catalyst for up to six runs are the important highlights of this process.
- Thale, Pranila B.,Borase, Pravin N.,Shankarling, Ganapati S.
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p. 52724 - 52728
(2016/06/14)
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- A nanowire the platinum accepts method for catalytic synthesis of amides (by machine translation)
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The invention relates to a nanowire the platinum accepts method for catalytic synthesis of amides. Specifically, the method comprises the following steps: adding the reaction vessel in the nanowire the platinum accepts in alcoholic, decompression except mellow, further adding alchlor, reaction solvent, pyridine, amine compounds, aldehyde compound and an oxidizing agent, under the mixing conditions, the heating reaction in in oil bath, after purification by column chromatography, to obtain amides, wherein: the states the aldehyde class compounds, amine compounds, alchlor, pyridine, the platinum accepts molar ratio of the oxidizing agent and 0.5-3 : 0.5-3 : 0.1-0.5: 0.5-2 : 0.1% - 2% : 0.5-5, the heating of the reaction temperature is 80-140°C, the reaction time is 16-24 hours. Because the nanowire the platinum accepts as the catalyst, the invention is not only high catalytic activity, and the performance is stable, at the same time the method of the present invention can obtain a higher yield, mild condition, process is simple, easy to operate. (by machine translation)
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Paragraph 0121-0123
(2017/02/28)
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- Platinum nanowires catalyzed direct amidation with aldehydes and amines
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Different from the conventional synthesis methods and substrates, we designed a brand new method for synthesizing amides with platinum nanowires as catalysts and tert-butylhydroperoxide (TBHP) as the oxidant. Influence of factors, such as the catalyst, solvents, and the reaction temperature, were studied to determine the optimal reaction conditions. In addition, we explored the substrate generality and observed excellent yields.
- Xu, Dawei,Shi, Linyan,Ge, Danhua,Cao, Xueqin,Gu, Hongwei
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p. 478 - 481
(2016/04/19)
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- Tert -Butyl Peroxybenzoate Mediated Selective and Mild N-Benzoylation of Ammonia/Amines under Catalyst- and Solvent-Free Conditions
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A new protocol for the synthesis of amides from tert-butyl peroxybenzoate (TBPB) and ammonia/amines has been developed under catalyst- and solvent-free conditions. The ammonia, primary and secondary amines reacted smoothly with TBPB to furnish the corresponding primary, secondary, and tertiary amides in excellent yields. TBPB proved to be an efficient and highly chemoselective benzoylating reagent for aliphatic amines in the presence of aromatic amines/hydroxyl groups.
- Yadav, Dilip Kumar T.,Bhanage, Bhalchandra M.
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supporting information
p. 1862 - 1866
(2015/08/06)
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- Efficient palladium-catalyzed aminocarbonylation of aryl iodides using palladium nanoparticles dispersed on siliceous mesocellular foam
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A highly dispersed nanopalladium catalyst supported on mesocellular foam (MCF), was successfully used in the heterogeneous catalysis of aminocarbonylation reactions. During the preliminary evaluation of this catalyst it was discovered that the supported palladium nanoparticles exhibited a "release and catch" effect, meaning that a minor amount of the heterogeneous palladium became soluble and catalyzed the reaction, after which it re-deposited onto the support. It's catchy! An efficient palladium-catalyzed protocol for the aminocarbonylation of aryl iodides is reported in which the palladium immobilized on the amino-functionalized mesocellular foam (MCF) was found to operate through a "release and catch" mechanism (see scheme). A very low content of palladium was found in solution upon completion of the reaction and a variety of different aryl iodides were converted to the corresponding amides under mild conditions.
- Tinnis, Fredrik,Verho, Oscar,Gustafson, Karl P. J.,Tai, Cheuk-Wai,Baeckvall, Jan-E.,Adolfsson, Hans
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supporting information
p. 5885 - 5889
(2014/05/20)
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- The direct amidation of α-diketones with amines via TBHP-promoted oxidative cleavage of C(sp2)-C(sp2) bonds
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A novel and efficient direct amidation of α-diketones with amines via TBHP-promoted oxidative cleavage of C(sp2)-C(sp2) bonds has been developed. The strategy provides an alternative approach to amides under metal-free conditions.
- Zhao, Qiong,Li, Hongji,Wang, Lei
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supporting information
p. 6772 - 6779
(2013/10/01)
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- Bis(cyclopentadienyldicarbonyliron) as a convenient carbon monoxide source in palladium-catalyzed carbonylative coupling of aryl iodides with amines, alcohols, and thiols
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Bis(cyclopentadienyldicarbonyliron) ([CpFe(CO)2]2) serves as a carbon monoxide source in carbonylative coupling reactions. Treatment of aryl iodides with primary amines in the presence of DBU and [CpFe(CO)2]2 under palladium catalysis provides the corresponding benzamides in good yields. Similar reactions with phenols and thiols provide the corresponding benzoate esters and thioesters, respectively. A catalytic amount of DMAP as an additive promoted the carbonylative coupling reactions with primary alcohol and secondary amine.
- Nakaya, Ryotaro,Yorimitsu, Hideki,Oshima, Koichiro
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experimental part
p. 904 - 906
(2011/12/05)
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- A practical, water-soluble, ionic scavenger for the solution-phase syntheses of amides
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A new ionic, water-soluble scavenger for acyl chlorides, 1-(2-aminoethyl)pyridinium bromide (1), has been investigated. Compound 1 was used for the rapid and simple purification of a series of benzamides and sulfonamides (Table) obtained by solution-phase synthesis from the corresponding amines (Scheme). The inexpensive scavenger, which can be prepared on large scale, was shown to readily 'eliminate' excess acyl chlorides (reagent) by simple aqueous extraction. The amides purified in this way were obtained in excellent yields and purities (Table), which makes 1 a versatile new reagent, especially for the combinatorial solution-phase synthesis of amide libraries.
- Lei, Ming,Tao, Xiao-Le,Wang, Yan-Guang
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p. 532 - 536
(2007/10/03)
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- Preparation of secondary and tertiary amides under neutral conditions by photochemical acylation of amines
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The smooth and neutral acylation of amines to form amides by photoactivation of N-acyl-5,7-dinitroindolines is described. An improved acylation of nitroindolines allows the convenient preparation of N-acylnitroindolines. This reaction makes possible the recycling of the nitroindoline released during the photoactivation.
- Helgen,Bochet
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p. 1968 - 1970
(2007/10/03)
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- N-Acyltetrazole as an intermediate for preparation of carboxylic acid derivatives
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A new mild and very efficient procedure for preparation of acid derivatives via N-acyl-5-phenyltetrazole is reported. The yields are high at -10°C and purification is simple but, because of the thermal instability of the intermediate, a certain amount of corresponding oxadiazole arises if the reaction is carried out at higher temperature.
- Jursic
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p. 361 - 364
(2007/10/02)
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- Aminolysis of 2,2,2-Trichloro-1-arylethanones in Aprotic Solvents
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The kinetics of the reaction of the title substrate with various alkylamines was studied in n-heptane, dichloromethane, dioxane, tetrahydrofuran, and acetonitrile.The reaction was third-order in amine when the solvent was n-heptane or dichloromethane.In the other solvents a second-order dependence on was observed.The fourth-order rate constants for the reaction of n-butylamine with various 2,2,2-trichloro-1-arylethanones in dichloromethane yielded a ρ value of 3.0.In all solvents the observed rate constans decreased with a temperature increase.Two mechanistic possibilities were suggested, the first one in solvents of low donicity, involving a T0 intermediate formed in a concerted process with the participation of an amine dimer; and the second one, a stepwise process in more basic solvents which takes place via a T+/- intermediate.Base-catalyzed collapse of the tetrahedral intermediates is the rate-determining step in both pathways.
- Druzian, Janice,Zucco, Cesar,Rezende, Marcos Caroli,Nome, Faruk
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p. 4767 - 4771
(2007/10/02)
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- THE USE OF 2,2,2-TRICHLORO-1-ARYLETHANONES AS BENZOYLATING AGENTS
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The preparation of several amides and hydrazides from the reaction of the title compounds with different nitrogen nucleophiles is shown to be a general high-yield conversion of synthetic utility.
- Rebelo, Ricardo Andrade,Rezende, Marcos Caroli,Nome, Faruk,Zucco, Cesar
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p. 1741 - 1748
(2007/10/02)
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- RUTHENIUM CATALYZED N-ALKYLATION OF AMIDES WITH ALCOHOLS.
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Amides reacted with primary alcohols in the presence of a catalytic amount of RuCl//2(PPh//3)//3 at 180 degree C to give the corresponding N-monoalkyl amides in fairly good yields. Thus, benzamide reacted with l-octanol to give N-octylbenzamide in 76% yield with excellent product selectivity. Little esterification of amides with alcohols occurred and selectivity to the N-alkylation was high. Most of the amides gave N-monoalkyl amides but no N,N-dialkyl amides. But formamide reacted with l-butanol to give N,N-dibutylformamide, as well as N-butylformamide, in low yield. RuCl//2(PPh//3)//3 was the most effective catalyst for this reaction and RuHCl(PPh//3)//3 also had some catalytic activity.
- Watanabe,Ohta,Tsuji
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p. 2647 - 2651
(2007/10/02)
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