- Graphene oxide: A convenient metal-free carbocatalyst for facilitating amidation of esters with amines
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Herein, we report a graphene oxide (GO) catalyzed condensation of non-activated esters and amines, that can enable diverse amides to be synthesized from abundant ethyl esters forming only volatile alcohol as a by-product. GO accelerates ester to amide conversion in the absence of any additives, unlike other catalysts. A wide range of ester and amine substrates are screened to yield the respective amides in good to excellent yields. The improved catalytic activity can be ascribed to the oxygenated functionalities present on the graphene oxide surface which forms H-bonding with the reactants accelerating the reaction. Improved yields and a wide range of functional group tolerance are some of the important features of the developed protocol.
- Patel, Khushbu P.,Gayakwad, Eknath M.,Shankarling, Ganapati S.
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Read Online
- A radical approach to N-desulfonylation
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The deprotection of N-sulfonylated amides can be achieved under neutral conditions by reaction with tributyltin hydride. Good yields are obtained using N-benzoyl and related amides while the corresponding N-acetyl derivatives are inert under the same reaction conditions. The mechanistic implications of this are discussed.
- Parsons, Andrew F.,Pettifer, Robert M.
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- In situ Generated Ruthenium Catalyst Systems Bearing Diverse N-Heterocyclic Carbene Precursors for Atom-Economic Amide Synthesis from Alcohols and Amines
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The transition-metal-catalyzed direct synthesis of amides from alcohols and amines is herein demonstrated as a highly environmentally benign and atom-economic process. Among various catalyst systems, in situ generated N-heterocyclic carbene (NHC)-based ruthenium (Ru) halide catalyst systems have been proven to be active for this transformation. However, these existing catalyst systems usually require an additional ligand to achieve satisfactory results. In this work, through extensive screening of a diverse variety of NHC precursors, we discovered an active in situ catalyst system for efficient amide synthesis without any additional ligand. Notably, this catalyst system was found to be insensitive to the electronic effects of the substrates, and various electron-deficient substrates, which were not highly reactive with our previous catalyst systems, could be employed to afford the corresponding amides efficiently. Furthermore, mechanistic investigations were performed to provide a rationale for the high activity of the optimized catalyst system. NMR-scale reactions indicated that the rapid formation of a Ru hydride intermediate (signal at δ=?7.8 ppm in the 1H NMR spectrum) after the addition of the alcohol substrate should be pivotal in establishing the high catalyst activity. Besides, HRMS analysis provided possible structures of the in situ generated catalyst system.
- Cheng, Hua,Xiong, Mao-Qian,Cheng, Chuan-Xiang,Wang, Hua-Jing,Lu, Qiang,Liu, Hong-Fu,Yao, Fu-Bin,Chen, Cheng,Verpoort, Francis
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- A Heterogeneous Niobium(V) Oxide Catalyst for the Direct Amidation of Esters
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This study reports the first example of a heterogeneous catalytic system for the direct amidation of various esters with amines. Of 25 types of catalyst, Nb2O5 shows the highest activity in the amidation of methyl benzoate with aniline. Nb2O5 gives high yields in the amidation of various esters and amines under solvent-free conditions, is reusable, and shows higher turnover numbers than previously reported homogeneous catalysts such as La(OTf)3. IR spectroscopic studies of ethyl acetate adsorbed on the catalysts show a strong acid-base interaction between the Nb5+ Lewis acid site and carbonyl oxygen, which can result in high reactivity of the ester with a nucleophile (amine) and, thus, high activity of Nb2O5. Kinetic results show that the activity of Nb2O5 does not markedly decrease with increasing aniline concentration, in contrast to reference catalysts TiO2 and La(OTf)3. The relatively low negative impact of basic molecules on the Lewis acid catalysis of Nb2O5 also enables its high activity.
- Ali, Md. Ayub,Siddiki, S. M. A. Hakim,Kon, Kenichi,Shimizu, Ken-Ichi
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- Desulfonylation of Amides Using Samarium Iodide
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The desulfonylation of N-sulfonyl amides can be achieved in reasonable to excellent yield by reaction with samarium(II) iodide (SmI2) in THF at room temperature. Deprotection of acyclic and cyclic amides bearing aryl and alkylsulfonyl groups is possible.
- Knowles, Haydn,Parsons, Andrew F.,Pettifer, Robert M.
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Read Online
- 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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- Dehydrogenative amide synthesis from alcohols and amines utilizing N-heterocyclic carbene-based ruthenium complexes as efficient catalysts: The influence of catalyst loadings, ancillary and added ligands
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The metal-catalyzed dehydrogenative coupling of alcohols and amines to access amides has been recognized as an atom-economic and environmental-friendly process. Apart from the formation of the amide products, three other kinds of compounds (esters, imines and amines) may also be produced. Therefore, it is of vital importance to investigate product distribution in this transformation. Herein, N-heterocyclic carbene-based Ru (NHC/Ru) complexes [Ru-1]-[Ru-5] with different ancillary ligands were prepared and characterized. Based on these complexes, we selected condition A (without an added NHC precursor) and condition B (with an added NHC precursor) to comprehensively explore the selectivity and yield of the desired amides. After careful evaluation of various parameters, the Ru loadings, added NHC precursors and the electronic/steric properties of ancillary NHC ligands were found to have considerable influence on this catalytic process.
- Wang, Wan-Qiang,Wang, Zhi-Qin,Sang, Wei,Zhang, Rui,Cheng, Hua,Chen, Cheng,Peng, Da-Yong
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- Simple Synthesis of Amides via Their Acid Chlorides in Aqueous TPGS-750-M
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The technology of surfactant chemistry is employed for amide bond construction via the reaction of acyl chlorides with amines in 2 wt % TPGS-750-M aqueous solution. Specifically, this highly efficient method enables a chromatography-free scalable process and recycling of the TPGS-750-M solution.
- Shi, Min,Ye, Ning,Chen, Wei,Wang, Hui,Cheung, Chiming,Parmentier, Michael,Gallou, Fabrice,Wu, Bin
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supporting information
p. 1543 - 1548
(2020/11/23)
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- Homoleptic Bis(trimethylsilyl)amides of Yttrium Complexes Catalyzed Hydroboration Reduction of Amides to Amines
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Homoleptic lanthanide complex Y[N(TMS)2]3 is an efficient homogeneous catalyst for the hydroboration reduction of secondary amides and tertiary amides to corresponding amines. A series of amides containing different functional groups such as cyano, nitro, and vinyl groups were found to be well-tolerated. This transformation has also been nicely applied to the synthesis of indoles and piribedil. Detailed isotopic labeling experiments, control experiments, and kinetic studies provided cumulative evidence to elucidate the reaction mechanism.
- Ye, Pengqing,Shao, Yinlin,Ye, Xuanzeng,Zhang, Fangjun,Li, Renhao,Sun, Jiani,Xu, Beihang,Chen, Jiuxi
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supporting information
p. 1306 - 1310
(2020/02/22)
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- Tris(o-phenylenedioxy)cyclotriphosphazene as a Promoter for the Formation of Amide Bonds between Aromatic Acids and Amines
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The atom-efficient formation of amide bonds has emerged as a top-priority research field in organic synthesis, as amide bonds constitute the backbones of proteins and represent an important structural motif in drug molecules. Currently, the increasing demand for novel discoveries in this field has focused substantial attention on this challenging subject. Herein, the degradable 1,3,5-triazo-2,4,6-triphosphorine (TAP) motif is presented as a new condensation system for the dehydrative formation of amide bonds between diverse combinations of aromatic carboxylic acids and amines. The underlying reaction mechanism was investigated, and potential catalyst intermediates were characterized using 31 P NMR spectroscopy and ESI mass spectrometry.
- Movahed, Farzaneh Soleymani,Sawant, Dinesh N.,Bagal, Dattatraya B.,Saito, Susumu
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p. 3253 - 3262
(2020/11/02)
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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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- Well-defined N-heterocyclic carbene/ruthenium complexes for the alcohol amidation with amines: The dual role of cesium carbonate and improved activities applying an added ligand
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Dehydrogenative amide bond formation from alcohols and amines has been regarded as an atom-economic and sustainable process. Among various catalytic systems, N-heterocyclic carbene (NHC)-based Ru catalytic systems have attracted growing interest due to the outstanding properties of NHCs as ligands. Herein, an NHC/Ru complex (1) was prepared and its structure was further confirmed with X-ray crystallography. In the presence of Cs2CO3, two NHC/Ru-based catalytic systems were disclosed to be active for this amide synthesis. System A, which did not contain any added ligand, required a catalyst loading of 1.00 mol%. Interestingly, improved catalytic performance was realized by the addition of an NHC precursor (L). Optimization of the amounts of L and other conditions gave rise to system B, a much more potent system with the Ru loading as low as 0.25 mol%. Moreover, an NHC-Ru-carbonate complex 6 was identified from the refluxing toluene of 1 and Cs2CO3, and further investigations revealed that 6 was an important intermediate for this catalytic reaction. Based on the above results, we claimed that the role of Cs2CO3 was to facilitate the formation of key intermediate 6. On the other hand, it provided the optimized basicity for the selective amide formation.
- Wang, Wan-Qiang,Yuan, Ye,Miao, Yang,Yu, Bao-Yi,Wang, Hua-Jing,Wang, Zhi-Qin,Sang, Wei,Chen, Cheng,Verpoort, Francis
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- Synthesis of amides from acid chlorides and amines in the bio-based solvent Cyrene
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Cyrene as a bio-alternative dipolar aprotic solvent: a waste minimizing and molar efficient protocol for the synthesis of amides from acid chlorides and primary amines in the bio-available solvent Cyrene is disclosed. This protocol removed the use of toxic solvents, such as dimethylformamide and dichloromethane. A simple aqueous work-up procedure for the removal of the high boiling solvent Cyrene resulted in up to a 55-fold increase in molar efficiency (Mol E.%) versus standard operating procedures. In order to rapidly compare the molar efficiency of this process against other methodologies an Excel based Mol. E% calculator was developed that automates many of the calculations. An investigation into the hydration of Cyrene found that it readily hydrates to form a geminal diol in the presence of water and that this process is exothermic.
- Bousfield, Thomas W.,Pearce, Katharine P. R.,Nyamini, Simbarashe B.,Angelis-Dimakis, Athanasios,Camp, Jason E.
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supporting information
p. 3675 - 3681
(2019/07/09)
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- Water-Tolerant and Atom Economical Amide Bond Formation by Metal-Substituted Polyoxometalate Catalysts
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A simple, safe, and inexpensive amide bond formation directly from nonactivated carboxylic acids and free amines is presented in this work. Readily available Zr(IV)- and Hf(IV)-substituted polyoxometalates (POM) are shown to be catalysts for the amide bond formation reaction under mild conditions, low catalyst loading, and without the use of water scavengers, dry solvents, additives for facilitating the amine attack, or specialized experimental setups commonly employed to remove water. Detailed mechanistic investigations revealed the key role of POM scaffolds which act as inorganic ligands to protect Zr(IV) and Hf(IV) Lewis acidic metals against hydrolysis and preserve their catalytic activity in amide bond formation reactions. The catalysts are compatible with a range of functional groups and heterocycles useful for medicinal, agrochemical, and material chemists. The robustness of the Lewis acid-POM complexes is further supported by the catalyst reuse without loss of activity. This prolific combination of Zr(IV)/Hf(IV) and POMs inaugurates a powerful class of catalysts for the amide bond formation, which overcomes key limitations of previously established Zr(IV)/Hf(IV) salts and boron-based catalysts.
- De Azambuja, Francisco,Parac-Vogt, Tatjana N.
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p. 10245 - 10252
(2019/11/03)
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- Method of preparing amides by catalyzed reaction of esters and amines
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The invention provides a method of preparing amides by catalyzed reaction of esters and amines. Raw materials in the method are simple and easily obtainable, the method is simple to perform, has no need for adding solvents and has high yield, and the applicable range of substrates is wide. The method comprises the steps of allowing an ester of formula (I) shown in the description and an amine of formula (II) shown in the description to react under the catalysis of the catalyst alkoxy rare-earth metal cluster containing the basic metal sodium to obtain a compound of formula (III) shown in the description; alternatively, allowing the ester of formula (I) and the amine of formula (II) to react under the catalysis of the catalyst alkoxy rare-earth metal cluster containing the basic metal sodium to obtain a compound of formula (V) shown in the description, wherein R1 is selected from alkyl, aryl or heteroaryl, R2, R3 and R4 are independently selected from alkyl alcohol, alkyl, cycloalkyl, heterocyclyl, aryl or heteroaryl, or R3 and R4 are independently selected from alkyl alcohol and alkyl while R3, R4 and atoms connected to them form a ring. The reaction formulas are shown in the description.
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Paragraph 0090; 0092; 0093
(2018/04/27)
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- Diboron-Catalyzed Dehydrative Amidation of Aromatic Carboxylic Acids with Amines
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Tetrakis(dimethylamido)diboron and tetrahydroxydiboron are herein reported as new catalysts for the synthesis of aryl amides by catalytic condensation of aromatic carboxylic acids with amines. The developed protocol is both simple and highly efficient over a broad range of substrates. This method thus represents an attractive approach for the use of diboron catalysts in the synthesis of amides without having to resort to stoichiometric or additional dehydrating agents.
- Sawant, Dinesh N.,Bagal, Dattatraya B.,Ogawa, Saeko,Selvam, Kaliyamoorthy,Saito, Susumu
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supporting information
p. 4397 - 4400
(2018/08/09)
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- Efficient N-Heterocyclic Carbene/Ruthenium Catalytic Systems for the Alcohol Amidation with Amines: Involvement of Poly-Carbene Complexes?
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The atom-economic direct amidation of alcohols with amines has been recently highlighted as an attractive and promising transformation. Among the versatile reported catalytic systems, in situ generated N-heterocyclic carbene (NHC)/ruthenium (Ru) catalytic systems have demonstrated their advantages such as easy operation and use of commercial Ru compounds. However, the existing catalyst loadings are relatively high, and additional insights for the in situ catalyst generation are still not well-documented. In this work, a variety of benzimidazole-based NHC precursors were initially synthesized. Through the screening of various NHC precursors and other reaction conditions, active in situ catalytic systems were discovered for the efficient amide synthesis. Notably, the catalyst loading is as low as 0.5 mol %. Furthermore, additional experiments were performed to validate the rationale for the superiority of the current catalytic systems over our previous system. It was observed that the ligand structure is one of the reasons for the higher activity. In addition, the higher ratio of the NHC precursor/[Ru] is another important factor for the improvement. Further HR-MS analysis identified the formation of two mono-NHC-Ru species as major species and two Ru species bearing multiple NHC ligands as minor species. Hopefully, the efficient and readily-accessible catalytic systems reported herein could demonstrate great potential for further practical applications.
- Cheng, Hua,Xiong, Mao-Qian,Zhang, Ni,Wang, Hua-Jing,Miao, Yang,Su, Wei,Yuan, Ye,Chen, Cheng,Verpoort, Francis
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p. 4338 - 4345
(2018/09/06)
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- A process for preparing N - alkyl amide method (by machine translation)
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The invention discloses a method for preparing N - alkyl amide of the method. In the reaction container, joins the nitrile, oxime, transition metal catalyst iridium complex [Cp * IrCl2 ]2 , Toluene; the reaction mixture in 100 °C reaction under 6 hours, cooling to room temperature; then the alcohol and alkali compound is added, the reaction mixture in the 130 °C react again under 12 hours later, then through the column separation, to obtain the target compound. The invention from the fully commercialized nitrile, proceed wowo and mellow, in the participation of transition metal iridium catalyst, to directly obtain N - alkyl amide, the reaction exhibits three significant advantages: 1) the use of the commercialization of the starting material; 2) low catalyst load; 3) is environment-friendly and easy to control. Therefore, the reaction in accordance with the requirement of green chemistry, has broad prospects of development. (by machine translation)
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Paragraph 0146; 0147; 0148; 0149; 0150
(2017/08/19)
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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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- Poly(methylhydrosiloxane) as a green reducing agent in organophosphorus-catalysed amide bond formation
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Development of catalytic amide bond formation reactions has been the subject of the intensive investigations in the past decade. Herein we report an efficient organophosphorus-catalysed amidation reaction between unactivated carboxylic acids and amines. Poly(methylhydrosiloxane), a waste product of the silicon industry, is used as an inexpensive and green reducing agent for in situ reduction of phosphine oxide to phosphine. The reported method enables the synthesis of a wide range of secondary and tertiary amides in very good to excellent yields.
- Hamstra, Daan F. J.,Lenstra, Danny C.,Koenders, Tjeu J.,Rutjes, Floris P. J. T.,Mecinovi?, Jasmin
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supporting information
p. 6426 - 6432
(2017/08/10)
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- Diphenylsilane as a coupling reagent for amide bond formation
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A simple procedure for amide bond formation using diphenylsilane as a coupling reagent is described. This methodology enables the direct coupling of carboxylic acids with primary and secondary amines, releasing only hydrogen and a siloxane as by-products. Only one equivalent of each partner is needed, providing a more sustainable amidation method producing minimal wastes. This methodology was also extended to the synthesis of peptides and lactams by addition of Hünig's base (DIPEA) and 4-dimethylaminopyridine (DMAP).
- Sayes, Morgane,Charette, André B.
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supporting information
p. 5060 - 5064
(2017/11/09)
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- Ruthenium(II) complexes encompassing 2-oxo-1,2-dihydroquinoline-3-carbaldehyde thiosemicarbazone hybrid ligand: A new versatile potential catalyst for dehydrogenative amide synthesis
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Ruthenium(II) complexes (1–6) supported by a series of 2-oxo-1,2-dihydroquinoline-3-carbaldehyde substituted thiosemicarbazone ligands [2-oxo-1,2-dihydroquinoline-3-carbaldehyde thiosemicarbazone (L1), 2-oxo-1,2-dihydroquinoline-3-carbaldehyde N-methyl thiosemicarbazone (L2), 2-oxo-1,2-dihydroquinoline-3-carbaldehyde N-phenylthiosemicarbazone (L3)] have been synthesized and structurally characterized by analytical, spectroscopic methods and X-ray crystallographic technique. The studies revealed that the ligands act as mononegative tridentate in ruthenium(II) complexes and a distorted octahedral geometry has been proposed for the complexes. In addition, the complexes have been found to catalyze the amidation of alcohols with amines in the presence of KtBuO–toluene system. The catalyst 3 displayed higher activity in substrates, including phenyl-, pyridine-, furan-, and thiophene-substituted alcohols with primary and secondary amines. The protocol is highly attractive because of easily available starting materials, high atom efficiency and environmental friendliness.
- Selvamurugan, Sellappan,Ramachandran, Rangasamy,Prakash, Govindan,Nirmala, Muthukumaran,Viswanathamurthi, Periasamy,Fujiwara, Shoji,Endo, Akira
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- Method for preparing amide compound from 2-diazo-1, 3-dicarbonyl compound as acylating agent
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The invention provides a method for preparing an amide compound from a 2-diazo-1, 3-dicarbonyl compound as an acylating agent under non-metallic catalysis and neutral conditions. The method uses 2-diazo-1, 3-dicarbonyl compound as a raw material and carries out different benzoyl protection on different amino compounds so that a series of amide compounds are prepared. The method is carried out under neutral conditions, prevents the limitation of reaction substrates under conventional alkaline conditions, and has mild reaction conditions, high reaction efficiency and a simple operation method. The method provides a new and convenient method for preparation of amide compounds and protection of amino groups and can be used in the fields of chemical medicine, biology and materials.
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Paragraph 0052; 0090-0095
(2017/08/28)
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- Synthesis and antifungal activity evaluation of new heterocycle containing amide derivatives
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A series of heterocycle containing amide derivatives (1-28) were synthesised by the combination of acyl chlorides (1a, 2a) and heterocyclic/homocyclic ring containing amines, and their in vitro antifungal activity was evaluated against five plant pathogenic fungi, namely Gibberella zeae, Helminthosporium maydis, Rhizoctonia solani, Botrytis cinerea and Sclerotinia sclerotiorum. Results of antifungal activity analysis indicated that some of the products showed good to excellent antifungal activity, as compound 2 showed excellent activity against G. zeae and R. solani and potent activity against H. maydi, B. cinerea and S. sclerotiorum, and compounds 1, 8 and 10 also displayed excellent antifungal potential against H. maydi, B. cinerea and S. sclerotiorum and good activity against R. solani when compared with the standard carbendazim.
- Wang, Xuesong,Gao, Sumei,Yang, Jian,Gao, Yang,Wang, Ling,Tang, Xiaorong
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p. 682 - 688
(2016/01/28)
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- Ruthenium(II) carbonyl complexes containing bidentate 2-oxo-1,2-dihydroquinoline-3-carbaldehyde hydrazone ligands as efficient catalysts for catalytic amidation reaction
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The coordination behavior of 2-oxo-1,2-dihydroquinoline-3-carbaldehyde hydrazone ligands in ruthenium(II) and the catalytic activity of newly synthesized complexes have been studied. The complexes [RuCl(CO)(PPh3)2(L1)] (1), [RuCl(CO)(AsPh3)2(L1)] (2), [RuCl(CO)(PPh3)2(L2)] (3) and [RuCl(CO)(AsPh3)2(L2)] (4) were synthesized by reactions of [RuHCl(CO)(EPh3)3] (E = P or As) precursors with hydrazone ligands and characterized by analytical and spectroscopic methods. The molecular structure of complex 2 was identified by means of single-crystal X-ray diffraction analysis. The structural analysis revealed that all the complexes possess a distorted octahedral geometry with the ligand coordinating in a uni-negative bidentate NO fashion. Further, the catalytic efficiency of the complexes have been investigated in the case of direct amidation of alcohols with amines. The influence of base, reaction temperature and catalyst loading in the amidation reaction was also evaluated. Notably, complex 3 was found to be very efficient catalyst towards amidation of alcohols with amine. A variety of aromatic (hetero) amines and alcohols with various functional groups have also been successfully used for amidations.
- Selvamurugan, Sellappan,Ramachandran, Rangasamy,Prakash, Govindan,Viswanathamurthi, Periasamy,Malecki, Jan Grzegorz,Endo, Akira
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supporting information
p. 119 - 127
(2015/12/30)
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- Combination of gold and iridium catalysts for the synthesis of N-alkylated amides from nitriles and alcohols
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An alternative and efficient approach for the synthesis of N-alkylated amides from nitriles and alcohols was proposed and accomplished. By the combination of [(IPr)Au(NTf2)] (IPr = 1,3-bis(diisopropylphenyl)imidazol-2-ylidene) and [CpIrCl2]2 (Cp = η5-pentamethylcyclopentadienyl), a series of nitriles were first hydrated to give amides, in which the resulting amides were further N-alkylated with a variety of alcohols as alkylating agents to afford N-alkylated amides with good to excellent yields. Compared with previous methods for the synthesis of N-alkylated amides from nitriles and alcohols as starting materials, this protocol could be accomplished with high atom economy under more environmentally benign conditions.
- Li, Feng,Ma, Juan,Lu, Lei,Bao, Xiaofeng,Tang, Wanying
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p. 1953 - 1960
(2015/04/27)
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- An attractive route to transamidation catalysis: Facile synthesis of new o-aryloxide-N-heterocyclic carbene ruthenium(II) complexes containing trans triphenylphosphine donors
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Well-defined robust ruthenium(II) complexes 3a-d bearing o-aryloxide-N-heterocyclic carbene ligands with different wingtip substituents (3a (R = Me), 3b (R = Ph), 3c (R = iPr) and 3d (R = Mes)) in the imidazole ring were synthesized in good yields by the reaction of imidazolium proligands with metal precursor [RuHCl(CO)(PPh3)3] by transmetallation from the corresponding silver carbene complexes. All the Ru(II)-NHC complexes have been characterized by elemental analyses, spectroscopic methods as well as ESI mass spectrometry. The molecular structure of the complex 3a was identified by means of single-crystal X-ray diffraction analysis, which revealed that the complexes possess a distorted octahedral geometry. In order to explore the catalytic potential of the synthesized complexes, all the four [Ru-NHC] complexes [3a-d] were tested as catalysts for transamidation of carboxamides with amines. Notably, the complex 3a was found to be very efficient and versatile catalyst toward transamidation of a wide range of amides with amines.
- Nirmala, Muthukumaran,Prakash, Govindan,Viswanathamurthi, Periasamy,Malecki, Jan Grzegorz
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- Catalytic chemical amide synthesis at room temperature: One more step toward peptide synthesis
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An efficient method has been developed for direct amide bond synthesis between carboxylic acids and amines via (2-(thiophen-2-ylmethyl)phenyl)boronic acid as a highly active bench-stable catalyst. This catalyst was found to be very effective at room temperature for a large range of substrates with slightly higher temperatures required for challenging ones. This methodology can be applied to aliphatic, α-hydroxyl, aromatic, and heteroaromatic acids as well as primary, secondary, heterocyclic, and even functionalized amines. Notably, N-Boc-protected amino acids were successfully coupled in good yields with very little racemization. An example of catalytic dipeptide synthesis is reported.
- Mohy El Dine, Tharwat,Erb, William,Berhault, Yohann,Rouden, Jacques,Blanchet, Jér?me
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p. 4532 - 4544
(2015/05/13)
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- Imidazolium-supported benzotriazole: an efficient and recoverable activating reagent for amide, ester and thioester bond formation in water
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An efficient and recyclable imidazolium-supported benzotriazole reagent (Im-CH2-BtH) as a novel synthetic auxiliary has been synthesized and its utility as a carboxyl group activating reagent via the formation of stable imidazolium-supported acyl benzotriazoles was explored for the synthesis of amides, esters and thioesters in water under microwave conditions. The reagent was reused five times without any noticeable loss in activity. It is moisture insensitive and highly stable under thermal and aerobic conditions. The application of imidazolium-supported N-acetyl benzotriazole leads to synthesis of paracetamol on the gram scale under greener conditions in 93% yield.
- Shakoor, S.M. Abdul,Choudhary, Sunita,Bajaj, Kiran,Muthyala, Manoj Kumar,Kumar, Anil,Sakhuja, Rajeev
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p. 82199 - 82207
(2015/10/12)
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- Tunable dehydrogenative amidation versus amination using a single ruthenium-NHC catalyst
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Mixed N-heterocyclic carbene (NHC)/phosphine complexes of the type [RuCl(p-cymene)(bimy)(PPh3)]- PF6 (bimy = benzimidazolin-2-ylidene) have been synthesized and fully characterized. Complex 1 bearing the 1,3-dibenzylbenzimidazolin-2-ylidene ligand is able to selectively catalyze both dehydrogenative amidation, mono-, and diamination (N-alkylation) through coupling of simple alcohols with amines effectively yielding a range of amides and secondary and tertiary amines. Selectivity is achieved by controlling the fate of the common hemiaminal intermediate, which in turn can be simply influenced by the choice of base and solvent.
- Xie, Xiaoke,Huynh, Han Vinh
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p. 4143 - 4151
(2015/11/11)
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- Catalyst and method for producing the same
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PROBLEM TO BE SOLVED: To provide a method for producing an amide compound from a primary alcohol and at least one selected from a primary amine, a secondary amine and derivatives of those under relatively mild conditions with high selectivity and a high conversion ratio.SOLUTION: A method for producing an amide compound comprises a step of obtaining the amide compound from a primary alcohol and at least one selected from a primary amine, a secondary amine and derivatives of those, in the presence of a catalyst comprising a carrier formed by crosslinking a crosslinkable functional group of a styrene-based polymer having a side chain containing the crosslinkable functional group, and a nanosize cluster and carbon black supported on the carrier, wherein the nanosize cluster is at least one selected from a nanosize gold cluster and a nanosize cluster of gold and at least one group 8 metal selected from iron, cobalt and nickel.
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Paragraph 0073; 0075; 0078
(2016/11/07)
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- The direct synthesis of N-alkylated amides via a tandem hydration/N-alkylation reaction from nitriles, aldoximes and alcohols
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A novel strategy for the direct synthesis of N-alkylated amides from nitriles, aldoximes and alcohols was proposed and accomplished in the presence of a Cp*Ir complex. This journal is the Partner Organisations 2014.
- Wang, Nana,Zou, Xiaoyuan,Ma, Juan,Li, Feng
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p. 8303 - 8305
(2014/07/22)
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- Semi-catalytic reduction of secondary amides to imines and aldehydes
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Secondary amides can be reduced by silane HSiMe2Ph into imines and aldehydes by a two-stage process involving prior conversion of amides into iminoyl chlorides followed by catalytic reduction mediated by the ruthenium complex [Cp(i-Pr3P)Ru(NCCH3)2]PF6 (1). Alkyl and aryl amides bearing halogen, ketone, and ester groups were converted with moderate to good yields under mild reaction conditions to the corresponding imines and aldehydes. This procedure does not work for substrates bearing the nitro-group and fails for heteroaromatic amides. In the case of cyano substituted amides, the cyano group is reduced to imine.
- Lee, Sun-Hwa,Nikonov, Georgii I.
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supporting information
p. 8888 - 8893
(2014/06/09)
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- METHOD FOR THE CATALYTIC REDUCTION OF ACID CHLORIDES AND IMIDOYL CHLORIDES
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The present application relates to methods for the catalytic reduction of acid chlorides and/or imidoyl chlorides. The methods comprise reacting the acid chloride or imidoyl chloride with a silane reducing agent in the presence of a catalyst such as [Cp(Pri3P)Ru(NCMe)2]+[PF6]?.
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Paragraph 0137
(2014/08/19)
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- N-heterocyclic carbene-catalyzed oxidation of aldehydes for the synthesis of amides via phenolic esters
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N-heterocyclic carbene-catalyzed oxidation using TEMPO is reported for the conversion of aldehydes to amides. A wide range of amides were synthesized in good yields (up to 72%) via a one-pot, sequential protocol involving oxidative esterification of aldehydes and subsequent aminolysis. To promote efficient aminolysis, various alkoxide leaving groups were evaluated.
- Ji, Miran,Lim, Seungyeon,Jang, Hye-Young
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p. 28225 - 28228
(2014/07/22)
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- Benzoic acid-catalyzed transamidation reactions of carboxamides, phthalimide, ureas and thioamide with amines
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An efficient and simple method for the transamidation of carboxamides, phthalimide, ureas and thioamide with amines catalyzed by commercially available benzoic acid under metal-free conditions is described. Furthermore, to the best of our knowledge, this is the first report about the transamidation of an aromatic thioamide with amines.
- Wu, Ji-Wei,Wu, Ya-Dong,Dai, Jian-Jun,Xu, Hua-Jian
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supporting information
p. 2429 - 2436
(2014/09/30)
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- Ruthenium-catalysed oxidation of alcohols to amides using a hydrogen acceptor
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A wider investigation into the synthesis of secondary amides from primary alcohols using a hydrogen acceptor using commercially available [Ru(p-cymene)Cl2]2 with bis(diphenylphosphino)butane (dppb) as the catalyst. The report looks at over 50 examples with varying functionality and steric bulk, whilst also covering the first reported results using microwave heating to effect the transformation.
- Watson, Andrew J.A.,Wakeham, Russell J.,Maxwell, Aoife C.,Williams, Jonathan M.J.
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supporting information
p. 3683 - 3690
(2014/05/20)
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- Sulfated tungstate: A highly efficient catalyst for transamidation of carboxamides with amines
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An environmentally benign protocol for the transamidation of carboxamides with amines using sulfated tungstate, as a heterogeneous catalyst, has been developed. The method has been successfully applied to the synthesis of a wide range of aromatic and aliphatic amides and phthalimides. Efficient transformation, mild reaction conditions, easy product isolation and the potential reusability of the catalyst are attractive features.
- Pathare, Sagar P.,Jain, Ashish Kumar H.,Akamanchi, Krishnacharya G.
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p. 7697 - 7703
(2013/06/27)
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- A simple base-mediated amidation of aldehydes with azides
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A practical and efficient amidation reaction involving aromatic aldehydes and various azides under mild conditions is described. A broad spectrum of functional groups was tolerated, and the amides were synthesized in moderate to excellent yields, presenting an attractive alternative to the currently available synthetic methods.
- Kulkarni, Sameer S.,Hu, Xiangdong,Manetsch, Roman
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supporting information
p. 1193 - 1195
(2013/03/13)
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- Synthesis and research of benzylamides of some isocyclic and heterocyclic acids as potential anticonvulsants
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A series of benzylamides of isocyclic and heterocyclic acids was synthesized and tested in Anticonvulsant Screening Project (ASP) of Antiepileptic Drug Development Program (ADDP) of NIH. Near all synthesized derivatives of heterocyclic acids showed activity. All obtained derivatives of mono- and bicyclic isocyclic acids were inactive. The power of action of heterocyclic acids derivatives seems does not depend upon kind of heteroatom (N, O or S). One of the compounds (2-furoic acid benzylamide (4)) appeared most promising. It showed in minimal clonic seizure (6Hz) test (ASP) in rats after i. p. administration: MES ED50 = 36.5 mg/kg, TOX TD50 = 269.75 mg/kg, and PI = 7.39.
- Strupinska, Marzanna,Rostafinska-Suchar, Grazyna,Pirianowicz-Chaber, Elzbieta,Stables, James P.,Jiang, Jeff,Paruszewski, Ryszard
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p. 681 - 686
(2013/10/01)
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- Direct amidation from alcohols and amines through a tandem oxidation process catalyzed by heterogeneous-polymer-incarcerated gold nanoparticles under aerobic conditions
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We describe herein a highly elegant and suitable synthesis of amide products from alcohols and amines through a tandem oxidation process that uses molecular oxygen as a terminal oxidant. Carbon-black-stabilized polymer-incarcerated gold (PICB-Au) or gold/cobalt (PICB-Au/Co) nanoparticles were employed as an efficient heterogeneous catalyst depending on alcohol reactivity and generated only water as the major co-product of the reaction. A wide scope of substrate applicability was shown with 42 examples. The catalysts could be recovered and reused without loss of activity by using a simple operation. Gold standard: A highly efficient green method for amide synthesis from alcohols and amines catalyzed by gold nanoparticles stabilized by styrene-based copolymers has been developed (see scheme). Two catalysts have been used with high selectivity depending on the combination of substrates. These Au nanoparticle catalysts can be recovered and reused several times by simple operations. Copyright
- Soule, Jean-Francois,Miyamura, Hiroyuki,Kobayashi, Shu
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supporting information
p. 2614 - 2626
(2013/11/19)
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- A general and selective copper-catalyzed reduction of secondary amides
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In situ-generated cationic copper/pybox catalyst systems allow for the selective reduction of secondary amides into the corresponding amines under mild conditions. This novel protocol has a wide substrate scope and shows good functional group tolerance. The Royal Society of Chemistry 2012.
- Das, Shoubhik,Join, Benoit,Junge, Kathrin,Beller, Matthias
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supporting information; experimental part
p. 2683 - 2685
(2012/04/04)
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- Dehydrogenative amide synthesis: Azide as a nitrogen source
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A new atom-economical strategy to amide linkage from an azide and alcohol liberating hydrogen and nitrogen was developed with an in situ generated ruthenium catalytic system. The reaction has broad substrate generality including diols for the synthesis of cyclic imides.
- Fu, Zhenqian,Lee, Jeongbin,Kang, Byungjoon,Hong, Soon Hyeok
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supporting information
p. 6028 - 6031
(2013/02/22)
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- Titanium(IV) isopropoxide as an efficient catalyst for direct amidation of nonactivated carboxylic acids
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Secondary and tertiary amides are formed in high yields, in an efficient and environmentally benign titanium(IV) isopropoxide catalyzed direct amidation of carboxylic acids with primary and secondary amines. Georg Thieme Verlag Stuttgart ? New York.
- Lundberg, Helena,Tinnis, Fredrik,Adolfsson, Hans
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supporting information
p. 2201 - 2204
(2012/10/30)
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- Direct amidation of carboxylic acids catalyzed by ortho-iodo arylboronic acids: Catalyst optimization, scope, and preliminary mechanistic study supporting a peculiar halogen acceleration effect
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The importance of amides as a component of biomolecules and synthetic products motivates the development of catalytic, direct amidation methods employing free carboxylic acids and amines that circumvent the need for stoichiometric activation or coupling reagents. ortho-Iodophenylboronic acid 4a has recently been shown to catalyze direct amidation reactions at room temperature in the presence of 4A molecular sieves as dehydrating agent. Herein, the arene core of ortho-iodoarylboronic acid catalysts has been optimized with regards to the electronic effects of ring substitution. Contrary to the expectation, it was found that electron-donating substituents are preferable, in particular, an alkoxy substituent positioned para to the iodide. The optimal new catalyst, 5-methoxy-2-iodophenylboronic acid (MIBA, 4f), was demonstrated to be kinetically more active than the parent des-methoxy catalyst 4a, providing higher yields of amide products in shorter reaction times under mild conditions at ambient temperature. Catalyst 4f is recyclable and promotes the formation of amides from aliphatic carboxylic acids and amines, and from heteroaromatic carboxylic acids and other functionalized substrates containing moieties like a free phenol, indole and pyridine. Mechanistic studies demonstrated the essential role of molecular sieves in this complex amidation process. The effect of substrate stoichiometry, concentration, and measurement of the catalyst order led to a possible catalytic cycle based on the presumed formation of an acylborate intermediate. The need for an electronically enriched ortho-iodo substituent in catalyst 4f supports a recent theoretical study (Marcelli, T. Angew. Chem. Int. Ed.2010, 49, 6840-6843) with a purported role for the iodide as a hydrogen-bond acceptor in the orthoaminal transition state.
- Gernigon, Nicolas,Al-Zoubi, Raed M.,Hall, Dennis G.
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p. 8386 - 8400,15
(2012/12/11)
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- Direct amidation of carboxylic acids catalyzed by ortho-iodo arylboronic acids: Catalyst optimization, scope, and preliminary mechanistic study supporting a peculiar halogen acceleration effect
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The importance of amides as a component of biomolecules and synthetic products motivates the development of catalytic, direct amidation methods employing free carboxylic acids and amines that circumvent the need for stoichiometric activation or coupling reagents. ortho-Iodophenylboronic acid 4a has recently been shown to catalyze direct amidation reactions at room temperature in the presence of 4A molecular sieves as dehydrating agent. Herein, the arene core of ortho-iodoarylboronic acid catalysts has been optimized with regards to the electronic effects of ring substitution. Contrary to the expectation, it was found that electron-donating substituents are preferable, in particular, an alkoxy substituent positioned para to the iodide. The optimal new catalyst, 5-methoxy-2-iodophenylboronic acid (MIBA, 4f), was demonstrated to be kinetically more active than the parent des-methoxy catalyst 4a, providing higher yields of amide products in shorter reaction times under mild conditions at ambient temperature. Catalyst 4f is recyclable and promotes the formation of amides from aliphatic carboxylic acids and amines, and from heteroaromatic carboxylic acids and other functionalized substrates containing moieties like a free phenol, indole and pyridine. Mechanistic studies demonstrated the essential role of molecular sieves in this complex amidation process. The effect of substrate stoichiometry, concentration, and measurement of the catalyst order led to a possible catalytic cycle based on the presumed formation of an acylborate intermediate. The need for an electronically enriched ortho-iodo substituent in catalyst 4f supports a recent theoretical study (Marcelli, T. Angew. Chem. Int. Ed.2010, 49, 6840-6843) with a purported role for the iodide as a hydrogen-bond acceptor in the orthoaminal transition state.
- Gernigon, Nicolas,Al-Zoubi, Raed M.,Hall, Dennis G.
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p. 8386 - 8400
(2013/01/15)
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- BORONIC ACID CATALYSTS AND METHODS OF USE THEREOF FOR ACTIVATION AND TRANSFORMATION OF CARBOXYLIC ACIDS
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The present application provides methods and catalysts for activation of carboxylic acids for organic reactions. In particular, methods are disclosed for direct nucleophilic addition reactions, such as, amidation reactions with amines, cycloadditions, and conjugate additions, using boronic acid catalysts of formula I, II or III: Also included are novel boronic acid catalysts of formula IV, V and III:
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Page/Page column 57
(2012/09/10)
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- Palladium-catalyzed direct arylations of five-membered heteroarenes bearing N-monoalkylcarboxamide substituents
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The palladium-catalyzed direct arylation of furan, thiophene, pyrrole, or pyrazole derivatives bearing CONHR substituents on C2, C3, or C5 with aryl bromides was studied. The use of KOAc as the base, DMAc as the solvent, and PdCl(C3H5)(dppb) as the catalyst was found to give regioselectively and without decarbamoylation the arylated heteroaromatics. Under these conditions, the amide substituent on the heteroaromatic does not act as a directing group. A wide range of functional groups such as acetyl, formyl, ester, nitrile, trifluoromethyl, and fluoro on the aryl bromide is tolerated. The palladium-catalyzed direct arylation of furan, thiophene, pyrrole, or pyrazole derivatives bearing CONHR substituents on C2, C3, or C5 with aryl bromides was studied. The use of KOAc as the base, DMAc as the solvent, and PdCl(C3H5)(dppb) as the catalyst was found to give regioselectively the arylated heteroaromatics.
- Laidaoui, Nouria,Roger, Julien,Miloudi, Abdellah,El Abed, Douniazad,Doucet, Henri
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experimental part
p. 4373 - 4385
(2011/10/09)
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- Powerful amide synthesis from alcohols and amines under aerobic conditions catalyzed by gold or gold/iron, -nickel or-cobalt nanoparticles
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Considering the importance of the development of powerful green catalysts and the omnipresence of amide bonds in natural and synthetic compounds, we report here on reactions between alcohols and amines for amide bond formation in which heterogeneous gold and gold/iron, -nickel, or-cobalt nanoparticles are used as catalysts and molecular oxygen is used as terminal oxidant. Two catalysts show excellent activity and selectivity, depending on the type of alcohols used. A wide variety of alcohols and amines, including aqueous ammonia and amino acids, can be used for the amide synthesis. Furthermore, the catalysts can be recovered and reused several times without loss of activity.
- Soule, Jean-Francois,Miyamura, Hiroyuki,Kobayashi, Shu
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supporting information; experimental part
p. 18550 - 18553
(2012/01/06)
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- N-heterocyclic carbene based ruthenium-catalyzed direct amide synthesis from alcohols and secondary amines: Involvement of esters
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A well-defined N-heterocyclic carbene based ruthenium complex was developed as a highly active precatalyst for the direct amide synthesis from alcohols and secondary amines. Notably, reaction of 1-hexanol and dibenzylamine afforded 60% of the corresponding amide using our catalytic system, while no amide formation was observed for this reaction with the previously reported catalytic systems. Unlike the previously reported amidation with less sterically hindered alcohols and amines, involvement of ester intermediates was observed (Figure presented).
- Chen, Cheng,Zhang, Yao,Hong, Soon Hyeok
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experimental part
p. 10005 - 10010
(2012/02/05)
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- Solvent-free protocol for amide bond formation via trapping of nascent phosphazenes with carboxylic acids
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A solvent-free synthesis of amides via the coupling of phosphazenes with carboxylic acids is reported. Increasing the rate of heating either by microwave irradiation or conventional heating results in multifold increase in the rate of amide bond formation. Synthesis of a library of amides including a potent antitumour candidate has been accomplished.
- Sathishkumar, Murugan,Shanmugavelan, Poovan,Nagarajan, Sangaraiah,Maheswari, Murugesan,Dinesh, Murugan,Ponnuswamy, Alagusundaram
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p. 2830 - 2833
(2011/06/23)
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