- Cobalt catalysed aminocarbonylation of thiols in batch and flow for the preparation of amides
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The synthesis of amides from thiols through a cobalt-catalyzed aminocarbonylation is shown. After optimizing all the reaction parameters, the methodology makes possible the obtention of amides with variable yields, while competing reactions such as the formation of disulfides and ureas can be limited. The process works well with aromatic thiols with electron donating groups (EDG) whereas other thiols give reaction with lower yields. The previous process has been transferred and optimized into flow equipment, thus allowing using less CO in a safer way, and permitting the scaling up of the synthesis. Two drugs, moclobemide and itopride were prepared with this methodology, albeit only in the second case with good results. A mechanistic pathway is proposed.
- Domínguez, Gema,Ordu?a, Jose Maria,Pérez-Castells, Javier
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p. 30398 - 30406
(2021/10/20)
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- Half-Sandwich Ruthenium Complexes Bearing Hemilabile κ2-(C,S)?Thioether-Functionalized NHC Ligands: Application to Amide Synthesis from Alcohol and Amine
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Amide synthesis is one of the most crucial transformations in chemistry and biology. Among various catalytic systems, N-heterocyclic carbene (NHC)-based ruthenium (Ru) catalyst systems have been proven to be active for direct synthesis of amides by sustainable acceptorless dehydrogenative Coupling of primary alcohols with amines. Most often, these catalytic systems usually use monodentate NHC and thus require an additional ligand to obtain high reactivity and selectivity. In this work, a series of cationic Ru(II)(η6-p-cymene) complexes with thioether-functionalized N-heterocyclic carbene ligands (imidazole and benzimidazole-based) have been prepared and fully characterized. These complexes have then been used in the amidation reaction and the most promising one (i. e. 3 c) has been applied on a large range of substrates. High conversions albeit with moderate yields have generally been obtained.
- Achard, Thierry,Bellemin-Laponnaz, Stéphane,Chen, Weighang,Egly, Julien,Maisse-Fran?ois, Aline
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supporting information
(2022/01/20)
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- The synthesis and structure of pyridine-oxadiazole iridium complexes and catalytic applications: Non-coordinating-anion-tuned selective C–N bond formation
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Several novel pyridine-oxadiazole iridium complexes were synthesized and characterized through X-ray crystallography. The designed iridium complexes revealed surprisingly high catalytic activity in C–N bondformation of amides and benzyl alcohols with the assistance of non-coordinating anions. In an attempt to achieve borrowing hydrogen reactions of amides with benzyl alcohols, N,N'-(phenylmethylene)dibenzamide products were unexpectedly isolated under non-coordinating anion conditions, whereas N-benzylbenzamide products were achieved in the absence of non-coordinating anions. The mechanism explorations excluded the possibility of “silver effect” (silver-assisted or bimetallic catalysis) and revealed that the reactivity of iridium catalyst was varied by non-coordinating anions. This work provided a convenient and useful methodology that allowed the iridium complex to be a chemoselective catalyst and demonstrated the first example of non-coordinating-anion-tuned selective C–N bond formation
- Yao, Wei,Zhang, Yilin,Zhu, Haiyan,Ge, Chenyang,Wang, Dawei
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p. 701 - 705
(2019/09/30)
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- Reductive Amidation without an External Hydrogen Source Using Rhodium on Carbon Matrix as a Catalyst
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An efficient method for preparation of secondary amides from primary amides and aldehydes using rhodium on carbon matrix as catalyst was developed. The method does not require any external hydrogen source and carbon monoxide is used as a reducing agent. The most active rhodium catalysts were characterized by BET, TEM and XPS techniques. Unexpectedly, it was found that heterogeneous rhodium on carbon matrix works as precatalyst for homogenous active species due to leaching of rhodium to the solution. Various secondary amides were synthesized and checked for antifungal activity. 4-Methoxy-N-(4-methoxybenzyl)benzamide demonstrated promising activity against Rhizoctonia Solani.
- Tsygankov, Alexey A.,Makarova, Maria,Afanasyev, Oleg I.,Kashin, Alexey S.,Naumkin, Alexander V.,Loginov, Dmitry A.,Chusov, Denis
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p. 112 - 117
(2019/11/28)
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- Visible light-promoted self-coupling of N-chloramines at room temperature: A metal-free access to substituted amides
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An efficient protocol to synthesize substituted amides via self-coupling of N-chlorobenzylamines has been developed under visible light-promoted mild condition. Both the electron-deficient and electron-rich benzylamines undergo self-coupling very readily to produce the amide linkage under given reaction conditions.
- Chaubey, Narendra R.
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supporting information
p. 3546 - 3552
(2019/11/14)
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- Direct Synthesis of Amides by Acceptorless Dehydrogenative Coupling of Benzyl Alcohols and Ammonia Catalyzed by a Manganese Pincer Complex: Unexpected Crucial Role of Base
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Amide synthesis is one of the most important transformations in chemistry and biology. The direct use of ammonia for the incorporation of nitrogen functionalities in organic molecules is an attractive and environmentally benign method. We present here a new synthesis of amides by acceptorless dehydrogenative coupling of benzyl alcohols and ammonia. The reaction is catalyzed by a pincer complex of earth-abundant manganese in the presence of a stoichiometric base, making the overall process economical, efficient, and sustainable. Interesting mechanistic insights based on detailed experimental observations, indicating the crucial role of the base, are provided.
- Daw, Prosenjit,Kumar, Amit,Espinosa-Jalapa, Noel Angel,Ben-David, Yehoshoa,Milstein, David
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supporting information
p. 12202 - 12206
(2019/08/20)
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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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- Ruthenium-Catalyzed Reductive Amidation without an External Hydrogen Source
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A catalytic reaction between aldehydes and primary amides that leads to N-alkylated amides was investigated. The developed protocol employs carbon monoxide as a deoxygenative agent and, therefore, avoids the use of an external hydrogen source. Cyclopentad
- Yagafarov, Niyaz Z.,Muratov, Karim M.,Biriukov, Klim,Usanov, Dmitry L.,Chusova, Olga,Perekalin, Dmitry S.,Chusov, Denis
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supporting information
p. 557 - 563
(2018/02/09)
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- Palladium-Catalyzed Oxidative Carbonylation of Aryl Hydrazines with CO and O2 at Atmospheric Pressure
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Palladium-catalyzed aerobic oxidative aminocarbonylation and alkoxycarbonylation reactions with aryl hydrazines as coupling partners have been developed. The oxidative carbonylation of aryl hydrazines proceeded smoothly at atmospheric pressure CO, employi
- Tu, Yongliang,Yuan, Lin,Wang, Tao,Wang, Changliu,Ke, Jiamei,Zhao, Junfeng
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p. 4970 - 4976
(2017/05/12)
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- Green and environment-friendly method for synthesizing amide bonds
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The invention provides a green and environment-friendly method for synthesizing amide bonds. The green and environment-friendly method includes forming C-Pd bonds from aryl hydrazine compounds under the oxidation effects of oxygen by the aid of palladium catalysts by means of oxidation hydrazine removal; carrying out carbonyl insertion reaction on the C-Pd bonds and carbon monoxide gas to generate palladium acyl species; feeding primary or secondary amine into palladium acyl and then carrying out reductive elimination to obtain a final product amide. The primary or secondary amine is used as a nucleophilic reagent. The green and environment-friendly method has the advantages that palladium catalytic carboamidation reaction is carried out on the aryl hydrazine compounds, normal-pressure CO is used as a carbonyl source for synthesizing the amide, and byproducts are nitrogen and water which are environmentally friendly; the green and environment-friendly method is novel and environmentally friendly, is high in efficiency and has great potential application value.
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Paragraph 0073; 0074; 0075; 0076; 0077; 0078; 0079-0081
(2017/07/01)
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- Environment-friendly amido bond synthesis method
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The invention discloses an environment-friendly amido bond synthesis method, which comprises the following steps: oxidizing an aryl hydrazine compound with O2 to form a C-Pd bond by taking Pd(OAc)2 as a catalyst and taking PPh3 as a ligand, inserting CO to a carbon-palladium bond to form an acyl palladium species as a carbonyl source, attacking carbonyl palladium by virtue of amine as a nucleophilic reagent, and performing reductive elimination to obtain a final product amide. According to the method, synthesis of the amide from the hydrazine compound is implemented by adopting CO as the carbonyl source by virtue of a carbonyl insertion method, and a byproduct does not comprise excessive pollutants such as haloid acid, so that the potential application value can be better achieved.
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Paragraph 0048; 0049; 0050; 0051; 0052
(2017/01/02)
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- Synthesis of imides and benzoylureas by direct oxidation of N-methylenes of amides and benzylureas
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Some amides and benzylureas can be oxidised to imides and benzoylureas, respectively, using silver(I) nitrate (20 mol %), copper(II) sulfate pentahydrate (20 mol %), ammonium persulfate (3.0 equiv.), and potassium fluoride (20 equiv.) in water at room temperature.
- Huang, Wenhua,Xu, Mei-Li
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- Microwave-assisted carbonylation and cyclocarbonylation of aryl iodides under ligand free heterogeneous catalysis
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"Chemical Equation Presented" Carbonylation reaction is a very effective transformation for the synthesis of esters, amides, and heterocyclic compounds. Heterogeneous catalyzed carbonylation reactions can be carried out using the association of Pd/C and microwave dielectric heating. Alkoxy carbonylation can be performed, with stoichiometric amounts of different primary and secondary alcohols in DMF in the presence of DBU as the base. Analogously, iodobenzene, CO, and amines can be transformed into the corresponding amides in good yields after a simple filtration to remove the catalyst. Pd/C was also successfully employed in microwave-assisted cyclocarbonylation of o-iodoaniline with acyl chlorides to give benzoxazinones. Pd/ C can be recycled two times without, a considerable difference in the reaction yields.
- Salvadori, Jessica,Balducci, Evita,Zaza, Silvia,Petricci, Elena,Taddei, Maurizio
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experimental part
p. 1841 - 1847
(2010/06/11)
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