- Enantioselective Synthesis of α-Aryl-β2-Amino-Esters by Cooperative Isothiourea and Br?nsted Acid Catalysis
-
The synthesis of α-aryl-β2-amino esters through enantioselective aminomethylation of an arylacetic acid ester in high yields and enantioselectivity via cooperative isothiourea and Br?nsted acid catalysis is demonstrated. The scope and limitatio
- Zhao, Feng,Shu, Chang,Young, Claire M.,Carpenter-Warren, Cameron,Slawin, Alexandra M. Z.,Smith, Andrew D.
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p. 11892 - 11900
(2021/04/28)
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- Method for preparing amide compounds through ionic liquid catalysis in high-pressure environment
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The invention relates to a method for preparing amide compounds through ionic liquid catalysis in a high-pressure environment. According to the method, ionic liquid 1-ethyl-3-methylimidazolium acetateis used as a catalyst and a solvent, oxygen is used as an oxidizing agent, and aromatic methanol or alkyl alcohol is converted into an amide compound under the conditions of high pressure and heating. The synthesis method provided by the invention has the advantages that the raw material and technical cost is low; compared with other traditional methods, the method is safe, low in toxicity, economical and environmentally friendly; and the method has few steps, is simple and convenient to operate, is beneficial to large-scale synthesis, and has important significance for synthesis of amide compounds and large-scale industrialization of preparation.
- -
-
Paragraph 0079-0082
(2021/01/24)
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- Efficient and accessible silane-mediated direct amide coupling of carboxylic acids and amines
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A straightforward method for the direct synthesis of amides from amines and carboxylic acids without exclusion of air or moisture using diphenylsilane with N-methylpyrrolidine has been developed. Various amides are made efficiently, and broad functional group compatibility is shown through a Glorius robustness study. A gram-scale synthesis demonstrates the scalability of this method. This journal is
- D'Amaral, Melissa C.,Jamkhou, Nick,Adler, Marc J.
-
supporting information
p. 288 - 295
(2021/01/28)
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- Ni-Catalyzed Regiodivergent and Stereoselective Hydroalkylation of Acyclic Branched Dienes with Unstabilized C(sp3) Nucleophiles
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Two complementary regiodivergent [(P,N)Ni]-catalyzed hydroalkylations of branched dienes are reported. When amides are employed as unstabilized C(sp3) nucleophiles, a highly regioselective 1,4-addition process is favored. The addition products are obtained in high yield and with excellent stereocontrol of the internal olefin. With use of a chiral ligand and imides as carbon nucleophiles, a 3,4-addition protocol was developed, enabling construction of two contiguous tertiary stereocenters in a single step with moderate to high levels of diastereocontrol and excellent enantiocontrol. Both methods operate under mild reaction conditions, display a broad scope, and show excellent functional group tolerance. The synthetic potential of the 3,4-hydroalkylation reaction was established via a series of postcatalytic modifications.
- Shao, Wen,Besnard, Céline,Guénée, Laure,Mazet, Clément
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p. 16486 - 16492
(2020/10/26)
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- Direct amide formation in a continuous-flow system mediated by carbon disulfide
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Amide bonds are ubiquitous in nature. They can be found in proteins, peptides, alkaloids, etc. and they are used in various synthetic drugs too. Amide bonds are mainly made by the use of (i) hazardous carboxylic acid derivatives or (ii) expensive coupling agents. Both ways make the synthetic technology less atom economic. We report a direct flow-based synthesis of amides. The developed approach is prominently simple and various aliphatic and aromatic amides were synthetized with excellent yields. The reaction in itself is carried out in acetonitrile, which is considered as a less problematic dipolar aprotic solvent. The used coupling agent, carbon disulfide, is widely available and has a low price. The utilized heterogeneous Lewis acid, alumina, is a sustainable material and it can be utilized multiple times. The technology is considerably robust and shows excellent reusability and easy scale-up is carried out without the need of any intensive purification protocols.
- Orsy, Gy?rgy,Fül?p, Ferenc,Mándity, István M.
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p. 7814 - 7818
(2020/12/28)
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- A Tripeptide Approach to the Solid-Phase Synthesis of Peptide Thioacids and N-Glycopeptides
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A general and robust method for the incorporation of aspartates with a thioacid side chain into peptides has been developed. Pseudoproline tripeptides served as building blocks for the efficient fluorenylmethyloxycarbonyl (Fmoc) solid-phase synthesis of t
- Sch?we, Markus Julian,Keiper, Odin,Unverzagt, Carlo,Wittmann, Valentin
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p. 15759 - 15764
(2019/11/19)
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- Ruthenium-Catalyzed Oxidative Amidation of Alkynes to Amides
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Complex CpRuCl(PPh3)2 catalyzes reactions of terminal alkynes with 4-picoline N-oxide and primary and secondary amines to afford the corresponding amides. The reactions occur in chlorinated solvent and aqueous medium, showing applications in peptide chemistry. Stoichiometric studies reveal that the true catalysts of the processes are the vinylidene cations [CpRu(=C=CHR)(PPh3)2]+ which are oxidized to the Ru(η2-CO)-ketenes by the N-oxide. Finally, nucleophilic additions of primary and secondary amines to the free ketenes yield the corresponding amides.
- álvarez-Pérez, Andrea,Esteruelas, Miguel A.,Izquierdo, Susana,Varela, Jesús A.,Saá, Carlos
-
supporting information
p. 5346 - 5350
(2019/07/08)
-
- Preparation method of dexmethylphenidate
-
The invention relates to a new synthetic route of dexmethylphenidate. Methyl phenylacetate serves as a raw material, and the dexmethylphenidate is synthesized at high yield through four steps of an amidation reaction, a diazotization reaction, a cyclization reaction and a rearrangement reaction. The preparation method of the dexmethylphenidate is high in yield, low in cost, environmentally friendly, easy to operate and suitable for industrialization.
- -
-
Paragraph 0022; 0025-0027
(2019/10/01)
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- Air-stable Bis(pentamethylcyclopentadienyl) Zirconium Perfluorooctanesulfonate as an Efficient and Recyclable Catalyst for the Synthesis of N-substituted Amides
-
Bis(pentamethylcyclopentadienyl) zirconium perfluorooctanesulfonate is an air-stable and water-tolerant Lewis acid. This complex exhibited good thermal stability and high solubility in polar organic solvents. The compound showed relatively strong acidity, with an acid strength of 0.8Ho≤3.3, and high catalytic efficiency for the synthesis of N-substituted amides via the reaction of carboxylic acids with amines, the Ritter reaction of nitriles with alcohols, and the amination of alcohols with amides. Moreover, the complex had good reusability. This catalytic system affords a simple and efficient way to synthesize N-substituted amides.
- Li, Ningbo,Wang, Lingxiao,Zhang, Liting,Zhao, Wenjie,Qiao, Jie,Xu, Xinhua,Liang, Zhiwu
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p. 3532 - 3538
(2018/08/01)
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- Repurposing n-butyl stannoic acid as highly efficient catalyst for direct amidation of carboxylic acids with amines
-
This is the first-time report on the repurposing n-butyl stannoic acid as a catalyst for direct amidation of carboxylic acids with amines. Notably, efficient amidation observed in comparison with all other catalytic methods reported up until now. The protocol has successfully applied to the synthesis of a variety of amides. Moderate reaction parameters, clean amidation with excellent yields of desired amides, ability to tolerate a variety of functional groups, easy product isolation; commercial availability and recyclability of the catalyst are key advantages of the current protocol.
- Potadar, Santoshkumar M.,Mali, Anil S.,Waghmode, Krishnakant T.,Chaturbhuj, Ganesh U.
-
supporting information
p. 4582 - 4586
(2018/11/27)
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- 4-Phenyl quinoline derivatives as potential serotonin receptor ligands with antiproliferative activity
-
Antagonists of signaling receptors are often effective non-toxic therapeutic agents. Over the years, there have been evidences describing the role of serotonin or 5-hydroxytryptamine (5-HT) in development of cancer. Although there are reports on the antip
- Joshi, Pranaya V.,Sayed, Alim A.,RaviKumar, Ameeta,Puranik, Vedavati G.,Zinjarde, Smita S.
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p. 246 - 258
(2017/05/12)
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- An Efficient One–pot Procedure for the Direct Preparation of 4,5-Dihydroisoxazoles from Amides
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A Mo(CO)6 (molybdenumhexacarbonyl) catalyzed reductive functionalization of amides to afford 5-amino substituted 4,5-dihydroisoxazoles is presented. The reduction of amides generates reactive enamines, which upon the addition of hydroximinoyl chlorides and base undergoes a 1,3-dipolar cycloaddition reaction that gives access to the desired heterocyclic compounds. The transformation of amides is highly chemoselective and tolerates functional groups such as nitro, nitriles, esters, and ketones. Furthermore, a versatile scope of 4,5-dihydroisoxazoles derived from a variety of hydroximinoyl chlorides and amides is demonstrated. (Figure presented.).
- Slagbrand, Tove,Kervefors, Gabriella,Tinnis, Fredrik,Adolfsson, Hans
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supporting information
p. 1990 - 1995
(2017/06/09)
-
- Facile preparation of pyrimidinediones and thioacrylamides: Via reductive functionalization of amides
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The development of an efficient protocol for the reductive functionalization of amides into pyrimidinediones and amino-substituted thioacrylamides is presented. Enamines are generated in a highly chemoselective amide hydrosilylation reaction catalyzed by
- Trillo, Paz,Slagbrand, Tove,Tinnis, Fredrik,Adolfsson, Hans
-
supporting information
p. 9159 - 9162
(2017/08/17)
-
- Diphenylsilane as a coupling reagent for amide bond formation
-
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.
-
supporting information
p. 5060 - 5064
(2017/11/09)
-
- Metal–Organic Framework Based on Copper and Carboxylate-Imidazole as Robust and Effective Catalyst in the Oxidative Amidation of Carboxylic Acids and Formamides
-
A metal–organic framework (MOF) based on copper and 1,3-bis(carboxymethyl)imidazole (bcmim) was prepared on a gram scale by using a precipitation method at room temperature. The Cu(bcmim)2MOF was shown to be an efficient catalyst for the preparation of amides through an oxidative coupling between carboxylic acids and formamides in the presence of an oxidant, such as tert-butyl hydroperoxide (TBHP). The method for the preparation of the amides is robust regardless of the carboxylic acid and gives good conversions with good selectivity. The heterogeneous catalyst was recovered unaltered after the reaction, was easily separated from the reaction mixture, and subsequently reactivated by suitable treatment. Moreover, the coupling reaction was scaled up to a gram scale, which allowed for the preparation of valuable products, such as fatty acid amides (i.e., 1-palmitoylpiperidine).
- Albert-Soriano, María,Pastor, Isidro M.
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supporting information
p. 5180 - 5188
(2016/10/26)
-
- Design and synthesis of ruthenium(II) OCO pincer type NHC complexes and their catalytic role towards the synthesis of amides
-
The present contribution describes the synthesis and characterization of a family of robust ruthenium complexes, supported by a tridentate pincer ligand of the type bis-phenolate-N-heterocyclic carbene [ tBu(OCO) 2-] (NHC). Ruthenium(II) complexes (1-3) bearing bis-phenolate-N-heterocyclic carbene ligand were synthesized in good yields by the reaction of imidazolinium proligand (HL) with metal precursors [RuHCl(CO)(EPh3)2(B)] (E = P or As; B = PPh3, AsPh3 or Py) by transmetalation from the corresponding silver carbene complex. All the Ru(II)-NHC complexes have been characterized by elemental analyses, spectroscopic methods as well as ESI mass spectrometry. Based on the spectral results, an octahedral geometry was assigned for all the complexes. The tridentate nature of the tBu(OCO) 2- ligand as well as some level of steric protection provided by the t Bu groups may rationalize the excellent stability of the Ru-Ccarbene bond in the present systems. Moreover, for the explorations of catalytic potential of the synthesized compounds, all the three [Ru-NHC] complexes (1-3) were tested as catalysts for amidation of alcohols with amines. Notably, the complex 1 was found to be very efficient and versatile catalyst towards amidation of a wide range of alcohols with amines. [Figure not available: see fulltext.].
- Nirmala, Muthukumaran,Viswanathamurthi, Periasamy
-
-
- Chelating Bis(1,2,3-triazol-5-ylidene) Rhodium Complexes: Versatile Catalysts for Hydrosilylation Reactions
-
NHC-rhodium complexes (NHC=N-heterocyclic carbenes) have been widely used as efficient catalysts for hydrosilylation reactions. However, the substrates were mostly limited to reactive carbonyl compounds (aldehydes and ketones) or carbon-carbon multiple bonds. Here, we describe the application of newly-developed chelating bis(tzNHC)-rhodium complexes (tz=1,2,3-triazol-5-ylidene) for several reductive transformations. With these catalysts, the formal reductive methylation of amines using carbon dioxide, the hydrosilylation of amides and carboxylic acids, and the reductive alkylation of amines using carboxylic acids have been achieved under mild reaction conditions.
- Nguyen, Thanh V. Q.,Yoo, Woo-Jin,Kobayashi, Shu
-
supporting information
p. 452 - 458
(2016/02/12)
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- Sequential substitution/ring cleavage/addition reaction of 1-(cyclohex-1-enyl)-piperidine and -pyrrolidine with chloropyruvates for the efficient synthesis of substituted 4,5,6,7-tetrahydro-1H-indole derivatives
-
Sequential substitution/ring cleavage/addition reaction of 1-(cyclohex-1-enyl)-piperidine and -pyrrolidine with chloropyruvates has been accomplished for the synthesis of various polysubstituted 4,5,6,7-tetrahydroindoles. This one-pot, general and highly regioselective method avoids harsh conditions and expensive catalysts. It proceeds with high atom-efficiency and shows a broad substrate scope and functional group tolerance, making it a highly practical approach for the preparation of various tetrahydroindole derivatives. A family of 17 tetrahydroindoles was synthesized in good yields, which is indicative of the general character of this reaction. 10 of the tetrahydroindole derivatives with various substituents were successfully transformed into the corresponding indoles. This methodology allows access to indoles bearing ω-halo- (mostly chloro-)butyl and pentyl substituents at the nitrogen atom (by variation of enamines) and at the C2, C3 positions (by variation of pyruvates, including bromoaryl and chloroalkyl derivatives). The reaction can be used in conjunction with enamine synthesis offering a practical three-component heteroannulation methodology to produce 4,5,6,7-tetrahydroindoles from cyclohexanone, pyrrolidine and arylchloropyruvates.
- Mamedov, Vakhid A.,Hafizova, Elena A.,Zamaletdinova, Anastasiya I.,Rizvanov, Il'dar Kh.,Mirgorodskaya, Alla B.,Zakharova, Lucia Ya.,Latypov, Shamil K.,Sinyashin, Oleg G.
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p. 9143 - 9153
(2015/11/09)
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- N-Heterocyclic carbene-based well-defined ruthenium hydride complexes for direct amide synthesis from alcohols and amines under base-free conditions
-
Readily synthesized, well-defined N-heterocyclic carbene-based ruthenium(II) hydride complexes were developed for amide synthesis from alcohols and amines under base-free conditions. Diverse amides were synthesized in fair-to-excellent yields. In the case of secondary amines, where direct dehydrogenative amidation is not feasible, a catalytic amount of a base was required to promote the transamidation of esters, which are byproducts of alcohol dimerization.
- Kim, Kunsoon,Kang, Byungjoon,Hong, Soon Hyeok
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p. 4565 - 4569
(2015/06/08)
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- Ammonium nitrate: A biodegradable and efficient catalyst for the direct amidation of esters under solvent-free conditions
-
A simple, metal-free, and environment-friendly procedure is developed for the direct conversion of esters to amides using ammonium nitrate as a catalyst under solvent-free conditions. Aryls, heteroaryls, and aliphatic esters are easily converted to the corresponding amides in excellent isolated yields (85-99%). An enantiopure ester and amine were both shown to react without racemization. The methodology has been successfully applied to preparation of procainamide.
- Ramesh, Perla,Fadnavis, Nitin W.
-
supporting information
p. 138 - 140
(2015/02/19)
-
- s-triazene based fluorous coupling reagent for direct amide synthesis
-
Abstract A new simple and efficient fluorous coupling reagent TriTFET (2,4,6-tris-(2,2,2-trifluoro-ethoxy)-[1,3,5] triazene) has been designed and synthesized for the direct amidation. The use of 5 mol % of TriTFET is good for the amide synthesis from carboxylic acids with amines in moderate to excellent yields (72-96%).
- Mangawa, Shrawan Kumar,Bagh, Sangram Keshari,Sharma, Kumkum,Awasthi, Satish K.
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supporting information
p. 1960 - 1963
(2015/03/18)
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- 2-Furanylboronic acid as an effective catalyst for the direct amidation of carboxylic acids at room temperature
-
2-Furanylboronic acid has been identified as an inexpensive and effective catalyst for the dehydrative amide formation of carboxylic acids and amines. This transformation can be efficiently carried out at room temperature and is applicable to a wide range of carboxylic acids with primary and secondary amines to afford amides in good to excellent yields.
- Tam, Eric Kwok Wai,Rita,Liu, Lionel Yiqian,Chen, Anqi
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p. 1100 - 1107
(2015/02/19)
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- Microwave-assisted heteropolyanion-based ionic liquids catalyzed transamidation of non-activated carboxamides with amines under solvent-free conditions
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An environmentally benign and highly efficient protocol for the transamidation of non-activated carboxamides with amines using heteropolyanion-based ionic liquids as catalysts under microwave-assisted and solvent-free conditions has been developed. As evaluated by the reactions of a structurally diverse set of amides and amines, the scope and utility of the transamidation proved to be quite general. Operational simplicity, solvent-free media, the potential reusability of catalysts and wide functional group tolerance are attractive features. This method provides a much improved protocol over the existing methods.
- Fu, Renzhong,Yang, Yang,Chen, Zhikai,Lai, Wenchen,Ma, Yongfeng,Wang, Quan,Yuan, Rongxin
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p. 9492 - 9499
(2015/03/04)
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- Metal-free carbon-carbon cross-couplings between the ion pairs in sulfonium tetraphenylborates
-
A series of sulfonium tetraphenylborates can be readily prepared by the metathesis of sulfonium halides with sodium tetraphenylborates. After heating at 120-150 °C, the sulfonium tetraphenylborates can smoothly undergo the cross-couplings between the tetraphenylborate anions and the sulfonium cations in the absence of a metal catalyst. For carbonylmethyl-, benzyl-, and allylsulfoniums, the corresponding carbonylmethyl-phenyl, benzyl-phenyl, and allyl-phenyl cross-coupling products can be obtained in 22-76% yields. An interionic electron-transfer mechanism for this cross-coupling reaction is proposed.
- Xu, Mei-Li,Huang, Wenhua
-
p. 4230 - 4232
(2014/07/22)
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- Ketene reactions with tertiary amines
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Tertiary amines react rapidly and reversibly with arylketenes in acetonitrile forming observable zwitterions, and these undergo amine catalyzed dealkylation forming N,N-disubstituted amides. Reactions of N- methyldialkylamines show a strong preference for methyl group loss by displacement, as predicted by computational studies. Loss of ethyl groups in reactions with triethylamine also occur by displacement, but preferential loss of isopropyl groups in the phenylketene reaction with diisopropylethylamine evidently involves elimination. Quinuclidine rapidly forms long-lived zwitterions with arylketenes, providing a model for catalysis by cinchona and related alkaloids in stereoselective additions to ketenes.
- Allen, Annette D.,Andraos, John,Tidwell, Thomas T.,Vukovic, Sinisa
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p. 679 - 685
(2014/04/03)
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- Amides in one pot from Carboxylic Acids and Amines via Sulfinylamides
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An efficient method has been developed for the direct amidification of carboxylic acids via sulfinylamides preformed in situ by the reaction of pure amines with prop-2- ene-1-sulfinyl chloride. The method can be applied to aliphatic acids, including pivalic acid, aromatic acids, and primary and secondary amines. It is compatible with acids bearing unprotected alcohol, phenol, and ketone moieties and applicable to the synthesis of peptides. It does not induce their a-epimerization.
- Bai, Jianfei,Zambron, Bartosz K.,Vogel, Pierre
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supporting information
p. 604 - 607
(2014/04/03)
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- A general and practical palladium-catalyzed direct a-arylation of amides with aryl halides
-
An efficient system for the direct catalytic intermolecular α-arylation of acetamide derivatives with aryl bromides and chlorides is presented. The palladium catalyst is supported by Kwong's indolebased phosphine ligand and provides monoarylated amides in up to 95% yield. Excellent chemoselectivities (>10:1) in the mono- and diarylation with aryl bromides were achieved by careful selection of bases, solvents, and stoichiometry. Under the coupling conditions, the weakly acidic α-protons of amides (pK a up to 35) were reversibly depotonated by lithium tert-butoxide (LiO-t-Bu), sodium tert-butoxide (NaO-t-Bu) or sodium bis(trimethylsilyl)amide [NaN(SiMe3)2].
- Zheng, Bing,Jia, Tiezheng,Walsh, Patrick J.
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supporting information
p. 165 - 178
(2014/03/21)
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- Hexaalkylguanidinium salts as ionic liquids - Applications in titanium and aluminium alcoholate assisted synthesis
-
The solubility of titanium and aluminium alcoholates and of titanium tetrakis(trimethylsilanolate) in several hexaalkylguanidinium-based room temperature ionic liquids was screened. The solvent/solute combinations which displayed the highest alcoholate solubility and stability were applied as Lewis-acidic catalytic media for several dehydrating cyclocondensations: lactamisation of ω-aminocarboxylic acids, direct amidation of carboxylic acids, synthesis of oxazolines from carboxylic acids and 2-aminoethanol, lactonisation of 6-hydroxyhexanoic acid, and Paal-Knorr synthesis of pyrroles.
- Arkhipova, Maria,Eichel, Svetlana,Maas, Gerhard
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p. 56506 - 56517
(2015/02/05)
-
- Visible-light-mediated eosin y catalyzed aerobic desulfurization of thioamides into amides
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A novel method for the metal-free efficient synthesis of amides from thioamides using visible light and in an air atmosphere in the presence of eosin Y as an organophotoredox catalyst is reported. The protocol involves aerobic desulfurization-oxygenation of thioamides into amides in good to excellent yields at r.t. in a one-pot operation under mild conditions with the formation of nontoxic elemental sulfur as the only by-product. On the basis of several relevant experiments performed, it has been shown that the present photooxidation does not involve a singlet oxygen and accordingly a plausible organocatalytic photoredox mechanism is proposed.
- Yadav, Arvind K.,Srivastava, Vishnu P.,Yadav, Lal Dhar S.
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p. 4119 - 4124
(2013/12/04)
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- BORONIC ACID CATALYSTS AND METHODS OF USE THEREOF FOR ACTIVATION AND TRANSFORMATION OF CARBOXYLIC ACIDS
-
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:
- -
-
Page/Page column 56-57
(2012/09/10)
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- Direct use of dioxygen as an oxygen source: Catalytic oxidative synthesis of amides
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The first transition-metal-catalyzed direct oxidative synthesis of amides by using dioxygen as an oxygen source has been developed under mild conditions, in which DBU was used as the key additive. The present methodology, which utilizes dioxygen as an oxidant and oxygen source and cheap copper salts as catalysts, opens up an interesting and attractive avenue for the synthesis of amide functionality.
- Wei, Wei,Hu, Xiao-Yu,Yan, Xiao-Wei,Zhang, Qiang,Cheng, Ming,Ji, Jian-Xin
-
supporting information; experimental part
p. 305 - 307
(2012/01/06)
-
- Direct amide coupling of non-activated carboxylic acids and amines catalysed by zirconium(IV) chloride
-
Amidst the green: A green, mild and effective protocol for the direct formation of secondary and tertiary amides from non-activated carboxylic acids and amines in good to excellent yields by employing ZrCl4 as the catalyst is presented (see scheme). The amide coupling protocol proved to be suitable for scaled up syntheses, and the mild reaction conditions conserve the enantiopurity of chiral starting materials. Copyright
- Lundberg, Helena,Tinnis, Fredrik,Adolfsson, Hans
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supporting information; experimental part
p. 3822 - 3826
(2012/05/20)
-
- Direct amidation of carboxylic acids catalyzed by ortho-iodo arylboronic acids: Catalyst optimization, scope, and preliminary mechanistic study supporting a peculiar halogen acceleration effect
-
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.
-
p. 8386 - 8400,15
(2012/12/11)
-
- Direct amidation of carboxylic acids catalyzed by ortho-iodo arylboronic acids: Catalyst optimization, scope, and preliminary mechanistic study supporting a peculiar halogen acceleration effect
-
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.
-
p. 8386 - 8400
(2013/01/15)
-
- Titanium(IV) isopropoxide as an efficient catalyst for direct amidation of nonactivated carboxylic acids
-
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
-
supporting information
p. 2201 - 2204
(2012/10/30)
-
- N-heterocyclic carbene based ruthenium-catalyzed direct amide synthesis from alcohols and secondary amines: Involvement of esters
-
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
-
experimental part
p. 10005 - 10010
(2012/02/05)
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- Oxidative synthesis of amides and pyrroles via dehydrogenative alcohol oxidation by ruthenium diphosphine diamine complexes
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A series of ruthenium complexes can perform the acceptorless dehydrogenation of diols as well as the reaction of amines and alcohols to form ester, lactam, and amide products. The ligand criteria necessary for high catalytic activity are identified to guide future catalyst development for amide formation from amines and alcohols. These complexes can be employed in a dehydrogenative Paal-Knorr pyrrole synthesis to give 2,5-dimethyl-N- alkylpyrroles.
- Schley, Nathan D.,Dobereiner, Graham E.,Crabtree, Robert H.
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scheme or table
p. 4174 - 4179
(2011/10/03)
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- Pd(II)-catalyzed synthesis of indoles from α-aryloxime O-pentafluorobenzoates via intramolecular aromatic C-H amination
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α-Aryl-a-aminocarbonyloxime O-pentafluorobenzoates are found to be promising precursors for synthesis of 2 3-disubstituted indole derivatives catalyzed by PdCl2(MeCN)2 in the presence of MgO as a base. The reaction is supposed to pro
- Chiba, Shunsuke,Zhang, Line,Sanjaya, Stephen,Ang, Gim Yean
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experimental part
p. 5692 - 5700
(2010/10/02)
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- A convenient one-pot preparation of N-substituted thioamides
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A convenient one-pot preparation of N-substituted thioamides from acyl halides, amines and H2O/PSCl3/Et3N in good to excellent yield has been reported through a solvent-free, microwave assisted method.
- Pandey, Lokesh Kumar,Pathak, Uma,Mazumder, Avik,Mathura, Sweta
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experimental part
p. 1225 - 1228
(2010/12/20)
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- Catalytic transamidation reactions compatible with tertiary amide metathesis under ambient conditions
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The carbon-nitrogen bond of carboxamides is extremely stable under most conditions. The present study reveals that simple zirconium- and hafnium-amido complexes are highly efficient catalysts for equilibrium-controlled transamidation reactions between sec
- Stephenson, Nickeisha A.,Zhu, Jiang,Gellman, Samuel H.,Stahl, Shannon S.
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experimental part
p. 10003 - 10008
(2009/12/08)
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- Direct and waste-free amidations and cycloadditions by organocatalytic activation of carboxylic acids at room temperature
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(Chemical Equation Presented) Taming carboxylic acids: ortho-Iodo- and ortho-bromophenylboronic acids are exceptional organocatalysts in atom-economical amidations between free carboxylic acids and amines, including functionalized ones, and can also provide LUMO-lowering activation in [4 + 2] cycloadditions of α,β-unsaturated carboxylic acids.
- Al-Zoubi, Raed M.,Marion, Olivier,Hall, Dennis G.
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supporting information; experimental part
p. 2876 - 2879
(2009/02/06)
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- A convenient aminolysis of esters catalyzed by 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) under solvent-free conditions
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Aminolysis of esters by using the organocatalyst 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) is reported. Secondary and tertiary amides were synthesized from alkyl or aryl esters with a variety of primary and secondary amines in good to excellent yields (60-94%) under solvent-free conditions (SFC).
- Sabot, Cyrille,Kumar, Kanduluru Ananda,Meunier, Stéphane,Mioskowski, Charles
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p. 3863 - 3866
(2008/02/02)
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- Cesium carbonate promoted aerobic oxidation of arylacetamides: an efficient access to N-substituted α-keto amides
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A novel cesium carbonate promoted aerobic oxidation reaction to prepare N-substituted α-keto amides in the presence of catalytic amount of tetra-n-butylammonium bromide was described. This reaction provides a very simple and convenient route from easily a
- Song, Bingrui,Wang, Siyuan,Sun, Caiyun,Deng, Hongmei,Xu, Bin
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p. 8982 - 8986
(2008/03/18)
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- Preparation of polymer-bound pyrazolone active esters for combinatorial chemistry
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The preparation of solid-phase active esters from a new pyrazolone linker resin is described. N-Acylation using this resin provides various amide products with a high conversion rate and good purity under mild conditions. The polymer-bound pyrazolone linkers are stable in the reaction conditions and are resistant to hydrolysis. Moreover, this resin can also be reused repeatedly without a loss of reactivity.
- Byun, Jang-Woong,Lee, Dong-Hoon,Lee, Yoon-Sik
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p. 8063 - 8067
(2007/10/03)
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- A facile one-carbon homologation of aryl aldehydes to amides.
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The easily accessible 2-aryl-1,1-dibromo-1-alkenes can be converted to amides under unusually mild conditions in good to excellent yields. Both electron-donating and electron-withdrawing substitutions on the aromatic rings are tolerated, and the reaction works well with hindered alkylamines. This simple homologation could find broad applications. [reaction: see text]
- Shen, Wang,Kunzer, Aaron
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p. 1315 - 1317
(2007/10/03)
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- Synthesis of amides from esters and amines under microwave irradiation
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Formamide, primary and secondary amines react with esters in the presence of potassium tert-butoxide under microwave irradiation. Substituted amides are formed in yields (generally more than 70%) much higher than under conventional heating.
- Zradni, Fatima-Zohra,Hamelin, Jack,Derdour, Aicha
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p. 3525 - 3531
(2007/10/03)
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- Efficient procedure for the preparation of amides using polymer-bound reagents
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An effective method for the conversion of acids into amides is presented. The two-step procedure includes the preparation of acid chloride intermediates using Pol-Ph3P and subsequent treatment of these intermediates with amines and polymer-bound base. The amides were accessible in high yields and purities without further purification.
- Buchstaller,Ebert,Anlauf
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p. 1001 - 1005
(2007/10/03)
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- A novel method for the mild and selective amidation of diesters and the amidation of monoesters
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The selective monoamidation of diesters and amidation of esters mediated by Lewis acids are described. The selective amidations of dimethyl pyridine-2,5-dicarboxylate (1) and dimethyl 2,3-indole-dicarboxylate (4) with primary and secondary amines mediated
- Guo, Zhenrong,Dowdy, Eric D.,Li, Wen-Sen,Polniaszek, Richard,Delaney, Edward
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p. 1843 - 1845
(2007/10/03)
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- HMDS-promoted in situ amidation reactions of carboxylic acids and amines
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A number of N-acylalkylenediamines were synthesized in high yields by in situ monoamidation of carboxylic acids with diamines. The amidation reactions were carried out simply by heating the substrates at 110 °C for 5-24 h in the presence of HMDS.
- Chou, Wen-Chih,Chou, Ming-Chen,Lu, Yann-Yu,Chen, Shyh-Fong
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p. 3419 - 3422
(2007/10/03)
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- Ligand exchange reaction of sulfoxides in organic synthesis: A versatile procedure for one-carbon homologation of methylesters to esters, thioesters, carboxylic acids and amides
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A novel two-step procedure for one-carbon homologation of methylesters to esters, thioesters, carboxylic acids and amides is described. Methylesters are reacted with lithium carbanion of chloromethyl phenyl sulfoxide to give α-chloro α-sulfinyl ketones in 70 to 90% yields. Potassium enolate of the α-chloro α-sulfinyl ketone was treated with tert-butyllithium at -78°C to give alkynolate via alkylidene carbenoid. This intermediate was treated with alcohols, thioles, 5% aqueous NaOH, and amine hydrochlorides to afford one-carbon homologated esters, thioesters, carboxylic acids and amides, respectively, in good to excellent yields.
- Satoh, Tsuyoshi,Unno, Hideaki,Mizu, Yasuhiro,Hayashi, Yasumasa
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p. 7843 - 7854
(2007/10/03)
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