- An efficient, economical and eco-friendly acylation of alcohols and amines by alum doped nanopolyaniline under solvent free condition
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We report acylation of alcohols and amines employing acetic acid as an acylating agent in solvent free condition by using alum doped nanopolyaniline (NDPANI) as a catalyst. This environmentally benign method does not use corrosive acid anhydrides and acid chlorides for acylation and does not produce waste product. Also, a non-toxic potash alum was used for doping of polyaniline rather than corrosive acids. The reaction conditions represent an advance over established method not only in omitting the need for expensive catalysts or solvents but also in shortening the reaction time significantly. The advantages of this catalyst are non-hazardous, cheap, reusable, easy to prepare and handling.
- Behera, Satyaranjan,Patra, Braja N.
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- Asymmetric Transfer Hydrogenation of α-Keto Amides; Highly Enantioselective Formation of Malic Acid Diamides and α-Hydroxyamides
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The asymmetric transfer hydrogenation (ATH) of α-keto-1,4-diamides using a tethered Ru/TsDPEN catalyst was achieved in high ee. Studies on derivatives identified the structural elements which lead to the highest enantioselectivities in the products. The α-keto-amide reduction products have been converted to a range of synthetically valuable derivatives.
- Gediya, Shweta K.,Vyas, Vijyesh K.,Clarkson, Guy J.,Wills, Martin
-
supporting information
p. 7803 - 7807
(2021/10/20)
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- Deconstructing Noncovalent Kelch-like ECH-Associated Protein 1 (Keap1) Inhibitors into Fragments to Reconstruct New Potent Compounds
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Targeting the protein-protein interaction (PPI) between nuclear factor erythroid 2-related factor 2 (Nrf2) and Kelch-like ECH-associated protein 1 (Keap1) is a potential therapeutic strategy to control diseases involving oxidative stress. Here, six classes of known small-molecule Keap1-Nrf2 PPI inhibitors were dissected into 77 fragments in a fragment-based deconstruction reconstruction (FBDR) study and tested in four orthogonal assays. This gave 17 fragment hits of which six were shown by X-ray crystallography to bind in the Keap1 Kelch binding pocket. Two hits were merged into compound 8 with a 220-380-fold stronger affinity (Ki = 16 μM) relative to the parent fragments. Systematic optimization resulted in several novel analogues with Ki values of 0.04-0.5 μM, binding modes determined by X-ray crystallography, and enhanced microsomal stability. This demonstrates how FBDR can be used to find new fragment hits, elucidate important ligand-protein interactions, and identify new potent inhibitors of the Keap1-Nrf2 PPI.
- Pallesen, Jakob S.,Narayanan, Dilip,Tran, Kim T.,Solbak, Sara M. ?.,Marseglia, Giuseppe,S?rensen, Louis M. E.,H?j, Lars J.,Munafò, Federico,Carmona, Rosa M. C.,Garcia, Anthony D.,Desu, Haritha L.,Brambilla, Roberta,Johansen, Tommy N.,Popowicz, Grzegorz M.,Sattler, Michael,Gajhede, Michael,Bach, Anders
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p. 4623 - 4661
(2021/05/07)
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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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- N-acetylation of amines in continuous-flow with acetonitrile—no need for hazardous and toxic carboxylic acid derivatives
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A continuous-flow acetylation reaction was developed, applying cheap and safe reagent, acetonitrile as acetylation agent and alumina as catalyst. The method developed utilizes milder reagent than those used conventionally. The reaction was tested on various aromatic and aliphatic amines with good conversion. The catalyst showed excellent reusability and a scale-up was also carried out. Furthermore, a drug substance (paracetamol) was also synthesized with good conversion and yield.
- Fül?p, Ferenc,Mándity, István M.,Orsy, Gy?rgy
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- IrIII-Catalyzed direct syntheses of amides and esters using nitriles as acid equivalents: A photochemical pathway
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An unprecedented IrIII[df(CF3)ppy]2(dtbbpy)PF6-catalyzed simple photochemical process for direct addition of amines and alcohols to the relatively less reactive nitrile triple bond is described herein. Various amides and esters are synthesized as the reaction products, with nitriles being the acid equivalents. A mini-library of different types of amides and esters is made using this mild and efficient process, which uses only 1 mol% of photocatalyst under visible light irradiation (λ = 445 nm). The reaction strategy is also efficient for gram-scale synthesis.
- Talukdar, Ranadeep
-
supporting information
p. 5303 - 5308
(2020/04/17)
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- Environmentally benign decarboxylative: N-, O-, and S-Acetylations and acylations
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An operationally simple and general method for acetylation and acylation of a wide variety of substrates (amines, alcohols, phenols, thiols, and hydrazones) has been reported. Meldrum's acid and its derivatives have been used as an air-stable, non-volatile, cost-effective, and easy to handle acetylating/acylating agent. Easily separable byproducts (CO2 and acetone) allowed the isolation of analytically pure acetylated products without the requirement of work-up and any chromatography. This journal is
- Ghosh, Santanu,Purkait, Anisha,Jana, Chandan K.
-
supporting information
p. 8721 - 8727
(2020/12/30)
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- Synthesis of diverse libraries of carboxamides via chemoselective N-acylation of amines by carboxylic acids employing Br?nsted acidic IL [BMIM(SO3H)][OTf]
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Chemoselective N-acylation of amines with carboxylic acids as acyl electrophiles and Br?nsted acidic IL [BMIM(SO3H)][OTf] as promoter is reported under both thermal and microwave irradiation to produce libraries of carboxamides in good to excellent yields after a simple workup. The protocol is compatible with structurally diverse 1° and 2° amines and works in the presence of sensitive functional groups such as thiols and phenols. The potential for recycling and reuse of the IL is also demonstrated.
- Savanur, Hemantkumar M.,Malunavar, Shruti S.,Prabhala, Pavankumar,Sutar, Suraj M.,Kalkhambkar, Rajesh G.,Laali, Kenneth K.
-
supporting information
(2019/09/30)
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- Frustrated Lewis Pair Catalyzed Hydrogenation of Amides: Halides as Active Lewis Base in the Metal-Free Hydrogen Activation
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A method for the metal-free reduction of carboxylic amides using oxalyl chloride as an activating agent and hydrogen as the final reductant is introduced. The reaction proceeds via the hydrogen splitting by B(2,6-F2-C6H3)3 in combination with chloride as the Lewis base. Density functional theory calculations support the unprecedented role of halides as active Lewis base components in the frustrated Lewis pair mediated hydrogen activation. The reaction displays broad substrate scope for tertiary benzoic acid amides and α-branched carboxamides.
- Sitte, Nikolai A.,Bursch, Markus,Grimme, Stefan,Paradies, Jan
-
supporting information
p. 159 - 162
(2019/01/04)
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- Providing a New Aniline Bioisostere through the Photochemical Production of 1-Aminonorbornanes
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Recent years have witnessed an increasing focus on saturated substructures within drug development as a result of the pharmacokinetic and toxicological benefits correlated with higher saturation content. However, the synthetic challenges presented by densely functionalized saturated architectures generally prohibit their evaluation. The abundance of anilines within high-throughput screening libraries is demonstrative of these competing needs. Anilines are prone to adverse metabolic processing, commonly necessitating re-engineering of a given drug lead to ameliorate CYP450 inhibition and/or glutathione adduction issues, but the ease with which these systems are prepared outweighs the toxicity risks. This article contributes to the need for aniline bioisosteres through the development of a robust, photochemical methodology that supplies 1-aminonorbornanes, saturated bicyclic ring systems that offer similar spatial occupancy to anilines while improving metabolic stability. The chemistry provided herein details an efficient and flexible route toward architecturally distinctive 1-aminonorbornanes through the use of visible-light photoredox catalysis. The incorporation of readily diversifiable functional handles (e.g., -OH, -CO2Me, -NHBoc, -NHCbz) illustrates the potential utility of these 1-aminonorbornanes within drug-discovery programs. Additionally, these motifs offer improved metabolic stability relative to that of their aniline congeners (as demonstrated through microsomal stability assays and metabolite identification efforts), indicating applicability of 1-aminonorbornanes as aniline bioisosteres. This report describes the photochemical conversion of aminocyclopropanes into 1-aminonorbornanes via formal [3 + 2] cycloadditions initiated by homolytic fragmentation of amine radical cation intermediates. Aligning with the modern movement toward sp3-rich motifs in drug discovery, this strategy provides access to a diverse array of substitution patterns on this saturated carbocyclic framework while offering the robust functional-group tolerance (e.g., -OH, -NHBoc) necessary for further derivatization. Evaluating the metabolic stability of selected morpholine-based 1-aminonorbornanes demonstrated a low propensity for oxidative processing and no proclivity toward reactive metabolite formation, suggesting a potential bioisosteric role for 1-aminonorbornanes. Continuous-flow processing allowed for efficient operation on the gram scale, providing promise for translation to industrially relevant scales. This methodology only requires low loadings of a commercially available, visible-light-active photocatalyst and a simple salt; thus, it stays true to sustainability goals while readily delivering saturated building blocks that can reduce metabolic susceptibility within drug development programs.
- Staveness, Daryl,Sodano, Taylor M.,Li, Kangjun,Burnham, Elizabeth A.,Jackson, Klarissa D.,Stephenson, Corey R.J.
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supporting information
p. 215 - 226
(2019/01/21)
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- Synthesis of 4-Vinylmorpholine Based on Acetylene
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It has been shown that from the possible methods for the synthesis of 4-vinylmorpholine, the vinylation of morpholine with acetylene remains acceptable. A technologically accessible method for vinylation of morpholine with acetylene at atmospheric pressure was developed.
- Asratyan,Bagdasaryan,Markosyan, A. Dzh.,Badalyan,Attaryan
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p. 342 - 345
(2018/05/15)
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- Manganese-Catalyzed Direct Conversion of Ester to Amide with Liberation of H2
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A simple and efficient Mn-catalyzed acylation of amines is achieved using both acyl and alkoxy functions of unactivated esters with the liberation of molecular hydrogen as a sole byproduct. The present protocol provides an atom-economical and sustainable route for the synthesis of amides from esters by employing an earth-abundant manganese salt and inexpensive phosphine-free tridentate ligand.
- Mondal, Akash,Subaramanian, Murugan,Nandakumar, Avanashiappan,Balaraman, Ekambaram
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supporting information
p. 3381 - 3384
(2018/06/11)
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- 1,1-Diacyloxy-1-phenylmethanes as versatile N-acylating agents for amines
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1,1-Diacyloxy-1-phenylmethanes and 1-pivaloxy-1-acyloxy-1-phenylmethanes have been used as bench stable N-acylating reagents for primary and secondary amines and anilines under solvent-free conditions to afford their corresponding amides in good yield.
- Chapman, Robert. S.L.,Tibbetts, Joshua. D.,Bull, Steven. D.
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p. 5330 - 5339
(2018/06/15)
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- Copper-(II) Catalyzed N-Formylation and N-Acylation of Aromatic, Aliphatic, and Heterocyclic Amines and a Preventive Study in the C-N Cross Coupling of Amines with Aryl Halides
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A Cu-(II) catalyzed N-formylation and N-acylation of amines with moderate to excellent yields, using N, N-dimethyl formamide (DMF) and N, N-dimethyl acetamide (DMA) as a formyl and acylating sources in the presence of 1,2,4-triazole is reported. This novel, highly efficient and simple protocol shows broad substrate scope for aliphatic, aromatic, and heterocyclic amines. In addition, the conditions to prevent N-formylation and N-acylation impurities in the C?N cross coupling of amines and aryl halides are described typically when DMF and DMA are used as solvents, with various catalysts, ligands, and bases.
- Sonawane, Rahul B.,Rasal, Nishant K.,Bhange, Dattatraya S.,Jagtap, Sangeeta V.
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p. 3907 - 3913
(2018/09/12)
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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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- Cu(II)-Mediated keto C(sp3)-H bond α-acyloxylation of N, N-dialkylamides with aromatic carboxylic acids
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The selective oxidative coupling of aromatic carboxylic acids with the C(sp3)-H bond adjacent to the keto group of alkylamides has been developed by employing a low cost copper source. This provides an efficient approach for synthesis of O-benzoylglycolamides. The protocol displayed good functional group tolerance. A broad range of benzoic acids directly coupled with alkylamides to afford a variety of O-benzoylglycolamides in moderate to good yields. In addition, a reasonable radical mechanism was proposed based on EPR experiments.
- Li, Wenjing,Yin, Changzhen,Yang, Xiao,Liu, Hailong,Zheng, Xueli,Yuan, Maolin,Li, Ruixiang,Fu, Haiyan,Chen, Hua
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supporting information
p. 7594 - 7599
(2017/09/27)
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- Doping of copper (I) oxide onto a solid support as a recyclable catalyst for acetylation of amines/alcohols/phenols and synthesis of trisubstituted imidazole
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A study of copper-mediated C-heteroatom especially C-N and C-O bond formations using simpler methodologies has been carried out. In the present work, acetylation of various substrates such as amines, phenols and alcohols; synthesis of 2,4,5-trisubstituted imidazole is done using simple and easily available starting materials. Copper (I) oxide was synthesized in situ by the reduction of Fehling's solution with glucose followed by its anchoring onto different supports like silica, HAP, basic alumina and cellulose. Comparison and contrasts between the reactivity of copper (I) oxide supported onto different supports for these reactions are made. The reactivity of copper (I) oxide seems to be largely dependent on the nature of support and the most active catalyst for a particular reaction was further characterized by different spectroscopic techniques such as FTIR, XRD, TGA, XPS, SEM, TEM and AAS. The catalysts were found to be stable, easily recyclable without any significant loss in activity. Graphical abstract: Applications of solid supported copper (I) oxides (where solid support is silica, HAP, cellulose and basic alumina) are studied for various organic transformations with special emphasis on C-N and C-O bond formation reactions.[Figure not available: see fulltext.]
- Gupta, Manjulla,Gupta, Monika
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p. 231 - 241
(2016/01/09)
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- The Effect of Ring-Size on the Anodic Oxidation of 'Cyclic Amides' in Methanol
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The anodic oxidation of three 'cyclic amides' of type N-acylazacycloalkanes [5- (I), 6- (II) and 7-membered (III) rings] has been studied in methanol under constant current electrolysis, at C anodes and in the presence of various supporting electrolytes, and different concentrations of substrates. Four major products were formed in good yields by all three substrates, namely N-acyl, α-azacycloalkenes, N-acyl, α-methoxyazacycloalkanes, N-acyl, α-methoxy, α'-azacycloalkenes and N-acyl, α,α′-dimethoxyazacycloalkanes. The relative ratios among products and selectivity were found to be highly dependent on the nature of the electrolyte used, and to a lesser extent on substrate concentration. In terms of ring-size effect it was found that the rate of oxidation and current efficiency (yield) was in the order: I > II > III. Also the latter two behaved similarly (but different from I) when various supporting electrolytes were used.
- Golub, Tatiana,Becker, James Y.
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p. 207 - 214
(2016/05/24)
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- Phosphovanadomolybdic acid catalyzed desulfurization-oxygenation of secondary and tertiary thioamides into amides using molecular oxygen as the terminal oxidant
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In the presence of phosphovanadomolybdic acids, e.g., H6PV3Mo9O40, desulfurization-oxygenation of various kinds of structurally diverse secondary and tertiary thioamides proceeded efficiently using molecular oxygen as the terminal oxidant, affording the corresponding amides in moderate to excellent yields. In addition, 18O-labeled amides could readily be synthesized using H218O as the oxygen source.
- Xu, Ning,Jin, Xiongjie,Suzuki, Kosuke,Yamaguchi, Kazuya,Mizuno, Noritaka
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p. 4865 - 4869
(2016/07/06)
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- Reaction Mechanism in Ionic Liquids: Kinetics and Mechanism of the Aminolysis of 4-Nitrophenyl Acetate
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In this work, we report a kinetic study of the reactions of the title compound with secondary alicyclic amines at different temperatures in acetonitrile and several ionic liquids (ILs). From this study, we have described that the reactions in MeCN and in
- Pavez, Paulina,Millán, Daniela,Rojas, Mabel,Morales, Javiera I.,Santos, José G.
-
supporting information
p. 337 - 343
(2016/05/02)
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- Microwave-promoted direct amidation of unactivated esters catalyzed by heteropolyanion-based ionic liquids under solvent-free conditions
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Abstract A simple and efficient procedure for the synthesis of amides directly from unactivated esters and amines catalyzed by heteropolyanion-based ionic liquids under microwave-promoted and solvent-free conditions has been reported. The practical protocol was found to be compatible with different structurally diverse substrates. Moderate to excellent yields, solvent-free media, and operational simplicity are the main highlights. Furthermore, the heteropolyanion-based ionic liquids were easily reusable for this amidation.
- Fu, Renzhong,Yang, Yang,Ma, Yunsheng,Yang, Fei,Li, Jingjing,Chai, Wen,Wang, Quan,Yuan, Rongxin
-
supporting information
p. 4527 - 4531
(2015/06/30)
-
- Preparation of conformationally restricted β2,2- and β2,2,3-amino esters and derivatives containing an all-carbon quaternary center
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β-Amino acids are routinely incorporated into peptidic drugs to increase their stability and to incur conformational biases. However, the synthesis of highly substituted β-amino acids still represents a great challenge. A new approach to their preparation is reported involving a Vilsmeier-Haack reaction with nonaromatic carbon nucleophiles. The highly challenging preparation of contiguous tertiary and all-carbon quaternary centers was successfully used to generate several β2,2,3-amino esters, such as derivatives of homoproline, homoalanine, and homopipecolinic esters.
- Romanens, Alexandre,Blanger, Guillaume
-
supporting information
p. 322 - 325
(2015/01/30)
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- An eco-friendly and highly efficient route for N-acylation under catalyst-free conditions
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An eco-friendly, simple, mild, chemoselective and highly efficient procedure for the acylation of primary and secondary amine function in various structurally and electronically aliphatic and aromatic compounds affording their corresponding N-Ac derivatives is developed. Mild conditions, simplicity and easier work-up are the main advantages of this method.
- Ouarna, Souad,K'tir, Hacène,Lakrout, Salah,Ghorab, Hamida,Amira, A?cha,Aouf, Zineb,Berredjem, Malika,Aouf, Nour-Eddine
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p. 913 - 919
(2015/10/28)
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- Direct Preparation of Amides from Amine Hydrochloride Salts and Orthoesters: A Synthetic and Mechanistic Perspective
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The conversion of a wide range of primary and secondary aliphatic and a few arylamine hydrochloride salts to their corresponding acetamides with trimethyl orthoacetate is described. Mechanistic studies using NMR and gas chromatography-mass spectrometry techniques indicate these reactions proceed via an O-methylimidate intermediate that undergoes in situ demethylation by chloride, affording the corresponding acetamides. Synthetically, this reaction represents a practical, high-yielding protocol with a simple workup for the rapid conversion of amine hydrochloride salts to acetamides.
- Di Grandi, Martin J.,Bennett, Caitlin,Cagino, Kristen,Muccini, Arnold,Suraci, Corey,Saba, Shahrokh
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supporting information
p. 2601 - 2607
(2015/11/28)
-
- Generation and trapping of ketenes in flow
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Ketenes were generated by the thermolysis of alkoxyalkynes under flow conditions, and then trapped with amines and alcohols to cleanly give amides and esters. For a 10 min reaction time, temperatures of 180, 160, and 140 °C were required for >95% conversion of EtO, iPrO, and tBuO alkoxyalkynes, respectively. Variation of the temperature and flow rate with inline monitoring of the output by IR spectroscopy allowed the kinetic parameters for the conversion of 1-ethoxy-1-octyne to be easily estimated (Ea = 105.4 kJ/mol). Trapping of the in-situ-generated ketenes by alcohols to give esters required the addition of a tertiary amine catalyst to prevent competitive [2+2] addition of the ketene to the alkoxyalkyne precursor.
- Henry, Cyril,Bolien, David,Ibanescu, Bogdan,Bloodworth, Sally,Harrowven, David C.,Zhang, Xunli,Craven, Andy,Sneddon, Helen F.,Whitby, Richard J.
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p. 1491 - 1499
(2015/03/04)
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- Designing of thermally stable amide functionalized benzimidazolium perchlorate ionic liquid for transamidation of primary carboxamides
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In the present work, we have designed and synthesized a thermally stable catalyst based on functionalized benzimidazolium perchlorate ionic liquid and tested its efficacy towards metal free and solvent free transamidation of amides and amines. The ionic liquid comprising the perchlorate ion has shown remarkably better activity than those which contain other anions and accordingly a plausible mechanism for the catalytic activity is arrived. The developed catalytic system has shown excellent activity towards the transamidation of alicyclic and aromatic amines with acetamide, benzamide and p-nitrobenzamide under mild conditions. Furthermore, the transamidation of nicotinamide with benzylamine in presence of the ionic liquid catalyst was found to occur with very good yields and thus provides a facile route for the synthesis of pharmaceutically significant compounds. The catalyst has exhibited very good thermal stability upto 203 °C and very good recyclability upto 5 runs without significant loss in its activity.
- Muskawar, Prashant Narayan,Thenmozhi,Bhagat, Pundlik Rambhau
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p. 158 - 167
(2015/09/28)
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- An eco-benign and highly efficient procedure for N-acylation catalyzed by heteropolyanion-based ionic liquids using carboxylic acid under solvent-free conditions
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An eco-benign and highly efficient route for N-acylation of amines has been developed by treating amines with corresponding carboxylic acids in the presence of 2 mol % of heteropolyanion-based ionic liquids as catalysts under solvent-free conditions. This practical reaction could tolerate a wide range of substrates. Thus, various N-acylation products including N-acyl α-amino acid derivatives were obtained in moderate to excellent yields at 70 C to 120 C. Moreover, recycling studies revealed that heteropolyanion-based ionic liquids were easily reusable for this N-acylation. This method provides a green and much improved protocol over the existing methods.
- Chen, Zhikai,Fu, Renzhong,Chai, Wen,Zheng, Hao,Sun, Lin,Lu, Qiang,Yuan, Rongxin
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p. 2237 - 2245
(2014/03/21)
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- Selectivities in acylation of primary and secondary amine with diacylaminoquinazolinones and diacylanilines
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The diacylaminoquinazolinones are highly selective acylating agents for primary amines in the presence of secondary amines. The chemoselective N-acetylation reagents have been investigated using 2-substituted N,Ndiacylaminoquinazolinones (DAQs) and 2-substitued-N-diacylanilines (DAAs). Determination of the selectivity ratios have been made by comparison of the crude product in each case with authentic samples of the amide products using NMR spectroscopy. The control experiments in which pairs of amines compete for acetyl chloride show some selectivity but not comparable with that of DAQs and DAAs selectivity. When the DAQs, DAAs and acetyl chloride react with mixtures of pyrrolidine and piperidine, they give amides in the corresponding ratios. The DAQs 1 and 2 react entirely with diethylamine without any competitive reaction with diphenylamine. The high level of chemoselectivity has also been observed when the 1 and 2 react exclusively with the ethanolamine without any competitive reaction with diethanolamine. Moreover, 1 and 2 react with succinimide without any competitive reaction with phthalimide.
- Al-Sehemi, Abdullah G.,Al-Amri, Reem S. Abdul-Aziz,Irfan, Ahmad
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p. 1115 - 1121
(2014/10/15)
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- Tris(pentafluorophenyl)borane catalyzed acylation of alcohols, phenols, amines, and thiophenols under solvent-free condition
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The acylation of alcohols, phenols, amines, and thiophenols was accomplished with 0.5 mol % of tris(pentafluorophenyl)borane [B(C 6F5)3] at ambient temperature under solvent-free condition. Major advantages of this method include high yield, short reaction time, simple procedure, compatibility with sensitive protecting groups as well as other functional groups, absence of racemization of optical active compounds, and epimerization of sugars.
- Prajapti, Santosh Kumar,Nagarsenkar, Atulya,Babu, Bathini Nagendra
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p. 1784 - 1787
(2014/03/21)
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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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- Transamidation of carboxamides catalyzed by Fe(III) and water
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The highly efficient transamidation of several primary, secondary, and tertiary amides with aliphatic and aromatic amines (primary and secondary) is described. The reaction is performed in the presence of a 5 mol % concentration of different hydrated salts of Fe(III), and the results show that the presence of water is crucial. The methodology was also applied to urea and phthalimide to demonstrate its versatility and wide substrate scope. An example of its use is an intramolecular application in the synthesis of 2,3-dihydro-5H-benzo[b]-1,4- thiazepin-4-one, which is the bicyclic core of diltiazem and structurally related drugs (Budriesi, R.; Cosimelli, B.; Ioan, P.; Carosati, E.; Ugenti, M. P.; Spisani, R. Curr. Med. Chem. 2007, 14, 279-287). A plausible mechanism that explains the role of water is proposed on the basis of experimental observations and previous mechanistic suggestions for transamidation reactions catalyzed by transition metals such as copper and aluminum. This methodology represents a significant improvement over other existing methods; it can be performed in air and with wet or technical grade solvents.
- Becerra-Figueroa, Liliana,Ojeda-Porras, Andrea,Gamba-Sánchez, Diego
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p. 4544 - 4552
(2014/06/09)
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- Carbonylation of quaternary ammonium salts to tertiary amides using NaCo(CO)4 catalyst
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We reported here the catalytic carbonylation of quaternary ammonium salts under anhydrous condition. Quaternary ammonium salts, a kind of versatile reagents that were widely used in organometallic chemistry, can be carbonylated to tertiary amides by an in situ prepared NaCo(CO)4 catalyst. It was found that the counterions (Cl-, Br-, I-, OTf-) in the quaternary ammonium salts played a significant role in the reaction and tetramethylammonium iodide could give high yield (96%) of N,N-dimethylacetamide (DMAc) with only 0.5 mol% cobalt catalyst. Under optimum conditions, several other quaternary ammonium iodides were also carbonylated to corresponding tertiary amides in moderate to excellent yields. Obviously, these results also give us a special apprehension that Me4NI and other quaternary ammonium salts could be possibly carbonylated to tertiary amides in the carbonylation reaction where they are used as promoters or solvents in most cases. Considering the high activity and moderate to excellent selectivity, this process could be a potential method for the synthesis of certain tertiary amides. Moreover, the cleaving mechanism of CN bonds and the possible catalytic intermediates were discussed in detail.
- Lei, Yizhu,Zhang, Rui,Wu, Qing,Mei, Hui,Xiao, Bo,Li, Guangxing
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p. 120 - 125
(2013/12/04)
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- Palladium-catalyzed carbonylation of quaternary ammonium halides to tertiary amides
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Catalytic carbonylation of quaternary ammonium salts under anhydrous conditions was investigated using palladium catalyst. The carbonylation of tetramethylammonium iodide was chosen as a model reaction and studied systematically. Ligand-free PdCl2 showed efficient catalytic performance for this transformation. A palladium catalyst loading as low as 0.05 mol% was sufficient for high yield (96.9%) of N,N-dimethylacetamide, corresponding to a turnover frequency of 242 h-1. Under optimum conditions, several other quaternary ammonium halides were also carbonylated to corresponding tertiary amides in moderate to excellent yields. The catalytic activity of commercial palladium on activated carbon (Pd/C) catalyst was also evaluated. The Pd/C catalyst exhibited high activity for this carbonylation reaction and could be recycled six times with a slight decrease in activity. Furthermore, mechanistic considerations concerning Pd-catalyzed carbonylation of quaternary ammonium halides were also discussed. Copyright
- Lei, Yizhu,Zhang, Rui,Wu, Linjuan,Wu, Qing,Mei, Hui,Li, Guangxing
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p. 310 - 314
(2014/04/03)
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- Immobilization of Candida cylindracea lipase on poly lactic acid, polyvinyl alcohol and chitosan based ternary blend film: Characterization, activity, stability and its application for N-a
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The ecofriendly ternary blend polymer film was prepared from the chitosan (CH), polylactic acid (PLA) and polyvinyl alcohol (PVA). Immobilization of Candida cylindracea lipase (CCL) was carried out on ternary blend polymer via entrapment methodology. The ternary blend polymer and immobilized biocatalyst were characterized by using N2 adsorption-desorption isotherm, SEM, FTIR, DSC, and (%) water content analysis through Karl Fischer technique. Biocatalyst was then subjected for the determination of practical immobilization yield, protein loading and specific activity. Immobilized biocatalyst was further applied for the determination of biocatalytic activity for N-acylation reactions. Various reaction parameters were studied such as effect of immobilization support (ratio of PLA:PVA:CH), molar ratio (dibutylamine:vinyl acetate), solvent, biocatalyst loading, time, temperature, and orbital speed rotation. The developed protocol was then applied for the N-acylation reactions to synthesize several industrially important acetamides with excellent yields. Interestingly, immobilized lipase showed fivefold higher catalytic activity and better thermal stability than the crude extract lipase CCL. Furthermore various kinetic and thermodynamic parameters were studied and the biocatalyst was efficiently recycled for four successive reuses. It is noteworthy to mention that immobilized biocatalyst was stable for period of 300 days.
- Badgujar, Kirtikumar C.,Dhake, Kishor P.,Bhanage, Bhalchandra M.
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p. 1335 - 1347
(2013/09/12)
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- A traceless approach to amide and peptide construction from thioacids and dithiocarbamate-terminal amines
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A novel and traceless strategy has been devised that allows a coupling of thioacids and dithiocarbamate-terminal amines. This strategy had been assumed to be dependent on the attachment of a functional equivalent of a cysteine side chain in earlier native chemical ligation approaches. This approach enables the traceless removal of CS2 to directly generate the desired amide bond and is compatible with a range of unprotected side chains of amino acid. The ability to produce amide or peptides by a traceless removal of the auxiliary is a significant virtue of the method. Meanwhile, the application of this new peptide-bond-forming reaction to the synthesis of novel endomorphin (EM) derivatives with various binding potencies was realized.
- Chen, Wenteng,Shao, Jiaan,Hu, Miao,Yu, Wanwan,Giulianotti, Marc A.,Houghten, Richard A.,Yu, Yongping
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p. 970 - 976
(2013/06/05)
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- Isopropenyl acetate, a remarkable, cheap and acylating agent of amines under solvent- and catalyst-free conditions: A systematic investigation
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Isopropenyl acetate was proved to be an efficient reagent for acetylation of amine in the absence of solvent and catalyst. The corresponding acetamides were obtained in very high yields without any purification.
- Pelagalli, Romina,Chiarotto, Isabella,Feroci, Marta,Vecchio, Stefano
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supporting information; experimental part
p. 2251 - 2255
(2012/09/08)
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- Synthesis and evaluation of a photochromic surfactant for organic reactions in aqueous media
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A novel photochromic azobenzene-based surfactant was described for organic chemistry in water. The molecule 4-butylazobenzyl-4′-triazologlucuronic acid sodium salt thus synthesized can be isomerized from its trans to its cis form reversibly in solution by simple light irradiation. That property allowed the recyclability of a model acetylation reaction performed in the surfactant media, compared to the well-known, commercially available sodium dodecyl sulfate surfactant media.
- Drillaud, Nicolas,Banaszak-Léonard, Estelle,Pezron, Isabelle,Len, Christophe
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p. 9553 - 9561
(2013/01/15)
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- Synthesis of amide libraries with immobilized HOBt
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Highly reactive N-acylating solid-phase reagents based on macroporous polystyrene-bound 1-hydroxybenzotriazole (P-HOBt) and silica-bound 1-hydroxybenzotriazole (Si-HOBt) were prepared and compared for reactivity by synthesis of small combinatorial libraries of acetamides and benzamides.
- Vokkaliga, Smitha,Jeong, Jeannie,Lacourse, William R.,Kalivretenos, Aristotle
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supporting information; experimental part
p. 2722 - 2724
(2011/06/19)
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- Reactions of aryl acetates with secondary alicyclic amines in ethanol/water mixtures: Effect of the solvent composition on the kinetics and mechanism
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We report a kinetic study on the reactions of secondary alicyclic amines toward 4-nitrophenyl, 2,4-dinitrophenyl, and 2,4,6-trinitrophenyl acetates (1, 2, and 3) in ethanol/water mixtures of different compositions. It is found that (i) the intermediate in the reaction of 1 is stabilized in a mixture of 90 vol% ethanol; (ii) for the reaction of 2, the mechanism is stepwise in water but concerted in the mixtures; (iii) For the reaction of 3, the mechanism is concerted along the whole range of composition; (iv) the effect of -NO 2 outweighs the solvent effect; (v) preferential solvation in the core of reaction can be ruled out.
- Castro, Enrique A.,Millan, Daniela,Aguayo, Raul,Campodonico, Paola R.,Santos, Jose G.
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supporting information; experimental part
p. 687 - 693
(2012/07/27)
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- A green approach to chemoselective N-acetylation of amines using catalytic amount of zinc acetate in acetic acid under microwave irradiation
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It has been found for the first time that zinc acetate alone can act as a selective A'-acetylating agent without any solvent under closed vessel microwave irradiation. It is also observed that the use of a catalytic amount of this reagent in acetic acid is sufficient enough for smooth running of A'-acetylation of a number of structurally diverse amines, and the reaction is chemoselective with respect to phenols, thiols, acids and alcohols. Herein is reported a simple, efficient, cost-effective and environmentally benign alternative method for chemoselective A'-acetylation of amines using catalytic amount of zinc acetate in acetic acid under microwave irradiation. The reaction procedure requires no other solvent, and is rapid with good to excellent yields.
- Brahmachari,Laskar,Sarkar
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experimental part
p. 1274 - 1281
(2010/12/24)
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- Efficient one-pot synthesis of N-substituted 2-aminochromones, their benzo-fused derivatives, and diaminobenzodipyrandiones of two new structural classes
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N-Substituted 2-aminochromones and their benzo-fused derivatives were obtained in high yields by a new one-pot synthesis, starting from the appropriate acetamides, salicylic acid or its benzo-fused derivatives, and phosphoryl chloride. By the same reaction, from suitable dihydroxybenzenedicarboxylic acids, some compounds of two new structural classes, 2,7-diaminobenzo[1,2-b:4,5-b']dipyran-4,9-diones and 2,8-diamino-4H,6H-benzo[1,2-b:5,4-b']dipyran-4,6-diones, were synthesized. Georg Thieme Verlag Stuttgart.
- Roma, Giorgio,Piras, Daniela,Di Braccio, Mario,Grossi, Giancarlo
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experimental part
p. 849 - 857
(2010/10/02)
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- Metal acetate/metal oxide in acetic acid: An efficient reagent for the chemoselective N-acetylation of amines under green conditions
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The use of catalytic amount of metal acetate or metal oxide in acetic acid is a new and highly efficient acetylating system for chemoselective N-acetylation of primary and secondary amines in excellent yields under reflux condition. No other solvent is required. The noted features of this method include mild reaction conditions, use of innocuous reagents, excellent yields, convenient work-up, and reuse of catalyst.
- Brahmachari, Goutam,Laskar, Sujay,Sarkar, Sajal
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experimental part
p. 288 - 295
(2010/10/18)
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- Acyl iodides in organic synthesis. Reactions with morpholine, piperidine, and N-hydrocarbylpiperidines
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Acyl iodides RCOI (R = Me, Ph) reacted with morpholine and piperidine to give the corresponding N-acyl derivatives and morpholine or piperidine hydroiodides. Reactions of acyl iodides with N-methyl- and N-ethylpiperidines involved cleavage of the exocyclic R-N bond with formation of N-acylpiperidine and alkyl iodide and were accompanied (to insignificant extent) by cleavage of the endocyclic N-C bond, leading to N-alkyl-N-(5-iodopentyl)acylamides. In the reaction of acetyl iodide with N-phenylpiperidine, the main process was cleavage of just endocyclic N-C bond to produce N-(5-iodopentyl)-N-phenylacetamide and its dehydroiodination product, N-(pent-4-en-1-yl)-N-phenylacetamide. Analogous reaction with benzoyl iodide afforded N-(5-iodopentyl)-N-phenylbenzamide in a poor yield.
- Voronkov,Tsyrendorzhieva,Rakhlin
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experimental part
p. 794 - 797
(2010/10/04)
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- PROCESS FOR PREPARING SECONDARY AMIDES BY CARBONYLATION OF A CORRESPONDING TERTIARY AMINE
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The present invention relates to a process for preparing secondary amides with good selectivity by carbonylating a corresponding tertiary amine with carbon monoxide in a reaction mixture in the presence of a metal catalyst and in the presence of a halogen containing promoter. The metal catalyst comprises palladium. A same or even a much better catalytic activity can be obtained with palladium than with the much more expensive rhodium, especially when the palladium is used in a low concentration. Moreover, also a good selectivity can be achieved.
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Page/Page column 4
(2010/06/14)
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- Candida antarctica lipase B-catalyzed synthesis of acetamides using [BMIm(PF6)] as a reaction medium
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An efficient protocol has been developed for synthesis of acetamides using Candida antarctica lipase B (CaL B) in [BMIm(PF6)] as a greener reaction medium. The reaction is applicable to a wide variety of aliphatic esters/acetic acid and amines providing excellent yields of corresponding acetamide. The catalyst exhibits remarkable activity and is reusable for up to four consecutive cycles.
- Dhake, Kishor P.,Qureshi, Ziyauddin S.,Singhal, Rekha S.,Bhanage, Bhalchandra M.
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experimental part
p. 2811 - 2814
(2009/09/30)
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- Acyl transfer catalysis with 1,2,4-Triazole anion
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1,2,4-Triazole anion has been identified as an active acyl transfer catalyst suitable for the aminolysis and transesterification of esters.
- Yang, Xing,Birman, Vladimir B.
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supporting information; experimental part
p. 1499 - 1502
(2009/09/06)
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- Chemoselective acylation of amines, thiols and phenols using 2,4,6-triacyloxy-1,3,5-triazine (TAT) as a new and effective reagent under mild condition
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A facile chemoselective acylation of amines, thiols and phenols using 2,4,6-triacyloxy-1,3,5-triazine (TAT) under mild condition is described. New reagent, high product yield, short reaction time, ease of operation and solvent free reaction condition is the most acceptable feature of the present method.
- Gholap, Somnath S.,Tambe, Ganesh B.,Gill, Charansingh H.
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experimental part
p. 179 - 182
(2010/04/05)
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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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- N1,N3-Diacyl-3,4-dihydropyrimidin-2(1H)-ones: neutral acyl group transfer reagents
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Readily available N1,N3-diacyl-3,4-dihydropyrimidin-2(1H)-ones efficiently acylate ammonia, primary and secondary amines to furnish primary, secondary and tertiary amides in good to excellent yields. The wide applicability of the procedure is demonstrated
- Singh, Kamaljit,Singh, Kawaljit
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experimental part
p. 10395 - 10399
(2010/02/28)
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- New, efficient, selective, and one-pot method for acylation of amines
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Hydrazine hydrate with acetic and propionic acids was an efficient reagent for acylation of primary and secondary amines at reflux temperatures. The reported one-pot method is high-yielding, simple, mild, and inexpensive. Copyright Taylor & Francis Group, LLC.
- Basanagouda, Mahantesha,Kulkarni, Manohar V.,Kalkhambkar, Raj G.,Kulkarni, Geeta M.
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p. 2929 - 2940
(2008/12/22)
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