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Artículos de revistas sobre el tema "Amidation reactions"

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Autor: Grafiati

Publicado: 1 de abril de 2023

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1

Liu, Yunyun y Baoli Zhao. "Step-Economical C–H Activation Reactions Directed by In Situ Amidation". Synthesis 52, n.º 21 (18 de mayo de 2020): 3211–18. http://dx.doi.org/10.1055/s-0040-1707124.

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Owing to the inherent ability of amides to chelate transition-metal catalysts, amide-directed C–H activation reactions constitute a major tactic in directed C–H activation reactions. While the conventional procedures for these reactions usually involve prior preparation and purification of amide substrates before the C–H activation, the step economy is actually undermined by the operation of installing the directing group (DG) and related substrate purification. In this context, directed C–H activation via in situ amidation of the crude material provides a new protocol that can significantly enhance the step economy of amide-directed C–H activation. In this short review, the advances in C–H bond activation reactions mediated or initiated by in situ amidation are summarized and analyzed.1 Introduction2 In Situ Amidation in Aryl C–H Bond Activation3 In Situ Amidation in Alkyl C–H Bond Activation4 Annulation Reactions via Amidation-Mediated C–H Activation5 Remote C–H Activation Mediated by Amidation6 Conclusion

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2

Gao, Yunling. "A new specific mechanism for thioacid/azide amidation: electronic and solvent effects". Open Chemistry 8, n.º 2 (1 de abril de 2010): 308–19. http://dx.doi.org/10.2478/s11532-009-0139-3.

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AbstractDetailed theoretical studies of azide/thioacid amidation are performed using density functional theory. The calculated results indicate that electronic properties of azide have significant effects on reaction pathways, which result in two distinct mechanisms for electron-rich and electron-poor azide coupling in the base-promoted amidation. For electron-rich azide amidation, after the concerted [3+2] cycloaddition of azide/thiocarboxylate, a new reaction channel is found challenging that recently mentioned, which follows two consecutive, unimolecular reactions with very low activation barriers (−1) to give an anionic amide and a nitrous sulfide (N2S). Distinct from electron-rich azide amidation, electron-poor azide first couples with thiocarboxylate to form a linear stable adduct, and then passes through the transition state of the rate-controlling step to afford the anionic amide, rather than the thiatrazoline. The free energy barrier of this step is 4.2 kcal mol−1 lower than that previously proposed. Comparatively, the azide/thioacid amidations undergo the concerted [3+2] cycloaddition and the subsequent retro-[3+2] cycloaddition process to give cis-enol form of the amide, which have higher activation barriers than those in the based-promoted amidation. Solvent effects investigated indicate that non-polar solvents, such as chloroform, are more preferable for the base-promoted thioacid/azide amidation.

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3

Zhao, Bei, Yang Xiao, Dan Yuan, Chengrong Lu y Yingming Yao. "Synthesis and characterization of bridged bis(amidato) rare earth metal amides and their applications in C–N bond formation reactions". Dalton Transactions 45, n.º 9 (2016): 3880–87. http://dx.doi.org/10.1039/c5dt04217h.

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Eight bis(amidato) rare-earth metal amides were successfully synthesized and well characterized, which exhibited high catalytic activities in both the direct amidation of aldehydes and the addition of amines with carbodiimine.

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4

Santos, A. Sofia, Artur M. S. Silva y M. Manuel B. Marques. "Sustainable Amidation Reactions - Recent Advances". European Journal of Organic Chemistry 2020, n.º 17 (28 de abril de 2020): 2501–16. http://dx.doi.org/10.1002/ejoc.202000106.

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5

Kasprzak, Artur, Agnieszka Zuchowska y Magdalena Poplawska. "Functionalization of graphene: does the organic chemistry matter?" Beilstein Journal of Organic Chemistry 14 (2 de agosto de 2018): 2018–26. http://dx.doi.org/10.3762/bjoc.14.177.

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Reactions applying amidation- or esterification-type processes and diazonium salts chemistry constitute the most commonly applied synthetic approaches for the modification of graphene-family materials. This work presents a critical assessment of the amidation and esterification methodologies reported in the recent literature, as well as a discussion of the reactions that apply diazonium salts. Common misunderstandings from the reported covalent functionalization methods are discussed, and a direct link between the reaction mechanisms and the basic principles of organic chemistry is taken into special consideration.

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6

Ji, Chong-Lei, Pei-Pei Xie y Xin Hong. "Computational Study of Mechanism and Thermodynamics of Ni/IPr-Catalyzed Amidation of Esters". Molecules 23, n.º 10 (18 de octubre de 2018): 2681. http://dx.doi.org/10.3390/molecules23102681.

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Nickel catalysis has shown remarkable potential in amide C–N bond activation and functionalization. Particularly for the transformation between ester and amide, nickel catalysis has realized both the forward (ester to amide) and reverse (amide to ester) reactions, allowing a powerful approach for the ester and amide synthesis. Based on density functional theory (DFT) calculations, we explored the mechanism and thermodynamics of Ni/IPr-catalyzed amidation with both aromatic and aliphatic esters. The reaction follows the general cross-coupling mechanism, involving sequential oxidative addition, proton transfer, and reductive elimination. The calculations indicated the reversible nature of amidation, which highlights the importance of reaction thermodynamics in related reaction designs. To shed light on the control of thermodynamics, we also investigated the thermodynamic free energy changes of amidation with a series of esters and amides.

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7

Pongracz, Tamas, Aswin Verhoeven, Manfred Wuhrer y Noortje de Haan. "The structure and role of lactone intermediates in linkage-specific sialic acid derivatization reactions". Glycoconjugate Journal 38, n.º 2 (18 de enero de 2021): 157–66. http://dx.doi.org/10.1007/s10719-020-09971-7.

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AbstractSialic acids occur ubiquitously throughout vertebrate glycomes and often endcap glycans in either α2,3- or α2,6-linkage with diverse biological roles. Linkage-specific sialic acid characterization is increasingly performed by mass spectrometry, aided by differential sialic acid derivatization to discriminate between linkage isomers. Typically, during the first step of such derivatization reactions, in the presence of a carboxyl group activator and a catalyst, α2,3-linked sialic acids condense with the subterminal monosaccharides to form lactones, while α2,6-linked sialic acids form amide or ester derivatives. In a second step, the lactones are converted into amide derivatives. Notably, the structure and role of the lactone intermediates in the reported reactions remained ambiguous, leaving it unclear to which extent the amidation of α2,3-linked sialic acids depended on direct aminolysis of the lactone, rather than lactone hydrolysis and subsequent amidation. In this report, we used mass spectrometry to unravel the role of the lactone intermediate in the amidation of α2,3-linked sialic acids by applying controlled reaction conditions on simple and complex glycan standards. The results unambiguously show that in common sialic acid derivatization protocols prior lactone formation is a prerequisite for the efficient, linkage-specific amidation of α2,3-linked sialic acids, which proceeds predominantly via direct aminolysis. Furthermore, nuclear magnetic resonance spectroscopy confirmed that exclusively the C2 lactone intermediate is formed on a sialyllactose standard. These insights allow a more rationalized method development for linkage-specific sialic derivatization in the future.

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8

Buhaienko, Ihor, Maksym Kyrylenko y Volodymyr Mylenkyi. "Mathematical modeling of the technological process and synthesis of the amidation control system". Proceedings of the NTUU “Igor Sikorsky KPI”. Series: Chemical engineering, ecology and resource saving, n.º 1 (29 de marzo de 2022): 55–61. http://dx.doi.org/10.20535/2617-9741.1.2022.254159.

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There is still no exact mathematical model or control system for sodium sulphacyl production, so not all available control systems are accurate and not all possible disturbances of the system during operation have been identified. An urgent problem is to create an optimal mathematical model and use it as the basis for the synthesis of an amidator control system using a controller. In creating a mathematical model for the synthesis of the control system for the amidation process, it is necessary to understand the component of its mechanism. The amidation reaction takes place with a significant heat release, as well as through the available catalyst in the amidator, and side reactions occur. Using static and dynamic characteristics, a mathematical model was created, from which a control system was developed using a PID controller. After a mathematical model has been developed, it becomes clear that the amidator must be cooled constantly for its correct operation, because the lower the temperature of the amide at the outlet, the better the product. The temperature must be maintained at a level of 324K to 327K with water supply for cooling at 19-20 kg/s. The implemented automatic process control allows the production capacity to be managed at minimal cost. The PID controller, which is configured according to the formula of the transfer function of the amidator and the transport delay link, was selected as the main controller. The controller used includes two components: integral and differential. The synthesis of the control system based on the PID controller made it possible to fully investigate the process taking into account the disturbances, which were still uncertain, increased the rate of reaching a steady level, and reduced production costs.

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9

Arkhipenko, Sergey, Marco T. Sabatini, Andrei S. Batsanov, Valerija Karaluka, Tom D. Sheppard, Henry S. Rzepa y Andrew Whiting. "Mechanistic insights into boron-catalysed direct amidation reactions". Chemical Science 9, n.º 4 (2018): 1058–72. http://dx.doi.org/10.1039/c7sc03595k.

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10

Tortajada, Andreu, Marino Börjesson y Ruben Martin. "Nickel-Catalyzed Reductive Carboxylation and Amidation Reactions". Accounts of Chemical Research 54, n.º 20 (29 de septiembre de 2021): 3941–52. http://dx.doi.org/10.1021/acs.accounts.1c00480.

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11

Kumar, Dhivya, Richard E. Mains y Betty A. Eipper. "60 YEARS OF POMC: From POMC and α-MSH to PAM, molecular oxygen, copper, and vitamin C". Journal of Molecular Endocrinology 56, n.º 4 (mayo de 2016): T63—T76. http://dx.doi.org/10.1530/jme-15-0266.

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A critical role for peptide C-terminal amidation was apparent when the first bioactive peptides were identified. The conversion of POMC into adrenocorticotropic hormone and then into α-melanocyte-stimulating hormone, an amidated peptide, provided a model system for identifying the amidating enzyme. Peptidylglycine α-amidating monooxygenase (PAM), the only enzyme that catalyzes this modification, is essential; mice lacking PAM survive only until mid-gestation. Purification and cloning led to the discovery that the amidation of peptidylglycine substrates proceeds in two steps: peptidylglycine α-hydroxylating monooxygenase catalyzes the copper- and ascorbate-dependent α-hydroxylation of the peptidylglycine substrate; peptidyl-α-hydroxyglycine α-amidating lyase cleaves the N–C bond, producing amidated product and glyoxylate. Both enzymes are contained in the luminal domain of PAM, a type 1 integral membrane protein. The structures of both catalytic cores have been determined, revealing how they interact with metals, molecular oxygen, and substrate to catalyze both reactions. Although not essential for activity, the intrinsically disordered cytosolic domain is essential for PAM trafficking. A phylogenetic survey led to the identification of bifunctional membrane PAM in Chlamydomonas, a unicellular eukaryote. Accumulating evidence points to a role for PAM in copper homeostasis and in retrograde signaling from the lumen of the secretory pathway to the nucleus. The discovery of PAM in cilia, cellular antennae that sense and respond to environmental stimuli, suggests that much remains to be learned about this ancient protein.

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12

Szostak, Michal y Guangchen Li. "Non-Classical Amide Bond Formation: Transamidation and Amidation of Activated Amides and Esters by Selective N–C/O–C Cleavage". Synthesis 52, n.º 18 (15 de mayo de 2020): 2579–99. http://dx.doi.org/10.1055/s-0040-1707101.

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In the past several years, tremendous advances have been made in non-classical routes for amide bond formation that involve transamidation and amidation reactions of activated amides and esters. These new methods enable the formation of extremely valuable amide bonds via transition-metal-catalyzed, transition-metal-free, or metal-free pathways by exploiting chemoselective acyl C–X (X = N, O) cleavage under mild conditions. In a broadest sense, these reactions overcome the formidable challenge of activating C–N/C–O bonds of amides or esters by rationally tackling nN → π*C=O delocalization in amides and nO → π*C=O donation in esters. In this account, we summarize the recent remarkable advances in the development of new methods for the synthesis of amides with a focus on (1) transition-metal/NHC-catalyzed C–N/C–O bond activation, (2) transition-metal-free highly selective cleavage of C–N/C–O bonds, (3) the development of new acyl-transfer reagents, and (4) other emerging methods.1 Introduction2 Transamidation of Amides2.1 Transamidation by Metal–NHC Catalysis (Pd–NHC, Ni–NHC)2.2 Transition-Metal-Free Transamidation via Tetrahedral Intermediates2.3 Reductive Transamidation2.4 New Acyl-Transfer Reagents2.5 Tandem Transamidations3 Amidation of Esters3.1 Amidation of Esters by Metal–NHC Catalysis (Pd–NHC, Ni–NHC)3.2 Transition-Metal-Free Amidation of Esters via Tetrahedral Intermediates3.3 Reductive Amidation of Esters4 Transamidations of Amides by Other Mechanisms5 Conclusions and Outlook

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13

Liu, Yi, Puying Luo, Yang Fu, Tianxin Hao, Xuan Liu, Qiuping Ding y Yiyuan Peng. "Recent advances in the tandem annulation of 1,3-enynes to functionalized pyridine and pyrrole derivatives". Beilstein Journal of Organic Chemistry 17 (22 de septiembre de 2021): 2462–76. http://dx.doi.org/10.3762/bjoc.17.163.

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Great progress has been made in the tandem annulation of enynes in the past few years. This review only presents the corresponding reactions of 1,3-enyne structural motifs to provide the functionalized pyridine and pyrrole derivatives. The functionalization reactions cover iodination, bromination, trifluoromethylation, azidation, carbonylation, arylation, alkylation, selenylation, sulfenylation, amidation, esterification, and hydroxylation. We also briefly introduce the applications of the products and the reaction mechanisms for the synthesis of corresponding N-heterocycles.

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14

Wan, Jie-Ping y Yanfeng Jing. "Recent advances in copper-catalyzed C–H bond amidation". Beilstein Journal of Organic Chemistry 11 (17 de noviembre de 2015): 2209–22. http://dx.doi.org/10.3762/bjoc.11.240.

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Copper catalysis has been known as a powerful tool for its ubiquitous application in organic synthesis. One of the fundamental utilities of copper catalysis is in the C–N bond formation by using carbon sources and nitrogen functional groups such as amides. In this review, the recent progress in the amidation reactions employing copper-catalyzed C–H amidation is summarized.

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15

Vishe, Mahesh, Radim Hrdina, Amalia I. Poblador-Bahamonde, Céline Besnard, Laure Guénée, Thomas Bürgi y Jérôme Lacour. "Remote stereoselective deconjugation of α,β-unsaturated esters by simple amidation reactions". Chemical Science 6, n.º 8 (2015): 4923–28. http://dx.doi.org/10.1039/c5sc01118c.

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16

Wang, Xiao. "Challenges and outlook for catalytic direct amidation reactions". Nature Catalysis 2, n.º 2 (febrero de 2019): 98–102. http://dx.doi.org/10.1038/s41929-018-0215-1.

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17

Roscales, Silvia y Aurelio G. Csáky. "How to make C–N bonds using boronic acids and their derivatives without transition metals". Chemical Society Reviews 49, n.º 15 (2020): 5159–77. http://dx.doi.org/10.1039/c9cs00735k.

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18

Steven, Alan. "Micelle-Mediated Chemistry in Water for the Synthesis of Drug Candidates". Synthesis 51, n.º 13 (21 de mayo de 2019): 2632–47. http://dx.doi.org/10.1055/s-0037-1610714.

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Micellar reaction conditions, in a predominantly aqueous medium, have been developed for transformations commonly used by synthetic chemists working in the pharmaceutical industry to discover and develop drug candidates. The reactions covered in this review are the Suzuki–Miyaura, Miyaura borylation, Sonogashira coupling, transition-metal-catalysed CAr–N coupling, SNAr, amidation, and nitro reduction. Pharmaceutically relevant examples of these applications will be used to show how micellar conditions can offer advantages in yield, operational ease, amount of waste generated, transition-metal catalyst loading, and safety over the use of organic solvents, irrespective of the setting in which they are used.1 Introduction2 Micelles as Solubilising Agents3 Micelles as Nanoreactors4 Designer Surfactants5 A Critical Evaluation of the Case for Chemistry in Micelles6 Scope of Review7 Suzuki–Miyaura Coupling8 Miyaura Borylation9 Sonogashira Coupling10 Transition-Metal-Catalysed CAr–N Couplings11 SNAr12 Amidation13 Nitro Reduction14 Micellar Sequences15 Summary and Outlook

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19

Ziyaei Halimehjani, Azim, Petr Beier, Maryam Khalili Foumeshi, Ali Alaei y Blanka Klepetářová. "Tandem Alkylation/Michael Addition Reaction of Dithiocarbamic Acids with Alkyl γ-Bromocrotonates: Access to Functionalized 1,3-Thiazolidine-2-thiones". Synthesis 53, n.º 13 (25 de enero de 2021): 2219–28. http://dx.doi.org/10.1055/a-1372-1619.

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AbstractThiazolidine-2-thiones were prepared via a novel multicomponent reaction of primary amines (amino acids), carbon disulfide, and γ-bromocrotonates. The reaction proceeds via a domino alkylation/intramolecular Michael addition to provide the corresponding thiazolidine-2-thiones in high to excellent yields. By using diamines in this protocol, bis(thiazolidine-2-thiones) derivatives were synthesized. The synthetic utility of the adducts was demonstrated by hydrolysis, amidation, and oxidation reactions.

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20

Kadari, Lingaswamy, William Erb, Thierry Roisnel, Palakodety Radha Krishna y Florence Mongin. "Iodoferrocene as a partner in N-arylation of amides". New Journal of Chemistry 44, n.º 37 (2020): 15928–41. http://dx.doi.org/10.1039/d0nj03470c.

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21

Ma, Nan, Zheyuan Liu, Jianhui Huang y Yanfeng Dang. "Mechanistic studies of Cp*Ir(iii)/Cp*Rh(iii)-catalyzed branch-selective allylic C–H amidation: why is Cp*Ir(iii) superior to Cp*Rh(iii)?" Organic & Biomolecular Chemistry 19, n.º 17 (2021): 3850–58. http://dx.doi.org/10.1039/d1ob00446h.

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22

Lin, Chia-Hsin, Bor-Cherng Hong y Gene-Hsiang Lee. "Asymmetric synthesis of functionalized pyrrolizidines by an organocatalytic and pot-economy strategy". RSC Advances 6, n.º 10 (2016): 8243–47. http://dx.doi.org/10.1039/c5ra25103f.

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An enantioselective synthesis of indolizidines was achieved with a one-step purification by sequential asymmetric Michael–oxidative esterification–Michael–reduction–reductive Mannich–amidation reactions.

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23

Rocco, Daniele, Isabella Chiarotto, Leonardo Mattiello, Fabiana Pandolfi, Daniela Zane y Marta Feroci. "Electrochemical synthesis and amidation of benzoin: benzamides from benzaldehydes". Pure and Applied Chemistry 91, n.º 10 (25 de octubre de 2019): 1709–15. http://dx.doi.org/10.1515/pac-2018-1118.

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Abstract The benzoin condensation starting from benzaldehyde and the subsequent benzoin amidation to benzamide can be efficiently carried out under very mild conditions in an electrolysis cell. Among the advantages of using electrochemistry to generate our active reagents, the use of the easily dosed and non pollutant electron, instead of stoichiometric amounts of redox reagents or bases, usually renders the electrochemical methodology “greener” than classical organic reactions. Benzoin is obtained in good yield (85 %) carrying out the reaction in the room temperature ionic liquid BMIm-BF4. In this electrochemical reaction this liquid salt assumes the double role of solvent-supporting electrolyte system and precatalyst, yielding the corresponding N-heterocyclic carbene. The subsequent benzoin amidation is carried out by electrochemically generated superoxide anion, in the presence of an aliphatic primary or secondary amine. In this case the system superoxide/molecular oxygen acts as base and oxidant, yielding very good yields of benzamides (up to 89 %).

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24

Xia, Ji-Bao, Yan-Lin Li y Zheng-Yang Gu. "Transition-Metal-Catalyzed Intermolecular C–H Carbonylation toward Amides". Synlett 32, n.º 01 (17 de agosto de 2020): 07–13. http://dx.doi.org/10.1055/s-0040-1706416.

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The amide linkage is one of the most important structural moieties in both chemistry and biology. Here, we briefly discuss recent advances in catalytic intermolecular C–H carbonylation reactions for the synthesis of amides, with particular attention to our intermolecular C–H amidation of arenes with carbon monoxide and organic azides to produce amides.1 Introduction2 Representative Methods for Amide Synthesis3 C–H Aminocarbonylation with Carbon Monoxide and Amines4 C–H Amidation to Amides with Carbon Monoxide and Azides5 Summary and Outlook

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25

Mkhonazi, Blessing D., Malibongwe Shandu, Ronewa Tshinavhe, Sandile B. Simelane y Paseka T. Moshapo. "Solvent-Free Iron(III) Chloride-Catalyzed Direct Amidation of Esters". Molecules 25, n.º 5 (26 de febrero de 2020): 1040. http://dx.doi.org/10.3390/molecules25051040.

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Amide functional groups are prominent in a broad range of organic compounds with diverse beneficial applications. In this work, we report the synthesis of these functional groups via an iron(iii) chloride-catalyzed direct amidation of esters. The reactions are conducted under solvent-free conditions and found to be compatible with a range of amine and ester substrates generating the desired amides in short reaction times and good to excellent yields at a catalyst loading of 15 mol%.

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26

Paggiola, Giulia, Nolwenn Derrien, Jonathan D. Moseley, Anthony Green, Sabine L. Flitsch, James H. Clark, Con Robert McElroy y Andrew J. Hunt. "Application of bio-based solvents for biocatalysed synthesis of amides with Pseudomonas stutzeri lipase (PSL)". Pure and Applied Chemistry 92, n.º 4 (28 de abril de 2020): 579–86. http://dx.doi.org/10.1515/pac-2019-0808.

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AbstractBio-based solvents were investigated for the biocatalysed amidation reactions of various ester-amine combinations by Pseudomonas stutzeri lipase (PSL). Reactions were undertaken in a range of green and potentially bio-based solvents including terpinolene, p-cymene, limonene, 2-methyl THF, ɣ-valerolactone, propylene carbonate, dimethyl isosorbide, glycerol triacetate and water. Solvent screenings demonstrated the importance and potential of using non-polar bio-based solvents for favouring aminolysis over hydrolysis; whilst substrate screenings highlighted the unfavourable impact of reactants bearing bulky para- or 4-substituents. Renewable terpene-based solvents (terpinolene, p-cymene, D-limonene) were demonstrated to be suitable bio-based media for PSL amidation reactions. Such solvents could provide a greener and more sustainable alternative to traditional petrochemical derived non-polar solvents. Importantly, once the enzyme (either PSL or CALB) binds with a bulky para-substituted substrate, only small reagents are able to access the active site. This therefore limits the possibility for aminolysis to take place, thereby promoting the hydrolysis. This mechanism of binding supports the widely accepted ‘Ping Pong – Bi Bi’ mechanism used to describe enzyme kinetics. The work highlights the need to further investigate enzyme activity in relation to para- or 4-substituted substrates. A priority in PSL chemistry remains a methodology to tackle the competing hydrolysis reaction.

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27

Belousov, Artem S., Anton L. Esipovich, Evgeny A. Kanakov y Ksenia V. Otopkova. "Recent advances in sustainable production and catalytic transformations of fatty acid methyl esters". Sustainable Energy & Fuels 5, n.º 18 (2021): 4512–45. http://dx.doi.org/10.1039/d1se00830g.

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This review highlights the recent advances in the sustainable production of fatty acid methyl esters and their transformations, including oxidation, amidation, hydrogenation, deoxygenation, ethoxylation, metathesis, and isomerisation reactions.

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28

Kurouchi, Hiroaki. "Diprotonative stabilization of ring-opened carbocationic intermediates: conversion of tetrahydroisoquinoline to triarylmethanes". Chemical Communications 56, n.º 59 (2020): 8313–16. http://dx.doi.org/10.1039/d0cc01969k.

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Superacid-promoted conversion of tetrahydroisoquinolines to triarylmethanes via tandem reactions of C–N bond scission, Friedel–Crafts alkylation, C–O bond scission, and electrophilic aromatic amidation was developed.

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29

Mahato, Sachinta, Sougata Santra, Grigory V. Zyryanov y Adinath Majee. "Metal-Free Amidation Reactions of Terminal Alkynes with Benzenesulfonamide". Journal of Organic Chemistry 84, n.º 6 (26 de febrero de 2019): 3176–83. http://dx.doi.org/10.1021/acs.joc.8b03065.

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30

Liu, Bingxian, Bin Li y Baiquan Wang. "Ru(ii)-catalyzed amidation reactions of 8-methylquinolines with azides via C(sp3)–H activation". Chemical Communications 51, n.º 91 (2015): 16334–37. http://dx.doi.org/10.1039/c5cc06230f.

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31

Wang, Chao, Lingling Huang, Min Lu, Bei Zhao, Yaorong Wang, Yong Zhang, Qi Shen y Yingming Yao. "Anionic phenoxy-amido rare-earth complexes as efficient catalysts for amidation of aldehydes with amines". RSC Adv. 5, n.º 115 (2015): 94768–75. http://dx.doi.org/10.1039/c5ra20285j.

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A series of anionic organo-rare-earth amido complexes stabilized by dianionic phenoxy-amido ligands were synthesized, and their catalytic property for the amidation reactions of aldehydes with amines was explored.

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32

Li, C., C. D. Oldham y S. W. May. "NN-dimethyl-1,4-phenylenediamine as an alternative reductant for peptidylglycine α-amidating mono-oxygenase catalysis". Biochemical Journal 300, n.º 1 (15 de mayo de 1994): 31–36. http://dx.doi.org/10.1042/bj3000031.

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C-terminal alpha-amidation is a structural feature essential to the biological activity of many peptide hormones. Peptidylglycine alpha-amidating mono-oxygenase (PAM; EC 1.14.17.3) catalyses conversion of glycine-extended peptide hormone precursors into their corresponding alpha-hydroxyglycine derivatives. This reaction is the first step in the C-terminal amidation process. We report here that in the presence of molecular O2, copper and PAM substrate, NN-dimethyl-1,4-phenylenediamine (DMPD) serves as the requisite electron donor for the mono-oxygenase, being oxidized in the process to a stable and highly chromophoric cation radical. By monitoring the rate of increase in absorbance at 515 nm, PAM activity can be easily followed. This provides a spectrophotometric assay for PAM, which represents the first continuous assay reported for this enzyme. DMPD-supported PAM-catalysed mono-oxygenation exhibits normal Michaelis-Menten kinetic behaviour. Steady-state kinetic studies established that both the ascorbate-supported and DMPD-supported PAM reactions exhibit apparent ‘Ping Pong’ kinetics. In addition, both electron donors give rise to similar pH profiles and identical inhibition patterns towards known competitive inhibitors of PAM. The stoichiometry between formation of the DMPD cation radical and the alpha-hydroxyglycine PAM product was determined to be 2:1, the value expected for a monooxygenase-catalysed reaction. The optimum pH for the DMPD-supported continuous PAM assay was found to be about 5.5. The major advantage of this assay over all previously reported methods is that it is continuous; thus accurate initial rates are easily obtained. Moreover, unlike previous assay methods, 125I-labelled or chromophorically modified substrates are not required. Kinetic parameters for a broad range of PAM substrates and inhibitors have been successfully obtained using this assay.

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33

Kasahara, Takahito y Marco A. Ciufolini. "Further studies toward himandrine via sequential oxidative amidation – intramolecular Diels–Alder reactions". Canadian Journal of Chemistry 91, n.º 1 (enero de 2013): 82–90. http://dx.doi.org/10.1139/cjc-2012-0340.

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Exploratory work toward the alkaloid himandrine evaluated the directing ability of a pyrrolidine C-3 substituent in a diastereotopic group elective intramolecular Diels–Alder reaction of a spirodienone obtained by the oxidative amidation of a phenol. The study also defined a technique for the construction of ring D of the alkaloid.

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34

Bera, Shyamal Kanti, Rosalin Bhanja y Prasenjit Mal. "DDQ in mechanochemical C–N coupling reactions". Beilstein Journal of Organic Chemistry 18 (1 de junio de 2022): 639–46. http://dx.doi.org/10.3762/bjoc.18.64.

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2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) is a commonly known oxidant. Herein, we report that DDQ can be used to synthesize 1,2-disubstituted benzimidazoles and quinazolin-4(3H)-ones via the intra- and intermolecular C–N coupling reaction under solvent-free mechanochemical (ball milling) conditions. In the presence of DDQ, the intramolecular C(sp2)–H amidation of N-(2-(arylideneamino)phenyl)-p-toluenesulfonamides leads to 1,2-disubstituted benzimidazoles and the one-pot coupling of 2-aminobenzamides with aryl/alkyl aldehydes resulted in substituted quinazolin-4(3H)-one derivatives in high yields.

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35

MOORE, Allison B. y Sheldon W. MAY. "Kinetic and inhibition studies on substrate channelling in the bifunctional enzyme catalysing C-terminal amidation". Biochemical Journal 341, n.º 1 (24 de junio de 1999): 33–40. http://dx.doi.org/10.1042/bj3410033.

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A series of experiments has been conducted to investigate the possibility that substrate channelling might occur in the bifunctional forms of enzymes carrying out C-terminal amidation, a post-translational modification essential to the biological activity of many neuropeptides. C-terminal amidation entails sequential action by peptidylglycine mono-oxygenase (PAM, EC 1.14.17.3) and peptidylamidoglycolate lyase (PGL, EC 4.3.2.5), with the mono-oxygenase catalysing conversion of a glycine-extended pro-peptide into the corresponding α-hydroxyglycine derivative, which is then converted by the lyase into amidated peptide plus glyoxylate. Since the mono-oxygenase and lyase reactions exhibit tandem reaction stereospecificities, channelling of the α-hydroxy intermediate might occur, as is the case for some other multifunctional enzymes. Selective inhibition of the mono-oxygenase domain by competitive ester inhibitors, as well as mechanism-based mono-oxygenase inactivation by the novel olefinic inhibitor 5-acetamido-4-oxo-6-phenylhex-2-enoate (N-acetylphenylalanyl acrylate), has little to no effect on the kinetic parameters of the lyase domain of the AE from Xenopus laevis. Similarly, inhibition of the lyase domain by the potent dioxo inhibitor 2,4-dioxo-5-acetamido-6-phenylhexanoate has little effect on the activity of the monooxygenase domain in the bifunctional enzyme. A series of experiments on intermediate accumulation and conversion were also carried out, along with kinetic investigations of the reactivities of the monofunctional and bifunctional forms of PAM and PGL towards substrates and inhibitors. Taken together, the results demonstrate the kinetic independence of the mono-oxygenase and lyase domains, and provide no evidence for substrate channelling between these domains in the bifunctional amidating enzyme.

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36

Chen, Mei-Lan, Jian-Qing Min, Sheng-Dong Pan y Mi-Cong Jin. "Surface core–shell magnetic polymer modified graphene oxide-based material for 2,4,6-trichlorophenol removal". RSC Advances 4, n.º 108 (2014): 63494–501. http://dx.doi.org/10.1039/c4ra14150d.

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A novel well-designed graphene oxide-based magnetic polymer (GO-Fe₃O₄@P) has been successfully synthesizedviadistillation–precipitation polymerization, ring-opening and amidation reactions and showed good adsorption capacity to 2,4,6-TCP.

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37

Wang, Danfeng, Hai Huang y Xiaolin Zhu. "Development of anthrazoline photocatalysts for promoting amination and amidation reactions". Chemical Communications 58, n.º 21 (2022): 3529–32. http://dx.doi.org/10.1039/d1cc07315j.

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Herein, we report the synthesis, photophysical and electrochemical properties of a series of anthrazoline organophotocatalysts, as well as their photocatalytic competencies in promoting C–N bond formation in combination with nickel catalyst.

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38

Hernández, José G., Karen J. Ardila-Fierro, Dajana Barišić y Hervé Geneste. "Multi-faceted reactivity of N-fluorobenzenesulfonimide (NFSI) under mechanochemical conditions: fluorination, fluorodemethylation, sulfonylation, and amidation reactions". Beilstein Journal of Organic Chemistry 18 (7 de febrero de 2022): 182–89. http://dx.doi.org/10.3762/bjoc.18.20.

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In the search for versatile reagents compatible with mechanochemical techniques, in this work we studied the reactivity of N-fluorobenzenesulfonimide (NFSI) by ball milling. We corroborated that, by mechanochemistry, NFSI can engage in a variety of reactions such as fluorinations, fluorodemethylations, sulfonylations, and amidations. In comparison to the protocols reported in solution, the mechanochemical reactions were accomplished in the absence of solvents, in short reaction times, and in yields comparable to or higher than their solvent-based counterparts.

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39

Yoshino, Tatsuhiko y Shigeki Matsunaga. "Cp*CoIII-Catalyzed C–H Functionalization and Asymmetric Reactions Using External Chiral Sources". Synlett 30, n.º 12 (7 de mayo de 2019): 1384–400. http://dx.doi.org/10.1055/s-0037-1611814.

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This account describes Cp*CoIII-catalyzed C–H functionalization reactions developed in our group between 2013 and 2018. Cp*CoIII catalysts not only serve as inexpensive alternatives to Cp*RhIII catalysts but also exhibit unique reactivity and selectivity in several transformations. In the latter part of this review, we introduce catalytic asymmetric C–H functionalization reactions using achiral RhIII or CoIII catalysts with chiral disulfonates or carboxylic acids as external chiral sources.1 Introduction and Overview2 Cp*CoIII-Catalyzed C–H Functionalization Reactions2.1 C–H Addition Reactions to Polar Double Bonds2.2 Cp*Co(CO)I2 and [Cp*CoI2]2 Precursors for the C2-selective C–H Amidation of Indoles2.3 C–H Functionalization of Carbamoyl-Protected Indoles Using Alkynes2.4 C–H Allylation Using Allyl Alcohols2.5 Cyclization Reactions of O-Acyloximes and Alkynes2.6 Other Miscellaneous Reactions3 Enantioselective C–H Functionalization Reactions by Hybrid Catalysis3.1 Cp*RhIII/Chiral Disulfonate Catalysts for the Enantioselective C–H Addition to Enones3.2 Enantioselective C–H Cleavage Using Chiral Carboxylic Acids4 Summary and Perspective

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40

Martin, Stephen F., Michael P. Dwyer y Christopher L. Lynch. "Application of AlMe3-mediated amidation reactions to solution phase peptide synthesis". Tetrahedron Letters 39, n.º 12 (marzo de 1998): 1517–20. http://dx.doi.org/10.1016/s0040-4039(98)00071-9.

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41

Ganiek, Maximilian A., Matthias R. Becker, Guillaume Berionni, Hendrik Zipse y Paul Knochel. "Barbier Continuous Flow Preparation and Reactions of Carbamoyllithiums for Nucleophilic Amidation". Chemistry – A European Journal 23, n.º 43 (17 de julio de 2017): 10280–84. http://dx.doi.org/10.1002/chem.201702593.

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42

Lamani, Manjunath y Kandikere Ramaiah Prabhu. "NIS-Catalyzed Reactions: Amidation of Acetophenones and Oxidative Amination of Propiophenones". Chemistry - A European Journal 18, n.º 46 (5 de octubre de 2012): 14638–42. http://dx.doi.org/10.1002/chem.201202703.

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43

Cho, Inha, Zhi-Jun Jia y Frances H. Arnold. "Site-selective enzymatic C‒H amidation for synthesis of diverse lactams". Science 364, n.º 6440 (9 de mayo de 2019): 575–78. http://dx.doi.org/10.1126/science.aaw9068.

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A major challenge in carbon‒hydrogen (C‒H) bond functionalization is to have the catalyst control precisely where a reaction takes place. In this study, we report engineered cytochrome P450 enzymes that perform unprecedented enantioselective C‒H amidation reactions and control the site selectivity to divergently construct β-, γ-, and δ-lactams, completely overruling the inherent reactivities of the C‒H bonds. The enzymes, expressed in Escherichia coli cells, accomplish this abiological carbon‒nitrogen bond formation via reactive iron-bound carbonyl nitrenes generated from nature-inspired acyl-protected hydroxamate precursors. This transformation is exceptionally efficient (up to 1,020,000 total turnovers) and selective (up to 25:1 regioselectivity and 97%, please refer to compound 2v enantiomeric excess), and can be performed easily on preparative scale.

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44

Vázquez, Ester y Maurizio Prato. "Functionalization of carbon nanotubes for applications in materials science and nanomedicine". Pure and Applied Chemistry 82, n.º 4 (13 de marzo de 2010): 853–61. http://dx.doi.org/10.1351/pac-con-09-10-40.

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Carbon nanotubes (CNTs) can be functionalized using a variety of efficient protocols. Especially, esterification and amidation reactions are exploited along with 1,3-dipolar cycloadditions. The use of microwaves (MWs) to activate the reactivity of CNTs is also reported. Innovative NMR methodologies can be introduced to investigate the covalent attachment of organic moieties to CNTs.

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45

Goodreid, Jordan D., Petar A. Duspara, Caroline Bosch y Robert A. Batey. "Amidation Reactions from the Direct Coupling of Metal Carboxylate Salts with Amines". Journal of Organic Chemistry 79, n.º 3 (13 de enero de 2014): 943–54. http://dx.doi.org/10.1021/jo402374c.

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46

Chou, Wen-Chih, Ming-Chen Chou, Yann-Yu Lu y Shyh-Fong Chen. "HMDS-promotedin situ amidation reactions of car☐ylic acids and amines". Tetrahedron Letters 40, n.º 17 (abril de 1999): 3419–22. http://dx.doi.org/10.1016/s0040-4039(99)00505-5.

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47

Barfoot, Christopher, Gerald Brooks, Pamela Brown, Steven Dabbs, David T. Davies, Ilaria Giordano, Alan Hennessy et al. "Flexible palladium-catalysed amidation reactions for the synthesis of complex aryl amides". Tetrahedron Letters 51, n.º 20 (mayo de 2010): 2685–89. http://dx.doi.org/10.1016/j.tetlet.2010.03.051.

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48

Trumbo, David L. "Polymers based on methyl acrylamidoglycolate methyl ether (MAGME): Michael addition-amidation reactions". Polymer Bulletin 31, n.º 5 (noviembre de 1993): 523–29. http://dx.doi.org/10.1007/bf00297887.

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49

Nguyen, Thanh V. y Demelza J. M. Lyons. "A novel aromatic carbocation-based coupling reagent for esterification and amidation reactions". Chemical Communications 51, n.º 15 (2015): 3131–34. http://dx.doi.org/10.1039/c4cc09539a.

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50

Rajabi, Fatemeh, Mojdeh Raessi, Rick A. D. Arancon, Mohammad Reza Saidi y Rafael Luque. "Supported cobalt oxide nanoparticles as efficient catalyst in esterification and amidation reactions". Catalysis Communications 59 (enero de 2015): 122–26. http://dx.doi.org/10.1016/j.catcom.2014.09.044.

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