- A novel solid-phase chlorinating reagent for the synthesis of acyl chlorides
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Cyanuric chloride was loaded onto a modified Wang resin, which was successfully used to convert carboxylic acids to their corresponding acyl chlorides. The formation of acyl chlorides were confirmed by condensation with various amines or alcohols to form the corresponding amides or esters.
- Luo, Guanglin,Xu, Li,Poindexter, Graham S.
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- Aminolysis of Triphenylantimony Dicarboxylates and Its Application to Catalytic Amidation
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Triphenylantimony dicarboxylates (Ph3Sb(O2CR)2, where R=Me, CF3, Ph and CH2NH-Z) readily reacted with amines (R'NH2, where R'=n-C6H13, s-Bu, C6H11, and Ph) to afford corresponding amides and triphenylstibine oxide in fairly good yields.The amidation of RCO2H with R'NH2 was also catalyzed by the organoantimony compounds.
- Nomura, Ryoki,Wada, Takao,Yamada, Yasuhiro,Matsuda, Haruo
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- A mild and general solid-phase method for the synthesis of chiral polyamines. Solution studies on the cleavage of borane-amine intermediates from the reduction of secondary amides
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A mild oxidative workup protocol using iodine in an acetic acid-acetate buffer solution is described for the cleavage of borane-amine adducts arising from the borane-promoted reduction of polyamides supported onto practical trityl-based resins. Chiral polyamines with diverse side-chain functionalities can be generated as free bases without premature release from the solid support and with essentially no racemization using this method. A series of model oligomeric secondary diamides 6 containing various α-amino acid residues (Val, Phe, Tyr, Ser, Cys, Met, Gln, Trp) provided triamine products 8 in high yields and good to excellent purity. On the other hand, a substrate containing a tertiary amide (15) formed a rather unusual triaminoborane intermediate that required more stringent workup conditions to liberate the polyamine product 20. The reduction of oligomeric tertiary amides such as 9 was found sluggish, but these compounds could nonetheless be obtained in high purity from in situ reductive amination of the corresponding secondary amines. Control studies, carried out in solution with model secondary amide 23, confirmed the efficiency of the buffered iodine solution and highlighted several advantages (no heating necessary, no need for strong bases or acids) over existing methods for the cleavage of borane-amine adducts. A possible mechanism involving all buffer components (iodine, acetic acid, and acetate ion) is proposed in which borane-amine adducts are transformed first to the monoiodoborane-amine and then to the corresponding acetoxyborane-amine adduct of much weaker coordination affinity. The latter would dissociate readily and get trapped by the acetic acid to provide the desired secondary amine. This reduction/oxidative workup protocol is useful as a general method for the facile solid-phase synthesis of polyamines for eventual release in solution and use in various applications. It is also potentially very useful toward the synthesis and screening of bead-supported libraries of free oligoamines assembled through split-pool methods.
- Manku,Laplante,Kopac,Chan,Hall
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- Preparation, structure, and reactivity of bicyclic benziodazole: A new hypervalent iodine heterocycle
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A new bicyclic organohypervalent iodine heterocycle derivative of benziodazole was prepared by oxidation of 2-iodo-N,N'-diiso-propylisophthalamide with m-chloroperoxybenzoic acid under mild conditions. Single crystal X-ray crystallography of this compound revealed a five-membered bis-heterocyclic structure with two covalent bonds between the iodine atom and the nitrogen atoms. This novel benziodazole is a very stable compound with good solubility in common organic solvents. This compound can be used as an efficient reagent for oxidatively assisted coupling of carboxylic acids with alcohols or amines to afford the corresponding esters or amides in moderate yields.
- Jarvi, Melissa E.,Makitalo, Cody L.,Rohde, Gregory T.,Saito, Akio,Shea, Michael T.,Yoshimura, Akira,Yusubov, Mekhman S.,Zhdankin, Viktor V.
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- Zirconium-catalyzed direct amide bond formation between carboxylic esters and amines
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Development of catalytic amide bond formation reactions from readily available starting materials remains a challenging task for modern organic chemistry. Herein, we report that unactivated carboxylic esters and amines react in the presence of 10 mol % of zirconocene dichloride (Cp2ZrCl2) in toluene at 110 °C to afford amides in very good to excellent conversions. The Zr-catalyzed reaction is amenable for the amidation of aliphatic and aromatic carboxylic esters with primary and secondary amines. The reaction proceeds with almost complete retention of configuration for chiral esters and chiral amines.
- Lenstra, Danny C.,Nguyen, D. Thao,Mecinovi?, Jasmin
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- Chemoselective calcium-catalysed direct amidation of carboxylic esters
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Unactivated carboxylic esters and primary amines undergo calcium-catalysed direct amide bond formation in excellent yields under homogeneous conditions in toluene. This green and mild reaction proceeds chemoselectively with esters, whereas related carboxylic acids and amides remain unreactive.
- Nguyen, D. Thao,Lenstra, Danny C.,Mecinovi?, Jasmin
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- Organocatalytic and enantioselective [4+2] cyclization between hydroxymaleimides and: Ortho -hydroxyphenyl para -quinone methide-selective preparation of chiral hemiketals
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A cinchona alkaloid squaramide promoted enantioselective [4+2] cyclization between hydroxymaleimides and ortho-hydroxyphenyl p-QMs has been disclosed, and a wide range of chiral hemiketals containing chromane and succinimide frameworks with two adjacent quaternary stereogenic centers have been prepared for the first time with excellent results (up to 99% yield, up to 99?:?1 dr, up to >99% ee) under mild conditions. This journal is
- Xiang, Min,Li, Chen-Yi,Song, Xiang-Jia,Zou, Ying,Huang, Zhi-Cheng,Li, Xia,Tian, Fang,Wang, Li-Xin
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- Mechanistic studies into metal-catalyzed aldoxime to amide rearrangements
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The metal-catalyzed rearrangement of aldoximes into primary amides is a completely atom economical synthetic method for the preparation of one of the most important functional groups in chemistry. There have been several reports of various metals successfully catalyzing this reaction, however, there are conflicting views as to the mechanism involved. Herein we report new experimental evidence to support the mechanism and whether this is universal to all catalysts reported or metal specific. We also describe our further studies into the mechanism of the nickel-catalyzed acylation of amines with aldoximes. Copyright
- Allen, C. Liana,Lawrence, Ruth,Emmett, Liam,Williams, Jonathan M. J.
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Read Online
- Amide Bond Formation via the Rearrangement of Nitrile Imines Derived from N-2-Nitrophenyl Hydrazonyl Bromides
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We report how the rearrangement of highly reactive nitrile imines derived from N-2-nitrophenyl hydrazonyl bromides can be harnessed for the facile construction of amide bonds. This amidation reaction was found to be widely applicable to the synthesis of primary, secondary, and tertiary amides and was used as the key step in the synthesis of the lipid-lowering agent bezafibrate. The orthogonality and functional group tolerance of this approach was exemplified by the N-acylation of unprotected amino acids.
- Boyle, Mhairi,Livingstone, Keith,Henry, Martyn C.,Elwood, Jessica M. L.,Lopez-Fernandez, J. Daniel,Jamieson, Craig
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supporting information
p. 334 - 338
(2022/01/20)
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- Practical one-pot amidation of N -Alloc-, N -Boc-, and N -Cbz protected amines under mild conditions
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A facile one-pot synthesis of amides from N-Alloc-, N-Boc-, and N-Cbz-protected amines has been described. The reactions involve the use of isocyanate intermediates, which are generated in situ in the presence of 2-chloropyridine and trifluoromethanesulfonyl anhydride, to react with Grignard reagents to produce the corresponding amides. Using this reaction protocol, a variety of N-Alloc-, N-Boc-, and N-Cbz-protected aliphatic amines and aryl amines were efficiently converted to amides with high yields. This method is highly effective for the synthesis of amides and offers a promising approach for facile amidation.
- Hong, Wan Pyo,Tran, Van Hieu,Kim, Hee-Kwon
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p. 15890 - 15895
(2021/05/19)
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- N -Heterocyclic carbene (NHC) catalyzed amidation of aldehydes with amines via the tandem N -hydroxysuccinimide ester formation
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A facile method for the amidation of aldehydes by a cascade approach was developed. This methodology, reported for the first time, uses a N-heterocyclic carbene (NHC) as the catalyst, and N-hydroxysuccinimide (NHS) mediated synthesis of amides utilising TBHP as the oxidant. Various substituted aldehydes reacted smoothly with NHS giving the corresponding active esters in moderate to good yields, which facilely converted into amides in one pot. In addition, the drug moclobemide was synthesized to represent the practical utility of the developed methodology. This journal is
- Singh, Ashmita,Narula
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supporting information
p. 7486 - 7490
(2021/05/13)
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- Synthesis and biological screening of a library of macamides as TNF-α inhibitors
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Thirty-five macamide analogues were synthesised by modifying the initial molecular structure. The resulting structures were confirmed using NMR and MS. Cytotoxicity and the anti-inflammatory activity of these synthetic macamides were evaluated in the THP-1 cell line. Preliminary biological evaluation indicated that most of these synthetic macamides did not present cytotoxicity (MTT assay) in the tested cell line with respect to the control (actinomycin D). Regarding the anti-inflammatory activity, several analogues had a greater potential for inhibition of TNF-α than natural macamides. Synthetic macamide 4a was the most active (IC50 = 0.009 ± 0.001 μM) compared to the C87 (control). Through looking at the link between the chemical structure and the activity, our study proves that changes made to natural macamides at the level of the alkyl chain, the benzyl position, the amide bond, and the addition of two methyl groups to the aromatic ring (meta position) lead us to obtaining new macamides with greater anti-inflammatory activity. This journal is
- Apaza Ticona, Luis,Serban, Andreea Madalina,Acero Gómez, Javier,Rumbero Sánchez, ángel,Tena Pérez, Víctor
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p. 1196 - 1209
(2020/11/03)
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- Palladium-Catalyzed α-Arylation of Carboxylic Acids and Secondary Amides via a Traceless Protecting Strategy
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A novel traceless protecting strategy is presented for the long-standing challenge of conducting the palladium-catalyzed α-arylation of carboxylic aids and secondary amides with aryl halides. Both of the presented coupling processes occur with a variety of carboxylic acids and amides and with a variety of aryl bromides containing a broad range of functional groups, including base-sensitive functionality like acyl, alkoxycarbonyl, nitro, cyano, and even hydroxyl groups. Five commercial drugs were prepared through this method in one step in 81-96% yield. Gram-scale synthesis of medication Naproxen and Flurbiprofen with low palladium loading further highlights the practical value of this method.
- He, Zhi-Tao,Hartwig, John F.
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supporting information
p. 11749 - 11753
(2019/08/26)
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- Synthesis of Aliphatic Carboxamides Mediated by Nickel NN2-Pincer Complexes and Adaptation to Carbon-Isotope Labeling
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The development of a nickel-mediated aminocarbonylation utilizing NN2-pincer Ni-complexes, alkylzinc reagents, stoichiometric carbon monoxide and amines is described for the first time, which can be adapted to late-stage carbon-isotope labeling. This work expands the scope of the highly established palladium-promoted version of the reaction, by allowing carbon-sp3 fragments to take part in the three-component reaction. Finally, the results obtained show a remarkable effect of the pincer ligand for the reductive elimination step with the amine, which is followed by 13C NMR spectroscopy studies.
- Neumann, Karoline T.,Donslund, Aske S.,Andersen, Thomas L.,Nielsen, Dennis U.,Skrydstrup, Troels
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supporting information
p. 14946 - 14949
(2018/09/25)
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- Synthesis of secondary amides by direct amidation using polymer supported copper(II) complex
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A new polymer supported Cu(II) complex has been synthesized and characterized by CHN analyses, IR and UV–Vis spectral studies, ESR and thermogravimetric analyses, ICP-OES, surface area measurements. This complex was screened for their catalytic study towards the direct amidation reaction. The effects of solvents, reaction time, temperature and catalyst amount for the direct formation of amides from aldehydes and benzylamine with the aid of heterogeneous copper complex were reported. The polymer supported Cu(II) catalyst could be reused more than five times without appreciable loss of its initial activity. The plausible reaction mechanism has been proposed. The catalytic activity of the unsupported complex was also compared with the polymer supported Cu(II) complex.
- Renuka,Gayathri
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p. 195 - 202
(2018/05/04)
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- Method for synthesizing N-alkylamide
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The invention discloses a method for synthesizing N-alkylamide. In a reaction container, adding nitrile, a complex of a transition-metal catalyst gold, a solvent tetrahydrofuran and H2O; reacting a reaction mixture for several hours at the temperature of 130-140 DEG C, cooling the reaction mixture to room temperature, performing vacuum pressure reduction to remove the solvent; adding a compound alcohol, alkali, the complex of a transition-metal catalyst iridium, a solvent toluene, reacting the reaction mixture for several hours at the temperature of 130 DEG C, through column separation, obtaining a target compound. According to the invention, with participation of the transition-metal catalyst, commercial nitrile is hydrolyzed to generate an amide intermediate, and then is subjected to an alkylation reaction with alcohol to obtain N-alkylamide. The reaction has three obvious advantages: 1) the commercial nitrile and alcohol which is almost nontoxic are taken as initial raw materials; 2) only water is generated as a by-product in the reaction, so that the reaction has no harm on environment; and 3) reaction atom economy is high. The reaction accords with green chemistry requirement, and has wide development prospect.
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Paragraph 0155-0158
(2016/12/07)
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- Selective Palladium-Catalyzed Aminocarbonylation of Olefins to Branched Amides
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A general and efficient protocol for iso-selective aminocarbonylation of olefins with aliphatic amines has been developed for the first time. Key to the success for this process is the use of a specific 2-phosphino-substituted pyrrole ligand in the presence of PdX2(X=halide) as a pre-catalyst. Bulk industrial and functionalized olefins react with various aliphatic amines, including amino-acid derivatives, to give the corresponding branched amides generally in good yields (up to 99 %) and regioselectivities (b/l up to 99:1).
- Liu, Jie,Li, Haoquan,Spannenberg, Anke,Franke, Robert,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 13544 - 13548
(2016/10/21)
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- N-Acyl-N-(4-chlorophenyl)-4-nitrobenzenesulfonamides: Highly selective and efficient reagents for acylation of amines in water
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A variety of N-acyl-N-(4-chlorophenyl)-4-nitrobenzenesulfonamides (1a-e) were synthesized in one pot from 4-chloroaniline under solvent-free conditions and have been developed as chemoselective N-acylation reagents. Selective protection of primary amines in the presence of secondary amines, acylation of aliphatic amines in the presence of aryl amines, and monofunctionalization of primary-secondary diamines as well as selective N-acylation of amino alcohols using these reagents are described. All of the acylation reactions were carried out in water as a green solvent. High stability and easy preparation of these acylating reagents are other advantages of this method.
- Ebrahimi, Sara,Saiadi, Safoura,Dakhilpour, Simin,Mirsattari, Seyed Nezamoddin,Massah, Ahmad Reza
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- Rhodium-catalyzed oxidative amidation of allylic alcohols and aldehydes: Effective conversion of amines and anilines into amides
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The rhodium-catalyzed oxidative amidation of allylic alcohols and aldehydes is reported. In situ generated [(BINAP)Rh]BF4 catalyzes the one-pot isomerization/oxidative amidation of allylic alcohols or direct amidation of aldehydes using acetone or styrene as the hydrogen acceptor. The conditions are general, affording good to excellent yields with a wide array of amine and aniline nucleophiles, and chemoselective, other alcohols do not participate in the oxidation reaction. Utilization of biphasic conditions is critical, as they promote an equilibrium between the imine/enamine byproducts and the hemiaminal, which can undergo oxidation to the amide.
- Wu, Zhao,Hull, Kami L.
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p. 969 - 975
(2016/02/05)
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- C-N Coupling of Amides with Alcohols Catalyzed by N-Heterocyclic Carbene-Phosphine Iridium Complexes
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N-Heterocyclic carbene-phosphine iridium complexes (NHC-Ir) were developed/found to be a highly reactive catalyst for N-monoalkylation of amides with alcohols via hydrogen transfer. The reaction produced the desired product in high isolated yields using a wide range of substrates with low catalyst loading and short reaction times.
- Kerdphon, Sutthichat,Quan, Xu,Parihar, Vijay Singh,Andersson, Pher G.
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p. 11529 - 11537
(2015/12/04)
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- Combination of gold and iridium catalysts for the synthesis of N-alkylated amides from nitriles and alcohols
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An alternative and efficient approach for the synthesis of N-alkylated amides from nitriles and alcohols was proposed and accomplished. By the combination of [(IPr)Au(NTf2)] (IPr = 1,3-bis(diisopropylphenyl)imidazol-2-ylidene) and [CpIrCl2]2 (Cp = η5-pentamethylcyclopentadienyl), a series of nitriles were first hydrated to give amides, in which the resulting amides were further N-alkylated with a variety of alcohols as alkylating agents to afford N-alkylated amides with good to excellent yields. Compared with previous methods for the synthesis of N-alkylated amides from nitriles and alcohols as starting materials, this protocol could be accomplished with high atom economy under more environmentally benign conditions.
- Li, Feng,Ma, Juan,Lu, Lei,Bao, Xiaofeng,Tang, Wanying
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p. 1953 - 1960
(2015/04/27)
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- Copper-Catalyzed Ligand-Free Amidation of Benzylic Hydrocarbons and Inactive Aliphatic Alkanes
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An efficient copper-catalyzed amidation of benzylic hydrocarbons and inactive aliphatic alkanes with simple amides was developed. The protocol proceeded smoothly without any ligand, and a wide range of N-alkylated aromatic and aliphatic amides, sulfonamides, and imides were synthesized in good yields.
- Zeng, Hui-Ting,Huang, Jing-Mei
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supporting information
p. 4276 - 4279
(2015/09/15)
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- H-β-zeolite catalyzed transamidation of carboxamides, phthalimide, formamides and thioamides with amines under neat conditions
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Efficient transamidation of unactivated carboxamides, phthalimides, formamides and thioamides with amines under solvent-free conditions using H-β-zeolite as a green and recyclable heterogeneous catalyst is described. Easy work up, high purity of the products, recyclability and environmentally-friendly nature of the catalyst are the attractive features of the present methodology. This is the first report for the transamidation of thioamides under heterogeneous conditions.
- Rao, Sadu Nageswara,Chandra Mohan, Darapaneni,Adimurthy, Subbarayappa
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p. 95313 - 95317
(2015/11/24)
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- Direct amidation of carboxylic acids with amines under microwave irradiation using silica gel as a solid support
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A highly improved and green methodology for the direct amidation of carboxylic acids with amines using silica gel as a solid support and catalyst is described. The scope of this method is exemplified by the use of several aliphatic, aromatic, unsaturated and fatty acids. The reaction is also applied to different primary and secondary amines. Typically, the amines should be aliphatic, but aromatic amines can be used as well, though with lower yields. Several experiments to illustrate the selectivity of this methodology were also carried out with several more functionalized acids and amines. This approach is a substantial improvement over other previously described methods in amide synthesis.
- Ojeda-Porras, Andrea,Hernández-Santana, Alejandra,Gamba-Sánchez, Diego
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supporting information
p. 3157 - 3163
(2015/05/27)
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- A novel aromatic carbocation-based coupling reagent for esterification and amidation reactions
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A novel tropylium-based coupling reagent has been developed to facilitate the synthesis of a series of esters, amides, lactones and peptides under mild reaction conditions. Remarkably, this reagent can be used in catalytic amounts in conjunction with a sacrificial reagent, offering a new and efficient method for nucleophilic coupling reactions of carboxylic acids.
- Nguyen, Thanh V.,Lyons, Demelza J.M.
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supporting information
p. 3131 - 3134
(2015/06/17)
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- Rapid Vortex Fluidics: Continuous Flow Synthesis of Amides and Local Anesthetic Lidocaine
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Thin film flow chemistry using a vortex fluidic device (VFD) is effective in the scalable acylation of amines under shear, with the yields of the amides dramatically enhanced relative to traditional batch techniques. The optimized monophasic flow conditions are effective in ≤80seconds at room temperature, enabling access to structurally diverse amides, functionalized amino acids and substituted ureas on multigram scales. Amide synthesis under flow was also extended to a total synthesis of local anesthetic lidocaine, with sequential reactions carried out in two serially linked VFD units. The synthesis could also be executed in a single VFD, in which the tandem reactions involve reagent delivery at different positions along the rapidly rotating tube with in situ solvent replacement, as a molecular assembly line process. This further highlights the versatility of the VFD in organic synthesis, as does the finding of a remarkably efficient debenzylation of p-methoxybenzyl amines.
- Britton, Joshua,Chalker, Justin M.,Raston, Colin L.
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supporting information
p. 10660 - 10665
(2015/07/20)
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- Copper(I)-Catalyzed Reductive Cross-Coupling of N-Tosylhydrazones with Amides: A Straightforward Method for the Construction of C(sp3)- N Amide Bonds from Aldehydes
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A method for the one-pot synthesis of substituted amides from aldehydes and amides is presented. Namely, condensation of aldehydes with N-tosylhydrazide generated the N-tosylhydrazones which were then reductively cross-coupled in situ with primary or secondary amides in the presence of a copper catalyst to afford secondary or tertiary amides, respectively. The reaction proceeded efficiently for a wide range of aldehydes and amides under the optimized conditions, i.e., 10 mol% of tetrakis(acetonitrile)copper(I) tetrafluoroborate [Cu(CH3CN)4BF4], 1 mol% of tetra-n-butylammonium iodide [(n-Bu)4NI], and sodium hydroxide [NaOH] as base in tetrahydrofuran (THF) at 80 C. As a result, the method provides a straightforward route for the synthesis of substituted amides from readily available aldehydes via a transition metal-catalyzed C(sp3)- N amide bond forming reaction.
- Xu, Peng,Han, Fu-She,Wang, Yan-Hua
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supporting information
p. 3441 - 3446
(2016/01/25)
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- Catalyst-free amidation of aldehyde with amine under mild conditions
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A highly efficient, catalyst-free and one-pot procedure for the direct synthesis of amides from aldehydes and amines under mild conditions has been developed. Both aliphatic and aromatic aldehydes with primary or secondary amines are successfully converted to the corresponding amides, and it is observed that reactions can proceed in either aqueous or organic media.
- Yang, Hongyin,Hu, Wenjian,Deng, Shengjue,Wu, Tiantian,Cen, Haiman,Chen, Yiping,Zhang, Dela,Wang, Bo
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supporting information
p. 5912 - 5915
(2015/08/11)
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- The direct synthesis of N-alkylated amides via a tandem hydration/N-alkylation reaction from nitriles, aldoximes and alcohols
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A novel strategy for the direct synthesis of N-alkylated amides from nitriles, aldoximes and alcohols was proposed and accomplished in the presence of a Cp*Ir complex. This journal is the Partner Organisations 2014.
- Wang, Nana,Zou, Xiaoyuan,Ma, Juan,Li, Feng
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supporting information
p. 8303 - 8305
(2014/07/22)
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- Hydrogen bond organocatalysis of benzotriazole in transamidation of carboxamides with amines
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A new method of transamidation of carboxamides with amines catalyzed by benzotriazole has been developed.
- Nguyen, Thanh Binh,Ermolenko, Ludmila,Dau, Marie-Elise Tran Huu,Al-Mourabit, Ali
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p. 403 - 416
(2014/01/17)
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- Aromatic cation activation: Nucleophilic substitution of alcohols and carboxylic acids
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A new method for the nucleophilic substitution of alcohols and carboxylic acids using aromatic tropylium cation activation has been developed. This article reports the use of chloro tropylium chloride for the rapid generation of alkyl halides and acyl chlorides under very mild reaction conditions. It demonstrates, for the first time, the synthetic potential of tropylium cations in promoting chemical transformations.
- Nguyen, Thanh V.,Bekensir, Alp
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supporting information
p. 1720 - 1723
(2014/04/17)
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- An efficient, green and scale-up synthesis of amides from esters and amines catalyzed by Ru-MACHO catalyst under mild conditions
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An efficient, green and scale-up synthesis of amides from esters and amines has been developed using Ru-MACHO as a readily available catalyst. A diverse range of amides were obtained in moderate to excellent yields (55-98%). Furthermore, when the scale of the amidation reaction was increased to 240.0 mmol, the desired amide still could be obtained in high yield (48.2 g of N-benzylbenzamide, 95%).
- Han, Qian,Xiong, Xingquan,Li, Sizhong
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- Catalytic acceptorless dehydrogenations: Ru-Macho catalyzed construction of amides and imines
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A commercially available ruthenium(II) PNP type pincer catalyst (Ru-Macho) promotes formation of amides and imines from alcohols and amines via an acceptorless dehydrogenation pathway. The formation of secondary amides, tertiary amides, and secondary ketimines occurs in yields ranging from 35% to 95%.
- Oldenhuis, Nathan J.,Dong, Vy M.,Guan, Zhibin
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supporting information
p. 4213 - 4218
(2014/06/09)
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- Ruthenium-catalysed oxidation of alcohols to amides using a hydrogen acceptor
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A wider investigation into the synthesis of secondary amides from primary alcohols using a hydrogen acceptor using commercially available [Ru(p-cymene)Cl2]2 with bis(diphenylphosphino)butane (dppb) as the catalyst. The report looks at over 50 examples with varying functionality and steric bulk, whilst also covering the first reported results using microwave heating to effect the transformation.
- Watson, Andrew J.A.,Wakeham, Russell J.,Maxwell, Aoife C.,Williams, Jonathan M.J.
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supporting information
p. 3683 - 3690
(2014/05/20)
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- Selective catalytic sp3 C-O bond cleavage with C-N bond formation in 3-alkoxy-1-propanols
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The ruthenium catalyzed selective sp3 C-O cleavage with amide formation was reported in reactions of 3-alkoxy-1-propanol derivatives and amines. The cleavage only occurs at the C3-O position even with 3-benzyloxy-1-propanol. Based on the experimental results, O-bound and C-bound Ru enolate complexes were proposed as key intermediates for the unique selective sp3 C-O bond cleavage in 3-alkoxy-1-propanols.
- Chen, Cheng,Hong, Soon Hyeok
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supporting information; experimental part
p. 2992 - 2995
(2012/07/28)
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- Transamidation of primary amides with amines catalyzed by zirconocene dichloride
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Zirconocene dichloride (Cp2ZrCl2) has been shown to be an effective catalyst for the transamidation of primary amides with amines in cyclohexane at 80°C in 5-24 hours. For favourable substrates, the reaction can be performed at temperatures as low as 30°C.
- Atkinson, Benjamin N.,Chhatwal, A. Rosie,Lomax, Helen V.,Walton, James W.,Williams, Jonathan M. J.
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supporting information
p. 11626 - 11628,3
(2012/12/12)
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- Transamidation of primary amides with amines catalyzed by zirconocene dichloride
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Zirconocene dichloride (Cp2ZrCl2) has been shown to be an effective catalyst for the transamidation of primary amides with amines in cyclohexane at 80°C in 5-24 hours. For favourable substrates, the reaction can be performed at temperatures as low as 30°C.
- Atkinson, Benjamin N.,Chhatwal, A. Rosie,Lomax, Helen V.,Walton, James W.,Williams, Jonathan M. J.
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supporting information
p. 11626 - 11628
(2013/01/15)
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- Transamidation of primary amides with amines using hydroxylamine hydrochloride as an inorganic catalyst
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Metal-free catalysis: A method for the transamidation of primary amides with primary or secondary amines provides access to secondary and tertiary amides, by utilizing catalytic quantities of hydroxylamine hydrochloride to activate the chemically robust primary amide group (see scheme). A mechanism of primary amide activation through a hydrogen-bonding complex is proposed. Copyright
- Allen, C. Liana,Atkinson, Benjamin N.,Williams, Jonathan M. J.
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supporting information; experimental part
p. 1383 - 1386
(2012/04/18)
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- Mechanism of gold(I)-catalyzed rearrangements of acetylenic amine-N-oxides: Computational investigations lead to a new mechanism confirmed by experiment
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Figure Persented: Quantum mechanical studies of the mechanism of gold-catalyzed rearrangements of acetylenic amine-N-oxides to piperidinones or azepanones have revealed a new mechanism involving a concerted heteroretroene reaction, formally a 1,5 hydrogen shift from the N-alkyl groups to the vinyl position of a gold-coordinated methyleneisoxazolidinium or methyleneoxazinanium. Density functional calculations (B3LYP, B3LYP-D3) on the heteroretroene mechanism reproduce experimental regioselectivities and provide an explanation as to why the hydrogen is transferred from the smaller amine substituent. In support of the proposed mechanism, new experimental investigations show that the hydrogen shift is concerted and that gold carbenes are not involved as reaction intermediates.
- Noey, Elizabeth L.,Luo, Yingdong,Zhang, Liming,Houk
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supporting information; experimental part
p. 1078 - 1084
(2012/03/12)
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- Mechanistic investigation of the ruthenium-N-heterocyclic-carbene-catalyzed amidation of amines with alcohols
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The mechanism of the ruthenium-N-heterocyclic-carbene-catalyzed formation of amides from alcohols and amines was investigated by experimental techniques (Hammett studies, kinetic isotope effects) and by a computational study with dispersion-corrected density functional theory (DFT/M06). The Hammett study indicated that a small positive charge builds-up at the benzylic position in the transition state of the turnover-limiting step. The kinetic isotope effect was determined to be 2.29(±0.15), which suggests that the breakage of the C-H bond is not the rate-limiting step, but that it is one of several slow steps in the catalytic cycle. Rapid scrambling of hydrogen and deuterium at the α position of the alcohol was observed with deuterium-labeled substrates, which implies that the catalytically active species is a ruthenium dihydride. The experimental results were supported by the characterization of a plausible catalytic cycle by using DFT/M06. Both cis-dihydride and trans-dihydride intermediates were considered, but when the theoretical turnover frequencies (TOFs) were derived directly from the calculated DFT/M06 energies, we found that only the trans-dihydride pathway was in agreement with the experimentally determined TOFs. On the right pathway: Experimental and theoretical investigations indicate that the Ru-catalyzed amidation of amines with alcohols (see scheme) proceeds by alcohol coordination, β-hydride elimination, nucleophilic attack, and β-hydride elimination to the amide. Copyright
- Makarov, Ilya S.,Fristrup, Peter,Madsen, Robert
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supporting information
p. 15683 - 15692
(2013/01/16)
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- Borrowing hydrogen methodology for amine synthesis under solvent-free microwave conditions
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Application of microwave heating to the Borrowing Hydrogen strategy to form C-N bonds from alcohols and amines is presented, removing the need for solvent and reducing the reaction times while still yielding results comparable with those using thermal heating.
- Watson, Andrew J. A.,Maxwell, Aoife C.,Williams, Jonathan M. J.
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supporting information; experimental part
p. 2328 - 2331
(2011/05/17)
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- Microwave-assisted clean synthesis of amides via aza-wittig reaction under solvent-free condition
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A solvent-free microwave-assisted coupling of phosphazenes with acyl chlorides or carboxylic anhydrides in presence of triethylphosphite has been accomplished resulting in a clean synthesis of amides in good yields. Unlike the prevailing time-consuming solution phase methodologies employing chlorinated solvents, benzene (carcinogenic), etc, the present protocol is an eco friendly, rapid and simple approach.
- Murugan, Sathish Kumar,Sangaraiah, Nagarajan,Velan, Poovan Shanmuga,Murugan, Dinesh,Ponnuswamy, Alagusundaram
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experimental part
p. 2065 - 2069
(2012/02/03)
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- Defining the structural parameters that confer anticonvulsant activity by the site-by-site modification of (R)-N′-benzyl 2-amino-3-methylbutanamide
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Primary amino acid derivatives (PAADs) (N′-benzyl 2-substituted 2-amino acetamides) are structurally related to functionalized amino acids (FAAs) (N′-benzyl 2-substituted 2-acetamido acetamides) but differ by the absence of the terminal N-acetyl group. Both classes exhibit potent anticonvulsant activities in the maximal electroshock seizure animal model, and the reported structure-activity relationships (SARs) of PAADs and FAAs differ in significant ways. Recently, we documented that PAAD efficacy was associated with a hydrocarbon moiety at the C(2)-carbon, while in the FAAs, a substituted heteroatom one atom removed from the C(2)-center was optimal. Previously in this issue, we showed that PAAD activity was dependent upon the electronic properties of the 4′-N′-benzylamide substituent, while FAA activity was insensitive to electronic changes at this site. In this study, we prepared analogues of (R)-N′-benzyl 2-amino-3-methylbutanamide to identify the structural components for maximal anticonvulsant activity. We demonstrated that the SAR of PAADs and FAAs diverged at the terminal amide site and that PAADs had considerably more structural latitude in the types of units that could be incorporated at this position, suggesting that these compounds function according to different mechanism(s).
- King, Amber M.,De Ryck, Marc,Kaminski, Rafal,Valade, Anne,Stables, James P.,Kohn, Harold
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supporting information; experimental part
p. 6432 - 6442
(2011/12/01)
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- Mild decarboxylative activation of malonic acid derivatives by 1,1′-carbonyldiimidazole
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Chemical equations presented. Malonic acid derivatives undergo unusually mild decarboxylation when treated with N,N′-carbonyldiimidazole (CDI) at room temperature to generate the carbonyl imidazole moiety in high yield, which can be reacted further with a variety of nucleophiles in an efficient one-pot process.
- Lafrance, Danny,Bowles, Paul,Leeman, Kyle,Rafka, Robert
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supporting information; experimental part
p. 2322 - 2325
(2011/06/26)
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- Catalytic acylation of amines with aldehydes or aldoximes
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The simple nickel salt NiCl2?6H2O catalyzes the coupling of aldoximes with amines to give secondary or tertiary amide products. The aldoxime can be prepared in situ from the corresponding aldehyde. The use of 18O-labeled oximes has allowed insight into the mechanism of this reaction.
- Allen, C. Liana,Davulcu, Simge,Williams, Jonathan M. J.
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supporting information; experimental part
p. 5096 - 5099
(2011/02/21)
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- An iron-catalysed synthesis of amides from nitriles and amines
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The cheap, commercially available iron complex, Fe(NO3)3·9H2O, has been used to catalyse the formation of amides by the addition of amines to nitriles.
- Allen, C. Liana,Lapkin, Alexei A.,Williams, Jonathan M.J.
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experimental part
p. 4262 - 4264
(2009/10/26)
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- Microwave-assisted preparation of amides using a stable and reusable mesoporous carbonaceous solid acid
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An efficient and green microwave assisted protocol to prepare amides from amines via N-acylation using acidic polysaccharide derived mesoporous materials provides quantitative yields of amides in short reaction times.
- Luque, Rafael,Budarin, Vitaly,Clark, James H.,MacQuarrie, Duncan J.
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experimental part
p. 459 - 461
(2010/04/22)
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- Encapsulated reagents for nitrosation
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(Matrix presented) A novel class of stable, mild, and size-shape-selective nitrosating agents for secondary amides is introduced. These are based on reversible entrapment and release of reactive nitrosonium species by calix[4]arenes. The NO+ encapsulation controls the reaction selectivity.
- Zyryanov, Grigory V.,Rudkevich, Dmitry M.
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p. 1253 - 1256
(2007/10/03)
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- Solid-supported cyclohexane-1,3-dione (CHD): A "capture and release" reagent for the synthesis of amides and novel scavenger resin
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A three-step synthesis of cyclohexane-1,3-dione (CHD) resin 6 on polystyrene resin is described. Resin 6 was used to prepare an amide library of high purity by microwave-assisted serial "capture and release" and can be recycled for this purpose. High-loading CHD resin 10 was also shown to scavenge allyl cations in solution.
- Humphrey, Cara E.,Easson, Morag A. M.,Tierney, Jason P.,Turner, Nicholas J.
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p. 849 - 852
(2007/10/03)
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