- 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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- 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
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supporting information
p. 5303 - 5308
(2020/04/17)
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- Nickel-catalyzed: C-alkylation of thioamide, amides and esters by primary alcohols through a hydrogen autotransfer strategy
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A simple catalyst of Ni(OAc)2 and P(t-Bu)3 enables selective C-alkylation of thioacetamides and primary acetamides with alcohols for the first time. Monoalkylation of thioamides, amides and t-butyl esters occurs in excellent yields (>95%). Mechanistic studies reveal that the reaction proceeds via a hydrogen autotransfer pathway. This journal is
- Yang, Peng,Wang, Xiuhua,Ma, Yu,Sun, Yaxin,Zhang, Li,Yue, Jieyu,Fu, Kaiyue,Zhou, Jianrong Steve,Tang, Bo
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supporting information
p. 14083 - 14086
(2020/11/20)
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- Radical condensation between benzylic alcohols and acetamides to form 3-arylpropanamides
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A new radical condensation reaction is developed where benzylic alcohols and acetamides are coupled to generate 3-arylpropanamides with water as the only byproduct. The transformation is performed with potassium tert-butoxide as the only additive and gives rise to a variety of 3-arylpropanamides in good yields. The mechanism has been investigated experimentally with labelled substrates, trapping experiments and spectroscopic measurements. The findings indicate a radical pathway where potassium tert-butoxide is believed to serve a dual role as both base and radical initiator. The radical anion of the benzylic alcohol is proposed as the key intermediate, which undergoes coupling with the enolate of the amide to form the new C-C bond. Subsequent elimination to the corresponding cinnamamide and olefin reduction then affords the 3-arylpropanamides.
- Azizi, Kobra,Madsen, Robert
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p. 7800 - 7806
(2020/08/14)
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- Palladium-Catalyzed Hydrocarbonylative C-N Coupling of Alkenes with Amides
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An efficient palladium-catalyzed hydrocarbonylative C-N coupling of alkenes with amides has been developed. The reaction was performed via hydrocarbonylation of alkenes, followed by acyl metathesis with amides. Both intermolecular and intramolecular react
- Zhou, Xibing,Zhang, Guoying,Gao, Bao,Huang, Hanmin
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supporting information
p. 2208 - 2212
(2018/04/30)
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- Rhodium-Catalyzed Asymmetric Synthesis of β-Branched Amides
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A general asymmetric route for the one-step synthesis of chiral β-branched amides is reported through the highly enantioselective isomerization of allylamines, followed by enamine exchange, and subsequent oxidation. The enamine exchange allows for a rapid and modular synthesis of various amides, including challenging β-diaryl and β-cyclic.
- Wu, Zhao,Laffoon, Joshua D.,Nguyen, Trang T.,McAlpin, Jacob D.,Hull, Kami L.
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supporting information
p. 1371 - 1375
(2017/01/24)
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- Metal–Organic Framework Based on Copper and Carboxylate-Imidazole as Robust and Effective Catalyst in the Oxidative Amidation of Carboxylic Acids and Formamides
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A metal–organic framework (MOF) based on copper and 1,3-bis(carboxymethyl)imidazole (bcmim) was prepared on a gram scale by using a precipitation method at room temperature. The Cu(bcmim)2MOF was shown to be an efficient catalyst for the preparation of amides through an oxidative coupling between carboxylic acids and formamides in the presence of an oxidant, such as tert-butyl hydroperoxide (TBHP). The method for the preparation of the amides is robust regardless of the carboxylic acid and gives good conversions with good selectivity. The heterogeneous catalyst was recovered unaltered after the reaction, was easily separated from the reaction mixture, and subsequently reactivated by suitable treatment. Moreover, the coupling reaction was scaled up to a gram scale, which allowed for the preparation of valuable products, such as fatty acid amides (i.e., 1-palmitoylpiperidine).
- Albert-Soriano, María,Pastor, Isidro M.
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supporting information
p. 5180 - 5188
(2016/10/26)
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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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- Practical Synthesis of Amides via Copper/ABNO-Catalyzed Aerobic Oxidative Coupling of Alcohols and Amines
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A modular Cu/ABNO catalyst system has been identified that enables efficient aerobic oxidative coupling of alcohols and amines to amides. All four permutations of benzylic/aliphatic alcohols and primary/secondary amines are viable in this reaction, enabling broad access to secondary and tertiary amides. The reactions exhibit excellent functional group compatibility and are complete within 30 min-3 h at rt. All components of the catalyst system are commercially available.
- Zultanski, Susan L.,Zhao, Jingyi,Stahl, Shannon S.
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supporting information
p. 6416 - 6419
(2016/06/09)
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- A highly efficient catalytic α-alkylation of unactivated amides using primary alcohols
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The α-alkylation of unactivated amides with alcohols is described. Using a NCP-type pincer Ir complex as the precatalyst and KOtBu as the base, the reactions of secondary or tertiary acetamides with benzyl or nonbenzyl primary alcohols occur at 80 °C, furnishing the alkylation products in good yields. This method represents a practical and green means of α-alkylation of amides in a relatively mild, efficient, and selective manner with low catalyst loadings (0.5 mol %).
- Yao, Wubing,Ma, Xiaochen,Guo, Le,Jia, Xiangqing,Hu, Aiguo,Huang, Zheng
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supporting information
p. 2919 - 2921
(2016/06/13)
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- General and Mild Cobalt-Catalyzed C-Alkylation of Unactivated Amides and Esters with Alcohols
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The borrowing hydrogen or hydrogen autotransfer methodology is an elegant and sustainable or green concept to construct carbon-carbon bonds. In this concept, alcohols, which can be obtained from barely used and indigestible biomass, such as lignocellulose, are employed as alkylating reagents. An especially challenging alkylation is that of unactivated esters and amides. Only noble metal catalysts based on iridium and ruthenium have been used to accomplish these reactions. Herein, we report on the first base metal-catalyzed α-alkylation of unactivated amides and esters by alcohols. Cobalt complexes stabilized with pincer ligands, recently developed in our laboratory, catalyze these reactions very efficiently. The precatalysts can be synthesized easily from commercially available starting materials on a multigram scale and are self-activating under the basic reaction conditions. This Co catalyst class is also able to mediate alkylation reactions of both esters and amides. In addition, we apply the methodology to synthesize ketones and to convert alcohols into aldehydes elongated by two carbon atoms.
- Deibl, Nicklas,Kempe, Rhett
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supporting information
p. 10786 - 10789
(2016/09/09)
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- Ruthenium-catalyzed direct α-alkylation of amides using alcohols
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The highly efficient direct α-alkylation of unactivated amides has been accomplished using alcohols in the presence of the Ru-PNN catalyst (0.1 mol%) with a high turnover number. Using this approach, 2-oxindole was directly transformed into C3-alkylated 3-hydroxyindolin-2-one in one step without the use of any oxidant.
- Chaudhari, Moreshwar Bhagwan,Bisht, Girish Singh,Kumari, Pooja,Gnanaprakasam, Boopathy
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supporting information
p. 9215 - 9220
(2016/10/13)
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- Mild Amide-Cleavage Reaction Mediated by Electrophilic Benzylation
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An extremely mild method for amide-cleavage by using the triazine-based benzylating reagent 4-(4,6-diphenoxy-1,3,5-triazin-2-yl)-4-benzylmorpholinium trifluoromethanesulfonate (DPT-BM), which spontaneously releases benzyl cation species when being dissolved at room temperature, has been developed. O-Benzylation of the amide with DPT-BM and the subsequent hydrolysis of the resulting intermediate benzyl imidate salt afford the corresponding amine and benzyl ester, which can be converted by hydrogenolysis into a carboxylic acid under neutral conditions. O-Benzylation proceeds depending on both steric and electronic factors around the amide group. Thus, some amides have been selectively cleaved over other amides. Furthermore, intramolecular chemoselective cleavage of an amide group in the presence of an ester group was achieved. Such selective hydrolytic reactions cannot be performed with Meerwein reagents as well as under acidic or basic hydrolytic conditions.
- Yamada, Kohei,Karuo, Yukiko,Tsukada, Yuichi,Kunishima, Munetaka
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supporting information
p. 14042 - 14047
(2016/09/21)
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- Efficient metal-free hydrosilylation of tertiary, secondary and primary amides to amines
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Hydrosilylation of secondary and tertiary amides to amines is described using catalytic amounts of B(C6F5)3. The organic catalyst enables the reduction of amides with cost-efficient, non-toxic and air stable PMHS and TMDS hydrosilanes. The methodology was successfully extended to the more challenging reduction of primary amides.
- Blondiaux, Enguerrand,Cantat, Thibault
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supporting information
p. 9349 - 9352
(2014/08/05)
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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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- Amides in one pot from Carboxylic Acids and Amines via Sulfinylamides
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An efficient method has been developed for the direct amidification of carboxylic acids via sulfinylamides preformed in situ by the reaction of pure amines with prop-2- ene-1-sulfinyl chloride. The method can be applied to aliphatic acids, including pivalic acid, aromatic acids, and primary and secondary amines. It is compatible with acids bearing unprotected alcohol, phenol, and ketone moieties and applicable to the synthesis of peptides. It does not induce their a-epimerization.
- Bai, Jianfei,Zambron, Bartosz K.,Vogel, Pierre
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supporting information
p. 604 - 607
(2014/04/03)
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- Organocatalytic oxidation of aldehydes to mixed anhydrides
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TEMPO catalyzes the direct oxidation of aldehydes to mixed anhydrides in the presence of a carboxylic acid. The anhydrides can be converted in situ to esters, secondary, tertiary or Weinreb amides in high yield. Oxidation of the aldehyde directly to 2-propyl esters is also possible using only catalytic amounts of acid. The oxidation reactions are rapid and take place under mild conditions.
- Toledo, Hila,Pisarevsky, Evgeni,Abramovich, Adi,Szpilman, Alex M.
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supporting information
p. 4367 - 4369
(2013/06/05)
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- Internal redox amidation of α,β-unsaturated aldehydes in ionic liquids. The electrochemical route
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A simple, N-heterocyclic carbene (NHC) activated synthesis of amides has been performed via electrolysis, carried out under galvanostatic control, of an ionic liquid (Bmim-BF4) followed by addition to the catholyte of an α,β-unsaturated aldehyde and amine. Amides have been isolated, in good to elevated yields, in the absence of any base, co-catalyst and organic solvent. The selectivity of amidation, versus the formation of imine as by-product, has been related to the molar ratio electrogenerated NHC/aldehyde. The results, obtained using ionic liquids and electrochemical procedures, have been compared with those obtained using organic solvents and classical procedures.
- Feroci, Marta,Chiarotto, Isabella,Inesi, Achille
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p. 692 - 699
(2013/04/10)
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- Iridium-catalyzed selective α-alkylation of unactivated amides with primary alcohols
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The first α-alkylation of unactivated amides with primary alcohols is described. An effective and robust iridium pincer complex has been developed for selective α-alkylation of tertiary and secondary acetamides involving a borrowing hydrogen methodology. The method is compatible with alcohols bearing various functional groups. This presents a convenient and environmentally benign protocol for α-alkylation of amides.
- Guo, Le,Liu, Yinghua,Yao, Wubing,Leng, Xuebing,Huang, Zheng
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supporting information
p. 1144 - 1147
(2013/04/10)
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- Phosphorus oxychloride as an efficient coupling reagent for the synthesis of esters, amides and peptides under mild conditions
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A mild method is described for the conversion of carboxylic acids into esters, amides, as well as peptides without racemization through carboxyl activation by the reagent combination of POCl3 and DMAP. Long chain alcohols could be converted to the corresponding ester in good yields. 31P NMR spectrum was used to detect phosphorus-containing intermediates in ongoing reactions directly, and a possible mechanism has been proposed based on these results. The Royal Society of Chemistry 2013.
- Chen, Hu,Xu, Xunfu,Liu, Liu,Tang, Guo,Zhao, Yufen
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p. 16247 - 16250
(2013/09/23)
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- Aerobic amide bond formation with N-hydroxysuccinimide
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Breathe easy: Molecular oxygen is one of the most abundant, atom-efficient, and economical oxidants. An aerobic oxidative amide formation from aldehydes and amines is reported. The method uses a catalytic amount of Co(OAc) 2 and N-hydroxysuccinimide as reaction promoters. It is applicable to chiral substrates without loss of their optical purity. Copyright
- Yao, Haoyi,Yamamoto, Kana
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supporting information; experimental part
p. 1542 - 1545
(2012/09/08)
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- Pseudomonas stutzeri lipase: A useful biocatalyst for aminolysis reactions
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The use of Pseudomonas stutzeri lipase (PSL) as a biocatalyst for aminolysis reactions with bulky substrates has been investigated. PSL compared favorably to Novozym 435 (immobilized Candida antarctica lipase B, NOV435) in the aminolysis of various bulky methyl esters and amines. While NOV435 demonstrated a higher rate of aminolysis with methyl 2-phenylpropionic acid as the acyl donor, PSL outperformed NOV435 with secondary amines as the nucleophile. Methanol inhibition and a low affinity for bulky acyl donors were found to be the two main reasons for relatively low rates in the PSL-catalyzed aminolysis reactions. It was demonstrated that the use of molsieve 4A had a significant effect on the aminolysis rate and amide yield, since it enabled the effective removal of the inhibiting methanol from the reaction mixture.
- Van Pelt,Teeuwen,Janssen,Sheldon,Dunn,Howard,Kumar,Martinez,Wong
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experimental part
p. 1791 - 1798
(2011/10/09)
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- Zinc-catalyzed reduction of amides: Unprecedented selectivity and functional group tolerance
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(Chemical Equation Presented) A novel zinc-catalyzed reduction of tertiary amides was developed. This system shows remarkable chemoselectivity and substrate scope tolerating ester, ether, nitro, cyano, azo, and keto substituents. Copyright
- Das, Shoubhik,Addis, Daniele,Zhou, Shaolin,Junge, Kathrin,Beller, Matthias
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supporting information; experimental part
p. 1770 - 1771
(2010/04/25)
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- Hydrogenation of BF2 complexes with 1,3-dicarbonyl ligands
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The catalytic hydrogenation (H2, Pd/C) of a set of BF2 complexes with a 1,3-dicarbonyl structural unit leading to monocarbonyl compounds has been studied. The transformation presented is general for the aryl-substituted derivatives and occurs under mild conditions (H2, 1 bar, 25 °C) in methanol or THF.
- ?tefane, Bogdan,Polanc, Slovenko
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experimental part
p. 2339 - 2343
(2009/07/18)
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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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- Catalytic amide formation with α′-hydroxyenones as acylating reagents
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α′-Hydroxyenones undergo clean, catalytic amidations with amines promoted by the combination of an N-heterocyclic carbene and 1,2,4-triazole. The Royal Society of Chemistry 2009.
- Chiang, Pei-Chen,Kim, Yoonjoo,Bode, Jeffrey W.
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supporting information; experimental part
p. 4566 - 4568
(2010/01/06)
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- Highly efficient method for the synthesis of carboxamides from carboxylic acids and amines using pyridine-3-sulfonyl chloride (3-PSC)
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The use of pyridine-3-sulfonyl chloride (3-PSC) in dehydrating condensation was investigated. This novel reagent was successfully employed as a mild dehydrating reagent for preparing various carboxamides in good to excellent yields from the corresponding carboxylic acids and amines. Copyright
- Funasaka, Setsuo,Kato, Koji,Mukaiyama, Teruaki
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p. 506 - 507
(2008/09/21)
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- Mild, powerful, and robust methods for esterification, amide formation, and thioesterification between acid chlorides and alcohols, amines, thiols, respectively
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We developed two efficient practical methods for esterification, amide formation, and thioesterification between acid chlorides and alcohols, amines, thiols, respectively. The present mild and robust reaction was performed by two separate methods both by combining cheap and readily available amines, N-methylimidazole, and N,N,N′,N′-tetramethylethylenediamine (TMEDA). Method A uses catalytic N-methylimidazole and TMEDA with an equimolar amount of K2CO3, whereas Method B uses equimolar amounts of N-methylimidazole and TMEDA. The salient features are as follows. (i) With regard to reactivity, Method B was superior to Method A for esterification and thioesterification, whereas cost-effective Method A was superior to Method B for amide formation. (ii) Amide formation proceeded smoothly between acid chlorides and less nucleophilic and stereocongested amines such as 2,6-dichloroaniline. (iii) This protocol was applied to the successful synthesis of two agrochemicals, bromobutide and carpropamid.
- Nakatsuji, Hidefumi,Morimoto, Mami,Misaki, Tomonori,Tanabe, Yoo
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p. 12071 - 12080
(2008/03/13)
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- Cesium carbonate promoted aerobic oxidation of arylacetamides: an efficient access to N-substituted α-keto amides
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A novel cesium carbonate promoted aerobic oxidation reaction to prepare N-substituted α-keto amides in the presence of catalytic amount of tetra-n-butylammonium bromide was described. This reaction provides a very simple and convenient route from easily a
- Song, Bingrui,Wang, Siyuan,Sun, Caiyun,Deng, Hongmei,Xu, Bin
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p. 8982 - 8986
(2008/03/18)
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- Tris(2,4,6-trimethoxyphenyl)phosphine: Base catalyst in the transformation of α,β-unsaturated aldehydes to saturated carboxylic-acid derivatives
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We have focused on the basicity of Tris(2,4,6-trimethoxyphenyl)phosphine (TTMPP) in organic synthesis. To extend the utility of TTMPP, we examined the reaction of α,β-unsaturated aldehydes with trimethylsilyl cyanide in the presence of TTMPP. Furthermore, to clarify the basic character of TTMPP, we measured 31P NMR of TTMPP and related compounds. First, the reaction of cinnamaldehydes with trimethylsilyl cyanide in the presence of a catalytic amount of TTMPP afforded the corresponding saturated carboxylic acids after hydrolysis with 1M HCl. Treatment of the reaction mixture with alcohols or amines instead of 1M HCl gave the corresponding saturated esters and amides, respectively. As a result of studies of the reaction mechanism, it was revealed that the reaction proceeded via silylcyanation of α,β-unsaturated aldehydes with trimethylsilyl cyanide to produce trimethylsilyl ethers of cyanohydrin and subsequent isomerization that formed α-trimethylsiloxy vinyl cyanides, which were hydrolyzed to give saturated carboxylic acids. Copyright Taylor & Francis Group, LLC.
- Hayashi, Masahiko,Kawabata, Hirotoshi,Yoshimoto, Kazuya,Tanaka, Takanori
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p. 433 - 445
(2007/10/03)
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- Highly efficient method for the synthesis of carboxamides from carboxylic acids and amines using benzenesulfonic anhydride (BSA)
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A highly efficient method by using benzenesulfonic anhydride (BSA) in the presence of 4-(dimethylamino)pyridine (DMAP) to synthesize carboxamides from various carboxylic acids and amines including sterically hindered ones is established. This reaction proceeds smoothly to provide the desired product in high yield. Copyright
- Funasaka, Setsuo,Kato, Koji,Mukaiyama, Teruaki
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p. 1456 - 1457
(2008/03/14)
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- Efficient method for dehydration condensation using pyridine-3-carboxylic anhydride (3-PCA): Synthesis of carboxamides from nearly equimolar amounts of carboxylic acids and amines
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A highly useful method for the preparation of carboxamides from various carboxylic acids and amines is established by using pyridine-3-carboxylic anhydride (3-PCA) in the presence of 4-(dimethylamino)pyridine (DMAP). This reaction proceeds smoothly under mild conditions by simple experimental procedure. Copyright
- Funasaka, Setsuo,Mukaiyama, Teruaki
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p. 658 - 659
(2008/02/07)
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- Water solvent method for esterification and amide formation between acid chlorides and alcohols promoted by combined catalytic amines: Synergy between N-methylimidazole and N,N,N′,N′-tetramethylethylenediamine (TMEDA)
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An efficient method for esterification between acid chlorides and alcohols in water as solvent has been developed by combining the catalytic amines, N-methylimidazole and N,N,N′,N′-tetramethylethylenediamine (TMEDA). The present Schotten-Baumann-type reaction was performed by maintaining the pH at around 11.5 using a pH controller to prevent the decomposition of acid chlorides and/or esters and to facilitate the condensation. The choice of catalysts (0.1 equiv.) was crucial: the combined use of N-methylimidazole and TMEDA exhibited a dramatic synergistic effect. The catalytic amines have two different roles: (i) N-methylimidazole forms highly reactive ammonium intermediates with acid chlorides and (ii) TMEDA acts as an effective HCl binder. The production of these intermediates was rationally supported by a careful 1H NMR monitoring study. Related amide formation was also achieved between acid chlorides and primary or secondary amines, including less nucleophilic or water-soluble amines such as 2-(or 4-)chloroaniline, the Weinreb N-methoxyamine, and 2,2-dimethoxyethanamine.
- Nakatsuji, Hidefumi,Morita, Jun-Ichi,Misaki, Tomonori,Tanabe, Yoo
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p. 2057 - 2062
(2007/10/03)
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- A convenient method for the synthesis of carboxamides and thioesters by using tetrakis(2-methylimidazol-1-yl)silane
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Tetrakis(2-methylimidazol-1-yl)silane [Si(2-Me-Im)4], a new dehydrating reagent having silicon-imidazole linkage, reacted readily with carboxylic acids at room temperature to form the corresponding 1-acyl-2-methylimidazole intermediates, which smoothly underwent subsequent condensation with nucleophiles such as amines or thiols to afford the corresponding carboxamides or thioesters in good to excellent yields, respectively.
- Tozawa, Takashi,Yamane, Yoshinobu,Mukaiyama, Teruaki
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p. 629 - 641
(2007/10/03)
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- Efficient synthesis of thioesters and amides from aldehydes by using an intermolecular radical reaction in water
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The combination of the water-soluble radical initiator, 2,2′-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride (VA-044) and the surfactant, cetyltrimethyl-ammonium bromide (CTAB), was found to be the most suitable condition for the effective and direct synthesis of useful active thioesters (pentafluorophenyl thioesters) in water. In addition, the direct amidation of aldehydes was achieved by the addition of the amines to the thioesterification reaction mixture in water.
- Nambu, Hisanori,Hata, Kayoko,Matsugi, Masato,Kita, Yasuyuki
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p. 719 - 727
(2007/10/03)
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- Self-encapsulation of homogeneous catalyst species into polymer gel leading to a facile and efficient separation system of amine products in the Ru-catalyzed reduction of carboxamides with polymethylhydrosiloxane (PMHS)
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A practical procedure for production of amines is offered by the ruthenium-catalyzed reduction of carboxamides with polymethylhydrosiloxane, in which encapsulation of the catalyst species into the formed insoluble siloxane resins contributes to the separation of both metallic and siloxane residues from the product. Copyright
- Motoyama, Yukihiro,Mitsui, Kaoru,Ishida, Toshiki,Nagashima, Hideo
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p. 13150 - 13151
(2007/10/03)
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- An effective method for the synthesis of carboxamides by using tetrakis(pyridine-2-yloxy)silane as a mild coupling reagent
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Tetrakis(pyridin-2-yloxy)silane [Si(OPy)4] is easily prepared by trans-silylation between silicon tetrachloride and trimethyl(pyridin-2-yloxy) silane in the molar ratio of 1:4. This novel reagent is effectively employed as a mild dehydrating reagent in forming various carboxamides from the corresponding carboxylic acids and amines that involve secondary or tertiary alkyl substituted ones in good to high yields without using any basic promoters such as tertiary amines or 4-(dimethylamino)pyridine. Copyright
- Tozawa, Takashi,Yamane, Yoshinobu,Mukaiyama, Teruaki
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p. 1334 - 1335
(2007/10/03)
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- A convenient method for preparations of 1-acylimidazoles and carboxamides by using novel imidazolylsilane derivatives
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Various imidazolylsilane derivatives were synthesized by a trans-silylation procedure between 1-(trimethylsilyl)imidazoles and chlorosilanes. Among them, tris- and tetrakis(imidazol-1-yl)silane compounds reacted smoothly with free carboxylic acids to form the corresponding 1-acylimidazoles, which subsequently underwent condensation with amines to afford carboxamides in good to high yields. These results indicate that novel reagents containing silicon-imidazole linkage are effectively utilized as dehydrating reagents to form carboxylic acid derivatives from free carboxylic acids and nucleophiles under mild conditions. Copyright
- Tozawa, Takashi,Yamane, Yoshinobu,Mukaiyama, Teruaki
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p. 734 - 735
(2007/10/03)
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- An efficient method for the preparation of carboxamides by dehydration condensation using tetrakis(1,1,1,3,3,3-hexafluoro-2-propoxy)silane
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The use of tetraalkoxysilanes, particularly tetrakis(perfluoroalkoxy) silanes, in dehydration condensation of carboxylic acids with amines was investigated. Tetrakis(1,1,1,3,3,3-hexafluoro-2-propoxy)silane, Si[OCH(CF 3)2]4, prepared easily from silicon tetrachloride and sodium 1,1,1,3,3,3-hexafluoro-2-propoxide, was found to be an effective dehydrating reagent for preparing various carboxamides in good to high yields from the corresponding carboxylic acids and amines. Copyright
- Tozawa, Takashi,Yamane, Yoshinobu,Mukaiyama, Teruaki
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p. 1586 - 1587
(2007/10/03)
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- The effective use of substituted benzoic anhydrides for the synthesis of carboxamides
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Various carboxamides are synthesized from the corresponding carboxylic acids and amines with high product-selectivities using 2-methyl-6-nitrobenzoic or 2,4,6-trichlorobenzoic anhydride in the presence of 4-(dimethylamino) pyridine.
- Shiina, Isamu,Kawakita, Yo-Ichi
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p. 4729 - 4733
(2007/10/03)
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- Simple, Mild, and Practical Esterification, Thioesterification, and Amide Formation Utilizing p-Toluenesulfonyl Chloride and N-Methylimidazole
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We have developed an efficient method for the esterification or thioesterification of equimolar amounts of carboxylic acids and alcohols or thiols using a novel reagent, p-toluenesulfonyl chloride (TsCl) together with N-methylimidazole. The present method is simple, mild, and reactive, uses readily available and economical reagents. The choice of amine is critical for the present method. The amine, N-methylimidazole, has two roles: (i) as an HCl scavenger for the initial smooth generation of mixed anhydrides between carboxylic acids and TsCl and (ii) successive formation of highly reactive ammonium intermediates from mixed anhydrides. This method could be applied to various types of carboxylic acids, alcohols, and thiols: a) several functionalities were tolerated; b) two N-Cbz amino acids were smoothly esterified without racemization; and c) the labile 1β-methylcarbapenem key intermediate and a pyrethroid insecticide, prallethrin, were successfully prepared. The related amide formation between carboxylic acids and primary or secondary amines was also performed. The proposed reaction mechanism involves a novel method for producing the reactive acylammonium intermediates. The production of these intermediates was rationally supported by a careful 1H NMR monitoring study.
- Wakasugi, Kazunori,Iida, Akira,Misaki, Tomonori,Nishii, Yoshinori,Tanabe, Yoo
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p. 1209 - 1214
(2007/10/03)
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- Novel and efficient method for esterification, amidation between carboxylic acids and equimolar amounts of alcohols, and amines utilizing Me2NSO2Cl and N,N-dimethylamines; Its application to the synthesis of coumaperine, a natural chemopreventive dieneamide
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Various carboxylic esters or amides were prepared in good to excellent yield between carboxylic acids and equimolar amounts of alcohols or amines under very mild conditions (0-45°C; within 3 h) using dimethylsulfamoyl chloride (Me2NSO2Cl; 1) combined with N,N-dimethylamines (Me2NR: 2a; R=Me, 2b; R=Bu). The choice of the sulfamoyl chloride and the amine is crucial for the reaction; that is, sterically uncrowded amines accelerated the present esterification and amidation. This agent had some advantages over methanesulfonyl chloride (3)/amines as for the atom-economy, avoidance of side reactions, and had very high chemoselectivity toward the carboxyl group vs the hydroxyl group; the experiment was performed by the addition of 1 to the mixture of carboxylic acids and alcohols. Application of this method to the synthesis of coumaperine, a chemopreventive natural product, was performed using the present amidation as a key step.
- Wakasugi, Kazunori,Nakamura, Atsushi,Iida, Akira,Nishii, Yoshinori,Nakatani, Nobuji,Fukushima, Shoji,Tanabe, Yoo
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p. 5337 - 5345
(2007/10/03)
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- A new method for the synthesis of carboxamides and peptides using 1,1′-carbonyldioxydi[2(1H)-pyridone] (CDOP) in the absence of basic promoters
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Various carboxamides or peptides are synthesized from the corresponding carboxylic acids and amines or α-amino acids using 1,1′-carbonyldioxydi[2(1H)-pyridone]. The reaction proceeds in the absence of basic promoters such as triethylamine or 4-(dimethylamino)pyridine, therefore, the undesired racemization does not occur at all in the segment coupling producing Z-Gly-Phe-Val-OMe and Z-Phe-Val-Ala-OMe.
- Shiina, Isamu,Kawakita, Yo-Ichi
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p. 1951 - 1955
(2007/10/03)
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- Lewis base-catalyzed transformation of α,β-unsaturated aldehydes to saturated carboxylic acids, esters and amides
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The reactions of α,β-unsaturated aldehydes such as (E)-cinnamaldehyde and 2- or 4-methoxycinnamaldehyde with trimethylsilyl cyanide in the presence of a catalytic amount of a Lewis base such as TTMPP and DBU afforded the corresponding saturated carboxylic acids after hydrolysis.
- Kawabata, Hirotoshi,Hayashi, Masahiko
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p. 5645 - 5647
(2007/10/03)
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- Me2NSO2Cl and N,N-dimethylamines; a novel and efficient agent for esterification, amidation between carboxylic acids, and equimolar amounts of alcohols and amines
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Various carboxylic esters or amides were prepared in good to excellent yields between carboxylic acids and equimolar amounts of alcohols or amines under very mild conditions using dimethylsulfamoyl chloride (Me2NSO2Cl) combined with N,N-dimethylamines. The choice of the sulfamoyl chloride and the amine is crucial for the reactions.
- Wakasugi, Kazunori,Nakamura, Atsushi,Tanabe, Yoo
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p. 7427 - 7430
(2007/10/03)
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- THE CONVERSION OF CARBOXYLIC ACIDS TO AMIDES VIA TIN(II) REAGENTS
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Unsymmetrical tin(II) amides can be generated, in situ, by adding one equivalent of an amine to bis(bistrimethylamino) tin, Sn2.Treatment of carboxylic acids with these tin(II) reagents derived from alkyl or aryl amines results in smooth conversion to the corresponding N-alkyl or N-aryl amides.
- Burnell-Curty, Cynthia,Roskamp, Eric J.
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p. 5193 - 5196
(2007/10/02)
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- Tin(II) Amides: New Reagents for the Conversion of Esters to Amides
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Mixed tin(II) amides are generated, in situ, via addition of aliphatic amines to Sn2.Condensation of these reagents with esters yields amides.
- Wang, Wei-Bo,Roskamp, Eric J.
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p. 6101 - 6103
(2007/10/02)
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