- Enhancing Ligand-Free Fe-Catalyzed Aminocarbonylation of Alkynes by ZrF4
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Zirconium fluoride was utilized to promote efficiently iron-catalyzed aminocarbonylation between alkynes and amines without the use of extra ligands. In particular, this new system is applicable to a wide range of amine and alkyne substrates affording α,β-unsaturated amides in good to excellent yields. Preliminary mechanistic studies reveal the activation model involving interactions of ZF4 with both iron catalyst and amine substrates.
- Huang, Zijun,Dong, Yanan,Li, Yudong,Makha, Mohamed,Li, Yuehui
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p. 5236 - 5240
(2019/09/03)
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- Enantioselective Epoxidation of Electron-Deficient Alkenes Catalyzed by Manganese Complexes with Chiral N4 Ligands Derived from Rigid Chiral Diamines
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A series of tetradentate sp2N/sp3N hybrid chiral N4 ligands derived from rigid chiral diamines were synthesized, which enabled the first manganese-catalyzed enantioselective epoxidation of electron-deficient alkenes with hydrogen peroxide (H2O2) as an oxidant. The reaction furnishes enantiomerically pure epoxy amides, epoxy ketones as well as epoxy esters in good yields and excellent enantioselectivities (up to 99.9% ee) with lower catalyst loading. Preliminary studies on structure–activity relationship demonstrated that maintaining comparatively lower electron-donating ability of the sp3N and relatively higher electron-donating ability of sp2N of the N4 ligands is beneficial to getting higher activity and selectivity, thus providing us a new view to understand epoxidation with H2O2. (Figure presented.).
- Chen, Xiangning,Gao, Bao,Su, Yijin,Huang, Hanmin
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p. 2535 - 2541
(2017/08/16)
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- An efficient mechanochemical synthesis of amides and dipeptides using 2,4,6-trichloro-1,3,5-triazine and PPh3
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A rapid, facile, and efficient mechanochemical synthesis of amides from carboxylic acids has been developed through an in situ acid activation with 2,4,6-trichloro-1,3,5-triazine and a catalytic amount of PPh3. Under room temperature solvent-drop grinding of the reactants in the presence of an inorganic base, a variety of carboxylic acids including aromatic acids, aliphatic acids, and N-protected α-amino acids undergo amidation to afford amides in moderate to excellent yields. The method is also compatible with Fmoc, Cbz, and Boc protecting groups which yields protected optically active dipeptides without detectable racemization.
- Duangkamol, Chuthamat,Jaita, Subin,Wangngae, Sirilak,Phakhodee, Wong,Pattarawarapan, Mookda
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p. 52624 - 52628
(2015/06/25)
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- Catalytic role of PPh3 and its polymer bound analog in the amidation of carboxylic acids mediated by 2,4,6-trichloro-1,3,5-triazine
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Abstract The catalytic role of PPh3 and its polymer bound analog was investigated in the 2,4,6-trichloro-1,3,5-triazine (TCT) mediated amidation of carboxylic acids. In the presence of inorganic bases which were inert toward TCT, carboxylic acids rapidly reacted with amines to afford amides in good to excellent yields. The described method also enabled the synthesis of optically active protected dipeptides without racemization. Formation of triazinylphosphonium chloride during the PPh3 catalyzed acid activation was confirmed based on 31P NMR studies.
- Duangkamol, Chuthamat,Jaita, Subin,Wangngae, Sirilak,Phakhodee, Wong,Pattarawarapan, Mookda
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supporting information
p. 4997 - 5001
(2015/08/03)
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- Significance of reagent addition sequence in the amidation of carboxylic acids mediated by PPh3 and I2
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The outcome of the amidation reaction mediated by PPh3-I2 was found to be highly dependent on the addition sequence of the reagents. When triethylamine was subjected to a mixture containing PPh3, I2, and a carboxylic acid, acid anhydride was generated almost instantly, before treatment with an amine, presumably via an attack of carboxylate ion onto the acyl function of an acyloxyphosphonium salt. Nevertheless, when a PPh3-I2 mixture was treated with an amine, then a carboxylic acid, prior to adding the base, amide was rapidly formed in high yield with high chemoselectivity, most likely through an intermediate O,N-pentacoordinate phosphorane species as confirmed by ESI-MS technique.
- Wangngae, Sirilak,Duangkamol, Chuthamat,Pattarawarapan, Mookda,Phakhodee, Wong
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p. 25789 - 25793
(2015/10/20)
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- Enhancing the scope of the Diels-Alder reaction through isonitrile chemistry: Emergence of a new class of acyl-activated dienophiles
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α,β-Unsaturated imides, formylated at the nitrogen atom, comprise a new and valuable family of dienophiles for servicing Diels-Alder reactions. These systems are assembled through extension of recently discovered isonitrile chemistry to the domain of α,β-unsaturated acids. Cycloadditions are facilitated by Et2AlCl, presumably via chelation between the two carbonyl groups of the N-formyl amide. Applications of the isonitrile/Diels-Alder logic to the IMDA reaction, as well as methodologies to modify the N-formyl amide of the resultant cycloaddition product, are described. It is expected that this easily executed chemistry will provide a significant enhancement for application of Diels-Alder reactions to many synthetic targets.
- Townsend, Steven D.,Wu, Xiangyang,Danishefsky, Samuel J.
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p. 10659 - 10663
(2012/08/08)
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- NHC-catalyzed C-O or C-N bond formation: Efficient approaches to α,β-unsaturated esters and amides
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Simple and efficient NHC-catalyzed transformations of bromoenal or α,β-dibromoenal into α,β-unsaturated esters or amides with high stereoselectivity through C-O or C-N bond formation have been demonstrated. The NHC-catalyzed processes occur under mild con
- Zhang, Bo,Feng, Peng,Cui, Yuxin,Jiao, Ning
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supporting information; experimental part
p. 7280 - 7282
(2012/07/28)
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- A general and selective iron-catalyzed aminocarbonylation of alkynes: Synthesis of acryl- and cinnamides
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Entering the iron age: The first general method for iron-catalyzed monocarbonylation of alkynes has been developed. A range of structurally diverse cinnamides and acrylamides have been obtained smoothly starting from commercially available amines and alkynes in the presence of [Fe 3(CO)12] and ligand L (see scheme). The method is highly chemo- and regioselective and requires no expensive catalyst.
- Driller, Katrin Marie,Prateeptongkum, Saisuree,Jackstell, Ralf,Beller, Matthias
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scheme or table
p. 537 - 541
(2011/03/16)
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- Copper-catalyzed β-boration of α,β-unsaturated carbonyl compounds with tetrahydroxydiborane
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The copper-catalyzed β-boration of α,β-unsaturated carbonyl compounds with tetrahydroxydiborane has been developed. This diboron reagent allows direct, efficient access to boronic acids and their derivatives. Primary, secondary, and tertiary α,β-unsaturated amides are converted to the corresponding β-trifluoroboratoamides in good to excellent yields. The β-boration of a variety of α,β-unsaturated esters and ketones is also reported.
- Molander, Gary A.,McKee, Silas A.
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supporting information; experimental part
p. 4684 - 4687
(2011/11/06)
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- Samarium-mediated mild and facile method for the synthesis of amides
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Samarium-mediated facile method for the formation of amide bonds by the reaction of acyl chlorides and amines is described. The reaction afforded high yields of the desired amides under mild and neutral conditions.
- Shi, Feng,Li, Jian,Li, Chunju,Jia, Xueshun
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experimental part
p. 6049 - 6051
(2010/11/21)
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- Oxidative amidation and azidation of aldehydes by NHC catalysis
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Figure presented N-Heterocyclic carbene catalyzed oxidative amidations of various aldehydes to the corresponding hexafluoroisopropylesters by using the readily available organic oxidant A are described. The hexafluoroisopropylesters prepared in situ are shown to be highly useful active esters for amide bond formation. In addition, oxidative azidation of aldehydes is presented. These mild organocatalytic processes do not use any transition metal.
- De Sarkar, Suman,Studer, Armido
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supporting information; experimental part
p. 1992 - 1995
(2010/07/10)
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- Oxidation of aliphatic α,β-unsaturated aldimines to amides specifically by oxone with AlCl3
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α,β-Unsaturated aldimines were specifically oxidized to amides with Oxone in the presence of AlCl3 as a Lewis acid in CH2Cl2. No migration of aryl group occurred in the rearrangement reaction. Copyright Taylor & Francis Group, LLC.
- Lu, Zhou,Peng, Lijun,Wu, Wentao,Wu, Longmin
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p. 2357 - 2366
(2008/09/21)
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- A mild and efficient reaction for conversion of carboxylic acids into acid bromides with ethyl tribromoacetate/triphenylphosphine under acid-free conditions
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Acid bromides were prepared efficiently from carboxylic acids with readily available ethyl tribromoacetate and triphenylphosphine at room temperature under neutral conditions. The present process is applicable to the preparation of various acid bromides from aromatic and aliphatic carboxylic acids. Aromatic carboxylic acids were found to be more reactive than aliphatic carboxylic acids under reaction conditions.
- Kang, Dong Ho,Joo, Tae Young,Lee, Eun Hwa,Chaysripongkul, Skaydaw,Chavasiri, Warinthorn,Jang, Doo Ok
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p. 5693 - 5696
(2007/10/03)
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- Synthesis and reactions of 2-substituted ethyl N-alkylmalonylhydroxamic acids
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Alkylation of O-silylated N-alkylmalonylhydroxamic acids provides a method for the synthesis of 2-substituted N-alkylmalonyl hydroxamic acids. The substituent at C-2 does not materially change the chemistry of the α-lactam intermediates produced from them. They can be converted to unsymmetric ureas and hydantoins in high yields. The addition of unsaturated substituents at C-2 is used to produce cyclic ureas containing medium rings via RCM reactions.
- Hoffman, Robert V.,Madan, Sachin
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p. 4876 - 4885
(2007/10/03)
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- A mild and efficient procedure for the preparation of acid chlorides from carboxylic acids
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Various carboxylic acids are converted into the corresponding acid chlorides by treatment with trichloroacetonitrile and triphenylphosphine in methylene chloride at room temperature. Aryl acids show higher reactivity than alkyl acids under the conditions.
- Jang, Doo Ok,Park, Doo Jin,Joonggon, Kim
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p. 5323 - 5326
(2007/10/03)
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- A novel carbonylative decomplexation of alkyne-dicobalt hexacarbonyls: Hyrocarbamoylation of alkynes
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A novel carbonylative decomplexation of alkyne-dicobalt hexacarbonyls, i.e. hydrocarbamoylation of alkynes, was carried out by reaction of the complexes with 10 equiv, of primary and secondary amines.
- Sugihara, Takumichi,Okada, Yoshinari,Yamaguchi, Masahiko,Nishizawa, Mugio
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p. 768 - 770
(2007/10/03)
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- Reactivity of substituted and unsubstituted diphenylphosphonium diylides towards carbonic anhydride derivatives
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The reactivity of diphenylphosphonium diylides was investigated towards carbonic anhydric derivatives. Unsubstituted and substituted non-stabilized diylides react with phenylisocyanate and dicyclohexylcarbodiimide, leading to the formation of new monoylide type intermediates. These last ones react in situ with carbonyl compounds through a Wittig reaction leading respectively to α,β-unsaturated amides and amidines. Substituted semi-stabilized or stabilized diylides, in similar conditions lead to the formation of alkenes. In all the cases a high E stereoselectivity, determined by 1H-NMR and 13-C-NMR, was observed.
- Cristau,Taillefer,Urbani,Fruchier
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p. 2005 - 2020
(2007/10/03)
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- Chemoselective alcoholysis of acylureas
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Two methods for the chemoselective alcoholysis of acylureas were developed to generate esters and amides, respectively. In alcoholysis using sodium methoxide in methanol, methoxide attacked the acyl carbonyl to give the corresponding methyl ester. While in alcoholysis using lithium benzyloxide in diethyl ether, benzyloxide attacked the urea carbonyl to give the amide. The chemoselectivity originates in the different chelating abilities of the metals and the polarity of the solvents.
- Kishikawa,Eida,Kohmoto,Yamamoto,Yamada
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p. 173 - 175
(2007/10/02)
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- Michael Addition of Malononitrile to α-Acetylcinnamamides
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The reaction of α-acetylcinnamamides 7a-e with malononitrile using piperidine as the catalyst is described.When one or two equivalents of malononitrile are used, the 2-amino-4H-pyran 6a or the polyfunctionalized carbocycles 9b-e, respectively, can be isolated as major products, depending on the experimental conditions.Compounds 9b-e apparently arise from a sequential Michael plus Knoevenagel addition of two molecules of malononitrile followed by Thorpe cyclization.The structure of 9b was determined by an X-ray crystallographic analysis, which revealed a twisted cyclohexadiene ring with characteristic crystal packing.Key Words: Cinnamamides, α-acetyl / Malononitrile / 4H-Pyrans / Michael additions
- Martin, Nazario,Martinez-Grau, Angeles,Seoane, Carlos,Marco, Jose L.,Albert, Armando,Cano, Felix H.
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p. 801 - 804
(2007/10/02)
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- Amides and formamidines with antinociceptive activity (note II)
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Forty amides, formamidines and trifluoromethylsulfonylamides bearing on the nitrogen a cyclohexyl residue, eventually 2-substituted, were prepared and tested for analgesic activity against a chemical stimulus. Good activity was exhibited by amides 9, 11 and 28, by formamidine 34, as well as by triflylamide 40. Eleven additional compounds exhibited a moderate activity.
- Pau,Boatto,Cerri,Palomba,Nicolai,Sparatore,Varoni
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p. 1291 - 1299
(2007/10/02)
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- Condensation of Lithium Diphenylphosphonium Diylides with Carbonic Anhydride Derivatives. A New One-Pot Synthesis of α,β-Unsaturated Anilides and Amidines.
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Lithium diphenylphosphonium diylides readily attack phenylisocyanate and dicyclohexylcarbodiimide.The formed semi-stabilised ylides bear a metallated amide or amidine functium.Their use in situ as Wittig reagents towards aldehydes and ketones is shown to be a new one-pot, E-stereoselective synthesis for α,β-unsaturated anilides and amidines.Moreover, the corresponding phosphonium salts were isolated.Key Words: lithium phosphonium diylides; pseudo-acylation reaction; Wittig-reaction; vinylic amides and amidines.
- Cristau, Henri-Jean,Perraud-Darcy, Anne,Ribeill, Yves
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p. 2693 - 2696
(2007/10/02)
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- THE DIRECT CONVERSION OF CARBOXYLIC ACIDS TO CARBOXAMIDES VIA REACTION WITH UNSOLVATED BIS(DIORGANOAMINO) MAGNESIUM REAGENTS
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It has been found that unsolvated bis(diorganoamino) magnesium compounds react smoothly with carboxylic acids to give the corresponding carboxamides directly in good to excellent yields.
- Sanchez, Ramiro,Vest, Gary,Despres, Lisa
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p. 2909 - 2914
(2007/10/02)
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- 3,3'-(Phenylphosphinylidene)bis and 3,3'-(Phenylphosphinylidene)bis. New Activating Agents
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New activating agents, 3,3'-(phenylphophinylidene)bis (4) and 3,3'-(phenylphosphinylidene)bis (5), were readily prepared by the reaction of phenylphosphonic dichloride (3) with 2(3H)-benzoxazolone (1) and 2(3H)-benzothiazolone (2) respectively in the presence of triethylamine at room temperature.The new activating agents 4 and 5 were found to be useful for the preparation of amides, esters, and dipeptides under mild conditions.Furthemore, the direct polycondensation of isophthalic acid with aromatic diamines using the activating agent 4 in the presence of pyridine proceeded fast at room temperature to produce polyamides with inherent viscosities up to 0.80 dL/g.
- Ueda, Mitsuru,Mochizuki, Amane,Hiratsuka, Ichiro,Oikawa, Hideaki
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p. 3291 - 3297
(2007/10/02)
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- 1,2-Benzisoxazol-3-yl Diphenyl Phosphate: A New, Reactive Activating Agent for the Synthesis of Amides, Esters, and Peptides via Condensation
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A new activating agent for condensations, 1,2-benzisoxazol-3-yl diphenyl phosphate (1), was readily prepared in high yield by the reaction of 1,2-benzisoxazol-3-ol (2) with diphenyl phosphorochloridate (3) in the presence of triethylamine in benzene.The reaction of the carboxylic acids with the amines in the presence of 1 was investigated by two procedures, a two-step method and a one-step procedure.Both methods gave the corresponding amides and esters in high yields under mild conditions, but the one-step procedure was found to be superior to the two-step procedure because of its simplicity and speed.Furthermore, the activating agent 1 was shown to be a useful peptide forming reagent.
- Ueda, Mitsuru,Oikawa, Hideaki
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p. 760 - 763
(2007/10/02)
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