- Minisci-Type Alkylation of N-Heteroarenes by N-(Acyloxy)phthalimide Esters Mediated by a Hantzsch Ester and Blue LED Light
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A synthetic method that enables the Hantzsch ester-mediated Minisci-type C2-alkylation of quinolines, isoquinolines and pyridines by N-(acyloxy)phthalimide esters (NHPI) under blue LED (light emitting diode) light (456 nm) is described. Achieved under mild reaction conditions at room temperature, the metal-free synthetic protocol was shown to be applicable to primary, secondary and tertiary NHPIs to give the alkylated N-heterocyclic products in yields of 21–99%. On introducing a chiral phosphoric acid, an asymmetric version of the reaction was also realised and provided product enantiomeric excess (ee) values of 53–99%. The reaction mechanism was delineated to involve excitation of an electron-donor acceptor (EDA) complex, formed from weak electrostatic interactions between the Hantzsch ester and NHPI, which generates the posited radical species of the redox active ester that undergoes addition to the N-heterocycle.
- Kyne, Sara Helen,Li, Jiacheng,Siang Tan, Suan,Wai Hong Chan, Philip
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supporting information
(2022/01/11)
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- Reactivity of α-Amino Acids in the Reaction with Esters in Aqueous–1,4-Dioxane Media
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The kinetics of the reaction of a series of α-amino acids with 4-nitrophenyl acetate, 4-nitrophenyl benzoate, and 2,4,6-trinitrophenyl benzoate in aqueous 1,4-dioxane medium has been studied. Kinetics of the reactions involving 4-nitrophenyl acetate and 2,4,6-trinitrophenyl benzoate has complied with the Br?nsted dependence and revealed linear correlation between rate constant logarithm and the energy difference of the frontier orbitals of α-amino acids anions.
- Kochetova,Kustova,Kuritsyn
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- Regioselective synthesis of tetrasubstituted pyrroles by 1,3-dipolar cycloaddition and spontaneous decarboxylation
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We developed a novel regioselective synthesis of tetrasubstituted pyrroles via the classic 1,3-dipolar cycloaddition of α,β-unsaturated benzofuran-3(2H)-one and azlactones (1) followed by spontaneous decarboxylation. The complete regiochemical control of tetrasubstituted pyrroles was confirmed by the orthogonal synthesis of complementary regioisomers (7a and 7b) simply by using different azlactones (1a and 1b, respectively).
- Kim, Yongju,Kim, Jonghoon,Park, Seung Bum
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supporting information; experimental part
p. 17 - 20
(2009/08/07)
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- Microwave-assisted synthesis of amide under solvent-free conditions
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An efficient and environmentally friendly synthetic method for the synthesis of primary amides under microwave irradiation was described, in which the primary amine was directly reacted with acid without any catalytic agents. The reaction took place in 8-12-min, which was much shorter than the traditional synthetic methods, with almost quantitative yields. The influential factor of the reaction was discussed. The tautomerization between the carboxylic acid group and the H atom in α-carbon of L-amino acid was observed, presumably a dehydrated intermediate forming from this tautomerized isomer. Copyright Taylor & Francis Group, LLC.
- Wang, Xiao-Jian,Yang, Qian,Liu, Fei,You, Qi-Dong
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p. 1028 - 1035
(2008/09/18)
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- METHOD OF AMIDOCARBONYLATION REACTION
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A novel method of an amidocarbonylation reaction among an aldehyde compound, an amide compound, and carbon monoxide, which comprises using a palladium-supporting crosslinked-polymer composition containing palladium clusters having a major-axis length of 20 nm or shorter to conduct the amidocarbonylation reaction. Thus, an N-acyl-±-amino acid can be more efficiently and selectively synthesized in a clean reaction system. Also provided is a catalyst for use in the method.
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Page/Page column 11
(2008/06/13)
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- A study of amidocarbonylation reactions catalyzed by Pd/HZSM-5
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A HZSM-5-supported palladium catalyst, which was prepared by the conventional impregnation method, was utilized in amidocarbonylation reactions. Several important parameters were optimized to give moderate to excellent yields. The catalyst recycling of Pd/HZSM-5, for the first time, was achieved for at least four run times without depreciation of catalytic activity. The studies of TEM images revealed that agglomeration of the palladium species of Pd/ HZSM-5 catalyst was avoided after reaction, which was quite different from the case of Pd/C catalyst.
- Ke, Wu Yang,Xuan, Zhen Jiang
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p. 806 - 809
(2007/10/03)
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- Palladium-catalyzed amidocarbonylation improved by recyclable ionic liquids
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Two types of ionic liquids (halide anion ionic liquids and Brensted acidic ionic liquids) were first applied to improve the palladium-catalyzed amidocarbonylation. Both the palladium catalyst and the ionic liquids could be recycled at least five times without significant loss in catalytic activity. Georg Thieme Verlag Stuttgart.
- Zhu, Bingchun,Jiang, Xuanzhen
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p. 2795 - 2798
(2008/02/11)
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- Platinum-catalyzed amidocarbonylation
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The first example of platinum-catalyzed amidocarbonylation of aldehydes with amides and carbon monoxide is described. In contrast to precedent palladium catalysis, a remarkable ligand acceleration by phosphines was observed. Furthermore, an optically active N-acetyl amino acid was partially epimerized under the platinum-catalyzed conditions, while faster racemization was observed under the palladium catalysis.
- Sagae, Takahiro,Sugiura, Masaharu,Hagio, Hiroyuki,Kobayashi, Shu
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p. 160 - 161
(2007/10/03)
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- Rhodium-catalysed racemisation of N-acyl α-amino acids
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The first transition metal-catalysed racemisation of N-acyl α-amino acids, which is of importance for kinetic resolution processes, is described. Enantiomerically pure N-acyl α-amino acids were efficiently racemised under mild conditions using various rhodium complexes as catalysts, e.g. [Rh(cod)Cl]2, in the presence of phosphines. (C) 2000 Elsevier Science Ltd.
- Hateley, Martin J.,Schichl, Daniel A.,Kreuzfeld, Hans-J?rn,Beller, Matthias
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p. 3821 - 3824
(2007/10/03)
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- Solid-phase synthesis of α-amino acids by radical addition to a dehydroalanine derivative
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The first synthesis of N-acetyl-a-amino acids by radical addition on solid support to commercially available 2-acetamidoacrylic acid using the mercury method is described. The reaction proceeds in acceptable chemical efficiency (49-60%) depending on the nature of the mercury halide agent. Cleavage by mild acid treatment released the product from the solid support in excellent purity.
- Yim, Anne-Marie,Vidal, Yves,Viallefont, Philippe,Martinez, Jean
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p. 4535 - 4538
(2007/10/03)
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- A new improved palladium-catalyzed amidocarbonylation
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A new and improved variant of the palladium-catalyzed amidocarbonylation to yield N-acyl-α-amino acids is described. Using Pd/C as catalyst the products were prepared in good to excellent yields (up to 98 %). Advantages of the Pd/C-catalyst with regard to former catalyst systems are demonstrated by the preparation of N-substituted non-natural amino acids which are of current interest as structural units of peptoids.
- Beller, Matthias,Moradi, Wahed A.,Eckert, Markus,Neumann, Helfried
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p. 4523 - 4526
(2007/10/03)
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- Efficient chemoenzymatic synthesis of enantiomerically pure α-amino acids
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A general two-step chemoenzymatic synthesis for enantiomerically pure natural and nonnatural α-amino acids is presented. In the first step of the sequence, the ubiquitous educts aldehyde, amide and carbon monoxide react by palladium-catalyzed amidocarbonylation to afford the racemic N-acyl amino acids in excellent yields. In the second step, enzymatic enantioselective hydrolysis yields the free optically pure a-amino acid and the other enantiomer as the N-acyl derivative, both in optical purities of 85-99.5% ee. The advantage of the chemoenzymatic process compared to other amino acid synthesis are demonstrated by the preparation of various functionalized (-OR, -Cl, -F, -SR) α-amino acids on a 10-g scale.
- Beller, Matthias,Eckert, Markus,Geissler, Holger,Napierski, Bernd,Rebenstock, Heinz-Peter,Holla, E. Wolfgang
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p. 935 - 941
(2007/10/03)
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- Palladium-catalyzed amidocarbonylation - A new, efficient synthesis of N-acyl amino acids
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For the first time palladium catalysts have been used successfully for the amidocarbonylation reaction. The activity of the cobalt catalysts that were used exclusively beforehand has now been exceeded by an order of magnitude, and the reaction can be performed under far milder conditions. Palladium-catalyzed amidocarbonylation reactions can now be used for the synthesis of a much wider range of N-acyl amino acids.
- Beller,Eckert,Vollmuller,Bogdanovic,Geissler
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p. 1494 - 1496
(2007/10/03)
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- Syngas reactions XIV. Amidocarbonylation as a route to α-amidocarboxylic acids
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The amidocarbonylation of olefin and aldehyde substrates has been applied to the synthesis of a variety of amidocarboxylic acids, including surface active agents (e.g.C14-C16 N-acyl-α-amino acids), specialty surfactants (such as the sarcosinates), intermediates for sweeteners (e.g. aspartame), food additives (e.g. glutamic acid), and certain chelating agents.Homogeneous cobalt and rhodium-based catalysts, modified, for example, with sulfoxide and bidentate phosphine ligands, have been tailored to the synthesis of each individual class of product.Process studies, including examinations of reaction rate, product selectivity, as well as catalyst stability, have been undertaken for N-acetylglycine and amido acid surfactant syntheses.
- Lin, J.J.,Knifton, John F.
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- A general and accurate nmr determination of the enantiomeric purity of α-aminoacids and α-aminoacid derivatives
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Derivatization of α-aminoacids, α-aminoesters and α-aminolactones as N-acetyl derivatives allow the accurate NMR determination of the enantiomeric purity. In these conditions the major coordination site with a chiral shift reagent will correspond to the NMR observation site. Experimental factors leading to the highest ΔΔδ values are ascertained. No straightforward correlation with absolute configurations can be established.
- Calmes, Monique,Daunis, Jacques,Jacquier, Robert,Verducci, Jean
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p. 2285 - 2292
(2007/10/02)
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- ON THE CATALYTIC AMIDOCARBONYLATION OF SUBSTITUTED ALLYLIC ALCOHOLS
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Substituted allylic alcohols (3-methyl-2-buten-1-ol and 2-methyl-3-buten-2-ol) were isomerized and amidocarbonylated.In addition to the expected product, N-acetylleucine, arising from their rearrengement to 3-methylbutanal and subsequent amidocarbonylation (22percent yield), we isolated two additional products (28percent yield).These were shown by spectroscopic methods and by syntheses, via amidocarbonylations of the respective aldehydes, to be 2-acetamido-5-methylhexanoic acid and 2-acetamido-4-methylhexanoic acid.Their formation is postulated to be the sequential result of (i) dehydration first to form isoprene, (ii) hydroformylation and hydrogenation of isoprene to give 3-methyl-1-pentanal and 4-methyl-1-pentanal, and (iii) aldehyde amidocarbonylation.Treatment of isoprene itself under the same conditions also gave these latter two acetylamino acids.
- Yuan, Sun-Shine,Ajami, Alfred M.
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p. 255 - 258
(2007/10/02)
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- NEW SYNTHETIC ROUTE TO N-ACYL-α-AMINO ACIDS VIA AMIDOCARBONYLATION BY MEANS OF HOMOGENEOUS BINARY CATALYST SYSTEMS
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New catalytic processes which lead to the formation of N-acyl-α-amino acids promoted by homogeneous binary systems are described: (a) the isomerization-amidocarbonylation of allylic alcohols catalyzed by transition metal binary systems, e.g., Co-Rh, Co-Pd, Co-Fe, giving various aliphatic N-acyl-α-amino acids; (b) the isomerization-amidocarbonylation of oxiranes catalyzed by cobalt-Lewis acid systems giving N-acyl-α-amino acids; The process is extremely effective for the synthesis of N-acetylphenylalanine from styrene oxide and (c) the hydroformylation-amidocarbonylation of trifluoropropene catalyzed by cobalt-rhodium binary system giving N-acetyltrifluorovaline in excellent regioselectivity and yield.Possible mechanisms for these new processes are discussed.
- Hirai, Kenji,Fujita, Makoto,Fuchikami, Takamasa
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p. 203 - 214
(2007/10/02)
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- DIRECT CONVERSION OF ALLYLIC ALCOHOLS INTO N-ACYL-α-AMINO ACIDS BY CATALYTIC AMIDOCARBONYLATION BY MEANS OF HOMOGENEOUS BINARY SYSTEMS
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N-Acyl-α-amino acids are synthesized by the amidocarbonylation of allylic alcohols catalyzed by homogeneous binary systems which consist of cobalt carbonyl and rhodium (or iron or palladium) complexes.
- Hirai, Kenji,Takahashi, Yoshitaka,Ojima, Iwao
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p. 2491 - 2494
(2007/10/02)
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