- Synthesis of chiral Rh-bichep complexes, highly efficient catalysts for asymmetric hydrogenations
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Chiral cationic and neutral Rh complexes RhX(bichep)(nbd) (X=Cl,ClO4; NBD=norbornadiene;bichep=2,2′-bis(dicyclohexylphosphino)-6,6'-dimethyl-l, r-biphenyl) are highly active and excellent catalysts for enantioselective hydrogenation of prochiral olefms and ketones under mild reaction conditions.
- Chiba, Takeshi,Miyashita, Akira,Nohira, Hiroyuki,Takaya, Hidemasa
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Read Online
- Cobalt-Catalyzed C(sp2)-H Carbonylation of Amino Acids Using Picolinamide as a Traceless Directing Group
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Herein we report an efficient protocol for the C(sp2)-H carbonylation of amino acid derivatives based on an inexpensive cobalt(II) salt catalyst. Carbonylation was accomplished using picolinamide as a traceless directing group, CO (1 atm) as the carbonyl
- Lukasevics, Lukass,Cizikovs, Aleksandrs,Grigorjeva, Liene
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supporting information
p. 2748 - 2753
(2021/04/12)
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- Electrochemical anion pool synthesis of amides with concurrent benzyl ester synthesis
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An electrosynthesis method for amide bond formation has been developed in an attempt to increase the atom economy for this class of reactions. This "anion pool" method electrochemically generates strong nucleophiles from amine substrates. The amine nucleophiles then react with acid anhydrides to generate amides, and the by-product from this reaction undergoes further chemical transformations to generate pharmaceutically relevant benzoic esters. These one-pot reactions are operationally simple, are performed at room temperature, and avoid rare transition metals and added bases. The amide synthesis is amenable to primary and secondary amines and a variety of anhydrides with yields up to 90% obtained. Atom economy and process mass index (PMI) values calculated for this procedure indicate that this process can be considered greener compared to traditional amide synthesis routes used by industry. Furthermore, this electrochemical approach showed unique selectivity when substrates that contained two inequivalent amine moieties were examined.
- Mevan Dissanayake,Melville, Alex D.,Vannucci, Aaron K.
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p. 3165 - 3171
(2019/06/18)
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- Clickable coupling of carboxylic acids and amines at room temperature mediated by SO2F2: A significant breakthrough for the construction of amides and peptide linkages
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The construction of amide bonds and peptide linkages is one of the most fundamental transformations in all life processes and organic synthesis. The synthesis of structurally ubiquitous amide motifs is essential in the assembly of numerous important molecules such as peptides, proteins, alkaloids, pharmaceutical agents, polymers, ligands and agrochemicals. A method of SO2F2-mediated direct clickable coupling of carboxylic acids with amines was developed for the synthesis of a broad scope of amides in a simple, mild, highly efficient, robust and practical manner (>110 examples, >90% yields in most cases). The direct click reactions of acids and amines on a gram scale are also demonstrated using an extremely easy work-up and purification process of washing with 1 M aqueous HCl to provide the desired amides in greater than 99% purity and excellent yields.
- Wang, Shi-Meng,Zhao, Chuang,Zhang, Xu,Qin, Hua-Li
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supporting information
p. 4087 - 4101
(2019/04/30)
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- Synthesis and antimicrobial activities of novel sorbic and benzoic acid amide derivatives
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A series of sorbic and benzoic acid amide derivatives were synthesized by conjugating sorbic acid (SAAD, a1–a7) or benzoic acid (BAAD b1–b6) with amino acid esters and their antimicrobial activities were investigated against Escherichia coli, Bacillus subtilis and Staphylococcus aureus, mixed bacteria from rancid milk, Saccharomyces cerevisiae, and Aspergillus niger. The antimicrobial activity of sorbic acid amides was better than that of benzoic acid amides. The minimum inhibitory concentrations (MIC) of compound isopropyl N-[1-oxo-2, 4-hexadien-1-yl]-L-phenylalaninate (a7) were 0.17 mM against B. subtilis, and 0.50 mM against S. aureus, while the MIC values of sorbic acid were more than 2 mM respectively. Also, compound a7 displayed pH-independent antimicrobial activity in the range of pH 5.0–9.0 and was effective at pH 9.0. These results demonstrated that the conjugation of sorbic acid with amino acid esters led to significant improvement of in vitro antimicrobial attributes, but little effect was observed for benzoic acid amide derivatives.
- Wei, Qingyi,Wang, Xiaomei,Cheng, Jun-Hu,Zeng, Guangxiang,Sun, Da-Wen
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p. 220 - 232
(2018/06/26)
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- Dynamic Kinetic Resolution of Azlactones by a Chiral N, N-Dimethyl-4-aminopyridine Derivative Containing a 1,1′-Binaphthyl Unit: Importance of Amide Groups
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A dynamic kinetic resolution (DKR) of azlactones in the presence of benzoic acid and a binaphthyl-based N,N-4-dimethylaminopyridine (DMAP) derivative 1i having two amide groups at the 3,3′-positions of a binaphthyl unit is developed. The reaction proceeded smoothly with a wide range of azlactones to provide α-amino acid derivatives with good to high enantiomeric ratios (er's). A multigram-scale reaction (2.5 g) for the DKR of azlactone 2d was also demonstrated, and the resulting product was converted to unnatural α-amino acid 6d′.
- Mandai, Hiroki,Hongo, Kohei,Fujiwara, Takuma,Fujii, Kazuki,Mitsudo, Koichi,Suga, Seiji
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supporting information
p. 4811 - 4814
(2018/08/24)
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- Alpha-amino acrylate microbicide and preparation method and application thereof
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The invention provides an alpha-amino acrylate microbicide and a preparation method and application thereof. The alpha-amino acrylate microbicide has a specific chemical structure formula shown as a formula I, and the formula I is shown in the description. The alpha-amino acrylate microbicide has the advantages that by utilizing the design principle of pesticide molecules, a medical leading compound with anti-coronavirus activity is performed with structure modification of agricultural plant virus-resisting activity, a series of alpha-amino acrylate derivatives is designed and synthesized, and particularly, the alpha-amino acrylate derivative containing piperidine ring is synthesized; the known compound is used as a positive reference compound to systematically screen the biology activity; a plurality of high-efficiency anti-virus leading molecules are provided for the developing of new pesticides, and the positive meaning is realized for the reduction application of the pesticide and the protection of environment ecology.
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Paragraph 0145; 0148
(2017/10/13)
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- Preparation method of chiral alpha-amino acid
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The invention discloses a preparation method of chiral alpha-amino acid. Initial raw materials comprising aldehyde and N-acryl substituted glycine undergo Erlenmeyer-Plochl cyclization, hydrolysis or alcoholysis, asymmetric catalytic hydrogenation and acid hydrolysis to obtain the chiral alpha-amino acid compound. The method adopting the above synthesis route has the advantages of mild reaction conditions, simple technological operation, safe and stable production, realization of high yield, good chemical purity and good optical purity of the above obtained product, wide application range, and suitableness for industrial production.
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- Stereoselective Synthesis of 1,3-Diaminotruxillic Acid Derivatives: An Advantageous Combination of C-H-ortho-Palladation and On-Flow [2+2]-Photocycloaddition in Microreactors
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The stereoselective synthesis of ε-isomers of dimethyl esters of 1,3-diaminotruxillic acid in three steps is reported. The first step is the ortho-palladation of (Z)-2-aryl-4-aryliden-5(4H)-oxazolones 1 to give dinuclear complexes 2 with bridging carboxylates. The reaction occurs through regioselective activation of the ortho-C-H bond of the 4-arylidene ring in carboxylic acids. The second step is the [2+2]-photocycloaddition of the C-C exocyclic bonds of the oxazolone skeleton in 2 to afford the corresponding dinuclear ortho-palladated cyclobutanes 3. This key step was performed very efficiently by using LED light sources with different wavelengths (465, 525 or 625 nm) in flow microreactors. The final step involved the depalladation of 3 by hydrogenation in methanol to afford the ε-1,3-diaminotruxillic acid derivatives as single isomers.
- Serrano, Elena,Juan, Alberto,Garca-Montero, Angel,Soler, Tatiana,Jimnez-Mrquez, Francisco,Cativiela, Carlos,Gomez, M. Victoria,Urriolabeitia, Esteban P.
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supporting information
p. 144 - 152
(2016/01/25)
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- An eco-benign and highly efficient procedure for N-acylation catalyzed by heteropolyanion-based ionic liquids using carboxylic acid under solvent-free conditions
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An eco-benign and highly efficient route for N-acylation of amines has been developed by treating amines with corresponding carboxylic acids in the presence of 2 mol % of heteropolyanion-based ionic liquids as catalysts under solvent-free conditions. This practical reaction could tolerate a wide range of substrates. Thus, various N-acylation products including N-acyl α-amino acid derivatives were obtained in moderate to excellent yields at 70 C to 120 C. Moreover, recycling studies revealed that heteropolyanion-based ionic liquids were easily reusable for this N-acylation. This method provides a green and much improved protocol over the existing methods.
- Chen, Zhikai,Fu, Renzhong,Chai, Wen,Zheng, Hao,Sun, Lin,Lu, Qiang,Yuan, Rongxin
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p. 2237 - 2245
(2014/03/21)
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- A [3+3] cyclization strategy for asymmetric synthesis of alkyl substituted piperidine-2-ones using 1,2-cyclic sulfamidates: A formal synthesis of (S)-coniine from l-norvaline
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Regioselective ring-opening reactions of a set of representative 1,2-cyclic sulfamidates with lithium triethylorthopropiolate proceeded efficiently to deliver the corresponding δ-amino-α,β-unsaturated esters after acidic hydrolysis. Hydrogenation of the unsaturated esters and subsequent thermal cyclization afforded the related alkyl substituted piperidine-2-ones. This approach represents a novel [3+3] cyclization strategy for the asymmetric synthesis of alkyl substituted piperidin-2-ones. Efficiency of the cyclization process is illustrated by a formal asymmetric synthesis of (S)-coniine from l-norvaline.
- Karanfil, Abdullah,Balta, Berrin,Eskici, Mustafa
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p. 10218 - 10229,12
(2020/09/02)
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- Iron-catalyzed efficient synthesis of amides from aldehydes and amine hydrochloride salts
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A practical and efficient method for the synthesis of amides has been developed by iron-catalysed oxidative amidation of aldehydes with amine hydrochloride salts. A wide range of amides have been obtained in good to excellent yields under mild conditions. The application of this novel amide formation reaction to the synthesis of pharmaceutical compounds has been successfully demonstrated. Copyright
- Ghosh, Subhash Chandra,Ngiam, Joyce S. Y.,Chai, Christina L. L.,Seayad, Abdul M.,Dang, Tuan Thanh,Chen, Anqi
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supporting information; experimental part
p. 1407 - 1412
(2012/07/13)
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- Amino acid based chiral N-amidothioureas. Acetate anion binding induced chirality transfer
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N-Amidothioureas generated from amine-dimethylated natural l-phenylalanine and its d-enantiomer bearing a chiral carbon that is by 2 atoms or 3 chemical bonds away from the anion binding site establish chiral communication upon acetate anion binding to the thiourea moiety.
- Wang, Fang,He, Wen-Bin,Wang, Jin-He,Yan, Xiao-Sheng,Zhan, Ying,Ma, Ying-Ying,Ye, Li-Cai,Yang, Rui,Cai, Fu,Li, Zhao,Jiang, Yun-Bao
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p. 11784 - 11786
(2011/12/02)
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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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- Enantioselective benzoylation of α-amino esters using (S)-1-benzoyl-2-(α-acetoxyethyl)benzimidazole, a chiral benzimidazolide
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(Chemical Equation Presented) A new chiral benzimidazolide is developed as a nonenzymatic acylating agent for enantioselective benzoylation of racemic α-amino esters. The process is highly efficient, which exhibits uniformly high enantioselectivity for α-amino esters with or without aryl substituents under mild reaction conditions. The chiral benzimidazolide is inexpensive and is easily accessible.
- Karnik, Anil V.,Kamath, Suchitra S.
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p. 7435 - 7438
(2008/02/11)
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- Highly enantioselective decarboxylative protonation of α- aminomalonates mediated by thiourea Cinchona alkaloid derivatives: Access to both enantiomers of cyclic and acyclic α-aminoacids
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Equation Presented Thiourea derived cinchona alkaloids promote the asymmetric decarboxylase protonation of cyclic, acyclic, or bicyclic α-aminomalonate hemiesters under mild and metal-free conditions to afford enantioenriched aminoesters in high yields and enantioselectivities up to 93%. Both enantiomers of the aminoesters have been synthesized with the same selectivity when using organic base 3 and its pseudoenantiomer 6 derived from quinine.
- Amere, Mukkanti,Lasne, Marie-Claire,Rouden, Jacques
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p. 2621 - 2624
(2008/02/10)
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- Dynamic kinetic resolution: Synthesis of optically active α-amino acid derivatives
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Candida antarctica lipase B (Novozyme) is an effective catalyst for the dynamic kinetic resolution of racemic 2-benzyl-4-substituted-5(4H)- oxazolones, in the presence of an alcohol, yielding optically active N- benzoyl amino acid esters. The reaction has been optimised with respect to the solvent and the effect of a catalytic amount of organic base is investigated. (C) 2000 Elsevier Science Ltd.
- Brown, Stuart A.,Parker, Marie-Claire,Turner, Nicholas J.
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p. 1687 - 1690
(2007/10/03)
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- Heterogenised catalysts on zeolites. Synthesis of new chiral Rh(I) complexes with (2S,4R)-trans-4-RCOO-2-(t-butylaminocarbonyl) pyrrolidines and (2S,4S)-cis-4-RCONH-2-(t-butylaminocarbonyl) pyrrolidines. Heterogenisation on silica and a USY-zeolite and study of the role of support on their catalytic profile in hydrogenation of olefins
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Novel chiral ligands (2S,4R)-2-(t-butylaminocarbonyl)-4-[3-(alkylaminocarbonyl)propanoyloxy]pyrrolidine and (2S,4S)-cis-4-(alkylaminocarbonylamino)-2-(t-butyl-aminocarbonyl)pyrrolidine (4a,b; 9a,b), (a: alkyl = t-butyl; b: alkyl = 3-triethoxysilylpropyl) and their rhodium complexes were synthesised and characterised. The reactions of [{Rh(cod)Cl}2] and [RhCl(PPh3)3] with the chiral ligands in the presence of a non-coordinating anion (PF-6) gave the cationic complexes [Rh(L2)(ligand)][PF6] (L2 = cod, PPh3). The structures of these complexes were elucidated by elemental analyses, IR spectroscopy and 1H, 13C and 31P NMR measurements. The metal complexes bearing a triethoxysilyl group were covalently bonded to silica and modified USY-zeolite and Rh-heterogenised complexes were obtained. A comparative study (homogeneous versus supported) was made for the catalytic activity in hydrogenation reactions.
- Corma,Iglesias,Mohino,Sanchez
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p. 147 - 156
(2007/10/03)
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- BICHEP-Ru complexes, highly efficient catalysts for asymmetric hydrogenation of carbonyl compounds
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Newly prepared [RuX(p-cymene)(bichep)]X (X = I, Cl) and Ru(OAc)2(bichep) (bichep = 2,2'-bis(dicyclohexylphosphino)-6,6'-dimethyl-1,1'-biphenyl) proved to be highly efficient catalysts for asymmetric hydrogenation of carbonyl compounds bearing phenylglyoxyloyl group under mild conditions.
- Chiba,Miyashita,Nohira,Takaya
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p. 2351 - 2354
(2007/10/02)
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- Optically active complexes of transition metals (RhI, RuII, CoII and NiII) with 2-aminocarbonylpyrrolidine ligands. Selective catalysts for hydrogenation of prochiral olefins
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The synthesis and characterization of optically active complexes containing organic amides of the type , , , RuCl2(COD)L>, , X and X, where L = (S)-2-t-butylaminocarbony
- Corma, A.,Iglesias, M.,Pino, C. del,Sanchez, F.
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p. 233 - 246
(2007/10/02)
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- New Rhodium Complexes anchored on Modified USY Zeolites. A Remarkable Effect of the Support on the Enantioselectivity of Catalytic Hydrogenation of Prochiral Alkenes
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Rh-complexes with N-based chiral ligands, when anchored on a modified USY-zeolite which contains profuse supermicropores, produce a remarkable increase of enantioselectivity (>95percent) in the hydrogenation of N-acyldehydrophenylalanine derivatives and represent a truly heterogeneous counterpart of the homogeneous organometallic catalysts.
- Corma, A.,Iglesias, M.,Pino, C. del,Sanchez, F.
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p. 1253 - 1255
(2007/10/02)
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- Asymmetric Synthesis. Asymmetric Catalytic Hydrogenation Using Chiral Chelating Six-Membered Ring Diphosphines
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Rhodium(I) catalysts formed by the two chiral chelating six-membered ring diphosphines, 2,4-bis(diphenylphosphino)pentane (skewphos) and 1,3-bis(diphenylphosphino)butane (chairphos), are efficient catalysts for the hydrogenation of amino acid precursors.The two chiral phosphines differ in that skewphos probably adopts a chiral conformation whereas chairphos probably adopts an achiral conformation.This comparison evidences the importance of ring conformations in determining optical yields.The mechanism of asymmetric hydrogenation is discussed, and a number of particular and general conclusions are drawn which may prove useful in predicting optical yields from asymmetric synthesis.
- MacNeil, Patricia A.,Roberts, Nicholas K.,Bosnich, B.
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p. 2273 - 2280
(2007/10/02)
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