- Preparation of acyl fluorides with hydrogen fluoride-pyridine and 1,3-dicyclohexylcarbodiimide
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This work presents an efficient procedure for preparing acyl fluorides by simply reacting carboxylic acid with hydrogen fluoride-pyridine and 1,3-dicyclohexylcarbodiimide (DCC) in dichloromethane. The acyl fluorides were converted in situ to the corresponding benzyl carboxylic esters by adding benzyl alcohol and triethylamine to the reaction mixture.
- Chen, Chinpiao,Chien, Chin-Tzu,Su, Chu-Hsiang
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- 3-(5-NITRO-2-PYRIDON-1-YL)-1,2-BENZOISOTHIAZOLE 1,1-DIOXIDE (BID-NPy) AS A NEW EFFECTIVE CONDENSING REAGENT
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3-(5-Nitro-2-pyridon-1-yl)-1,2-benzoisothiazole 1,1-dioxide (BID-NPy) was found to be a useful condensing reagent.Various dipeptides and esters were prepared in good yields using this reagent.
- Ahmed, Alauddin,Fukuda, Hirohiko,Inomata, Katsuhiko,Kotake, Hiroshi
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- Efficient esterification of carboxylic acids with alkyl halides catalyzed by fluoride ions in ionic liquids
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Ionic liquids based on 1,3-dialkylimidazolinium methanesulfonate have been used as efficient reusable reaction media in the esterification of several carboxylic acids with alkyl halides catalyzed by fluoride ions. The method has wide applicability, and it is mild and green; it is useful for the protection of acids, via ester formation, for alkali labile molecules.
- Brinchi,Germani,Savelli
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- Novel palladium(II) complex containing a chelating anionic N-O ligand: Efficient carbonylation catalyst
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(matrix presented) A novel palladium(II) complex containing chelating anionic pyridine-2-carboxylato and labile tosylato ligands is a highly efficient catalyst for the carbonylation of organic alcohols and olefins to carboxylic acids/esters. Carbonylation of primary, secondary, and tertiary alcohols as well as linear and functionalized terminal olefins was studied. In all cases remarkable activity and selectivity were observed. The catalyst is stable under reaction conditions even in the absence of excess phosphine ligands.
- Jayasree,Seayad,Chaudhari
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- S,S-Bis Dithiocarbonate. A New Reactive Coupling Agent for the Direct Esterification of Carboxylic Acids
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S,S-Bis dithiocarbonate, prepared from 4,6-dimethyl-2-pyrimidinethiol hydrochloride and phosgene in the presence of triethylamine in dichloromethane/toluene, is a new reactive coupling agent for the direct esterification of carboxylic acids with alcohols.
- Kim, Sunggak,Kim, Sung Soo
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- Use of diethoxymethane as a solvent for phase-transfer esterification of carboxylic acids
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The esterification of carboxylic acids with selected primary alkyl halides in diethoxymethane (DEM) utilizing solid-liquid phase-transfer catalysis has been studied. The use of DEM as the solvent simplifies the process in that a single solvent can be used for both reaction and workup.
- Coleman, M. Todd
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- Convenient esterification of carboxylic acids by SN2 reaction promoted by a protic ionic-liquid system formed in situ in solvent-free conditions
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The reaction of esterification of benzoic acid with benzyl chloride was chosen as a model reaction to study the esterification by SN2 promoted by tertiary amine as deprotonating agent. The use of ionic liquid (IL) 1,3-dimethylimidazolium methanesulfonate [MMIm][OMs] as reaction medium has proven to give quantitative yield of the ester, but interestingly the reaction does occur even in solvent-free conditions, where the acid + the amine form a liquid system (a protic IL) in situ. This last methodology was extended to several carboxylic acids in conditions of atom economy (i.e., without excess of any reagent), giving moderately good yields of esters (54-78%) recovered by weight in pure form.
- Cardellini, Fabio,Brinchi, Lucia,Germani, Raimondo,Tiecco, Matteo
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- One-electron Oxidation of Carboxylates by Hexachloroosmate(V) Ion
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Hexachloroosmate(V) cleanly oxidizes tetrabutylammonium tert-butylcyanoacetate to decarboxylative-coupling products, meso- and rac-2,3-di-tert-butylsuccinonitrile, thus constituting the first metal ion-based oxidant to be found to simulate properly this aspect of the Kolbe anodic oxidation of carboxylates.
- Eberson, Lennart,Nilsson, Monica
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- Convenient synthesis of benzyl and allyl esters using benzyl and allyl 2,2,2-trichloro-acetimidate
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Benzyl and allyl 2,2,2-trichloroacetimidate are efficient reagents for the preparation of benzyl and allyl esters of carboxylic acids in the presence of a catalytic amount of boron trifluoride-diethyl ether complex.
- Kokotos, George,Chiou, Antonia
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- Cobalt(II)-catalyzed direct acetylation of alcohols with acetic acid
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Cobalt(II) chloride hexahydrate (CoCl2·6H2O) efficiently catalyzes the acetylation of alcohols with AcOH in high yields. This protocol is also effective with other carboxylic acids, trifluoroacetic acid, propanoic acid, phenylacetic acid and benzoic acid, affording the corresponding acylated products in moderate to good yields. Removal of water is not necessary in these reactions. The catalyst can be filtered and recycled without loss of activity.
- Velusamy, Subbarayan,Borpuzari, Sarbani,Punniyamurthy
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- Heteroleptic 1D coordination polymers: 5-Coordinated zinc(II) polymer as an efficient transesterification catalyst
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The synthesis of three 1D coordination polymers (CPs), [Zn(TPPZ)(HCCB)]n·DMF·H2O (1) [Cd(TPPZ)(HCCB)]n(2) and [Co(TPPZ)(HCCB)]n(3), based on the N,N,N-chelating κ3-2,3,5,6-tetrakis(2-pyridyl)pyrazine (TPPZ) and polymerizing carboxylate (–COO?) 3-(carboxy-methylamino)-4-chlorobenzoic acid (H3CCB) ligands, using a solvothermal method, have been described. The CPs have been adequately characterized by satisfactory elemental analyses, FT-IR, UV–vis, emission, TGA and PXRD analysis. The structure of 1 has been verified by single crystal X-ray diffraction analysis. The structural data revealed the 5-coordinated heteroleptic polymeric framework is exclusively extended through the H3CCB carboxylate group and strong N,N,N-chelating TPPZ ligand acts as a branch terminating site. Notably, the structure of 1 is comprised of one unit of each H2O and DMF solvent in its crystal lattice. In contrast, 2 and 3 exclude lattice solvents, as suggested by PXRD studies, after thermal desolvation of 1. Furthermore, 1 with 5-coordinated Zn(II) centers exhibited an efficient catalytic performance for transesterification reactions, with remarkable stability and good reusability.
- Wani, Manzoor A.,Kumar, Ashish,Pandey, Mrituanjay D.,Pandey, Rampal
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- Palladium-catalyzed carbonylation of benzyl alcohol and its analogs promoted by HI in aqueous systems
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Carbonylation of benzyl alcohol catalyzed by a palladium(0) complex and promoted by hydrogen iodide gives phenylacetic acid in excellent yields in aqueous systems. The catalysis is proposed to proceed through a benzylpalladium species formed by the oxidative addition of benzyl iodide, produced in situ by the interaction of benzyl alcohol with HI, to a Pd(0) species. Application of the carbonylation process to other arylmethanol analogs provided convenient means to prepare 3-isochromanone, 1,4-benzenediacetic acid, 2-hydroxybenzeneacetic acid and 2-naphthaleneacetic acid.
- Lin, Yong-Shou,Yamamoto, Akio
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- Synthesis of Quinolines via the Metal-free Visible-Light-Mediated Radical Azidation of Cyclopropenes
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We report the synthesis of quinolines using cyclopropenes and an azidobenziodazolone (ABZ) hypervalent iodine reagent as an azide radical source under visible-light irradiation. Multisubstituted quinoline products were obtained in 34-81% yield. The reaction was most efficient for 3-trifluoromethylcyclopropenes, affording valuable 4-trifluoromethylquinolines. The transformation probably proceeds through the cyclization of an iminyl radical formed by the addition of the azide radical on the cyclopropene double bond, followed by ring-opening and fragmentation.
- Smyrnov, Vladyslav,Muriel, Bastian,Waser, Jerome
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supporting information
p. 5435 - 5439
(2021/07/21)
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- Photoinduced Diverse Reactivity of Diazo Compounds with Nitrosoarenes
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A diverse reactivity of diazo compounds with nitrosoarene in an oxygen-transfer process and a formal [2 + 2] cycloaddition is reported. Nitosoarene has been exploited as a mild oxygen source to oxidize an in situ generated carbene intermediate under visible-light irradiation. UV-light-mediated in situ generated ketenes react with nitosoarenes to deliver oxazetidine derivatives. These operationally simple processes exemplify a transition-metal-free and catalyst-free protocol to give structurally diverse α-ketoesters or oxazetidines.
- Roy, Sourav,Kumar, Gourav,Chatterjee, Indranil
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supporting information
p. 6709 - 6713
(2021/09/08)
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- ZWITTERIONIC CATALYSTS FOR (TRANS)ESTERIFICATION: APPLICATION IN FLUOROINDOLE-DERIVATIVES AND BIODIESEL SYNTHESIS
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An amide/iminium zwitterion catalyst has a catalyst pocket size that promotes transesterification and dehydrative esterification. The amide/iminium zwitterions are easily prepared by reacting aziridines with aminopyridines. The reaction can be applied a wide variety of esterification processes including the large-scale synthesis of biodiesel. The amide/iminium zwitterions allow the avoidance of strongly basic or acidic condition and avoidance of metal contamination in the products. Reactions are carried out at ambient or only modestly elevated temperatures. The amide/iminium zwitterion catalyst is easily recycled and reactions proceed in high to quantitative yields.
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Paragraph 0015; 0028
(2021/01/29)
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- Benzyne-Mediated Esterification Reaction
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A benzyne-mediated esterification of carboxylic acids and alcohols under mild conditions has been realized, which is made possible via a selective nucleophilic addition of carboxylic acid to benzyne in the presence of alcohol. After a subsequent transesterification with alcohol, the corresponding esters can be produced efficiently. This benzyne-mediated protocol can be used on the modification of Ibuprofen, cholesterol, estradiol, and synthesis of nandrolone phenylpropionate. In addition, benzyne can also be used to promote lactonization and amidation reaction.
- Li, Yang,Shi, Jiarong,Zhao, Jinlong
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supporting information
p. 7274 - 7278
(2021/10/01)
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- A solvent-reagent selection guide for Steglich-type esterification of carboxylic acids
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The Steglich esterification is a widely employed method for the formation of esters under mild conditions. A number of issues regarding the sustainability of this transformation have been identified, chiefly the use of hazardous carbodiimide coupling reagents in conjunction with solvents with considerable issues such as dichloromethane (DCM) and N,N-dimethylformamide (DMF). To overcome these issues, we have developed a solvent-reagent selection guide for the formation of esters via Steglich-type reactions with the aim of providing safer, more sustainable conditions. Optimum reaction conditions have been identified after high-throughput screening of solvent-reagent combinations, namely the use of Mukaiyama's reagent (Muk) in conjunction with solvent dimethyl carbonate (DMC). The new reaction conditions were also exemplified through the synthesis of a small selection of building-block like molecules and includes the formation of t-butyl esters.
- Jordan, Andrew,Sneddon, Helen F.,Sydenham, Jack,Whymark, Kyran D.
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supporting information
p. 6405 - 6413
(2021/09/10)
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- Electrochemically Enabled, Nickel-Catalyzed Dehydroxylative Cross-Coupling of Alcohols with Aryl Halides
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As alcohols are ubiquitous throughout chemical science, this functional group represents a highly attractive starting material for forging new C-C bonds. Here, we demonstrate that the combination of anodic preparation of the alkoxy triphenylphosphonium ion and nickel-catalyzed cathodic reductive cross-coupling provides an efficient method to construct C(sp2)-C(sp3) bonds, in which free alcohols and aryl bromides - both readily available chemicals - can be directly used as coupling partners. This nickel-catalyzed paired electrolysis reaction features a broad substrate scope bearing a wide gamut of functionalities, which was illustrated by the late-stage arylation of several structurally complex natural products and pharmaceuticals.
- Li, Zijian,Sun, Wenxuan,Wang, Xianxu,Li, Luyang,Zhang, Yong,Li, Chao
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supporting information
p. 3536 - 3543
(2021/03/08)
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- Blue Light-Promoted N?H Insertion of Carbazoles, Pyrazoles and 1,2,3-Triazoles into Aryldiazoacetates
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Blue light irradiation of aryldiazoacetates leads to the formation of free carbenes, which can react with carbazoles, pyrazoles and 1,2,3-triazoles to afford the corresponding N?H inserted products. These reactions are performed under air and at room temperature, allowing the mild preparation of a variety of motifs found in biologically relevant targets. (Figure presented.).
- Stivanin, Mateus L.,Fernandes, Alessandra A. G.,da Silva, Amanda F.,Okada, Celso Y.,Jurberg, Igor D.
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p. 1106 - 1111
(2020/01/25)
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- 1,3,4-OXADIAZOLE DERIVATIVE COMPOUNDS AS HISTONE DEACETYLASE 6 INHIBITOR, AND PHARMACEUTICAL COMPOSITION COMPRISING THE SAME
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The present invention relates to novel compounds having a histone deacetylase 6 (HDAC6) inhibitory activity, optical isomers thereof or pharmaceutically acceptable salts thereof, a pharmaceutical use thereof, and a method for preparing the same. According to the present invention, the novel compounds, optical isomers thereof or pharmaceutically acceptable salts thereof have the histone deacetylase 6 (HDAC6) inhibitory activity, and are effective in preventing or treating HDAC6-related diseases, comprising infectious diseases; neoplasm; internal secretion; nutritional and metabolic diseases; mental and behavioral disorders; neurological diseases; eye and ocular adnexal diseases; circulatory diseases; respiratory diseases; digestive diseases; skin and subcutaneous tissue diseases; musculoskeletal system and connective tissue diseases; and teratosis or deformities, and chromosomal aberration.
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Page/Page column 49
(2020/02/16)
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- Preparation of Organic Nitrates from Aryldiazoacetates and Fe(NO3)3·9H2O
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A thermal protocol is reported for the formal insertion of nitric acid into aryldiazoacetates using Fe(NO3)3·9H2O. This strategy is mild and high yielding and allows the preparation of a large variety of members of an unprecedented family of organic nitrates. The nitrate group can be also readily transformed into other functional groups and heterocyclic moieties and can possibly allow new biological explorations of untapped potential associated with their NO-releasing ability.
- Thurow, Samuel,Fernandes, Alessandra A. G.,Quevedo-Acosta, Yovanny,De Oliveira, Matheus F.,De Oliveira, Marcelo G.,Jurberg, Igor D.
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supporting information
p. 6909 - 6913
(2019/09/12)
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- Amide/Iminium Zwitterionic Catalysts for (Trans)esterification: Application in Biodiesel Synthesis
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A class of zwitterionic organocatalysts based on an amide anion/iminium cation charge pair has been developed. The zwitterions are easily prepared by reacting aziridines with aminopyridines. They are catalytically applicable to transesterifications and dehydrative esterifications. Mechanistic studies reveal that the amide anion and iminium cation work synergistically in activating the reaction partners, with the iminium cationic moiety interacting with the carbonyl substrates through nonclassical hydrogen bonding. The reaction can be applied to large-scale synthesis of biodiesel under mild conditions.
- Lam, Ying-Pong,Ng, Wing-Hin,Tan, Fei,Tse, Ying-Lung Steve,Wang, Xinyan,Yeung, Ying-Yeung
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p. 8083 - 8092
(2019/08/26)
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- Solvent-Free N-Alkylation of Amides with Alcohols Catalyzed by Nickel on Silica–Alumina
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The N-alkylation of phenylacetamide with benzyl alcohol has been studied using Ni/SiO2–Al2O3. In the optimized conditions, the desired product was isolated in an excellent 98 % yield. The reaction could advantageously be performed in neat conditions, with a slight excess of amide and a catalytic amount of base. These conditions were tested on a large range of amides and alcohols, affording 24 compounds in 13 to 99 % isolated yields.
- Charvieux, Aubin,Le Moigne, Louis,Borrego, Lorenzo G.,Duguet, Nicolas,Métay, Estelle
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supporting information
p. 6842 - 6846
(2019/11/11)
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- Sterically congested ester formation from α-substituted malononitrile and alcohol by an oxidative method using molecular oxygen
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A metal-free oxidative esterification or thio-esterifica-tion of readily available substituted malononitrile and alcohol or thiol has been developed by simply mixing α-substituted malononitrile and alcohol or thiol in the presence of base under a molecular oxygen atmosphere. Sterically hindered ester or thioester can be prepared efficiently.
- Hayashi, Yujiro,Li, Jing,Asano, Hirotaka,Sakamoto, Daisuke
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supporting information
p. 675 - 677
(2018/11/23)
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- Formyloxyacetoxyphenylmethane and 1,1-diacylals as versatile O-formylating and O-acylating reagents for alcohols
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Formyloxyacetoxyphenylmethane, symmetric 1,1-diacylals and mixed 1-pivaloxy-1-acyloxy-1-phenylmethanes have been used as moisture stable O-formylating and O-acylating reagents for primary and secondary alcohols, allylic alcohols and phenols under solvent/catalyst free conditions to afford their corresponding esters in good yield.
- Chapman, Robert S.L.,Francis, Molly,Lawrence, Ruth,Tibbetts, Joshua D.,Bull, Steven D.
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p. 6442 - 6452
(2018/10/02)
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- Palladium-Catalyzed Decarboxylative Carbonylative Transformation of Benzyl Aryl Carbonates: Direct Synthesis of Aryl 2-Arylacetates
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A procedure on palladium-catalyzed decarboxylative alkoxycarbonylation of carbonates for the synthesis of aryl 2-arylacetates has been developed. A broad range of aryl 2-arylacetates were obtained in good yields under mild conditions under a carbon monoxide atmosphere. Interestingly, other alcohols can be added as nucleophiles as well, and the corresponding esters were also obtained in good yields.
- Xu, Jian-Xing,Wu, Xiao-Feng
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supporting information
p. 5938 - 5941
(2018/09/21)
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- Palladium-catalyzed carbonylation of benzylic ammonium salts to amides and esters: Via C-N bond activation
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An efficient palladium-catalyzed carbonylation reaction of readily available quaternary ammonium salts with CO is reported for the first time to afford arylacetamides and arylacetic acid esters via benzylic C-N bond cleavage. This protocol features mild reaction conditions under atmospheric pressure of CO, a redox-neutral process without an additional oxidant, and a broad substrate scope for various kinds of amines, alcohols and phenols.
- Yu, Weijie,Yang, Shuwu,Xiong, Fei,Fan, Tianxiang,Feng, Yan,Huang, Yuanyuan,Fu, Junkai,Wang, Tao
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supporting information
p. 3099 - 3103
(2018/05/22)
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- Esterification of the Primary Benzylic C-H Bonds with Carboxylic Acids Catalyzed by Ionic Iron(III) Complexes Containing an Imidazolinium Cation
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The first iron-catalyzed esterification of the primary benzylic C-H bonds with carboxylic acids using di-tert-butyl peroxide as an oxidant is achieved by novel ionic iron(III) complexes containing an imidazolinium cation. The use of well-defined, air-stable, and available iron(III) complex in a 5 mol % loading and readily available starting materials with a broad generality and outstanding sterically hindered tolerance renders this methodology a useful alternative to other protocols that are typically employed for the synthesis of benzyl esters.
- Lu, Bing,Zhu, Fan,Sun, Hong-Mei,Shen, Qi
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supporting information
p. 1132 - 1135
(2017/03/14)
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- 2,2,6,6-Tetramethylpiperidinium triflate (TMPT): a highly selective and self-separated catalyst for esterification
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An eco-friendly and readily accessible 2,2,6,6-tetramethylpiperidinium triflate was found as highly-selective and self-separated catalyst for esterification under solvent-free condition. The X-ray crystallography revealed that it formed a ‘hydrophobic wall’ which could effectively eliminate the generated water from the reactive sites. Moreover, it could precipitate from the reaction system with excellent recovery ratio (>99%) and be reused for ten times without any significant loss of activity.
- Gao, Lan,Liu, Taoping,Tao, Xiaochun,Huang, Yongmin
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supporting information
p. 4905 - 4909
(2016/10/24)
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- Chemoenzymatic synthesis and antileukemic activity of novel C9- and C14-functionalized parthenolide analogs
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Parthenolide is a naturally occurring terpene with promising anticancer properties, particularly in the context of acute myeloid leukemia (AML). Optimization of this natural product has been challenged by limited opportunities for the late-stage functionalization of this molecule without affecting the pharmacologically important α-methylene-γ-lactone moiety. Here, we report the further development and application of a chemoenzymatic strategy to afford a series of new analogs of parthenolide functionalized at the aliphatic positions C9 and C14. Several of these compounds were determined to be able to kill leukemia cells and patient-derived primary AML specimens with improved activity compared to parthenolide, exhibiting LC50values in the low micromolar range. These studies demonstrate that different O–H functionalization chemistries can be applied to elaborate the parthenolide scaffold and that modifications at the C9 or C14 position can effectively enhance the antileukemic properties of this natural product. The C9-functionalized analogs 22a and 25b were identified as the most interesting compounds in terms of antileukemic potency and selectivity toward AML versus healthy blood cells.
- Tyagi, Vikas,Alwaseem, Hanan,O'Dwyer, Kristen M.,Ponder, Jessica,Li, Qi Ying,Jordan, Craig T.,Fasan, Rudi
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p. 3876 - 3886
(2016/08/04)
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- Carboxyl activation of 2-mercapto-4,6-dimethylpyrimidine through n-acyl-4,6-dimethylpyrimidine-2-thione: A chemical and spectrophotometric investigation
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2-Mercapto-4,6-dimethylpyrimidine, as effective carboxyl activating group, has been successfully proved by converting it into respective acyl derivatives and the subsequent conversion to the amides and esters respectively using amines, amino alcohols and alcohols. The aminolysis and esterification were monitored chemically and spectrophotometrically. This paved way to establish that the above mercaptopyrimidine derivative is an efficient carboxyl activating group applicable in solid phase peptide synthesis.
- Rajan
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p. 287 - 291
(2015/01/30)
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- SO3H and NH2+ functional carbon-based solid acid catalyzed transesterification and biodiesel production
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A SO3H and NH2+ functional carbon-based solid acid was used as a highly active heterogeneous catalyst for the transesterification of various carboxylic methyl esters with alcohols under mild conditions. It also showed high catalytic performance for transesterification of triolein with methanol or isopropanol. Furthermore, it was able to catalyze simultaneous esterification and transesterification of rice oil and butter respectively, the yields of biodiesel obtained were up to 94%, and the catalyst could be easily recovered and reused more than ten times without loss of activity, which indicated the carbon-based solid acid was a potential catalyst for the biodiesel industry.
- Cai, Liangzhen,Meng, Decai,Zhan, Shaoqi,Yang, Xiaoxia,Liu, Taoping,Pu, Huiming,Tao, Xiaochun
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p. 72146 - 72149
(2015/09/08)
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- A Strained Disilane-Promoted Carboxylation of Organic Halides with CO2 under Transition-Metal-Free Conditions
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By using a strained four-membered ring disilane (3,4-benzo-1,1,2,2-tetraethyldisilacyclobutene) and CsF, a wide range of aryl, alkenyl, alkynyl, benzyl, allyl, and alkyl halides was successfully carboxylated under an ambient CO2 atmosphere (CO2 balloon) at room temperature within 2 h. In this carboxylation, a highly reactive silyl anion, which is generated from the disilane and CsF, is a key to facilitating the formation of a carbanion equivalent. The resulting anionic species can be trapped with CO2 to produce carboxylic acids with high efficiency.
- Mita, Tsuyoshi,Suga, Kenta,Sato, Kaori,Sato, Yoshihiro
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supporting information
p. 5276 - 5279
(2015/11/18)
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- Dehalogenation of functionalized alkyl halides in water at room temperature
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Alkyl bromides and chlorides can be reduced to the corresponding hydrocarbons utilizing zinc in the presence of an amine additive. The process takes place in water at ambient temperatures, enabled by a commercially available designer surfactant. The reaction medium can be readily recycled, and the amount of organic solvent invested for product isolation is minimal, leading to very low E Factors. This journal is
- Isley, Nicholas A.,Hageman, Matt S.,Lipshutz, Bruce H.
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p. 893 - 897
(2015/03/04)
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- Formation of different isomers of phosphine-imidazolyl and -pyridyl ruthenium(II) complexes affecting the catalyst activity in the acceptorless dehydrogenation of alcohols
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The synthesis, reactivity, and catalytic activity of RuII complexes with different pyridine- and imidazole-based P,N ligands are reported. The investigations reveal a strong influence of the N-heterocycle and the steric demand of the phosphine groups on the stability of different isomers of [L2RuX2] (L = P,N ligand; X = Cl, H). The imidazole-based complex 5 with dicyclohexylphosphine groups was found to be the most active precatalyst for the acceptorless dehydrogenation of primary alcohols, whereas different phosphine groups at the imidazole ligand as well as pyridine-based ligands caused a drop in catalytic activity. In the presence of a primary amine, imines are preferentially formed under these conditions. In summary, the investigations show that comparably small changes in the ligand moiety have a strong effect on the relative stability of stereoisomers for both hydride and chloride complexes, whereas isomerization of the kinetic reaction products was observed in some cases. The described changes in the ligand moiety most probably have a strong impact on the relative stabilities of isomeric intermediates as well and thus affect the catalytic activity of these complexes.
- Langer, Robert,Gese, Alexander,Gesevi?ius, Donatas,Jost, Maximilian,Langer, Bastian R.,Schneck, Felix,Venker, Alexander,Xu, Weiqin
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p. 696 - 705
(2015/02/19)
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- The carbon material functionalized with NH2+ and SO3H groups catalyzed esterification with high activity and selectivity
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A novel carbon-based solid acid was conveniently prepared by heating a mixture of d-glucose, p-toluenesulfonic acid and diphenylammonium tosylate. Its structure was measured by XRD, FT-IR, XPS, 13C MAS NMR and EA to illustrate that the carbon material has been functionalized with NH2+ and SO3H groups and has a strong "hydrophobic effect". It can be used to catalyze the esterification reaction of carboxylic acids with equimolar amounts of sterically demanding and acid-sensitive alcohols with high reactivity (yield up to 90%) and selectivity (up to 95%) in heptane at 80 °C. It could be easily recovered and reused more than ten times without loss of activity.
- Zhan, Shaoqi,Tao, Xiaochun,Cai, Liangzhen,Liu, Xiaohui,Liu, Taoping
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supporting information
p. 4649 - 4653
(2015/02/19)
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- Ethyl 2-cyano-2-(2-nitrobenzenesulfonyloxyimino)acetate (o -NosylOXY): A recyclable coupling reagent for racemization-free synthesis of peptide, amide, hydroxamate, and ester
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Ubiquitousness of amide and ester functionality makes coupling reactions extremely important. Although numerous coupling reagents are available, methods of preparation of the common and efficient reagents are cumbersome. Those reagents generate a substantial amount of chemical waste and lack recyclability. Ethyl 2-cyano-2-(2-nitrobenzenesulfonyloxyimino)acetate (o-NosylOXY), the first member of a new generation of coupling reagents, produces byproducts that can be easily recovered and reused for the synthesis of the same reagent, making the method more environmentally friendly and cost-effective. The synthesis of amides, hydroxamates, peptides, and esters using this reagent is described. The synthesis of the difficult sequences, for example, the islet amyloid polypeptide (22-27) fragment (with a C-terminal Gly, H-Asn-Phe-Gly-Ala-Ile-Leu-Gly-NH 2) and acyl carrier protein (65-74) fragment (H-Val-Gln-Ala-Ala-Ile- Asp-Tyr-Ile-Asn-Gly-OH), following the solid-phase peptide synthesis (SPPS) protocol and Amyloid β (39-42) peptide (Boc-Val-Val-IIe-Ala-OMe), following solution-phase strategy is demonstrated. Remarkable improvement is noticed with respect to reaction time, yield, and retention of stereochemistry. A mechanistic investigation and recyclability are also described.
- Dev, Dharm,Palakurthy, Nani Babu,Thalluri, Kishore,Chandra, Jyoti,Mandal, Bhubaneswar
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p. 5420 - 5431
(2014/07/08)
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- Direct, rapid and convenient synthesis of esters and thioesters using PPh3/N-chlorobenzotriazole system
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We have developed an efficient method for esterification and thioesterification of various carboxylic acids with different alcohols and thiols using PPh3/N-chlorobenzotriazole mixed reagent in CH2Cl2 at room temperature.
- Rouhi-Saadabad, Hamed,Akhlaghinia, Batool
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p. 253 - 263
(2014/02/14)
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- Carboxyl activation of 3-mercapto-5,6-diphenyl-1,2,4-triazine through N-phenylacetyl-5,6-diphenyl-1,2,4-triazine-3-thione
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The carboxyl activation ability of 3-mercapto-5,6-diphenyl-1,2,4-triazine has been established by coverting it into N-phenylacetyl-5,6-diphenyl-1,2,4-triazine-3-thione and this was then subjected to aminolysis and esterification with amines and alcohols respectively and selective aminolysis with aminoalcohols-monitoring chemically and confirmed spectrophotometrically by UV-Visible scannings. It could be proved that 3- mercapto-5,6-diphenyl-1,2,4-triazine is an efficient carboxyl activating group which can be successfully applied in solid phase peptide synthesis.
- Rajan
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p. 119 - 126
(2019/01/21)
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- Scandium triflate catalyzed ester synthesis using primary amides
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A scandium triflate (ScOTf)3 catalyzed methodology has been developed to synthesize esters from primary amides. Various primary and secondary aliphatic alcohols have been shown to react in n-heptane with a range of primary amides for 24 h.
- Atkinson, Benjamin N.,Williams, Jonathan M.J.
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supporting information
p. 6935 - 6938
(2015/01/16)
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- Versatile and sustainable alcoholysis of amides by a reusable CeO 2 catalyst
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CeO2 catalyzed the esterification between an equivalent molar ratio of primary amides and alcohols under neutral conditions, which provides the first versatile reusable catalytic system for direct alcoholysis of amides to esters with wider scope and 67 times higher turnover number (TON) than previous catalytic systems.
- Siddiki, S. M. A. Hakim,Touchy, Abeda Sultana,Tamura, Masazumi,Shimizu, Ken-Ichi
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p. 35803 - 35807
(2014/11/07)
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- Ketene reactions with tertiary amines
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Tertiary amines react rapidly and reversibly with arylketenes in acetonitrile forming observable zwitterions, and these undergo amine catalyzed dealkylation forming N,N-disubstituted amides. Reactions of N- methyldialkylamines show a strong preference for methyl group loss by displacement, as predicted by computational studies. Loss of ethyl groups in reactions with triethylamine also occur by displacement, but preferential loss of isopropyl groups in the phenylketene reaction with diisopropylethylamine evidently involves elimination. Quinuclidine rapidly forms long-lived zwitterions with arylketenes, providing a model for catalysis by cinchona and related alkaloids in stereoselective additions to ketenes.
- Allen, Annette D.,Andraos, John,Tidwell, Thomas T.,Vukovic, Sinisa
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supporting information
p. 679 - 685
(2014/04/03)
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- Palladium on carbon-bromobenzene mediated esterification and transesterification
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A series of carboxylic acids were converted into their corresponding esters using the Pd/C catalyzed hydrogenation conditions in the presence of catalytic bromobenzene in alcohols and the method could also be applicable for the transesterification of esters. Good to excellent yields were obtained for different aliphatic or aromatic starting materials. The success of this esterification relies on the in situ generation of hydrobromic acid (HBr) from bromobenzene which provides a mild and acidic reaction environment. The palladium catalyst exhibits a remarkable activity and is reusable for up-to three consecutive cycles.
- Aavula, Sanjeev Kumar,Chikkulapalli, Anil,Hanumanthappa,Jyothi, Indira,Vinod Kumar,Manjunatha, Sulur G.
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p. 5690 - 5694
(2013/09/24)
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- Ethyl 2-(tert-butoxycarbonyloxyimino)-2-cyanoacetate (Boc-Oxyma) as coupling reagent for racemization-free esterification, thioesterification, amidation and peptide synthesis
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Here we report the synthesis and utility of ethyl 2-(tert- butoxycarbonyloxyimino)-2-cyanoacetate (Boc-Oxyma) as an efficient coupling reagent for racemization-free esterification, thioesterification, amidation reactions and peptide synthesis that uses equimolar amounts of acids and alcohols, thiols, amines or amino acids, respectively. Its application to solid phase as well as solution phase peptide synthesis is also demonstrated and a mechanistic investigation is discussed. Boc-Oxyma is similar to the well known coupling agent COMU {1-[1-cyano-2-ethoxy-2-oxoethylideneaminooxy)- dimethylaminomorpholino] uronium hexafluorophosphate} in terms of its high reactivity and mechanism of action. However, it is not only much easier to prepare, but also to recover and reuse, thereby generating far less chemical waste.
- Thalluri, Kishore,Nadimpally, Krishna Chaitanya,Chakravarty, Maharishi Parasar,Paul, Ashim,Mandal, Bhubaneswar
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supporting information
p. 448 - 462
(2013/05/09)
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- A lewis acid-promoted pinner reaction
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Carbonitriles and alcohols react in a Lewis acid-promoted Pinner reaction to carboxylic esters. Best results are obtained with two equivalents of trimethylsilyl triflate as Lewis acid. Good yields are achieved with primary alcohols and aliphatic or benzylic carbonitriles, but the straightforward synthesis of acrylates and benzoates starting with acrylonitrile and benzonitrile, respectively, is similarly possible. Phenols are not acylated under these reaction conditions. The method has been used for the first total synthesis of the natural product monaspilosin. In the reaction of benzyl alcohols variable amounts of amides are formed in a Ritter-type side reaction.
- Pfaff, Dominik,Nemecek, Gregor,Podlech, Joachim
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supporting information
p. 1572 - 1577
(2013/10/22)
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- Synthesis of alkyl-ynol-ethers by anti-Michael addition of metal alkoxides to β-substituted alkynylsulfones
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The reaction of metal alkoxides with β-substituted 2-(p-tolylsulfonyl)acetylenes, involving an anti-Michael addition reaction followed by the in situ elimination of the sulfonyl moiety, provides a direct method for the synthesis of alkyl alkynyl ethers bearing aryl or TIPS groups joined to the triple bond. Arylalkynyl ethers derived from primary alkoxides are in situ hydrolyzed into arylacetic esters. Copyright
- Marzo, Leyre,Parra, Alejandro,Frias, Maria,Aleman, Jose,Garcia Ruano, Jose Luis
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p. 4405 - 4409
(2013/07/26)
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- Alcohol assisted C-C bond breaking: Copper-catalyzed deacetylative α-arylation of β-keto esters and amides
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A method of alcohol-assisted copper-catalyzed highly selective deacetylative α-arylation of β-keto esters and amides has been demonstrated, which illustrated an efficient example of achieving α-aryl esters and amides. From the synthetic point of view, this arylation protocol is general and practical, representing a simple way to produce α-arylated carbonyl compounds from basic starting materials at low cost.
- Ke, Jie,He, Chuan,Liu, Huiying,Xu, Huan,Lei, Aiwen
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supporting information
p. 6767 - 6769
(2013/07/26)
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- Ruthenium-catalyzed self-coupling of primary and secondary alcohols with the liberation of dihydrogen
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The dehydrogenative self-condensation of primary and secondary alcohols has been studied in the presence of RuCl2(IiPr)(p-cymene). The conversion of primary alcohols into esters has been further optimized by using magnesium nitride as an additive, which allows the reaction to take place at a temperature and catalyst loading lower than those described previously. Secondary alcohols were dimerized into racemic ketones by a dehydrogenative Guerbet reaction with potassium hydroxide as the additive. The transformation gave good yields of the ketone dimers with a range of alkan-2-ols, whereas more substituted secondary alcohols were unreactive. The reaction proceeds by dehydrogenation to the ketone, followed by an aldol reaction and hydrogenation of the resulting enone.
- Makarov, Ilya S.,Madsen, Robert
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p. 6593 - 6598
(2013/07/26)
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- Aniline mediated oxidative C-C bond cleavage of α-alkoxy aldehydes in air and a model reaction for the synthesis of α-(d)-amino acid derivatives
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A metal-free and 4-methyl aniline mediated method for the oxidative C-C bond cleavage has been developed. The reaction proceeds in air using molecular oxygen as the oxidant, affording one-carbon shortened esters in moderate to good yields within a short time. Moreover, it provides a model reaction for the highly enantioselective synthesis of (d)-serine esters by combining with a l-proline catalyzed Mannich reaction.
- Hu, Bin,Li, Yunfeng,Li, Zhongjun,Meng, Xiangbao
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supporting information
p. 4138 - 4141
(2013/07/05)
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- Palladium-catalyzed α-arylation of 2-chloroacetates and 2-chloroacetamides
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A method has been developed for the Pd-catalyzed synthesis of α-(hetero)aryl esters and amides through a Suzuki-Miyaura cross-coupling reaction. This method avoids the use of strong base, does not necessitate inert or low temperature formation of reagents, and does not require the use of a large excess of organometallic reagent. Utilization of organotrifluoroborate salts as nucleophilic partners allows a variety of functional groups and heterocyclic compounds to be tolerated.
- Molander, Gary A.,Traister, Kaitlin M.,Barcellos, Thiago
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p. 4123 - 4131
(2013/06/05)
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- Visible-light-induced photocatalytic reductive transformations of organohalides
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A photo opportunity: A visible-light-excited iridium catalyst delivers electrons from an amine to an organohalide. The electron transfer then induces reductive scission of the carbon-halogen bond, generating the corresponding alkyl, alkenyl, and aryl radical that can undergo cyclization and hydrodehalogenation reactions. Copyright
- Kim, Hyejin,Lee, Chulbom
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supporting information
p. 12303 - 12306
(2013/02/23)
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- Synthesis of pyrimidine-containing nucleoside β-(R/S)- hydroxyphosphonate analogues
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A concise route to nucleoside β-hydroxyphosphonate analogues is described. The use of a nucleoside β-ketophosphonate as the key intermediate allowed both the (R) and (S) isomers of β-hydroxyphosphonate analogues in the pyrimidine series to be accessed. Such derivatives may be considered as stable mimics of 5′-monophosphate nucleosides and, therefore, could be the starting point for the development of potential therapeutic agents. Copyright
- Meurillon, Maia,Chaloin, Laurent,Perigaud, Christian,Peyrottes, Suzanne
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supporting information; experimental part
p. 3794 - 3802
(2011/09/30)
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- Protic acid immobilized on solid support as an extremely efficient recyclable catalyst system for a direct and atom economical esterification of carboxylic acids with alcohols
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(Chemical Equation Presented) A convenient and clean procedure of esterification is reported by direct condensation of equimolar amounts of carboxylic acids with alcohols catalyzed by an easy to prepare catalyst system of perchloric acid immobilized on silica gel (HClO4-SiO2). The direct condensation of aryl, heteroaryl, styryl, aryl alkyl, alkyl, cycloalkyl, and long-chain aliphatic carboxylic acids with primary/secondary alkyl/cycloalkyl, allyl, propargyl, and long-chain aliphatic alcohols has been achieved to afford the corresponding esters in excellent yields. Chiral alcohol and N-t-Boc protected chiral amino acid also resulted in ester formation with the representative carboxylic acid or alcohol without competitive N-t-Boc deprotection and detrimental effect on the optical purity of the product demonstrating the mildness and chemoselectivity of the procedure. The esters of long-chain (>C10) acids and alcohols are obtained in high yields. The catalyst is recovered and recycled without significant loss of activity. The industrial application of the esterification process is demonstrated by the synthesis of prodrugs of ibuprofen and a few commercial flavoring agents. Other protic acids such as H2SO4, HBr, TfOH, HBF4, and TFA that were adsorbed on silica gel were less effective compared to HClO4-SiO2 following the order HClO4-SiO 2 ? H2SO4-SiO2 > HBr-SiO 2 > TfOH-SiO2 ? HBF4-SiO2 ≈ TFA-SiO2. When HClO4 was immobilized on other solid supports the catalytic efficiency followed the order HClO4-SiO 2 > HClO4-K10 > HClO4-Al 2O3 (neutral) > HClO4-Al2O 3 (acidic) > HClO4-Al2O3 (basic).
- Chakraborti, Asit K.,Singh, Bavneet,Chankeshwara, Sunay V.,Patel, Alpesh R.
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supporting information; experimental part
p. 5967 - 5974
(2009/12/24)
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- Pd-catalyzed deoxygenation of mandelate esters
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(Chemical Equation Presented) A new approach to the synthesis of phenylacetic acids and esters has been developed via the palladium-catalyzed deoxygenation of mandelate esters.
- Milne, Jacqueline E.,Murry, Jerry A.,King, Anthony,Larsen, Robert D.
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supporting information; experimental part
p. 445 - 447
(2009/04/10)
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- Zwitterionic salts as mild organocatalysts for transesterification
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(Chemical Equation Presented) The exothermic reaction of 3,5-bis(trifluoromethyl)phenyl or 4-nitrophenyl isothiocyanate with 4-pyrrolidinopyridine (PPY) gave the corresponding arylaminothiocarbonylpyridinium salts in quantitative yields. These novel zwitterionic salts were effective as organocatalysts for the transesterification reaction of an equimolar mixture of methyl carboxylates and alcohols in hydrocarbons such as heptane and octane under azeotropic reflux conditions with the removal of methanol. In sharp contrast, PPY was inert as a catalyst under the same reaction conditions.
- Ishihara, Kazuaki,Niwa, Masatoshi,Kosugi, Yuji
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supporting information; experimental part
p. 2187 - 2190
(2009/05/27)
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- Tetraarylphosphonium-supported carbodiimide reagents: Synthesis, structure optimization and applications
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(Chemical Equation Presented) New tetraarylphosphonium (TAP)-supported alkyl- and arylcarbodiimides were synthesized and used as coupling reagents for esterification reactions, amidation reactions and dehydration reactions of hydroxyesters. Taking advantage of the solubility properties imparted by the tetraarylphosphonium unit, a simple precipitation and filtration allowed complete separation of the urea by-products. This paper describes the structure optimization study of the various TAP-supported carbodiimide reagents to obtain the desired reactivity and solubility profile. Furthermore, we have demonstrated that the diimide reagent can be regenerated from the urea to recycle the reagents.
- Ginisty, Maryon,Roy, Marie-Noelle,Charette, Andre B.
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p. 2542 - 2547
(2008/09/19)
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- A facile, catalytic and environmentally benign method for esterification of carboxylic acids and transesterification of carboxylic esters with nearly equimolar amounts of alcohols
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A practical and green chemical process for the esterification of carboxylic acids with alcohols and transesterification of carboxylic esters in good to excellent yields by using K5CoW12O14· 3H2O (0.1 mol%) as catalyst is reported. The catalyst exhibited remarkable reusable activity. Georg Thieme Verlag Stuttgart.
- Bose, D. Subhas,Satyender, Apuri,Das, A. P. Rudra,Mereyala, Hari Babu
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p. 2392 - 2396
(2008/02/08)
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- Selective esterification of aliphatic carboxylic acids in the presence of aromatic carboxylic acids over monoammonium salt of 12-tungstophosphoric acid
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Monoammonium salt of 12-tungstophosphoric acid [(NH4)H 2PW12O40] was found to be a practical and useful heterogeneous catalyst for an efficient and selective esterification of aliphatic carboxylic acids with alcohols in the presence of aromatic carboxylic acids. The heteropoly acid-based heterogeneous catalyst has the advantages of a simple workup procedure, water insolubility, and good activity. Copyright Taylor & Francis LLC.
- Giri,Prabhavathi Devi,Gangadhar,Narasimha Rao,Lingaiah,Sai Prasad,Prasad
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- Organocatalytic Mitsunobu reactions
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A catalytic Mitsunobu reaction system is described in which the azo reagent is used as an organocatalyst and iodosobenzene diacetate is used as the stoichiometric oxidant. In this system, iodosobenzene diacetate oxidizes the formed hydrazine byproduct to regenerate the azo reagent. Yields obtained in the catalytic reactions using a variety of carboxylic acids and alcohols were slightly lower than those obtained from corresponding stoichiometric reactions. Both primary and secondary alcohols can be used as substrates in this reaction system, with the secondary alcohols affording products with inverted stereochemistry at the carbinol center. Copyright
- But, Tracy Yuen Sze,Toy, Patrick H.
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p. 9636 - 9637
(2007/10/03)
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