- Spontaneous oscillatory in vitro chiral conversion of simple carboxylic acids and its possible mechanism
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In earlier studies, we have collected experimental evidence (mostly from thin-layer chromatography and polarimetry) on the spontaneous oscillatory in vitro chiral conversion of simple carboxylic acids dissolved in 70% aqueous ethanol. To elucidate this phenomenon, we developed a simple theoretical model of two linked Templators. Recently, we have obtained additional experimental evidence of the spontaneous condensation of chiral carboxylic acids, based on the biuret test (amino acids), high performance liquid chromatography, and 13C NMR spectroscopy (profens and hydroxy acids). We briefly describe our experimental results in the context of the existing literature and outline an improved theoretical model for these phenomena. Our system resembles in some respects the reported oscillatory condensation of organic silanols. Here, the key reaction is the formation of carboxylic acid-derived enols. Finally, we discuss the importance of the oscillatory chiral conversion of simple carboxylic acids for biochemistry, pharmacology, and related life sciences. Copyright
- Sajewicz, Mieczyslaw,Matlengiewicz, Marek,Leda, Marcin,Gontarska, Monika,Kronenbach, Dorota,Kowalska, Teresa,Epstein, Irving R.
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- A Novel Enzymatic Decarboxylation Proceeds via a Thiol Ester Intermediate
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It is proposed that arylmalonate decarboxylase (AMDase)-catalyzed decarboxylation proceeds via a thiol ester intermediate.Kinetics and CD spectra indicated that α-bromohenylacetate is a competititve inhibitor.TOF mass data indicated that the inhibitor bound with the enzyme through a thiol ester bond which was formed between a cysteine residue of the enzyme and the carboxyl group of the inhibitor.This result was also supported by reactivation of the enzyme by the addition of 2-mercaptoethanol, which is expected to cleave the enzyme-inhibitor bond via nucleophilic attack on the thiol ester linkage.
- Kawasaki, Takayasu,Watanabe, Masakatsu,Ohta, Hiromichi
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- Effects of alkali halide salts on hydrocarboxylation of styrene catalyzed by water-soluble palladium phosphine complexes
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Hydrocarboxylation of styrene catalyzed by water-soluble Pd-TPPTS complexes was investigated. The reaction conditions, including reaction pressure, temperature, time and etc. have a significant influence on the catalytic performance. It was found that the yield of total acids and the selectivity towards 3-phenylpropionic acid were enhanced by adding a suitable amount of alkali metal halide salts. In addition, the reaction mechanism and the role of alkali metal halide salts in the reaction were discussed on the basis of the characterization of 1H NMR and 31P NMR.
- He, Zhenhong,Hou, Zhenshan,Luo, Yanping,Zhou, Liang,Liu, Yuanfeng,Eli, Wumanjiang
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- Highly Regioselective Iron-Promoted Hydrocarboxylation of Styrene
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The reaction of Li with styrene under carbon monoxide (1 atm) in a H2O/i-PrOH/LiOH system promotes a highly regioselective (98percent) hydrocarboxylation to 2-phenylpropionic acid.In contrast, when conducted under argon, the reaction predominantly (90percent) leads to 3-phenylpropionic acid.
- Brunet, Jean-Jacques,Neibecker, Denis,Srivastava, Radhey S.
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- Nickel-catalyzed asymmetric allylation of alkyl Grignard reagents, effect of ligands, leaving groups and a kinetic resolution with a hard nucleophile
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Enantioselective addition of Grignard reagents to methyl 1,3-diphenylallyl ether in the presence of Ni(0)-phosphine catalysts is reported. Kinetic resolution (79% ee) observed in the addition of MeMgBr has important implications for the mechanism and further development of this reaction as a valuable synthetic reaction.
- Nomura, Nobuyoshi,RajanBabu
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- Synthesis of Mn-doped TiO2 by novel route and photocatalytic mineralization/intermediate studies of organic pollutants
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The doping of TiO2 particles with various manganese (Mn) concentrations (0.25–1.0%) were synthesized using simple sol–gel and modified sol–gel technique. The characteristics of synthesized particles were found employing standard analytical techniques such as X-ray diffraction, scanning electron microscopy and UV–Vis spectroscopy. The photocatalytic activity of the synthesized particles was compared by investigating the mineralization of two selected organic pollutants like ketoprofen and chlorothalonil. The photocatalysts which were produced by improved sol–gel technique show the lower value of band gap energy and small size crystallite and, hence, exhibit better photocatalytic activity. The outcomes also designate that the concentration of dopant Mn 0.75% indicated the highest photocatalytic activity than other concentrations of dopant in the mineralization of both the compounds. The mineralization kinetics of both compounds was studied under various situations like reaction pH and catalyst dosage. The mineralization rates were highly affected by all the above parameters. An effort has also been performed to highlight the intermediates produced during the photooxidation of both the compounds using the GC–MS analysis method. Both compounds show the production of several intermediates. A possible pathway for the production of different products has been suggested.
- Umar, Khalid,Ibrahim, Mohamad Nasir Mohamad,Ahmad, Akil,Rafatullah, Mohd
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- Enantioselective Synthesis of Chiral Carboxylic Acids from Alkynes and Formic Acid by Nickel-Catalyzed Cascade Reactions: Facile Synthesis of Profens
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We report a stereoselective conversion of terminal alkynes to α-chiral carboxylic acids using a nickel-catalyzed domino hydrocarboxylation-transfer hydrogenation reaction. A simple nickel/BenzP* catalyst displayed high activity in both steps of regioselective hydrocarboxylation of alkynes and subsequent asymmetric transfer hydrogenation. The reaction was successfully applied in enantioselective preparation of three nonsteroidal anti-inflammatory profens (>90 % ees) and the chiral fragment of AZD2716.
- Fu, Kaiyue,Ma, Yu,Sun, Yaxin,Tang, Bo,Yang, Guang,Yang, Peng,Yue, Jieyu,Zhang, Li,Zhou, Jianrong Steve
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supporting information
(2021/11/22)
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- Chemoselective reduction of ?,¢-unsaturated carbonyl and carboxylic compounds by hydrogen iodide
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The selective reduction of ?,¢-unsaturated carbonyl compounds was achieved to produce saturated carbonyl compounds with aqueous HI solution. The introduction of an aryl group at an ? or ¢ position efficiently facilitated the reduction with good yield. The reaction was applicable to compounds bearing carboxylic acids and halogen atoms. Through the investigation of the reaction mechanism, it was found that Michael-type addition of iodide occurred to produce ¢-iodo compounds followed by the reduction of C-I bond via anionic and radical paths.
- Matsumoto, Shoji,Marumoto, Hayato,Akazome, Motohiro,Otani, Yasuhiko,Kaiho, Tatsuo
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p. 590 - 599
(2021/03/29)
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- Dynamic Kinetic Resolution of I-Substituted Cyclic β-Ketoesters via Asymmetric Hydrogenation: Constructing Chiral Cyclic β-Hydroxyesters with Three Contiguous Stereocenters
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An efficient asymmetric hydrogenation of racemic I-substituted cyclic β-ketoesters via dynamic kinetic resolution to provide chiral cyclic β-hydroxy esters with three contiguous stereocenters is reported. Using a chiral spiro iridium catalyst (R)-5 (Ir-SpiroSAP), a series of racemic I-Aryl/alkyl substituted cyclic β-ketoesters were hydrogenated to the corresponding chiral cyclic β-hydroxy esters in high yields (84-97%) with good to excellent enantioselectivities (69->99% ee) and cis,cis-selectivities (up to >99:1).
- Yang, Dan,Wu, Xiong,Zheng, Xiao-Jie,Xie, Jian-Hua,Zhou, Qi-Lin
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supporting information
p. 5153 - 5157
(2021/07/20)
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- Catalytic α-Deracemization of Ketones Enabled by Photoredox Deprotonation and Enantioselective Protonation
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This study reports the catalytic deracemization of ketones bearing stereocenters in the α-position in a single reaction via deprotonation, followed by enantioselective protonation. The principle of microscopic reversibility, which has previously rendered this strategy elusive, is overcome by a photoredox deprotonation through single electron transfer and subsequent hydrogen atom transfer (HAT). Specifically, the irradiation of racemic pyridylketones in the presence of a single photocatalyst and a tertiary amine provides nonracemic carbonyl compounds with up to 97% enantiomeric excess. The photocatalyst harvests the visible light, induces the redox process, and is responsible for the asymmetric induction, while the amine serves as a single electron donor, HAT reagent, and proton source. This conceptually simple light-driven strategy of coupling a photoredox deprotonation with a stereocontrolled protonation, in conjunction with an enrichment process, serves as a blueprint for other deracemizations of ubiquitous carbonyl compounds.
- Chen, Shuming,Gao, Anthony Z.,Ivlev, Sergei I.,Meggers, Eric,Nie, Xin,Ye, Chen-Xi,Zhang, Chenhao
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supporting information
p. 13393 - 13400
(2021/09/03)
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- Insertion of Diazo Esters into C-F Bonds toward Diastereoselective One-Carbon Elongation of Benzylic Fluorides: Unprecedented BF3Catalysis with C-F Bond Cleavage and Re-formation
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Selective transformation of C-F bonds remains a significant goal in organic chemistry, but C-F insertion of a one-carbon-atom unit has never been established. Herein we report the BF3-catalyzed formal insertion of diazo esters as one-carbon-atom sources into C-F bonds to accomplish one-carbon elongation of benzylic fluorides. A DFT calculation study revealed that the BF3 catalyst could contribute to both C-F bond cleavage and re-formation. This elongation provided α-fluoro-α,β-diaryl esters with a high level of diastereoselectivity. Various benzylic fluorides and diazo esters were applicable. The synthetic utility of this method was demonstrated by the synthesis of a fluoro analogue of a compound that is used as a transient receptor and potential canonical channel inhibitor.
- Wang, Fei,Nishimoto, Yoshihiro,Yasuda, Makoto
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supporting information
p. 20616 - 20621
(2021/11/23)
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- A direct synthesis of carboxylic acidsviaplatinum-catalysed hydroxycarbonylation of olefins
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The platinum-catalysed hydroxycarbonylation of olefins is reported for the first time. Using a combination of PtCl2/2,2′-bis(tert-butyl(pyridin-2-yl)phosphanyl)-1,1′-binaphthalene (Neolephos) in the presence of sulfuric acid [0.6 M] in acetic acid selective carbonylation of terminal aliphatic olefins proceeds to good yields and selectivities to the corresponding carboxylic acids. Comparing the reactivity of different butenes (iso- andn-butenes), the terminal olefin can be selectively carbonylated.
- Schneider, Carolin,Franke, Robert,Jackstell, Ralf,Beller, Matthias
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p. 2703 - 2707
(2021/05/05)
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- Desulfonylative Electrocarboxylation with Carbon Dioxide
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Electrocarboxylation of organic halides is one of the most investigated electrochemical approaches for converting thermodynamically inert carbon dioxide (CO2) into value-added carboxylic acids. By converting organic halides into their sulfone derivatives, we have developed a highly efficient electrochemical desulfonylative carboxylation protocol. Such a strategy takes advantage of CO2as the abundant C1 building block for the facile preparation of multifunctionalized carboxylic acids, including the nonsteroidal anti-inflammatory drug ibuprofen, under mild reaction conditions.
- Zhong, Jun-Song,Yang, Zi-Xin,Ding, Cheng-Lin,Huang, Ya-Feng,Zhao, Yi,Yan, Hong,Ye, Ke-Yin
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supporting information
p. 16162 - 16170
(2021/09/02)
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- Photocatalytic Carboxylation of Phenyl Halides with CO2 by Metal-Organic Frameworks Materials
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In this work, important commercial pharmaceutical intermediates, phenylpropionic acid compounds, are successfully obtained by catalyzing the reaction of carbon dioxide with phenyl halides using MOF-5, a typical metal-organic framework (MOF) material. The influence of temperature, pressure, catalyst type and light on the reaction is investigated, and a 90.3% selectivity towards fluorophenylpropionic acid is reached. Significantly, the catalysts are effective for varied benzyl compounds containing different substituent groups. The catalysts are stable and remain active after three cycles.
- Han, Jianyu,Qiu, Xueying,Su, Lina,Tang, Zhiyong,Zhang, Yin
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p. 312 - 316
(2021/01/04)
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- Relative activity of metal cathodes towards electroorganic coupling of CO2 with benzylic halides
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Electrochemical reduction of benzylic halides represents a convenient route to generating carbanions for their subsequent coupling with CO2 to obtain various carboxylic acids. Despite the industrial prospects of this synthetic process, it still lacks systematic studies of the efficient catalysts and reaction media design. In this work, we performed a detailed analysis of the catalytic activity of a series of different metal electrodes towards electroreduction of benzylic halides to corresponding radicals and carbanions using cyclic voltammetry. Specifically, we screened and summarized the performance of 12 bulk metal cathodes (Ag, Au, Cu, Pd, Pt, Ni, Ti, Zn, Fe, Al, Sn, and Pb) and 3 carbon-based materials (glassy carbon, carbon cloth, and carbon paper) towards electrocarboxylation of eight different benzylic halides and compare it to direct CO2 reduction in acetonitrile. Extensive experimental studies along with a detailed analysis of the results allowed us to map specific electrochemical properties of different metal electrodes, i.e., the potential zones related to the one- and two-electron reduction of organic halides as well as the potential windows where the electrochemical activation of CO2 does not occur. The reported systematic analysis should facilitate the development of nanostructured electrodes based on group 10 and 11 transition metals to further optimize the efficiency of electrocarboxylation of halides bearing specific substituents and make this technology competitive to current synthetic methods for the synthesis of carboxylic acids.
- Engelhardt, Helen,Klinkova, Anna,Medvedev, Jury J.,Medvedeva, Xenia V.
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- Suppressing carboxylate nucleophilicity with inorganic salts enables selective electrocarboxylation without sacrificial anodes
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Although electrocarboxylation reactions use CO2as a renewable synthon and can incorporate renewable electricity as a driving force, the overall sustainability and practicality of this process is limited by the use of sacrificial anodes such as magnesium and aluminum. Replacing these anodes for the carboxylation of organic halides is not trivial because the cations produced from their oxidation inhibit a variety of undesired nucleophilic reactions that form esters, carbonates, and alcohols. Herein, a strategy to maintain selectivity without a sacrificial anode is developed by adding a salt with an inorganic cation that blocks nucleophilic reactions. Using anhydrous MgBr2as a low-cost, soluble source of Mg2+cations, carboxylation of a variety of aliphatic, benzylic, and aromatic halides was achieved with moderate to good (34-78%) yields without a sacrificial anode. Moreover, the yields from the sacrificial-anode-free process were often comparable or better than those from a traditional sacrificial-anode process. Examining a wide variety of substrates shows a correlation between known nucleophilic susceptibilities of carbon-halide bonds and selectivity loss in the absence of a Mg2+source. The carboxylate anion product was also discovered to mitigate cathodic passivation by insoluble carbonates produced as byproducts from concomitant CO2reduction to CO, although this protection can eventually become insufficient when sacrificial anodes are used. These results are a key step toward sustainable and practical carboxylation by providing an electrolyte design guideline to obviate the need for sacrificial anodes.
- Corbin, Nathan,Lazouski, Nikifar,Manthiram, Karthish,Steinberg, Katherine,Yang, Deng-Tao
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p. 12365 - 12376
(2021/10/08)
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- Synthesis of Dibenzo[ a, e ]cyclooctene-5,11(6 H,12 H)-diones via the Elusive Benzocyclobutenone Anion
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We reported here a facile synthesis of dibenzo[a,e]cyclooctene- 5,11(6H,12H)-diones via dimerization of benzocyclobutenones in the presence of simple base via the elusive benzocyclobutenone anion. The temperature effect played a crucial role in the dimerization reaction. Further synthesis of 5,11-disubstituted dibenzo[a,e]cyclooctenes (dibenzo[a,e][8]annulenes) from dibenzo[a,e]cyclooctene-5,11-(6H,12H)-diones was also explored.
- Huang, Yingchao,Chen, Jun,Liu, Yu,Lu, Ping
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p. 4477 - 4483
(2021/09/06)
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- Uncommon overoxidative catalytic activity in a new halo-tolerant alcohol dehydrogenase
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Alcohol dehydrogenases (ADH) are versatile and useful enzymes employed as biocatalysts, especially for the selective oxidation of primary and secondary alcohols, and for the reduction of carbonyl moieties. A new alcohol dehydrogenase (HeADH-II) has been identified from the genome of the halo-adapted bacterium Halomonas elongata, which proved stable in the presence of polar organic solvents and salt exposure. Unusual for this class of enzymes, HeADH-II lacks enantiopreference and is capable of oxidizing both alcohols and aldehydes, enabling a direct overoxidation of primary alcohols to carboxylic acids. HeADH-II was coupled with a NADH-oxidase from Lactobacillus pentosus (LpNOX) to increase the process yields and allowing recycling of the cofactor. The enzymatic oxidation of primary alcohols was also paired with in situ condensation of the intermediate aldehydes with hydroxylamine to prepare the corresponding aldoximes, with particular attention to perillartine (a powerful sweetener), whose enzymatic synthesis starting from natural sources, leads to an equally natural product.
- Contente, Martina L.,Fiore, Noemi,Cannazza, Pietro,Roura Padrosa, David,Molinari, Francesco,Gourlay, Louise,Paradisi, Francesca
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supporting information
p. 5679 - 5685
(2020/09/17)
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- Application of novel dimethyl carbonate methylation catalyst in preparation α- methyl phenylacetic acid
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The invention relates to the field, of medicine synthesis, and concretely relates to a novel dimethyl carbonate methylation catalyst α - in preparation IV methylbenzene acetic acid. as starting material I for preparing a target product, methylbenzeneacetic acid, by a methylation, decarboxylation and hydrolysis reaction, under the action of a catalyst by using a catalyst as a representative low-cost catalyst, in the form of a quaternary amine salt, and a catalyst prepared by using the catalyst as a representative low-cost catalyst, such as potassium α - potassium bromide acetate, as a catalyst, and a catalyst used in the, hydrolysis reaction of the quaternary, amine salt. IV. 98%. The preparation method comprises the following steps: preparing a target product from the quaternary ammonium. salt solution.
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Paragraph 0057-0058
(2020/03/17)
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- 1,3,2-Diazaphospholenes Catalyze the Conjugate Reduction of Substituted Acrylic Acids
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The potent nucleophilicity and remarkably low basicity of 1,3,2-diazaphospholenes (DAPs) is exploited in a catalytic, metal-free 1,4-reduction of free α,β-unsaturated carboxylic acids. Notably, the reduction occurs without a prior deprotonation of the carboxylic acid moiety and hence does not consume an additional hydride equivalent. This highlights the excellent nucleophilic character and low basicity of DAP-hydrides. Functional groups such as Cbz group or alkyl halides which can be problematic with classical transition-metal catalysts are well tolerated in the DAP-catalyzed process. Moreover, the transformation is characterized by a low catalyst loading, mild reaction conditions at ambient temperature as well as fast reaction times and high yields. The proof-of-principle for a catalytic enantioselective version is described.
- Reed, John H.,Cramer, Nicolai
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p. 4262 - 4266
(2020/07/13)
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- Cobalt-Catalyzed Asymmetric Hydrogenation of α,β-Unsaturated Carboxylic Acids by Homolytic H2 Cleavage
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The asymmetric hydrogenation of α,β-unsaturated carboxylic acids using readily prepared bis(phosphine) cobalt(0) 1,5-cyclooctadiene precatalysts is described. Di-, tri-, and tetra-substituted acrylic acid derivatives with various substitution patterns as well as dehydro-α-amino acid derivatives were hydrogenated with high yields and enantioselectivities, affording chiral carboxylic acids including Naproxen, (S)-Flurbiprofen, and a d-DOPA precursor. Turnover numbers of up to 200 were routinely obtained. Compatibility with common organic functional groups was observed with the reduced cobalt(0) precatalysts, and protic solvents such as methanol and isopropanol were identified as optimal. A series of bis(phosphine) cobalt(II) bis(pivalate) complexes, which bear structural similarity to state-of-the-art ruthenium(II) catalysts, were synthesized, characterized, and proved catalytically competent. X-band EPR experiments revealed bis(phosphine)cobalt(II) bis(carboxylate)s were generated in catalytic reactions and were identified as catalyst resting states. Isolation and characterization of a cobalt(II)-substrate complex from a stoichiometric reaction suggests that alkene insertion into the cobalt hydride occurred in the presence of free carboxylic acid, producing the same alkane enantiomer as that from the catalytic reaction. Deuterium labeling studies established homolytic H2 (or D2) activation by Co(0) and cis addition of H2 (or D2) across alkene double bonds, reminiscent of rhodium(I) catalysts but distinct from ruthenium(II) and nickel(II) carboxylates that operate by heterolytic H2 cleavage pathways.
- Chirik, Paul J.,Shevlin, Michael,Zhong, Hongyu
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supporting information
(2020/03/13)
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- Oxidation of aromatic and aliphatic aldehydes to carboxylic acids by Geotrichum candidum aldehyde dehydrogenase
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Oxidation reaction is one of the most important and indispensable organic reactions, so that green and sustainable catalysts for oxidation are necessary to be developed. Herein, biocatalytic oxidation of aldehydes was investigated, resulted in the synthesis of both aromatic and aliphatic carboxylic acids using a Geotrichum candidum aldehyde dehydrogenase (GcALDH). Moreover, selective oxidation of dialdehydes to aldehydic acids by GcALDH was also successful.
- Hoshino, Tomoyasu,Yamabe, Emi,Hawari, Muhammad Arisyi,Tamura, Mayumi,Kanamaru, Shuji,Yoshida, Keisuke,Koesoema, Afifa Ayu,Matsuda, Tomoko
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- Preparation method of p-bromomethyl isophenylpropionic acid
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The invention belongs to the field of synthesis of drug intermediates, and particularly relates to a preparation method of p-bromomethyl isophenylpropionic acid, which comprises the following steps: A, synthesis of alpha-methyl benzyl chloride: carrying out addition reaction on styrene serving as a raw material and hydrogen chloride gas in an organic solvent to generate alpha-methyl benzyl chloride, B, synthesis of 2-phenylpropionic acid: preparing alpha-methyl benzyl chloride into a Grignard solution through a Grignard reaction, the Grignard solution and carbon dioxide gas are subjected to acarboxylation reaction to generate a carboxylation solution, and the carboxylation solution is hydrolyzed to obtain 2-phenylpropionic acid, and C, synthesis of p-bromomethyl isophenylpropionic acid: carrying out bromomethylation reaction of 2-phenylpropionic acid, hydrobromic acid and polyformaldehyde so that p-bromomethyl isophenylpropionic acid is generated. The preparation method of p-bromomethyl isophenylpropionic acid provided by the invention has the advantages of cheap and accessible raw materials and simple technique, and is suitable for industrial production.
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Paragraph 0012; 0013; 0044; 0047; 0048; 0051; 0054; 0055
(2020/08/09)
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- Mechanistic Investigation of the Nickel-Catalyzed Carbonylation of Alcohols
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The carbonylation of alcohols represents a straightforward and atom-efficient methodology for the preparation of carboxylic acids. It is desirable to perform these reactions under precious metal-free and low-pressure conditions, with regioselectivity control. In this work, we present a detailed mechanistic study of a catalytic system based on NiI2, which can carbonylate benzylic alcohols in a highly regioselective manner to the corresponding branched carboxylic acids, core motifs for nonsteroidal drugs. The combination of catalytic amounts of nickel and iodide is crucial for efficient catalytic and regioselective conversion. Quantum-chemical computations were used to evaluate the underlying mechanistic processes. They revealed that a combination of two mechanisms is responsible for the observed reactivity and that the oxidative addition of alkyl halides to the Ni(0) species follows a radical oxidation pathway via two one-electron steps.
- Comba, Peter,Ghosh, Tamal,Hashmi, A. Stephen K.,Krieg, Saskia,Menche, Maximilian,Paciello, Rocco,Rück, Katharina S. L.,Sabater, Sara,Sch?fer, Ansgar,Schaub, Thomas
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supporting information
(2020/03/19)
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- Harnessing Applied Potential: Selective β-Hydrocarboxylation of Substituted Olefins
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The construction of carboxylic acid compounds in a selective fashion from low value materials such as alkenes remains a long-standing challenge to synthetic chemists. In particular, β-addition to styrenes is underdeveloped. Herein we report a new electrosynthetic approach to the selective hydrocarboxylation of alkenes that overcomes the limitations of current transition metal and photochemical approaches. The reported method allows unprecedented direct access to carboxylic acids derived from β,β-trisubstituted alkenes, in a highly regioselective manner.
- Alkayal, Anas,Buckley, Benjamin R.,Malkov, Andrei V.,Montanaro, Stephanie,Tabas, Volodymyr,Wright, Iain A.
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supporting information
(2020/02/13)
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- 2-phenylpropionic acid one-pot synthesis method
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The invention discloses a 2-phenylpropionic acid one-pot synthesis method. The 2-phenylpropionic acid one-pot synthesis method includes devices of a reaction flask, a collecting flask and a tail gas absorbing flask which are sequentially connected and comprises the following steps of 1) performing methylation reaction, specifically adding benzyl cyanide and sodium alkoxide into the reaction flask,filling carbon dioxide absorbent into the tail gas absorbing flask, controlling the temperature of the reaction flask to be 140-200 DEG C, slowly and dropwise adding dimethyl carbonate into the reaction flask, collecting vaporized gas-liquid mixtures from the reaction flask into the collecting flask, wherein gas in the gas-liquid mixtures is exhaust into the tail gas absorbing flask after passingthrough the collecting flask, after dropwise adding the dimethyl carbonate is completed, extracting the vaporized solution inside the collecting flask, distilling the vaporized solution to remove methyl alcohol, and then dropwise the distilled solution into the reaction flask to repeat the operations above; 2) filling water into the reaction flask for hydrolysis to obtain 2-phenylpropionic acid.The 2-phenylpropionic acid one-pot synthesis method has the advantages of being proper in reaction conditions and low in content of three wastes and production cost.
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Paragraph 0041; 0045-0046; 0047-0059
(2019/04/06)
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- Deracemizing α-Branched Carboxylic Acids by Catalytic Asymmetric Protonation of Bis-Silyl Ketene Acetals with Water or Methanol
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We report a highly enantioselective catalytic protonation of bis-silyl ketene acetals. Our method delivers α-branched carboxylic acids, including nonsteroidal anti-inflammatory arylpropionic acids such as Ibuprofen, in high enantiomeric purity and high yields. The process can be incorporated in an overall deracemization of α-branched carboxylic acids, involving a double deprotonation and silylation followed by the catalytic asymmetric protonation.
- Mandrelli, Francesca,Blond, Aurélie,James, Thomas,Kim, Hyejin,List, Benjamin
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supporting information
p. 11479 - 11482
(2019/07/18)
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- Preparation method of organic carboxylic acid
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The invention discloses a preparation method of organic carboxylic acid. The preparation method comprises the following steps that catalysts, olefins, water and solvents are added into a reaction container; CO is introduced; heating reaction is performed; after the reaction completion, separation is performed to obtain organic carboxylic acid; the catalysts comprise transition metal catalysts, ligands and catalysis assistants; the catalysis assistants comprise Lewis acid salt. The preparation method has the advantages that the dependency on protonic acid in the prior art is avoided; the Lewisacid salt is used as the catalysis assistant, so that the corrosion of a reaction system on equipment can be effectively prevented; the requirements on equipment are lowered. The preparation method has excellent substrate practicability; the operation steps are simple and fast; the reaction conditions are mild and are easy to control; the raw materials are cheap and can be easily obtained; the product yield and the product purity are high; the preparation method is suitable for large-scale industrial production; the normal/iso ratio of reaction products can be regulated and controlled throughthe catalysis assistants; the defects of regulating and controlling the normal/iso ratio of the reaction products by traditional phosphine ligands are overcome; the reaction progress of the reaction is simplified; the cost is favorably reduced.
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Paragraph 0038-0040; 0044-0046
(2019/10/15)
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- Electrogenerated Sm(II)-Catalyzed CO2 Activation for Carboxylation of Benzyl Halides
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Sm(II)-catalyzed carboxylation of benzyl halides is reported through the electrochemical reduction of CO2. The transformation proceeds under mild reaction conditions to afford the corresponding phenylacetic acids in good to excellent yields. This user-friendly and operationally simple protocol represents an alternative to traditional strategies, which usually proceeds through the C(sp3)-halide activation pathway.
- Bazzi, Sakna,Schulz, Emmanuelle,Mellah, Mohamed
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supporting information
p. 10033 - 10037
(2019/12/24)
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- Synthesis of Carboxylic Acids by Palladium-Catalyzed Hydroxycarbonylation
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The synthesis of carboxylic acids is of fundamental importance in the chemical industry and the corresponding products find numerous applications for polymers, cosmetics, pharmaceuticals, agrochemicals, and other manufactured chemicals. Although hydroxycarbonylations of olefins have been known for more than 60 years, currently known catalyst systems for this transformation do not fulfill industrial requirements, for example, stability. Presented herein for the first time is an aqueous-phase protocol that allows conversion of various olefins, including sterically hindered and demanding tetra-, tri-, and 1,1-disubstituted systems, as well as terminal alkenes, into the corresponding carboxylic acids in excellent yields. The outstanding stability of the catalyst system (26 recycling runs in 32 days without measurable loss of activity), is showcased in the preparation of an industrially relevant fatty acid. Key-to-success is the use of a built-in-base ligand under acidic aqueous conditions. This catalytic system is expected to provide a basis for new cost-competitive processes for the industrial production of carboxylic acids.
- Sang, Rui,Kucmierczyk, Peter,Dühren, Ricarda,Razzaq, Rauf,Dong, Kaiwu,Liu, Jie,Franke, Robert,Jackstell, Ralf,Beller, Matthias
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supporting information
p. 14365 - 14373
(2019/09/06)
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- Organocatalyzed Aerobic Oxidation of Aldehydes to Acids
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The first example organocatalyzed aerobic oxidation of aldehydes to carboxylic acids in both organic solvent and water under mild conditions is developed. As low as 5 mol % N-hydroxyphthalimide was used as the organocatalyst, and molecular O2 was used as the sole oxidant. No transition metals or hazardous oxidants or cocatalysts were involved. A wide range of carboxylic acids bearing diverse functional groups were obtained from aldehydes, even from alcohols, in high yields.
- Dai, Peng-Fei,Qu, Jian-Ping,Kang, Yan-Biao
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supporting information
p. 1393 - 1396
(2019/02/26)
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- Preparation method of 2-phenylpropionic acid
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The invention discloses a preparation method of 2-phenylpropionic acid. The preparation method of the 2-phenylpropionic acid comprises the following steps: (1) preparing 2-phenylpropyl aldehyde: dissolving styrene into methanol, adding catalysts acetone dicarbonyl rhodium and triethylamine, performing reaction and collecting fraction to obtain the 2-phenylpropyl aldehyde; and (2) preparing 2-phenylpropionic acid: dissolving the 2-phenylpropyl aldehyde into acetonitrile, adding an aqueous solution of hydrogen peroxide and sodium dihydrogen phosphate, adding a sodium hypochlorite solution into the system dropwise, performing reaction after adding dropwise, adding anhydrous sodium sulfite, standing and layering, taking an organic phase, washing with water, distilling, performing reduced-pressure distillation and collecting fraction to obtain the 2-phenylpropionic acid. During synthesis of the 2-phenylpropionic acid, the reaction can be completed only by two steps, so that the reaction steps are reduced, the reaction yield is increased, the cost is reduced, the yield can reach to 80 percent or more, the conversion rate is high, and the prepared product has stable quality and high purity.
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Paragraph 0017; 0019-0022
(2019/02/04)
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- Carboxylation of benzylic and aliphatic C-H bonds with CO2 induced by light/ketone/nickel
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A photoinduced carboxylation reaction of benzylic and aliphatic C-H bonds with CO2 is developed. Toluene derivatives capture gaseous CO2 at the benzylic position to produce phenylacetic acid derivatives when irradiated with UV light in the presence of an aromatic ketone, a nickel complex, and potassium tert-butoxide. Cyclohexane reacts with CO2 to furnish cyclohexanecar-boxylic acid under analogous reaction conditions. The present photoinduced carboxylation reaction provides a direct access from readily available hydrocarbons to the corresponding carboxylic acids with one carbon extension.
- Ishida, Naoki,Masuda, Yusuke,Imamura, Yuuya,Yamazaki, Katsushi,Murakami, Masahiro
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supporting information
p. 19611 - 19615
(2019/12/24)
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- Catalytic Transfer Hydrodebenzylation with Low Palladium Loading
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A highly-efficient catalytic system for hydrodebenzylation reaction is described. The cleavage of O-benzyl and N-benzyl protecting groups was performed using an uncommonly low palladium loading (0.02–0.3 mol%; TON up to 5000) in a relatively short reaction time. The approach was used for a variety of substrates including pharmaceutically important precursors, and gram-scale deprotection reaction was shown. Transfer conditions together with easy-to-make Pd/C catalyst are the key features of this debenzylation scheme. (Figure presented.).
- Yakukhnov, Sergey A.,Ananikov, Valentine P.
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supporting information
p. 4781 - 4789
(2019/09/16)
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- Photocarboxylation of Benzylic C-H Bonds
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The carboxylation of sp3-hybridized C-H bonds with CO2 is a challenging transformation. Herein, we report a visible-light-mediated carboxylation of benzylic C-H bonds with CO2 into 2-arylpropionic acids under metal-free conditions. Photo-oxidized triisopropylsilanethiol was used as the hydrogen atom transfer catalyst to afford a benzylic radical that accepts an electron from the reduced form of 2,3,4,6-tetra(9H-carbazol-9-yl)-5-(1-phenylethyl)benzonitrile generated in situ. The resulting benzylic carbanion reacts with CO2 to generate the corresponding carboxylic acid after protonation. The reaction proceeded without the addition of any sacrificial electron donor, electron acceptor or stoichiometric additives. Moderate to good yields of the desired products were obtained in a broad substrate scope. Several drugs were successfully synthesized using the novel strategy.
- Meng, Qing-Yuan,Schirmer, Tobias E.,Berger, Anna Lucia,Donabauer, Karsten,K?nig, Burkhard
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supporting information
p. 11393 - 11397
(2019/08/20)
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- Carbonylative Transformation of Allylarenes with CO Surrogates: Tunable Synthesis of 4-Arylbutanoic Acids, 2-Arylbutanoic Acids, and 4-Arylbutanals
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In this Communication, procedures for the selective synthesis of 4-arylbutanoic acids, 2-arylbutanoic acids, and 4-arylbutanals from the same allylbenzenes have been developed. With formic acid or TFBen as the CO surrogate, reactions proceed selectively and effectively under carbon monoxide gas-free conditions.
- Wu, Fu-Peng,Li, Da,Peng, Jin-Bao,Wu, Xiao-Feng
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supporting information
p. 5699 - 5703
(2019/08/01)
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- PROCESS FOR THE DIRECT CONVERSION OF ALKENES TO CARBOXYLIC ACIDS
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Process for the direct conversion of alkenes to carboxylic acids.
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Paragraph 0029-0032
(2019/07/10)
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- Biobased Poly(ethylene furanoate) Polyester/TiO2 Supported Nanocomposites as Effective Photocatalysts for Anti-inflammatory/Analgesic Drugs
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In the present study, polymer supported nanocomposites, consisting of bio-based poly(ethylene furanoate) polyester and TiO2 nanoparticles, were prepared and evaluated as effective photocatalysts for anti-inflammatory/analgesic drug removal. Nanocomposites were prepared by the solvent eVaporation method containing 5, 10, 15, and 20 wt% TiO2 and characterized using Fourier Transform Infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Thin films of them have been prepared by the melt press and optimization of the photocatalytic procedure was conducted for the most efficient synthesized photocatalyst. Finally, mineralization was evaluated by means of Total organic carbon (TOC) reduction and ion release, while the transformation products (TPs) generated during the photocatalytic procedure were identified by high-resolution mass spectrometry.
- Koltsakidou, Anastasia,Terzopoulou, Zoi,Kyzas, George Z.,Bikiaris, Dimitrios N.,Lambropoulou, Dimitra A.
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- Site-Selective, Remote sp3 C?H Carboxylation Enabled by the Merger of Photoredox and Nickel Catalysis
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A photoinduced carboxylation of alkyl halides with CO2 at remote sp3 C?H sites enabled by the merger of photoredox and Ni catalysis is described. This protocol features a predictable reactivity and site selectivity that can be modulated by the ligand backbone. Preliminary studies reinforce a rationale based on a dynamic displacement of the catalyst throughout the alkyl side chain.
- Sahoo, Basudev,Bellotti, Peter,Juliá-Hernández, Francisco,Meng, Qing-Yuan,Crespi, Stefano,K?nig, Burkhard,Martin, Ruben
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supporting information
p. 9001 - 9005
(2019/06/24)
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- A 2 - phenyl propionic acid preparation method
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The invention discloses a preparation method for 2-phenylpropionic acid. The preparation method is characterized by comprising a 2-phenyl-2-cyano methyl propionate preparation stage, a 2-phenyl propionitrile preparation stage and a 2-phenylpropionic acid preparation stage, wherein the 2-phenyl-2-cyano methyl propionate preparation stage comprises: mixing benzyl cyanide, dimethyl carbonate, methylbenzene and sodium methoxide to obtain a mixture, heating the mixture to 20-100 DEG C, controlling the pressure to 0.5-6MPa and carrying out thermal-insulation reaction for 1-10 hours; after the reaction is ended, steaming out a byproduct methanol under the normal pressure, cooling the mixture to 35 DEG C, dropwise adding dimethyl sulfate DMS at constant speed by controlling the temperature to 35-85 DEG C, and carrying out the thermal-insulation reaction for 1-10 hours at 45-105 DEG C after the dropwise-adding is ended; cooling to 35 DEG C, adding water, stirring, dissolving, and layering; desolventizing to recycle toluene, thereby obtaining compound ester; and carrying out basic hydrolysis reaction and acidification reaction to finally prepare a finished product, wherein the purity of the finished product is high, and the yield of the finished product is higher than 92%. Besides, the production process disclosed by the invention adopts simple equipment and is low in production cost.
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Paragraph 0027; 0033-0034; 0035; 0041-0042; 0043; 0049-0050
(2018/04/27)
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- A 2 - phenyl propionic acid preparation method
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The invention relates to a synthetic method of a medical intermediate: 2-phenylpropionic acid and belongs to the field of medicines. The conventional reaction process of 2-phenylpropionic acid is simplified from three steps to two steps. The preparation method comprises the following steps: by using styrene and sodium cyanide as raw materials, carrying out reaction under effects of potassium bicarbonate and a polymerization inhibitor at preferably 130-150 DEG C and 2.1-2.5MPa to prepare 2-phenyl propionitrile; carrying out alkaline hydrolysis and acidification on 2-phenyl propionitrile to obtain 2-phenylpropionic acid; and carrying out 3mmHg reduced pressure distillation on a coarse product to obtain high purity 2-phenylpropionic acid with the HPLC (high performance liquid chromatography) purity which is greater than 99%. In the whole reaction process, noble metal complexes are not used, so that the process is simple and easy to operate.
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Paragraph 0019; 0021
(2018/12/13)
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- Regioselectivity inversion tuned by iron(iii) salts in palladium-catalyzed carbonylations
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Impactful regioselectivity control is crucial for cost-effective chemical synthesis. By using cheap and abundant iron(iii) salts, the hydroxycarbonylations of both aromatic and aliphatic alkenes were significantly enhanced in both reactivity and selectivity (iso/n or n/iso up to >99:1). Moreover, Pd-catalyzed carbonylation selectivity can be switched from branched to linear by using different Fe(iii) salts. In addition, similar results were obtained for the carbonylation of secondary alcohols.
- Huang, Zijun,Cheng, Yazhe,Chen, Xipeng,Wang, Hui-Fang,Du, Chen-Xia,Li, Yuehui
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supporting information
p. 3967 - 3970
(2018/04/23)
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- A Core–Shell-Structured Silver Nanowire/Nitrogen-Doped Carbon Catalyst for Enhanced and Multifunctional Electrofixation of CO2
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Numerous catalysts have been successfully introduced for CO2 fixation in aqueous or organic systems. However, a single catalyst showing activity in both solvent types is still rare, to the best of our knowledge. We developed a core–shell-structured AgNW/NC700 composite using a Ag nanowire (NW) core encapsulated by a N-doped carbon (NC) shell at 700 °C. Through control experiments and density functional theory calculations, it was confirmed that Ag nanowires acted as the active sites for CO2 fixation and the uniformly coating of N-doped carbon created a CO2-rich environment around the Ag nanowires, which could significantly improve the catalytic activity of Ag nanowires for electrochemical CO2 fixation. Under mild conditions, up to 96 % faradaic efficiency of CO, 95 % yield of Ibuprofen and 92 % yield of propylene carbonate could be obtained in the electrochemical CO2 direct reduction, carboxylation and cycloaddition, respectively, using the same AgNWs/NC700 catalyst. These results might provide an alternative strategy for efficient electrochemical fixation of CO2.
- Yang, Heng-Pan,Zhang, Han-Wen,Wu, Yu,Fan, Liang-Dong,Chai, Xiao-Yan,Zhang, Qian-Ling,Liu, Jian-Hong,He, Chuan-Xin
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p. 3905 - 3910
(2018/09/27)
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- Platinum/nitrogen-doped carbon/carbon cloth: A bifunctional catalyst for the electrochemical reduction and carboxylation of CO2 with excellent efficiency
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A novel Pt-NP@NCNF@CC composite was prepared by the electrospinning technique. It is a highly efficient and binder-free catalyst for the direct reduction and carboxylation of CO2 with halides. Formate with 91% Faradaic efficiency and 2-phenylpropionic acid with 99% yield could be obtained, respectively. Moreover, this catalyst has excellent stability and reusability.
- Yang, Heng-Pan,Lin, Qing,Zhang, Han-Wen,Li, Guo-Dong,Fan, Liang-Dong,Chai, Xiao-Yan,Zhang, Qian-Ling,Liu, Jian-Hong,He, Chuan-Xin
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supporting information
p. 4108 - 4111
(2018/04/27)
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- A aldehyde or mellow directly converted into the carboxylic acid (by machine translation)
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The invention discloses a aldehyde or mellow oxidation can be directly transformed into carboxylic acid, is characterized in that the pure oxygen environment, in N - hydroxy imide compound under the catalysis of the imide compound or N - hydroxy and nitrous acid ester compound common under the catalysis, the CH2 OH and CHO oxidation directly converted into the carboxylic acid compounds. The invention using oxygen as the oxidizing agent, does not add any metal catalyst, environment-friendly, high catalytic efficiency, simple and convenient operation. With the previous metal catalytic system complex and different catalytic system, has some metal catalytic system in the process, the use of transition metal will cause the transition metal of the residual, the invention adopts the non-metallic catalytic system, environmental protection, preventing the metal residue problem, this to the solution of the drug in the synthesis of transition metal residue problem and provides a new method of thinking. (by machine translation)
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Paragraph 0062-0064
(2018/08/03)
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- Purified mCPBA, a Useful Reagent for the Oxidation of Aldehydes
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Purified mCPBA is a useful reagent for the oxidation of several classes of aldehyde. Although linear unbranched aliphatic aldehydes are oxidized to the corresponding carboxylic acids, α-branched ones undergo Baeyer–Villiger oxidation to formates. α-Branched α,β-unsaturated aldehydes provide enolformates and/or epoxides, which can be saponified to α-hydroxy ketones with shortening of the carbon chain by 1 carbon. Unbranched α,β-unsaturated aldehydes undergo an interesting Baeyer–Villiger oxidation/epoxidation/formate migration/BV oxidation cascade, which results in formyl-protected hydrates with an overall loss of two carbon atoms.
- Horn, Alexander,Kazmaier, Uli
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p. 2531 - 2536
(2018/03/21)
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- A biocatalytic method for the chemoselective aerobic oxidation of aldehydes to carboxylic acids
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Herein, we present a study on the oxidation of aldehydes to carboxylic acids using three recombinant aldehyde dehydrogenases (ALDHs). The ALDHs were used in purified form with a nicotinamide oxidase (NOx), which recycles the catalytic NAD+ at the expense of dioxygen (air at atmospheric pressure). The reaction was studied also with lyophilised whole cell as well as resting cell biocatalysts for more convenient practical application. The optimised biocatalytic oxidation runs in phosphate buffer at pH 8.5 and at 40 °C. From a set of sixty-one aliphatic, aryl-Aliphatic, benzylic, hetero-Aromatic and bicyclic aldehydes, fifty were converted with elevated yield (up to >99%). The exceptions were a few ortho-substituted benzaldehydes, bicyclic heteroaromatic aldehydes and 2-phenylpropanal. In all cases, the expected carboxylic acid was shown to be the only product (>99% chemoselectivity). Other oxidisable functionalities within the same molecule (e.g. hydroxyl, alkene, and heteroaromatic nitrogen or sulphur atoms) remained untouched. The reaction was scaled for the oxidation of 5-(hydroxymethyl)furfural (2 g), a bio-based starting material, to afford 5-(hydroxymethyl)furoic acid in 61% isolated yield. The new biocatalytic method avoids the use of toxic or unsafe oxidants, strong acids or bases, or undesired solvents. It shows applicability across a wide range of substrates, and retains perfect chemoselectivity. Alternative oxidisable groups were not converted, and other classical side-reactions (e.g. halogenation of unsaturated functionalities, Dakin-Type oxidation) did not occur. In comparison to other established enzymatic methods such as the use of oxidases (where the concomitant oxidation of alcohols and aldehydes is common), ALDHs offer greatly improved selectivity.
- Knaus, Tanja,Tseliou, Vasilis,Humphreys, Luke D.,Scrutton, Nigel S.,Mutti, Francesco G.
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supporting information
p. 3931 - 3943
(2018/09/11)
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- Visible-Light-Driven External-Reductant-Free Cross-Electrophile Couplings of Tetraalkyl Ammonium Salts
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Cross-electrophile couplings between two electrophiles are powerful and economic methods to generate C-C bonds in the presence of stoichiometric external reductants. Herein, we report a novel strategy to realize the first external-reductant-free cross-electrophile coupling via visible-light photoredox catalysis. A variety of tetraalkyl ammonium salts, bearing primary, secondary, and tertiary C-N bonds, undergo selective couplings with aldehydes/ketone and CO2. Notably, the in situ generated byproduct, trimethylamine, is efficiently utilized as the electron donor. Moreover, this protocol exhibits mild reaction conditions, low catalyst loading, broad substrate scope, good functional group tolerance, and facile scalability. Mechanistic studies indicate that benzyl radicals and anions might be generated as the key intermediates via photocatalysis, providing a new direction for cross-electrophile couplings.
- Liao, Li-Li,Cao, Guang-Mei,Ye, Jian-Heng,Sun, Guo-Quan,Zhou, Wen-Jun,Gui, Yong-Yuan,Yan, Si-Shun,Shen, Guo,Yu, Da-Gang
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p. 17338 - 17342
(2019/01/04)
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- Concise and Environmentally Friendly Asymmetric Total Synthesis of the Putative Structure of a Biologically Active 3-Hydroxy-2-piperidone Alkaloid
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An asymmetric total synthesis of stereoisomers of a putative structure of 3-hydroxy-2-piperidone alkaloid derivative is described. This route is not only concise and efficient but also is achieved under an environmentally friendly approach. To this end, a direct and double C-H oxidation reaction of simple benzylated piperidine and Baker's yeast reduction of a carbonyl group allowed the rapid access to the optically enriched (S)-1-benzyl-3-hydroxy-2-piperidone in only three steps. The NMR data agreed with those obtained in the first total synthesis (and in discrepancy with the natural product), however, optical rotation did not match with both neither the natural and synthetic material.
- Romero-Iba?ez, Julio,Cruz-Gregorio, Silvano,Quintero, Leticia,Sartillo-Piscil, Fernando
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p. 2878 - 2886
(2018/07/03)
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- Ozonation of ketoprofen with nitrate in aquatic environments: Kinetics, pathways, and toxicity
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In this study, nitrate ion (NO3-) was found to collaborate with ozone thereby accelerating the degradation of ketoprofen. NO3- was discovered to induce the generation of hydroxyl radicals (·OH), which was crucial to the decomposition of PPCPs in wastewater treatment plants. Kinetic studies on the decomposition of ketoprofen were investigated under different concentrations of NO3-. The impact mechanisms and degradation by-products were experimentally determined. The results revealed that all reactions fitted the pseudo-first-order kinetic model well. The presence of NO3- had the capacity to accelerate the ozonation of ketoprofen. The reaction by-products were evaluated by UPLC-Q-TOF-MS, and a total of five intermediates generated via the ozonation of ketoprofen were assessed. The transformation pathways were concluded to be hydroxylation, nitration, and debenzophenone and ketonized reactions. Additionally, the toxicity of the by-products was evaluated by employing Chlorella and Daphnia magna.
- Zeng, Yongqin,Lin, Xiaoxuan,Li, Fuhua,Chen, Ping,Kong, Qingqing,Liu, Guoguang,Lv, Wenying
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p. 10541 - 10548
(2018/03/26)
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- Ligand-Controlled Regioselective Hydrocarboxylation of Styrenes with CO2 by Combining Visible Light and Nickel Catalysis
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The ligand-controlled Markovnikov and anti-Markovnikov hydrocarboxylation of styrenes with atmospheric pressure of CO2 at room temperature using dual visible-light-nickel catalysis has been developed. In the presence of neocuproine as ligand, the Markovnikov product is obtained exclusively, while employing 1,4-bis(diphenylphosphino)butane (dppb) as the ligand favors the formation of the anti-Markovnikov product. A range of functional groups and electron-poor, -neutral, as well as electron-rich styrene derivatives are tolerated by the reaction, providing the desired products in moderate to good yields. Preliminary mechanistic investigations indicate the generation of a nickel hydride (H-NiII) intermediate, which subsequently adds irreversibly to styrenes.
- Meng, Qing-Yuan,Wang, Shun,Huff, Gregory S.,Konig, Burkhard
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supporting information
p. 3198 - 3201
(2018/03/13)
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- Synthetic method of fatty acid containing nitrogen heterocycle
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The invention discloses a synthetic method of fatty acid containing nitrogen heterocycle. The synthetic method comprises the following steps: (S1) adding a heterocyclic compound with substitution of chloromethyl groups, a catalyst and a solvent DMF into a reaction kettle; (S2) introducing carbon dioxide to lead the pressure in the kettle to be 2-4MPa, adjusting and reacting for 10-16 hours at thetemperature of 40-50 DEG C; (S3) adding diluted hydrochloric acid into the reaction kettle to carry out acidification, using ethyl acetate for extraction, combining organic phases, carrying out rotaryevaporation to remove liquid, and further carrying out vacuum drying, thus obtaining the fatty acid containing nitrogen heterocycle. The synthetic method disclosed by the invention has the beneficialeffects that a one-pot method is adopted, the raw materials are easy to obtain, price is low, aftertreatment of products is also simpler, the universality for a substrate is also very high, and the promotion and application are easy.
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Paragraph 0042
(2018/07/30)
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- A Ligand-Directed Catalytic Regioselective Hydrocarboxylation of Aryl Olefins with Pd and Formic Acid
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An effective Pd-catalyzed hydrocarboxylation of aryl olefins with Ac2O and formic acid is described. A variety of 2- and 3-arylpropanoic acids can be regioselectively formed by the judicious choice of ligand without the use of toxic CO gas.
- Liu, Wei,Ren, Wenlong,Li, Jingfu,Shi, Yuan,Chang, Wenju,Shi, Yian
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supporting information
p. 1748 - 1751
(2017/04/11)
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- Synthesis method of 4-bromomethyl isophenylpropionic acid
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The invention provides synthesis of 4-bromomethyl isophenylpropionic acid. The synthesis comprises the following steps: toluene and a methylation reagent undergo a reaction to produce isophenylpropionic acid at high temperature under an alkaline effect; carry out acid washing and distillation on a reaction solution to prepare qualified isophenylpropionic acid with purity more than 98 percent, so as to prepare a compound 4-bromomethyl isophenylpropionic acid: carrying out bromomethylation reaction on the qualified product isophenylpropionic acid to produce a compound 4-bromomethyl isophenylpropionic acid reaction solution; dissolving the reaction solution, washing with water, concentrating, washing and centrifuging to obtain a qualified finished product. Compared with the prior art, the raw materials are easy to obtain and the cost is low; the synthesis has the advantages of cheap and easily-obtained raw materials, small toxin, low cost, simplicity and convenience for operation and is applicable to industrialization; a few of three wastes are generated, and the wastes are comprehensively utilized and national industrial policies are met.
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Paragraph 0013
(2017/07/19)
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- New Strategy for Forging Contiguous Quaternary Carbon Centers via H 2 O 2 -Mediated Ring Contraction
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Stereospecific construction of contiguous quaternary carbon centers constitutes a major challenge in natural product synthesis. A general protocol that enables stereospecific construction of all stereoisomers of such a moiety remains elusive. In this article, we will discuss the oxidative ring contraction of all-substituted cyclic α-formyl ketones mediated by H 2 O 2, which provides a facile access to the stereospecific construction of contiguous quaternary carbon centers.
- Hu, Jiadong,Yu, Xin,Xie, Weiqing
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p. 2517 - 2524
(2017/09/28)
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