- Barbituric acid initiated rearrangement of 2,2'-pyridil into 5,5'-(2-pyrilidine)bisbarbituric acid.
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[reaction: see text] In the study of the barbituric acid initiated 2,2'-pyridil rearrangement, a very efficient synthetic procedure (isolated yield 80-90%) for the preparation of useful 2-pyrilidenes 3 was developed.
- Jursic, Branko S,Neumann, Donna M,Martin, Kenneth L,Stevens, Edwin D
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- Copper(II)-Catalyzed Selective Para Amination of Arylamine with Pyrazole by C?H Functionalization
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A coordinating activation strategy for selective para amination of arylamine with pyrazole is developed. Various substrates are compatible, giving the corresponding products in moderate to good yields. This strategy provides a practical solution for the efficient synthesis of arylamine-containing pharmacophores from simple starting materials. A single electron transfer mechanism is suggested for this reaction.
- Xu, Jun,Du, Kui,Shen, Jiabin,Shen, Chao,Chai, Kejie,Zhang, Pengfei
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- DNA-templated metal catalysis
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Hydrolysis of an ester substrate by a CuII complex catalyst, both attached to oligo-peptide nucleic acids (PNA), is accelerated up to 485-fold in the presence of a complementary DNA template. The approach combines the sequence selectivity of DNA-templated reactions with signal amplification by multiple turnover and the versatility of metal catalysis. Copyright
- Brunner, Jens,Mokhir, Andriy,Kraemer, Roland
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- ANODIC OXIDATION OF 2-PICOLINE
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Concentrations, temperature, and current density for anodic oxidation of 2-picoline were optimized by using three statistically designed experiments.Criteria for optimization were chemical yield, current efficiency, space-time yield and rate of anode corrosion.
- Toomey, Joseph E.,Chaney, Gregory A.
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- Detection of transient intermediates in the metal-dependent nonoxidative decarboxylation catalyzed by α-amino-β-carboxymuconate-ε- semialdehyde decarboxylase
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The first description of a metalloenzyme-mediated nonoxidative decarboxylation reaction was that catalyzed by α-amino-β-carboxymuconate-ε-semialdehyde decarboxylase (ACMSD) (Li, T.; Walker, A. L.; Iwaki, H.; Hasegawa, Y.; Liu, A. J. Am. Chem. Soc. 2005, 127, 12282-12290 and Liu, A.; Zhang, H. Biochemistry 2006, 45, 10407-10411). Here, we report a rapid kinetic study of the ACMSD reaction using the cobalt(II)-reconstituted enzyme. Two previously undetected intermediates of the reaction are characterized. These are proposed to be the aminomuconate-ε-semialdehyde (AMS) product of the decarboxylation in complex with the enzyme and the free AMS after release from ACMSD. It was possible to determine the rates of formation of the enzyme-substrate complex (2.4 × 106 s-1 M-1), release of the AMS product (8.8 s-1), and spontaneous cyclization of AMS to picolinic acid (0.05 s-1), which is the final product of the reaction. Reconstructed spectra of these reaction intermediates and a kinetic mechanism for the overall reaction are presented. Copyright
- Li, Tingfeng,Ma, John K.,Hosler, Jonathan P.,Davidson, Victor L.,Liu, Aimin
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- Highly Selective Detection of Hypochlorous Acid by a Bis-heteroleptic Ru(II) Complex of Pyridyl-1,2,3-triazole Ligand via C(sp2)-H Hydroxylation
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A Ru(II) complex (Ru-1) of a substituted pyridyl-1,2,3-triazole ligand (BtPT) for highly selective "light-up" detection of hypochlorous acid is presented. An unusual anti-Markovnikov HOCl addition to the C=C bond of 1,2,3-triazole and a highly specific C(sp2)-H hydroxylation over epoxidation made Ru-1 a highly selective luminescent HOCl probe. The abnormal regio- and stereoselective HOCl addition and subsequent hydroxylation mechanism in detail is supported by the combination of ESI-MS, 1H/13C NMR spectroscopy, and 1H NMR titration. The hydroxylation at the C5 center in 1,2,3-triazole increases the electron density and makes BtPT a better σ-donor as well as π-donor, which in turn increases the 3MC-3MLCT energy gap and inhibits the nonradiative decay from the excited state of Ru-1 and is the key reason for luminescence light-up. Most importantly, the exogenous and endogenous HOCl imaging in the living HEK293T cells is also demonstrated. The probe showed low cytotoxicity and efficiently permeated the cell membrane. The cell-imaging experiments revealed rapid staining of the extranuclear region of HEK293T cells which clearly indicates the presence of cytoplasmic HOCl. The endogenous HOCl generation and imaging, stimulated by lipopolysaccharides (LPS) and paraquat in the HEK293T cells, is also demonstrated.
- Sen, Bhaskar,Sheet, Sanjoy Kumar,Patra, Sumit Kumar,Koner, Debaprasad,Saha, Nirmalendu,Khatua, Snehadrinarayan
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- Use of bacteria for rapid, pH-neutral, hydrolysis of the model hydrophobic carboxylic acid ester p-nitrophenyl picolinate
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Caulobacter crescentus, Escherichia coli and Bacillus subtilis cultures promote the hydrolysis of the model ester p-nitrophenyl picolinate (PNPP) at neutral pH with high efficiency. Hydrolysis is related to cell concentration, while the interaction of PNPP with both bacterial cells and their extracellular molecules is required for a maximum rate of PNPP hydrolysis in C. crescentus cultures. Furthermore, C. crescentus cultures hydrolyse PNPP at concentrations useful in synthetic chemistry.
- Forest, Alexandra E.,Goldstine, Gordon G.,Murray, Sean R.,Schrodi, Yann
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- Reactivity of secondary N-alkyl acrylamides in Morita–Baylis–Hillman reactions
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The Morita–Baylis–Hillman (MBH) reaction of secondary N-alkyl acrylamides, discarded up to now from investigations of the scope of activated alkenes, was studied. Optimization of the reaction conditions revealed that a balance must be found between activation of the MBH coupling reaction and that of the undesired competitive aldehyde Cannizzaro reaction. Using 3-Hydroxyquinuclidine (3-HQD) in a 1:1 water-2-MeTHF mixture provides the appropriate conditions that were applicable to a wide range of diversely substituted secondary N-alkyl acrylamides and aromatic aldehydes, giving rise to novel amide-containing MBH adducts under mild and clean conditions.
- Ahmar, Mohammed,Queneau, Yves,Verrier, Charlie,Yue, Xiaoyang
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p. 319 - 330
(2021/10/29)
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- {BW12O40} Hybrids Modified by in Situ Synthesized Rigid Ligand with Supercapacitance and Photocatalytic Properties
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Organic rigid ligand-modified polyoxometalate-based materials possess complex and diverse structures, promising electrochemical energy storage properties and outstanding photocatalytic capabilities. Hence, two new [BW12O40]5-(abbreviated as {BW12O40})-based inorganic-organic hybrids [{Cu(en)2(H2O)}][{Cu(pdc)(en)}{Cu(en)2}(BW12O40)]·2H2O (1) and [{CuI5(pz)6(H2O)4}(BW12O40)] (2) (pdc = 2-picolinate, en = ethylenediamine, pz = pyrazine) were successfully synthesized through a hydrothermal method. Among them, pdc and pz were obtained by in situ transformation from 2,6-pyridinedicarboxylic acid (H2 pydc) and 2,3-pyrazinedicarboxylic acid (H2pzdc), respectively. In compound 1, the {BW12O40} clusters as an intermediate junction connect with {Cu(pdc)(en)}{Cu(en)2} and {Cu(en)2(H2O)} to form monomers, which in turn form supramolecular chains, sheets, and space network via hydrogen bonding. The {BW12O40} clusters are packed into copper-pyrazine frameworks in compound 2, and a unique polyoxometalate-based metal organic frameworks (POMOFs) structure with a new topology of {12}2{6.123.142}2{62.12.142.18}{62.123.16}{6}6 is formed via covalent bonds. When used as electrode materials for supercapacitors, the values of specific capacitance are 651.56 F g-1 for 1-GCE and 584.43 F g-1 for 2-GCE at a current density of 2.16 A g-1 and good cycling stability (90.94%, 94.81% of the initial capacity after 5000 cycles at 15.12 A g-1, respectively). The kinetic analysis reveals that surface capacitance plays a major role. Furthermore, both compounds can effectively degrade Rhodamine B (RhB) and Methylene blue (MB), showing the outstanding photocatalytic performance.
- Du, Nana,Gong, Lige,Wang, Chunmei,Wang, Chunxiao,Yu, Kai,Zhang, Wenjia,Zhou, Baibin
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supporting information
p. 16357 - 16369
(2021/11/13)
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- Reaction Acceleration Promoted by Partial Solvation at the Gas/Solution Interface
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The kinetics of organic reactions of different types in microvolumes (droplets, thin films, and sealed tubes) show effects of gas/solution interfacial area, reaction molecularity and solvent polarity. Partial solvation at the gas/solution interface is a major contributor to the 104-fold reaction acceleration seen in bimolecular but not unimolecular reactions in microdroplets. Reaction acceleration can be used to manipulate selectivity by solvent choice.
- Qiu, Lingqi,Wei, Zhenwei,Nie, Honggang,Cooks, R. Graham
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p. 1362 - 1365
(2021/09/14)
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- Selective oxidation of alkenes to carbonyls under mild conditions
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Herein, a practical and sustainable method for the synthesis of aldehydes, ketones, and carboxylic acids from an inexpensive olefinic feedstock is described. This transformation features very sustainable and mild conditions and utilizes commercially available and inexpensive tetrahydrofuran as the additive, molecular oxygen as the sole oxidant and water as the solvent. A wide range of substituted alkenes were found to be compatible, providing the corresponding carbonyl compounds in moderate-to-good yields. The control experiments demonstrated that a radical mechanism is responsible for the oxidation reaction.
- Huo, Jie,Xiong, Daokai,Xu, Jun,Yue, Xiaoguang,Zhang, Pengfei,Zhang, Yilan
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supporting information
p. 5549 - 5555
(2021/08/16)
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- Expanding the repertoire of nitrilases with broad substrate specificity and high substrate tolerance for biocatalytic applications
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Enzymatic conversion of nitriles to carboxylic acids by nitrilases has gained significance in the green synthesis of several pharmaceutical precursors and fine chemicals. Although nitrilases from several sources have been characterized, there exists a scope for identifying broad spectrum nitrilases exhibiting higher substrate tolerance and better thermostability to develop industrially relevant biocatalytic processes. Through genome mining, we have identified nine novel nitrilase sequences from bacteria and evaluated their activity on a broad spectrum of 23 industrially relevant nitrile substrates. Nitrilases from Zobellia galactanivorans, Achromobacter insolitus and Cupriavidus necator were highly active on varying classes of nitriles and applied as whole cell biocatalysts in lab scale processes. Z. galactanivorans nitrilase could convert 4-cyanopyridine to achieve yields of 1.79 M isonicotinic acid within 3 h via fed-batch substrate addition. The nitrilase from A. insolitus could hydrolyze 630 mM iminodiacetonitrile at a fast rate, effecting 86 % conversion to iminodiacetic acid within 1 h. The arylaliphatic nitrilase from C. necator catalysed enantioselective hydrolysis of 740 mM mandelonitrile to (R)-mandelic acid in 4 h. Significantly high product yields suggest that these enzymes would be promising additions to the suite of nitrilases for upscale biocatalytic application.
- Rayavarapu, Pratima,Shah, Shikha,Sunder, Avinash Vellore,Wangikar, Pramod P.
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p. 289 - 296
(2020/05/18)
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- Light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds
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Visible light-induced organic reactions are important chemical transformations in organic chemistry, and their efficiency highly depends on suitable photocatalysts. However, the commonly used photocatalysts are precious transition-metal complexes and elaborate organic dyes, which hamper large-scale production due to high cost. Here, for the first time, we report a novel strategy: light and oxygen-enabled sodium trifluoromethanesulfinate-mediated selective oxidation of C-H bonds, allowing high-value-added aromatic ketones and carboxylic acids to be easily prepared in high-to-excellent yields using readily available alkyl arenes, methyl arenes and aldehydes as materials. The mechanistic investigations showed that the treatment of inexpensive and readily available sodium trifluoromethanesulfinate with oxygen under irradiation of light could in situ form a pentacoordinate sulfide intermediate as an efficient photosensitizer. The method represents a highly efficient, economical and environmentally friendly strategy, and the light and oxygen-enabled sodium trifluoromethanesulfinate photocatalytic system represents a breakthrough in photochemistry. This journal is
- Fu, Hua,Liu, Can,Liu, Yong,Yang, Haijun,Zhu, Xianjin
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supporting information
p. 4357 - 4363
(2020/07/14)
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- Method for preparing organic acid by oxidative cleavage of aromatic secondary alcohol
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The invention relates to a method for preparing organic acids by oxidation of aromatic secondary alcohols. With air or oxygen as an oxygen source, a copper salt and an organic ligand as catalysts, aninorganic alkali is added, and aromatic secondary alcohols are subjected to carbon-carbon bond oxidative cracking to obtain the organic acids. The method has the advantages of high oxidation efficiency and high product yield; with the use of air or oxygen as the oxygen source, the method is economical and environmentally friendly and has good application prospects.
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Paragraph 0043-0046; 0051
(2020/09/16)
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- A sodium trifluoromethanesulfinate-mediated photocatalytic strategy for aerobic oxidation of alcohols
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A sodium trifluoromethanesulfinate-mediated photocatalytic strategy for the aerobic oxidation of alcohols has been developed for the first time, and the photoredox aerobic oxidation of secondary and primary alcohols provided the corresponding ketones and carboxylic acids, respectively, in high to excellent yields.
- Zhu, Xianjin,Liu, Can,Liu, Yong,Yang, Haijun,Fu, Hua
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p. 12443 - 12446
(2020/10/30)
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- Redox Cascades and Making of a C-C Bond: 1,2-Benzodiazinyl Radicals and a Copper Complex of a Benzodiazine
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Two 1,2-benzodiazinyl radicals, cinnolinyl radicals by name, were successfully isolated by cascade routes using 1,4-naphthoquinone as a precursor. Reaction of 1,4-naphthoquinone with hydrazine hydrate promotes a (5e + 5H+) redox cascade affording benzo[g]naphtho[1,2-c]cinnolinyl-7,12,14-trione (Cn·) in 69% yields, while the similar reaction with 2-hydrazinopyridine is a (7e + 7H+) oxidative cascade and furnishes N-pyridinecinnolinyl radical (PyCn·). The cascades are composed of C-N and C-C bond making reactions. The neutral even alternate arenes are always diamagnetic; thus, the isolation of Cn· and PyCn· is a breakthrough. The Cn·/Cn- and PyCn·/PyCn- redox couples are reversible, and the reaction of Cn· with [CuI(PPh3)3Cl] in the presence of hydrazine hydrate and Et3N affords a Cn- complex of copper(I), [(Cn-)CuI(PPh3)2] (1). Similar to phenalenyl radical, PyCn· exists in three redox states, PyCn+PyCn·, and PyCn-, in a smaller potential range (-0.30 V to -0.60 V vs Fc+/Fc couple) and can be used as an oxidant as well as a reductant. PyCn· acts as a catalyst for the oxidative cleavages of benzil to benzoic and 2,2′-pyridil to picolinic acids in methanol in the presence of air. The molecular and electronic structures of Cn·PyCn·, and 1·1/2MeOH were confirmed by single crystal X-ray crystallography, EPR spectroscopy, and DFT calculations.
- Mondal, Sandip,Bera, Sachinath,Ghosh, Prasanta
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- Directed C-H Functionalization Reactions with a Picolinamide Directing Group: Ni-Catalyzed Cleavage and Byproduct Recycling
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An efficient strategy for the cleavage of the picolinamide directing group (DG) and recycling of the byproduct generated has been developed. In this protocol, picolinamides were first Boc activated into tertiary N-Boc-N-substituted picolinamides. These were then cleaved via a Ni-catalyzed esterification reaction with EtOH to give valuable N-Boc protected amines. Ni(cod)2 was used as a catalyst without any ligands or base additives. The byproduct, ethyl 2-picolinate can be used to install the picolinamide DG in a direct or indirect manner on amines. The protocol exhibits a broad functional group tolerance and high yields. To demonstrate the utility of this approach, it was applied on many selected examples from the recent C-H functionalization literature featuring 2-picolinamide as a DG.
- Biswas, Sovan,Bheemireddy, Narendraprasad Reddy,Bal, Mathias,Van Steijvoort, Ben F.,Maes, Bert U. W.
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p. 13112 - 13123
(2019/10/17)
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- RhI-Catalyzed PIII-Directed C?H Bond Alkylation: Design of Multifunctional Phosphines for Carboxylation of Aryl Bromides with Carbon Dioxide
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We report the C?H alkylation of biarylphosphines at the ortho′ position(s) with alkenes by using rhodium(I) catalysis, which provides straightforward access to a large library of multifunctionalized phosphines. Some of these modified ligands outperformed commercially available phosphines in the Pd-catalyzed carboxylation of aryl bromides with carbon dioxide in the presence of a photoredox catalyst.
- Zhang, Zhuan,Roisnel, Thierry,Dixneuf, Pierre H.,Soulé, Jean-Fran?ois
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supporting information
p. 14110 - 14114
(2019/08/30)
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- Nickel-catalyzed carboxylation of aryl and heteroaryl fluorosulfates using carbon dioxide
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The development of efficient and practical methods to construct carboxylic acids using CO2 as a C1 synthon is of great importance. Nickel-catalyzed carboxylation of aryl fluorosulfates and heteroaryl fluorosulfates with CO2 is described, affording arene carboxylic acids with good to excellent yields under mild conditions. In addition, a one-pot phenol fluorosulfation/carboxylation is developed.
- Ma, Cong,Zhao, Chuan-Qi,Xu, Xue-Tao,Li, Zhao-Ming,Wang, Xiang-Yang,Zhang, Kun,Mei, Tian-Sheng
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p. 2464 - 2467
(2019/04/10)
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- Catalytic Oxidation of Alcohols Using a 2,2,6,6-Tetramethylpiperidine-N-hydroxyammonium Cation
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The oxidation of alcohols to aldehydes, ketones, and carboxylic acids is reported using 2,2,6,6-tetramethylpiperidine-4-acetamido-hydroxyammonium tetrafluoroborate as a catalyst in conjunction with sodium hypochlorite pentahydrate as a terminal oxidant. The reaction is generally complete within 30–120 min using an acetonitrile/water mix as the solvent, and no additives are required. Product yields are good to excellent and of particular note is that the methodology can be used to access aryl α-trifluoromethyl ketones.
- Miller, Shelli A.,Bisset, Kathryn A.,Leadbeater, Nicholas E.,Eddy, Nicholas A.
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supporting information
p. 1413 - 1417
(2019/01/04)
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- Microwave-assisted Cannizzaro reaction—Optimisation of reaction conditions
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The microwave-assisted Cannizzaro reaction was studied in order to develop fully reproducible synthetic protocols for transformation of aldehydes to carboxylic acid and alcohols. Optimised were the following process parameters: power, temperature, and time. Aromatic, heteroaromatic and aliphatic aldehydes were used in the studies. It was found that furfural, thiophene-2-carbaldehyde, pyridinecarboxaldehyde and aromatic aldehydes react under mild conditions, while 1-methyl-pyrrole-2-carboxaldehyde derivatives and aliphatic aldehydes require more drastic reaction conditions and a longer exposure time to microwave radiation.
- Janczewski, ?ukasz,Walczak, Ma?gorzata,Fr?czyk, Justyna,Kamiński, Zbigniew J.,Kolesińska, Beata
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supporting information
p. 3290 - 3300
(2019/11/05)
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- Electrochemical Oxidation of Alcohols and Aldehydes to Carboxylic Acids Catalyzed by 4-Acetamido-TEMPO: An Alternative to "anelli" and "pinnick" Oxidations
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An electrocatalytic method has been developed to oxidize primary alcohols and aldehydes to the corresponding carboxylic acids using 4-acetamido-2,2,6,6-tetramethylpiperidin-1-oxyl (ACT) as a mediator. The method successfully converts benzylic, aliphatic, heterocyclic, and other heteroatom-containing substrates to the corresponding carboxylic acids in aqueous solution at room temperature. The mild conditions enable retention of stereochemistry adjacent to the site of oxidation, as demonstrated in a 40 g-scale synthesis of a precursor to levetiracetam, a medication used to treat epilepsy.
- Rafiee, Mohammad,Konz, Zachary M.,Graaf, Matthew D.,Koolman, Hannes F.,Stahl, Shannon S.
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p. 6738 - 6744
(2018/06/19)
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- METHOD FOR PRODUCING HETEROAROMATIC CARBOXYLIC ACID
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PROBLEM TO BE SOLVED: To provide a method for producing heteroaromatic carboxylic acids at good yields, when producing the heteroaromatic carboxylic acids by the oxidation of methyl-substituted heteroaromatic compounds. SOLUTION: A method for producing a heteroaromatic carboxylic acid includes oxidizing a methyl-substituted heteroaromatic compound, having one or more methyl groups on a heteroaromatic ring, with a basic compound and a permanganate. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0039; 0043; 0044
(2018/08/09)
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- Visible-Light-Mediated Nickel(II)-Catalyzed C-N Cross-Coupling in Water: Green and Regioselective Access for the Synthesis of Pyrazole-Containing Compounds
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A regioselective green approach for the nickel(II)-catalyzed C-N cross-coupling between arylamines and pyrazoles through a photoredox process is reported. Moderate to good yield was observed for this reaction, performed in water under air at room temperature. This strategy provides a powerful tool for the green synthesis of pyrazole-containing bioactive molecules. In addition, a single-electron-transfer mechanism is proposed in this report.
- You, Guirong,Wang, Kai,Wang, Xiaodan,Wang, Guodong,Sun, Jian,Duan, Guiyun,Xia, Chengcai
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p. 4005 - 4009
(2018/07/22)
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- Urea-based amphiphilic porous organic polymer-supported palladium as a reusable catalyst for Suzuki–Miyaura coupling and hydroxycarbonylation reactions in water
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The development of environmentally friendly heterogeneous catalysts for organic reactions in water is becoming of growing importance for the development of sustainable processes. In this work, a porous organic polymer-supported palladium catalyst (Pd@UPOP-1) was successfully fabricated from 3,3′-diaminobenzidine and methylenediphenyl diisocyanate through a facile urea-forming condensation reaction. The structure and composition of the catalyst were characterized using several physicochemical methods. Pd@UPOP-1 was found to possess good porous structure and excellent amphiphilicity. Under mild reaction conditions, the catalyst showed excellent catalytic activity and good substrate compatibility for the Suzuki–Miyaura coupling reaction of aryl bromides, as well as the hydroxycarbonylation reaction of aryl iodides. In addition, the catalyst could be used for several consecutive recycles in both cases.
- Lei, Yizhu,Lan, Guosong,Zhu, Dajian,Wang, Renshu,Zhou, Xiao-Yu,Li, Guangxing
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- An Improved Rapid and Mild Deoxygenation of Amine N-oxides
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An improved mild and selective method for the deoxygenation of a variety of amine N-oxides has been carried out in the presence of silica gel under mild conditions at room temperature to afford corresponding amines in relatively good yields without purification. The reaction is tolerant of a variety of functional groups such as hydroxyl, ester, acid, carbonyl, and cyano groups, as well as halogens. This method would be of great utility to synthesize various pyridines and amines easily.
- Rajesh
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p. 486 - 491
(2017/12/29)
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- Catalyst-free aerobic oxidation of aldehydes into acids in water under mild conditions
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The first example of catalyst-free aerobic oxidation of aldehydes in water under respective acidic, neutral and alkaline conditions was developed. The sole oxidant is molecular oxygen of 1 atmosphere and reactions can proceed under extremely mild conditions. This procedure covers a wide range of aldehydes, and operates easily. No additives and catalysts were required for this purpose, and most of the aldehydes can be converted to their corresponding carboxylic acids with good to excellent yields, in addition, no side-product formation could be observed during or after the reactions. To well illustrate why the oxidation rate becomes fast firstly and then slows with increased temperatures, five control reactions were carried out and a Fe3+/Fe2+ recycling system was introduced to facilitate the aldehyde oxidation rate. The generality of this method offers the potential for industrial aldehyde-containing waste water treatment.
- Zhang, Yue,Cheng, Yujia,Cai, Huizhuo,He, Shaopo,Shan, Qiheng,Zhao, Hongwei,Chen, Yiping,Wang, Bo
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supporting information
p. 5708 - 5713
(2017/12/06)
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- Method for preparing aminopyridine from methylpyridine, and purifying method of aminopyridine
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The invention relates to the field of organic synthesis, and concretely relates to a method for preparing aminopyridine from methylpyridine, and a purifying method of aminopyridine. Crude aminopyridine is prepared from corresponding methylpyridine through oxidation, esterification, hydrazinolysis and rearrangement reactions, the reaction yield of every step is high, and a post-treatment technology is easy to industrially operate; in the oxidation reaction, beta-cyclodextrin is used as a catalyst, so the conversion rate of the oxidation reaction is increased, and the generation of byproducts is reduced; and anhydrous ethanol and an alkane reagent are used to re-crystallize the crude aminopyridine, and a decolorizing agent is combined, and the purity of the final product reaches 98% or more; and the purifying method has the advantages of simplicity, easiness in operation, easily available raw materials, and suitableness for industrial production.
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Paragraph 0036
(2017/09/01)
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- Experimental and mechanistic insights into copper(ii)-dioxygen catalyzed oxidative: N -dealkylation of N -(2-pyridylmethyl)phenylamine and its derivatives
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A di-(2-pyridylmethyl)phenylamine ((PyCH2)2NPh) supported Cu(ii)/O2 catalytic system was explored with the synthesis of pyridylmethyl-based compounds of carboxylate (PyCOOH), amide (PyC(O)NHPh), and imine (PyCHNPh) from the oxidative N-dealkylation of N-(2-pyridylmethyl)phenylamine (PyCH2NHPh) and its derivatives, by means of controlling the addition of a base and/or water to the reaction system under a dioxygen atmosphere at room temperature. Experimental studies showed that the imine and amide species could be precursors in succession in the way to the final oxidation state of carboxylates. A cyclic catalytic mechanism was proposed including the base triggered C-H bond activation of the 2-pyridylmethyl group (PyCH2-) and the intermolecular Cu-OOH α-hydrogen atom abstraction from the coordinated imine substrate (PyCHNPh).
- Wang, Yang,Liu, Haixiong,Zhang, Xiaofeng,Zhang, Zilong,Huang, Deguang
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supporting information
p. 9164 - 9168
(2017/11/15)
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- Oxalic acid as the: In situ carbon monoxide generator in palladium-catalyzed hydroxycarbonylation of arylhalides
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An efficient palladium-catalyzed hydroxycarbonylation reaction of arylhalides using oxalic acid as a CO source has been developed. The reaction features high safety, low catalyst loading, and a broad substrate scope, and provides a safe and tractable approach to access a variety of aromatic carboxylic acid compounds. Mechanistic studies revealed the decomposition pattern of oxalic acid.
- Shao, Changdong,Lu, Ailan,Wang, Xiaoling,Zhou, Bo,Guan, Xiaohong,Zhang, Yanghui
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supporting information
p. 5033 - 5040
(2017/07/10)
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- Oxidative C(OH)[sbnd]C bond cleavage of secondary alcohols to acids over a copper catalyst with molecular oxygen as the oxidant
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Selective oxidative cleavage of C[sbnd]C bond is pivotal for producing functionalized molecules, useful for organic synthesis and biomass utilization. We herein report the oxidative C(OH)[sbnd]C bond cleavage of secondary alcohols to acids over a copper/1, 10-phenanthroline complex with molecular oxygen as the oxidant. A wide range of secondary alcohols are converted into acids with up to 98% yields. More interestingly, it is effective for breaking up lignin model systems into acids, which is rarely achieved in previous studies. Density functional theory (DFT) calculations indicate a copper-oxo-bridged oxygen dimer is the active species for the C[sbnd]H bond cleavage which is the rate-determining step for C[sbnd]C bond.
- Wang, Min,Lu, Jianmin,Li, Lihua,Li, Hongji,Liu, Huifang,Wang, Feng
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p. 160 - 167
(2017/03/21)
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- Room Temperature Carbonylation of (Hetero) Aryl Pentafluorobenzenesulfonates and Triflates using Palladium-Cobalt Bimetallic Catalyst: Dual Role of Cobalt Carbonyl
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An efficient method for the carbonylation of (hetero) aryl pentafluorobenzenesulfonates and triflates under exceptionally mild conditions using palladium/dicobalt octacarbonyl [Pd/Co2(CO)8] has been developed. Besides acting as carbon monoxide (CO) source, Co2(CO)8enhances the reaction rate by accelerating the CO insertion through an in situ generated bimetallic palladium cobalt tetracarbonyl [Pd-Co(CO)4] complex. Under the optimized reaction condition, carbonylation of a wide range of activated and deactivated, as well as sterically hindered and heteroaromatic, substrates proceeded efficiently at room temperature. The high chemoselectivity and improved synthesis of biologically relevant Isoguvacine and Lazabemide intermediates highlights its scope as a valuable synthetic method. The generality of this protocol was further extended to other electrophiles (bromides, chlorides and tosylates). (Figure presented.).
- Joseph, Jayan T.,Sajith, Ayyiliath M.,Ningegowda, Revanna C.,Shashikanth, Sheena
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p. 419 - 425
(2017/02/10)
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- Biotransformation of aromatic and heterocyclic amides by amidase of whole cells of Rhodococcus sp. MTB5: Biocatalytic characterization and substrate specificity
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In this study, an amidohydrolase activity of amidase in whole cells of Rhodococcus sp. MTB5 has been used for the biotransformation of aromatic, monoheterocyclic and diheterocyclic amides to corresponding carboxylic acids. Benzoic acid, nicotinic acid and pyrazinoic acid are carboxylic acids which have wide industrial applications. The amidase of this strain is found to be inducible in nature. The biocatalytic conditions for amidase present in the whole cells of MTB5 were optimized against benzamide. The enzyme exhibited optimum activity in 50 mM potassium phosphate buffer pH 7.0. The optimum temperature and substrate concentrations for this enzyme were 50 °C and 50 mM, respectively. The enzyme was quite stable for more than 6 h at 30 °C. It showed substrate specificity against different amides, including aliphatic, aromatic and heterocyclic amides. Under optimized reaction conditions, the amidase is capable of converting 50 mM each of benzamide, nicotinamide and pyrazinamide to corresponding acids within 100, 160 and 120 min, respectively, using 5 mg dry cell mass (DCM) per mL of reaction mixture. The respective percent conversion of these amides was 95.02%, 98.00% and 98.44% achieved by whole cells. The amidase in whole cells can withstand as high as 383 mM concentration of product in a reaction mixture and above which it undergoes product feedback inhibition. The results of this study suggest that Rhodococcus sp. MTB5 amidase has the potential for large-scale production of carboxylic acids of industrial value.
- Ismailsab, Mukram,Monisha,Reddy, Pooja V.,Santoshkumar,Nayak, Anand S.,Karegoudar, Timmanagouda B.
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- Facile production of vitamin B3 and other heterocyclic carboxylic acids using an efficient Ag/ZnO/graphene-Si hybrid nanocatalyst
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Abstract: High yield of vitamin B3 is produced using Ag/ZnO/graphene nanocomposite (1?wt%) as a nanocatalyst after its activation by a silicon precursor such as trimethylsilyl chloride(TMSCl) or tert-butyldimethylsilyl chloride (TBSCl) under visible light. TBSCl has been proved as more efficient activating agent than TMSCl in the oxidation of heterocyclic alcohol derivatives to afford their corresponding carboxylic acids. 3-Pyridinemethanol was selected to be a model substrate to test the ability of Ag/ZnO/graphene-Si nanocatalysts. The oxidation reaction of alcohols was completed in short reaction time (30–60?min) at ambient condition to yield vitamin B3 and other heterocyclic carboxylic acids in excellent yields (86–99?%). A catalytic oxidation mechanism that is based on the generation of highly active catalytic oxidation species (oxygen radicals) has been proposed. The utility of this inexpensive and recyclable catalytic system without using molecular oxygen or any oxidants make this procedure interesting from a green chemistry point of view. Graphical Abstract: [Figure not available: see fulltext.]
- Attia, Yasser A.,Vázquez, Carlos Vázquez,Mohamed, Yasser M. A.
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p. 203 - 218
(2017/01/14)
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- Aerobic Oxidation of Diverse Primary Alcohols to Carboxylic Acids with a Heterogeneous Pd-Bi-Te/C (PBT/C) Catalyst
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Heterogeneous catalytic aerobic oxidation methods represent a near-ideal approach for the conversion of primary alcohols to carboxylic acids. Here, we report that a heterogeneous catalyst composed of Pd, Bi, and Te supported on activated carbon is highly effective for the oxidation of diverse benzylic and aliphatic primary alcohols, including 5-(hydroxymethyl)furfural (HMF) and substrates bearing heterocycles and other important functional groups. In many cases, the desired carboxylic acid product is obtained in >90% yield. Additionally, the catalyst has been demonstrated in a continuous-flow packed-bed reactor for the oxidation of benzyl alcohol, achieving near-quantitative yield while undergoing over 30 000 turnovers.
- Ahmed, Maaz S.,Mannel, David S.,Root, Thatcher W.,Stahl, Shannon S.
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supporting information
p. 1388 - 1393
(2017/09/22)
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- Copper(II) complexes of pyridine-oxazoline (Pyox) ligands: Coordination chemistry, ligand stability, and catalysis
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The coordination chemistry of copper(II) complexes bearing pyridine-oxazoline ("Pyox") ligands has been studied, with an aim of investigating their catalytic ability. Interestingly, the stability of the coordinated ligands has been shown to be much less than previously assumed: hydrolysis of the ligands by fortuitous water gives rise to 2-pyridine carboxylate formation, which encapsulate the copper in a two-dimensional coordination polymer 3. The complexes [Cu(R-Pyox)(NCMe)2(ClO4)2] {R = benzyl (Bn) 2a, phenyl (Ph) 2b, isopropyl (iPr) 2c} have been prepared, of which the benzyl derivative has been analysed by CW EPR spectroscopy. The complex [Cu(Bn-Pyox)(NCMe)2(ClO4)2] and the afore-mentioned coordination polymer have been crystallographically characterised. The performance of complexes 2a-c in the asymmetric allylic oxidation of cyclohexene is described.
- Hallett, Andrew J.,O'Brien, Thomas M.,Carter, Emma,Kariuki, Benson M.,Murphy, Damien M.,Ward, Benjamin D.
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- Laccase-catalysed biotransformation of collismycin derivatives. A novel enzymatic approach for the cleavage of oximes
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Analogues of the natural product collismycin bearing a carboxylic acid moiety has been efficiently synthesised from several collismycin precursors through a laccase-catalysed oxidation under mild conditions with TEMPO (2,2,6,6-tetramethylpiperidin-1-oxyl) as a mediator and aerial O2 as an oxidant in aqueous medium. The biotransformations proceeded with excellent yields (85-95%) and involved, depending on the precursor, the oxidation of a benzylic hydroxyl group or the bioconversion of an aldoxime group into carboxylic acid. Since the latter is herein reported for the first time, we explored the potential of this novel oxime cleavage with several synthetic aldo- and ketoximes. Thus, the laccase/TEMPO system proved to be an efficient and green alternative for the deprotection of both aromatic and aliphatic ketoximes into the corresponding ketones. On the other hand, the reaction with aldoximes leads to dimeric species generated by coupling reactions.
- González-Sabín, Javier,Ríos-Lombardía, Nicolás,García, Ignacio,Vior, Natalia M.,Bra?a, Alfredo F.,Méndez, Carmen,Salas, José A.,Morís, Francisco
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p. 989 - 994
(2016/02/27)
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- Electrocatalytic dechlorination of chloropicolinic acid mixtures by using palladium-modified metal cathodes in aqueous solutions
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In China, chloropicolinic acid (ClPA) mixtures comprising 3,5,6-trichloropicolinic acid, 3,6-dichloropicolinic acid (3,6-D), 3-ClPA, and 6-ClPA are discharged as organic wastes at a rate of approximately 300 tons per year. In this work, we developed an aqueous phase electrocatalytic hydrogenation (ECH) system based on Pd catalyst to dechlorinate the ClPA mixtures into picolinic acid (PA) at room temperature. Firstly, we evaluated the influence of cathode support and Pd loading on the catalytic performance of cathodes, as well as the effects of operating parameters on the intermediate product selectivity and dechlorination efficiency of the ECH process with 3,6-D as the target compound. Secondly, we analyzed the ECH dechlorination mechanism of 3,6-D with regard to the surface condition of cathode and catholyte pH, and the rate-limiting step of the dechlorination process was also discussed. Finally, we assessed the practicability of the ECH system to dechlorinate the ClPA mixtures into PA by using a plate-and-frame cell. Results demonstrated that Pd/Ni foam cathodes with Pd loading of 2.25-3.6 mg cm-2 exhibited the optimum ECH dechlorination performance, and the basic aqueous solution and high 3,6-D concentration favored the ECH process. The ClPA mixtures with 47 g L-1 concentration (the total concentration of ClPAs was approximately 250 mM) can be selectively dechlorinated into PA with 99% yield, 76.3% current efficiency, and 2.47 kW h kg-1 PA specific electric energy consumption at a current density of 208 A m-2 in a 1.25 M NaOH aqueous solution.
- Ma, Hongxing,Xu, Yinghua,Ding, Xufen,Liu, Qi,Ma, Chun-An
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p. 762 - 772
(2016/07/06)
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- One pot synthesis of α-ketoamides from ethylarenes and amines: a metal free difunctionalization strategy
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One-pot and metal free synthesis of α-ketoamides has been described through in situ generation of aryl ketones from easily available ethylarenes followed by amidation with various amines. This multiple oxidation protocol involves catalytic I2-pyridine-TBHP (t-butyl hydroperoxide) mediated oxidative benzylic carbonylation and sequential NaI-TBHP mediated oxidative amidation without using any solvent.
- Ramanathan, Mani,Kuo, Chun-Kai,Liu, Shiuh-Tzung
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p. 11446 - 11453
(2016/12/16)
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- Acceptorless dehydrogenation and aerobic oxidation of alcohols with a reusable binuclear rhodium(II) catalyst in water
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A water-soluble binuclear rhodium(ii) complex was found to be an efficient catalyst for both acceptorless dehydrogenation and aerobic oxidation of alcohols under air to produce carboxylic acids or ketones in water. The catalyst is highly efficient with substrate/catalyst ratios up to 5 × 103 being feasible, and could be recycled 19 times without significant loss of activity.
- Wang, Xuewei,Wang, Chao,Liu, Yuxuan,Xiao, Jianliang
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supporting information
p. 4605 - 4610
(2016/09/04)
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- A high-throughput screening method for determining the substrate scope of nitrilases
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Nitrile compounds are intermediates in the synthesis of pharmaceuticals such as atorvastatin. We have developed a chromogenic reagent to screen for nitrilase activity as an alternative to Nessler's reagent. It produces a semi-quantifiable blue colour and hydrolysis of 38 nitrile substrates by 23 nitrilases as cell-free extracts has been shown. This journal is
- Black, Gary W.,Brown, Nicola L.,Perry, Justin J. B.,Randall, P. David,Turnbull, Graeme,Zhang, Meng
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supporting information
p. 2660 - 2662
(2015/03/05)
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- Fused Selenazolinium Salt Derivatives with a Se-N+ Bond: Preparation and Properties
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Convenient methods for the preparation of stable, fused selenazolinium salt systems with a Se-N+ bond have been developed. The mechanism for the formation of the selenazole cycle was investigated in detail by conducting multinuclear NMR experiments. The ability of these compounds to form stable inner salts was demonstrated. We have shown the glutathione peroxidase (GPx) like properties of selenazolopyridinium salts by oxidizing sulfur-containing natural amino acids, as well as aromatic and heteroaromatic aldehydes. The molecular structures of most of the compounds were confirmed by X-ray diffraction studies.
- Arsenyan, Pavel,Vasiljeva, Jelena,Belyakov, Sergey,Liepinsh, Edvards,Petrova, Marina
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supporting information
p. 5842 - 5855
(2015/09/15)
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- Efficient and convenient oxidation of aldehydes and ketones to carboxylic acids and esters with H2O2 catalyzed by Co4HP2Mo15V3O62 in ionic liquid [TEBSA][BF4]
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A simple, efficient, and eco-friendly procedure for the oxidation of aldehydes and ketones to carboxylic acids and esters with H2O2 catalyzed by Co4HP2Mo15V3O62 in ionic liquid [TEBSA][BF4] has been developed. This atom-economical protocol affords the target products in good to high yields. The products can be separated by a simple extraction with organic solvent, and the catalytic system can be recycled and reused without loss of catalytic activity. Additionally, the possible mechanism of oxidation in the catalytic system is proposed. This journal is
- Hu, Yu-Lin,Li, De-Jiang,Li, Dong-Sheng
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p. 24936 - 24943
(2015/03/30)
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- Kinetic study on alkaline hydrolysis of Y-substituted phenyl picolinates: Effects of modification of nonleaving group from benzoyl to picolinyl on reactivity and reaction mechanism
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Second-order rate constants (kOH-) for alkaline hydrolysis of Y-substituted phenyl picolinates (6a-6i) have been measured spectrophotometrically. A linear Bronsted-type plot is obtained with βlg = -0.34, which is typical for reactions reported previously to proceed through a stepwise mechanism with formation of an addition intermediate being the rate-determining step (RDS). However, σYo constants result in a much poorer Hammett correlation than σY- constants. Furthermore, the Yukawa-Tsuno plot exhibits an excellent linear correlation with ρY = 0.82 and r = 0.72, indicating that a negative charge develops partially on the O atom of the leaving group in the RDS. Thus, the reactions have been concluded to proceed through a forced concerted mechanism with a highly unstable intermediate 7. Comparison of the current kinetic data with those reported previously for the corresponding reactions of Y-substituted phenyl benzoates has revealed that modification of the nonleaving group from benzoyl to picolinyl causes not only an increase in reactivity but also a change in the reaction mechanism (i.e., from a stepwise mechanism to a forced concerted pathway).
- Kim, Myung-Joo,Kim, Min-Young,Um, Ik-Hwan
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p. 1138 - 1142
(2015/07/15)
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- Reactivity of dinuclear copper(II) complexes with N -salicylidene glycine Schiff bases as carboxylesterase models
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Two phenoxo-bridged dinuclear copper(II) complexes (Cu2L1 2 , Cu2L2 2 ) with Nsalicylidene glycine Schiff bases were prepared and evaluated their performance for catalyzing the hydrolysis of p-nitrophenyl picolinate (PNPP)
- Xu, Bin,Jiang, Weidong,Liu, Fuan,Yu, Yongde,Dong, Juan
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p. 191 - 198
(2015/01/30)
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- Aerobic flow oxidation of alcohols in water catalyzed by platinum nanoparticles dispersed in an amphiphilic polymer
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We have developed a technique for the aqueous aerobic flow oxidation of alcohols in a continuous-flow reactor containing platinum nanoparticles dispersed on an amphiphilic polystyrene-poly(ethylene glycol) resin (ARP-Pt). Various primary and secondary alcohols including aliphatic, aromatic and heteroaromatic alcohols were efficiently oxidized within 73 seconds in a flowing aqueous system at 100-120°C under 40-70 bar of the system pressure to give the corresponding carboxylic acids and ketones, respectively, in up to 99% yield. Benzaldehydes could be also prepared selectively from benzyl alcohols by conducting the flow oxidation under the standard conditions in the presence of triethylamine. Moreover, a practical gram-scale synthesis of surfactants was realized in the aqueous aerobic continuous flow oxidation for 36-116 hours. This aerobic flow oxidation system provides a safe, clean, green, rapid and efficient practical method for oxidizing alcohols.
- Osako, Takao,Torii, Kaoru,Uozumi, Yasuhiro
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p. 2647 - 2654
(2015/02/05)
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- Co(ii), a catalyst for selective conversion of phenyl rings to carboxylic acid groups
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An inexpensive protocol for the conversion of -C6H4R into -COOH groups using Co(ii)-Oxone mixture as the catalytic system is described. A series of substrates containing substituted and non-substituted phenyl groups could be selectively converted into carboxylic acids. Initial mechanistic data have been provided.
- Sinha, Shashi Bhushan,Campos, Jess,Brudvig, Gary W.,Crabtree, Robert H.
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p. 49395 - 49399
(2014/12/10)
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- Laccase-Mediator System for Alcohol Oxidation to Carbonyls or Carboxylic Acids: Toward a Sustainable Synthesis of Profens
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By combining two green and efficient catalysts, such as the commercially available enzyme laccase from Trametes versicolor and the stable free radical 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO), the oxidation in water of some primary alcohols to the corresponding carboxylic acids or aldehydes and of selected secondary alcohols to ketones can be accomplished. The range of applicability of bio-oxidation is widened by applying the optimized protocol to the oxidation of enantiomerically pure 2-arylpropanols (profenols) into the corresponding 2-arylpropionic acids (profens), in high yields and with complete retention of configuration.
- Galletti, Paola,Pori, Matteo,Funiciello, Federica,Soldati, Roberto,Ballardini, Alberto,Giacomini, Daria
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p. 2684 - 2689
(2016/12/23)
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- Electrophilicity and nucleophilicity of commonly used aldehydes
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The present approach for determining the electrophilicity (E) and nucleophilicity (N) of aldehydes includes a kinetic study of KMNO4 oxidation and NaBH4 reduction of aldehydes. A transition state analysis of the KMNO4 promoted aldehyde oxidation reaction has been performed, which shows a very good correlation with experimental results. The validity of the experimental method has been tested using the experimental activation parameters of the two reactions. The utility of the present approach is further demonstrated by the theoretical versus experimental relationship, which provides easy access to E and N values for various aldehydes and offers an at-a-glance assessment of the chemical reactivity of aldehydes in various reactions. the Partner Organisations 2014.
- Pratihar, Sanjay
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p. 5781 - 5788
(2014/07/22)
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- Selective aerobic oxidation of alcohols to aldehydes, carboxylic acids, and imines catalyzed by a Ag-NHC complex
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Silver NHC catalysts have been developed for the selective oxidation of alcohols to aldehydes or carboxylic acids in the presence of BnMe3NOH or KOH under dry air. The aerobic oxidation conditions are mild, and the yield is excellent. Further tandem catalysis enables the one-pot synthesis of imines in excellent yield. Only 0.1 mol % of the catalyst is required.
- Han, Lei,Xing, Ping,Jiang, Biao
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supporting information
p. 3428 - 3431
(2014/07/21)
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- VO(acac)2: An efficient catalyst for the oxidation of aldehydes to the corresponding acids in the presence of aqueous H2O2
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VO(acac)2 catalyzes the oxidation of aldehydes (aromatic, aliphatic, and heterocyclic) to the corresponding acids efficiently and selectively in the presence of H2O2 as an oxidant. This method possesses functional-group compatibility, easy workup procedure, and shorter reaction time. The reaction is highly dependent on the solvent used. Performance of titania-supported VO(acac)2 in the oxidation of aldehyde was also investigated. Georg Thieme Verlag Stuttgart . New York.
- Talukdar, Dhrubajyoti,Sharma, Kiran,Bharadwaj, Saitanya K.,Thakur, Ashim Jyoti
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p. 963 - 966
(2013/06/27)
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- 1,2,3-Triazoles as versatile directing group for selective sp2 and sp3 C-H activation: Cyclization vs substitution
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Selective cyclization and substitution was achieved with designated 1,2,3-triazole acid auxiliary groups under Pd catalyzed C-H activation conditions. Both sp2 and sp3 C-H bonds were effectively activated, giving the desired products
- Ye, Xiaohan,He, Zhengrong,Ahmed, Tonia,Weise, Keith,Akhmedov, Novruz G.,Petersen, Jeffrey L.,Shi, Xiaodong
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p. 3712 - 3716
(2013/11/19)
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- Acid-induced degradation and ancillary ligand replacement of biscyclometalated iridium(III) complexes
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Three biscyclometalated iridium(III) complexes with three different ancillary ligands have been investigated with respect to the final products of acid-induced transformation in coordinating or non-coordinating solvents. All of these complexes, represented as [Ir(LC^N)2L O^O] and [Ir(LC^N)2LN^O], are susceptible to acid attack, followed by the departure of the ancillary ligand, LO^O or LN^O. Depending on the coordinating ability of the solvent molecule and whether or not a coordinating anion exists, the final product will be either a solvento complex or a dichloro-bridged iridium(III) dimer. Although coexistence of the solvento complex and dichloro-bridged iridium(III) dimer was observed under certain conditions, the conversion of the solvento complex into the dichloro-bridged iridium(III) dimer has been proven. Remaining solvent: Three biscyclometalated iridium(III) complexes with three different ancillary ligands are investigated with respect to the final products of acid-induced transformation in coordinating or non-coordinating solvents (see picture). Although coexistence of the solvento complex and dichloro-bridged iridium(III) dimer is observed under certain conditions, the conversion of the solvento complex into the dichloro-bridged iridium(III) dimer is seen. Copyright
- Zhou, Yuyang,Li, Wanfei,Liu, Yang,Zhou, Ming
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p. 413 - 418
(2013/07/19)
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- Effective palladium-catalyzed hydroxycarbonylation of aryl halides with substoichiometric carbon monoxide
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A protocol for the Pd-catalyzed hydroxycarbonylation of aryl iodides, bromides, and chlorides has been developed using only 1-5 mol % of CO, corresponding to a pCO as low as 0.1 bar. Potassium formate is the only stoichiometric reagent, acting as a mildly basic nucleophile and a reservoir of CO. The substoichiometric CO could be delivered to the reaction from an acyl-Pd(II) precatalyst, which provides both the CO and an active catalyst, and thereby obviates the need for handling a toxic gas.
- Korsager, Signe,Taaning, Rolf H.,Skrydstrup, Troels
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supporting information
p. 2891 - 2894
(2013/04/10)
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- Convenient and eco-friendly method for the conversion of benzylic alcohols into aldehydes, ketones, and carboxylic acids using NaOCl without any additives in 1,2-dimethoxyethane
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Oxidation of benzylic alcohols to aldehydes, ketones, and carboxylic acids using NaOCl in 1,2-dimethoxyethane without any additives has been developed. 4-Methylbenzyl alcohol and diphenyl methanol were converted into the corresponding aldehyde and ketone in 97% and 92% yield, respectively. Furthermore, 4-nitrobenzyl alcohol was directly converted into the corresponding carboxylic acid in 99% yield. Georg Thieme Verlag Stuttgart · New York.
- Fukuda, Naohiro,Kajiwara, Takeshi,Katou, Tomoaki,Majima, Keisuke,Ikemoto, Tomomi
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p. 1438 - 1442
(2013/07/26)
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