- Interaction of human arylamine n-acetyltransferase 1 with different nanomaterials
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Humans are exposed to nanoparticles in the environment as well as those in nanomaterials developed for biomedical applications. However, the safety and biologic effects of many nanoparticles remain to be elucidated. Over the past decade, our understanding of the interaction of proteins with various nanomaterials has grown. The protein corona can determine not only how nanoparticles interact with cells but also their biologic effects and toxicity. In this study, we describe the effects that several different classes of nanoparticles exert on the enzymatic activity of the cytosolic protein human arylamine N-acetyltransferase 1 (NAT1), a drug-metabolizing enzyme widely distributed in the body that is also responsible for the activation and detoxification of known carcinogens. We investigated three metal oxides (zinc oxide, titanium dioxide, and silicon dioxide), two synthetic clay nanoparticles (layered double hydroxide and layered silicate nanoparticles), and a self-assembling thermoresponsive polymeric nanoparticle that differ in size and surface characteristics. We found that the different nanoparticles induced very different responses, ranging from inhibition to marked enhancement of enzyme activity. The layered silicates did not directly inactivate NAT1, but was found to enhance substrate-dependent inhibition. These differing effects demonstrate the multiplicity of nanoparticle-protein interactions and suggest that enzyme activity may be compromised in organs exposed to nanoparticles, such as the lungs or reticulo-endothelial system. Copyright
- Deng, Zhou J.,Butcher, Neville J.,Mortimer, Gysell M.,Jia, Zhongfan,Monteiro, Michael J.,Martin, Darren J.,Minchin, Rodney F.
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- Metal-Free, Rapid, and Highly Chemoselective Reduction of Aromatic Nitro Compounds at Room Temperature
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In this study, we developed a metal-free and highly chemoselective method for the reduction of aromatic nitro compounds. This reduction was performed using tetrahydroxydiboron [B2(OH)4] as the reductant and 4,4′-bipyridine as the organocatalyst and could be completed within 5 min at room temperature. Under optimal conditions, nitroarenes with sensitive functional groups, such as vinyl, ethynyl, carbonyl, and halogen, were converted into the corresponding anilines with excellent selectivity while avoiding the undesirable reduction of the sensitive functional groups.
- Han, Min Su,Jang, Mingyeong,Lim, Taeho,Park, Byoung Yong
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p. 910 - 919
(2022/01/20)
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- Chemoselective reduction of nitroarenes, N-acetylation of arylamines, and one-pot reductive acetylation of nitroarenes using carbon-supported palladium catalytic system in water
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Developing and/or modifying fundamental chemical reactions using chemical industry-favorite heterogeneous recoverable catalytic systems in the water solvent is very important. In this paper, we developed convenient, green, and efficient approaches for the chemoselective reduction of nitroarenes, N-acetylation of arylamines, and one-pot reductive acetylation of nitroarenes in the presence of the recoverable heterogeneous carbon-supported palladium (Pd/C) catalytic system in water. The utilize of the simple, effective, and recoverable catalyst and also using of water as an entirely green solvent along with relatively short reaction times and good-to-excellent yields of the desired products are some of the noticeable features of the presented synthetic protocols. Graphic abstract: [Figure not available: see fulltext.].
- Zeynizadeh, Behzad,Mohammad Aminzadeh, Farkhondeh,Mousavi, Hossein
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p. 3289 - 3312
(2021/05/11)
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- Paracetamol and other acetanilide analogs as inter-molecular hydrogen bonding assisted diamagnetic CEST MRI contrast agents
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Paracetamol and a few other acetanilide derivatives are reported as a special class of diamagnetic Chemical Exchange Saturation Transfer (diaCEST) MRI contrast agents, that exhibit contrast only when the molecules form inter-molecular hydrogen bonding mediated molecular chains or sheets. Without the protection of the hydrogen bonding their contrast producing labile proton exchanges too quickly with the solvent to produce any appreciable contrast. Through a number of variable temperature experiments we demonstrate that under the conditions when the hydrogen bond network breaks and the high exchange returns back, the contrast drops quickly. The well-known analgesic drug paracetamol shows 12% contrast at a concentration of 15 mM at physiological conditions. With the proven safety track-record for human consumption and appreciable physiological contrast, paracetamol shows promise as a diaCEST agent forin vivostudies.
- Chakraborty, Subhayan,Peruncheralathan,Ghosh, Arindam
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p. 6526 - 6534
(2021/02/21)
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- Sequential Connection of Mutually Exclusive Catalytic Reactions by a Method Controlling the Presence of an MOF Catalyst: One-Pot Oxidation of Alcohols to Carboxylic Acids
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A functionalized metal-organic framework (MOF) catalyst applied to the sequential one-pot oxidation of alcohols to carboxylic acids controls the presence of a heterogeneous catalyst. The conversion of alcohols to aldehydes was acquired through aerobic oxidation using a well-known amino-oxy radical-functionalized MOF. In the same flask, a simple filtration of the radical MOF with mild heating of the solution completely altered the reaction media, providing radical scavenger-free conditions suitable for the autoxidation of the aldehydes formed in the first step to carboxylic acids. The mutually exclusive radical-catalyzed aerobic oxidation (the first step with MOF) and radical-inhibited autoxidation (the second step without MOF) are sequentially achieved in a one-pot manner. Overall, we demonstrate a powerful and efficient method for the sequential oxidation of alcohols to carboxylic acids by employing a readily functionalizable heterogeneous MOF. In addition, our MOF in-and-out method can be utilized in an environmentally friendly way for the oxidation of alcohols to carboxylic acids of industrial and economic value with broad functional group tolerance, including 2,5-furandicarboxylic acid and 1,4-benzenedicarboxylic acid, with good yield and reusability. Furthermore, MOF-TEMPO, as an antioxidative stabilizer, prevents the undesired oxidation of aldehydes, and the perfect "recoverability"of such a reactive MOF requires a re-evaluation of the advantages of MOFs from heterogeneity in catalytic and related applications.
- Kim, Seongwoo,Lee, Ha-Eun,Suh, Jong-Min,Lim, Mi Hee,Kim, Min
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supporting information
p. 17573 - 17582
(2020/12/22)
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- Synthetic method of 4-(5-nitrobenzo [d] oxazole-2-yl) aniline
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The invention discloses a synthetic method of 4-(5-nitrobenzo [d] oxazole-2-yl) aniline. The method comprises the following steps: mixing a substrate p-aminobenzoic acid with a reaction solvent; raising the temperature to a reaction temperature of 70-100 DEG C while stirring; dropping acetic anhydride after dissolution of the substrate, reacting for 0.5-1.5 hours after dropwise adding and then performing post-treatment of the reaction liquid to obtain p-acetaminobenzoic acid; mixing the p-acetaminobenzoic acid with 2-amino-4-nitrophenol and polyphosphoric acid, heating to 50-120 DEG C while stirring, carrying out a constant temperature reaction for 2-7 h and then performing post-treatment of the reaction liquid to obtain N-(4-(5-nitrobenzo [d] oxazole-2-yl) phenyl) acetamide; and mixing the N-(4-(5-nitrobenzo [d] oxazole-2-yl) phenyl) acetamide with the reaction solvent, heating to 80-110 DEG C while stirring and reacting for 3-5 h and then performing post-treatment of the reaction liquid to obtain the target product. The reaction process parameters are easy to control, the energy consumption is low, the yield is good, the purity is high and the industrial feasibility is high.
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Paragraph 0025-0029; 0044; 0045; 0048; 0049; 0052; 0053
(2020/05/01)
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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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- SO2F2-Activated Efficient Beckmann Rearrangement of Ketoximes for Accessing Amides and Lactams
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A novel, mild and practical protocol for the efficient activation of the Beckmann rearrangement utilizing the readily available and economical sulfuryl fluoride (SO2F2 gas) has been developed. The substrate scope of the operationally simple methodology has been demonstrated by 37 examples with good to nearly quantitative isolated yields (over 90 % yield in most cases) in a short time, including B(OH)2, COOH, NH2, and OH substituted substrates. A tentative mechanism was proposed involving formation and elimination of key intermediate, sulfonyl ester.
- Zhang, Guofu,Zhao, Yiyong,Xuan, Lidi,Ding, Chengrong
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supporting information
p. 4911 - 4915
(2019/07/31)
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- Ketoreductase catalyzed stereoselective bioreduction of α-nitro ketones
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We report here the stereoselective bioreduction of α-nitro ketones catalyzed by ketoreductases (KREDs) with publicly known sequences. YGL039w and RasADH/SyADH were able to reduce 23 class I substrates (1-aryl-2-nitro-1-ethanone (1)) and ten class II substrates (1-aryloxy-3-nitro-2-propanone (4)) to furnish both enantiomers of the corresponding β-nitro alcohols, with good-to-excellent conversions (up to >99%) and enantioselectivities (up to >99% ee) being achieved in most cases. To the best of our knowledge, KRED-mediated reduction of class II α-nitro ketones (1-aryloxy-3-nitro-2-propanone (4)) is unprecedented. Select β-nitro alcohols, including the synthetic intermediates of bioactive molecules (R)-tembamide, (S)-tembamide, (S)-moprolol, (S)-toliprolol and (S)-propanolol, were stereoselectively synthesized in preparative scale with 42% to 90% isolated yields, showcasing the practical potential of our developed system in organic synthesis. Finally, the advantage of using KREDs with known sequence was demonstrated by whole-cell catalysis, in which β-nitro alcohol (R)-2k, the key synthetic intermediate of hypoglycemic natural product (R)-tembamide, was produced in a space-time yield of 178 g L?1 d?1 as well as 95% ee by employing the whole cells of a recombinant E. coli strain coexpressing RasADH and glucose dehydrogenase as the biocatalyst.
- Wang, Zexu,Wu, Xiaofan,Li, Zhining,Huang, Zedu,Chen, Fener
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supporting information
p. 3575 - 3580
(2019/04/14)
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- Graphene oxide (GO) catalyzed transamidation of aliphatic amides: An efficient metal-free procedure
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Transamidation involves direct interconversion of an amide with amine, and represents an alternative to the common method of amide formation from the reaction of carboxylic acid with an amine. While the carboxamides have huge potential in biological systems and polymer industries, their formation from carboxylic acids requires activation by a suitable catalyst. A metal-free transamidation of aliphatic amide with aromatic amine catalyzed by graphene oxide (GO) has been developed and established as a general, synthetically useful and selective procedure. Graphene oxide bearing several carboxylic acids on the edges and having large surface area acts as an efficient and recyclable catalyst for transamidation.
- Bhattacharya, Suchandra,Ghosh, Pranab,Basu, Basudeb
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supporting information
p. 899 - 903
(2018/02/09)
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- An Efficient Aerobic Oxidation Protocol of Aldehydes to Carboxylic Acids in Water Catalyzed by an Inorganic-Ligand-Supported Copper Catalyst
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A method for the aerobic oxidation of aldehydes to carboxylic acids in water by using an inorganic-ligand-supported copper catalyst was developed. This method was performed with the use of atmospheric oxygen as the sole oxidant under extremely mild aqueous conditions, and furthermore, a wide range of aldehydes with various functional groups were tolerated. The copper catalyst could be recycled and used in successive reactions at least six times without any appreciable degradation in performance. This method is operationally simple and avoids the use of high-costing, toxic, air/moisture-sensitive, and commercially unavailable organic ligands. The generality of this method gives it potential to be used on the industrial scale.
- Yu, Han,Ru, Shi,Zhai, Yongyan,Dai, Guoyong,Han, Sheng,Wei, Yongge
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p. 1253 - 1257
(2018/02/16)
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- Visible-Light-Mediated Hydroxycarbonylation of Diazonium Salts
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A visible light-promoted catalytic photoredox hydroxycarbonylation was achieved on aryl diazonium salts whether preformed or generated in situ from the corresponding anilines. This strategy allows a straightforward access to a variety of carboxylic acids under mild conditions. (Figure presented.).
- Gosset, Cyrille,Pellegrini, Sylvain,Jooris, Romain,Bousquet, Till,Pelinski, Lydie
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p. 3401 - 3405
(2018/08/06)
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- Cytochrome P450 CYP199A4 from Rhodopseudomonas palustris Catalyzes Heteroatom Dealkylations, Sulfoxidation, and Amide and Cyclic Hemiacetal Formation
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The cytochrome P450 enzymes execute a range of selective oxidative biotransformations across many biological systems. The bacterial enzyme CYP199A4 catalyzes the oxidative demethylation of 4-methoxybenzoic acid. The benzoic acid moiety of the molecule binds in the active site of the enzyme such that the functional group at the para-position is held close to the heme iron. Therefore, CYP199A4 has the potential to catalyze alternative monooxygenase reactions with different para-substituted benzoic acid substrates such as thioethers and alkylamines. The oxidation of 4-methyl- and 4-ethyl-thiobenzoic acids by CYP199A4 resulted in sulfur oxidation. 4-Ethylthiobenzoic acid sulfoxidation and 4-ethylbenzoic acid hydroxylation by CYP199A4 occurred with high enantioselectivity (>74% enantiomeric excess). By way of contrast, CYP199A4 catalyzed exclusive oxidative N-demethylation over N-oxide formation with 4-methyl- and 4-dimethylaminobenzoic acids. Unexpectedly acetamide formation by CYP199A4 competes with dealkylation in the turnover of 4-ethyl- and diethyl-aminobenzoic acids. No oxidative dealkylation was observed with 3,4-ethylenedioxybenzoic with only hydroxylation to form a cyclic hemiacetal being detected. The X-ray crystal structures of four substrate-bound forms of the enzyme were solved and revealed subtle changes in the location of the para substituent which, when combined with the reactivity of the substituents, provided a basis for understanding the changes in selectivity. Furthermore, in the 4-ethylthiobenzoic acid-bound structure, the active site residue Phe298 moves to accommodate the substituent which points away from the heme iron. As such, the CYP199A4 enzyme provides ready access to a combination of structural, binding, and activity data with which to study a variety of reactions which are catalyzed by the P450 superfamily of enzymes.
- Coleman, Tom,Wong, Siew Hoon,Podgorski, Matthew N.,Bruning, John B.,De Voss, James J.,Bell, Stephen G.
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p. 5915 - 5927
(2018/05/29)
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- Benzoic acid derivatives with trypanocidal activity: Enzymatic analysis and molecular docking studies toward trans-sialidase
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Chagas, or American trypanosomiasis, remains an important public health problem in developing countries. In the last decade, trans-sialidase has become a pharmacological target for new anti-Chagas drugs. In this work, the aims were to design and find a new series of benzoic acid derivatives as trans-sialidase (TS) inhibitors and anti-trypanosomal agents. Three compounds (14, 18, and 19) sharing a para-aminobenzoic acid moiety showed more potent trypanocidal activity than the commercially available drugs nifurtimox and benznidazole in both strains: the lysis concentration of 50% of the population (LC50) was 0.15 μM on the NINOA strain, and LC50 0.22 μM on the INC-5 strain. Additionally, compound 18 showed a moderate inhibition (47%) on the trans-sialidase enzyme and a binding model similar to DANA (pattern A).
- Kashif, Muhammad,Moreno-Herrera, Antonio,Villalobos-Rocha, Juan Carlos,Nogueda-Torres, Benjamín,Pérez-Villanueva, Jaime,Rodríguez-Villar, Karen,Medina-Franco, José Luis,De Andrade, Peterson,Carvalho, Ivone,Rivera, Gildardo
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- Harnessing the Reactivity of Iridium Hydrides by Air: Iridium-Catalyzed Oxidation of Aldehydes to Acids in Water
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An iridium-catalyzed oxidation of aldehydes to acids was realized by using air as the oxidant and water as the solvent in the presence of base. Interestingly, the same type of catalysts were also used for the reduction of aldehydes under acidic conditions. A common iridium hydride intermediate is proposed for both redox reactions. The oxidation has a number of advantages such as high yields, great functionality tolerance, and easy purification without chromatography.
- Yang, Zhanhui,Luo, Renshi,Zhu, Zhongpeng,Yang, Xuerong,Tang, Weiping
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supporting information
p. 4095 - 4098
(2017/11/21)
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- Method for synthesizing p-acetamidobenzoic acid as organic synthesis intermediate
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The invention provides a method for synthesizing p-acetamidobenzoic acid as an organic synthesis intermediate. The method comprises following steps: 5 mol of para aminobenzoic acid is dissolved in a 1.5-1.8 L of a formic acid solution, the stirring speed is controlled to be 130-150 rpm, 6-6.5 mol of acetic formic anhydride is added, the temperature of the solution is increased to 50-55 DEG C, the solution is stirred continuously for 70-90 min and is subjected to reduced-pressure distillation for 50-70 min, 2-3 L of a potassium chloride solution is added to the residual solution, the temperature of the mixed solution is reduced to 10-15 DEG C, crystals are separated, filtered, washed with a sodium bromide solution, recrystallized in a diethyl ether solution and dehydrated with a dehydrating agent, and a p-acetamidobenzoic acid product is obtained finally, wherein the mass fraction of the formic acid solution is 80%-85%, the pressure of the reduced-pressure distillation is 50-60 kPa, and the mass fraction of the potassium chloride solution is 15%-20%.
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Paragraph 0006; 0010-0015
(2017/08/29)
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- A Flexible Polyphosphate-Driven Regeneration System for Coenzyme A Dependent Catalysis
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Coenzyme A (CoA) is a common cofactor in biochemical reactions, and CoA-dependent enzymes catalyze essential steps in anabolism and catabolism. This complex molecule also plays an important role in the synthesis of many high-value products, such as synthetic antibiotics, vitamins, pheromones, and biopolymers. Nevertheless, the synthetic potential for biocatalytic processes cannot be fully exploited owing to the lack of an efficient regeneration system. Here, we report an acyl-CoA regeneration system with integrated adenosine triphosphate (ATP) regeneration that is based on inexpensive polyphosphate as the single energy source. In the four-enzyme cascade, two cofactors, acyl-CoA and ATP, are each regenerated up to 2000 times. The applicability for different acyl donors and acceptors is shown by HPLC analysis. Owing to its flexibility toward virtually all relevant substrates, the system has the potential to make CoA-dependent reactions more accessible for chemical synthesis in vitro.
- Mordhorst, Silja,Maurer, Alice,Popadi?, Désirée,Brech, Johanna,Andexer, Jennifer N.
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p. 4164 - 4168
(2017/10/23)
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- Palladium-catalyzed oxidative coupling of arylboronic acid with isocyanide to form aromatic carboxylic acids
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A valuable palladium-catalyzed oxidative coupling of aryl- and alkenyl borides with isocyanide for the synthesis of corresponding carboxylic acids has been developed. With wide substrate scopes and good functional group tolerance, this reaction offers corresponding carboxylic acids in moderate to excellent yields.
- Chen, Zhen-Bang,Liu, Kui,Zhang, Fang-Ling,Yuan, Qing,Zhu, Yong-Ming
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p. 8078 - 8083
(2017/10/10)
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- Efficient Heterogeneous Gold(I)-Catalyzed Direct C(sp2)–C(sp) Bond Functionalization of Arylalkynes through a Nitrogenation Process to Amides
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The first heterogeneous gold(I)-catalyzed direct C(sp2)–C(sp) bond functionalization of arylalkynes through a nitrogenation process to amides has been achieved by using an ordered mesoporous silica (MCM-41)-immobilized phosphine gold(I) complex [MCM-41-PPh3-AuCl] as catalyst and silver carbonate (Ag2CO3) as cocatalyst with trimethylsilyl azide (TMSN3) as a nitrogen source, yielding a variety of amides in moderate to excellent yields under mild conditions. This heterogeneous phosphine gold(I) complex shows the same turnover numbers as the homogeneous chloro(triphenylphosphine)gold(I) (Ph3PAuCl) and can easily be recovered by simple filtration of the reaction solution and recycled at least eight times without significant loss of activity, providing a novel, efficient, practical and economic method for the synthesis of amides from alkynes. (Figure presented.).
- Nie, Quan,Yi, Feiyan,Huang, Bin,Cai, Mingzhong
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p. 3968 - 3976
(2017/11/20)
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- Catalytic Fehling's Reaction: An Efficient Aerobic Oxidation of Aldehyde Catalyzed by Copper in Water
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The first example of homogeneous copper-catalyzed aerobic oxidation of aldehydes is reported. This method utilizes atmospheric oxygen as the sole oxidant, proceeds under extremely mild aqueous conditions, and covers a wide range of various functionalized aldehydes. Chromatography is generally not necessary for product purification.
- Liu, Mingxin,Li, Chao-Jun
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supporting information
p. 10806 - 10810
(2016/09/03)
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- INDUCTION OF GATA2 BY HDAC1 AND HDAC2 INHIBITORS
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Provided herein are compounds, pharmaceutical compositions comprising such compounds, and methods of using such compounds to treat diseases or disorders associated with Gata2 deficiency, particularly diseases or disorders that involve any type of HDAC1 and/or HDAC2 expression. Such diseases include acute myeloid leukemia (AML); familial myelodysplastic syndrome (MDS); leukemia; sickle-cell anemia; beta-thalassemia; monocytopenia and mycobacterial infections; dendritic cell, nonocyte, B, and natural killer lymphoid deficiency; Emberger syndrome; asymptomatic neurocognitive impairment; mild neurocognitive disorder; and HIV- associated dementia.
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Page/Page column 80
(2016/05/02)
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- Copper(I)-Catalyzed Desulfinative Carboxylation of Sodium Sulfinates using Carbon Dioxide
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A copper(I)-catalyzed desulfinative carboxylation of sodium sulfinates using carbon dioxide has been developed. This reaction showed wide functional group tolerance. A series of sodium aryl- and alkenylsulfinates could be converted into the corresponding carboxylic acids in good to excellent yields. Additionally, the reaction mechanism was studied by in situ NMR analysis and isotopic labeling experiments.
- Sun, Song,Yu, Jin-Tao,Jiang, Yan,Cheng, Jiang
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supporting information
p. 2022 - 2026
(2015/06/23)
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- Substituent effects on energetics of peptide-carboxylate hydrogen bonds as studied by 1H NMR spectroscopy: Implications for enzyme catalysis
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Substituent effects in N-H···O hydrogen bonds were estimated by comparing the acidities of two series of model compounds: N-benzoylanthranilic acids (A) and 4-benzoylamidobenzoic acids (B). Intramolecular N-H···O hydrogen bonds were found to be present in the A series of compounds, while B acids were used as control models. The respective pKa values for A and B acids were determined experimentally in DMSO solution using proton NMR spectroscopy. With X = H, the pKa for A and B acids were observed to be 7.6 and 11.6, respectively, a difference of 4.0 units (ΔpKa). However, with X = p-NO 2, the ΔpKa value between A and B acids increased to 4.7 units: the pKa values for A and B acids were determined as 6.7 and 11.4, respectively. The ΔpKa values between A and B acids as a function of the X substituents were studied in 10 other examples. The effects of X substituents in A acids could be predicted on the basis of the observed linear Hammett correlations, and the sensitivity of each substituent effect was found to be comparable to those observed for the ionization of substituted benzoic acids (ρ = 1.04 for A acids, and ρ = 1.00 for benzoic acids).
- Emenike, Bright U.,Liu, Albert Tianxiang,Naveo, Elsy P.,Roberts, John D.
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p. 11765 - 11771
(2014/01/06)
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- Recyclable, highly efficient and low cost nano-MgO for amide synthesis under SFRC: A convenient and greener 'NOSE' approach
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A clean synthesis of amide derivatives has successfully been accomplished utilizing reusable nano-MgO under 'SFRC' (solvent free reaction condition). The 'green-ness' of this protocol makes it a benign alternative for the large scale synthesis.
- Das, Vijay Kumar,Devi, Rashmi Rekha,Thakur, Ashim Jyoti
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p. 118 - 125
(2013/06/26)
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- Selective Csp2-Csp bond cleavage: The nitrogenation of alkynes to amides
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Breakthrough: A novel catalyzed direct highly selective C sp 2-C sp bond functionalization of alkynes to amides has been developed. Nitrogenation is achieved by the highly selective C sp 2-Csp bond cleavage of aryl-substituted alkynes. The oxidant-free and mild conditions and wide substrate scope make this method very practical. Copyright
- Qin, Chong,Feng, Peng,Ou, Yang,Shen, Tao,Wang, Teng,Jiao, Ning
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supporting information
p. 7850 - 7854
(2013/08/23)
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- Thioacids mediated selective and mild N-acylation of amines
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N-Acylated amines are ubiquitous in nature. Selective N-acylation at neutral conditions remains a key area of interest. Here we are reporting the copper sulfate-mediated highly selective, mild, and rapid N-acylation of various aliphatic and aromatic amines using thioacids in methanol at neutral conditions. All N-acylated products of primary and secondary amines were isolated in good to excellent yields. This method is found to be highly selective for the amines and not sensitive to other functional groups such as phenols, alcohols, and thiols. The simple workup, high yields, and high selectivity of this reaction can be an attractive alternative to those of the existing acyl halide- and acid anhydride-mediated N-acylation reactions.
- Mali, Sachitanand M.,Bhaisare, Rupal D.,Gopi, Hosahudya N.
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p. 5550 - 5555
(2013/07/25)
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- Solvent free, highly chemoselective N and O-acylation on silica and silica magnesium oxide: A recyclable solid surface
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Silica or silica/magnesium oxide mixed surface mediates the N and O-acylation, benzoylation or sulfonylation of hosts of substrates under solvent free conditions at ambient temperature with high chemoselectivity.
- Ghosh, Pranab,Mandal, Amitava
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p. 261 - 268
(2012/10/29)
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- Nano rod-shaped and reusable basic Al2O3 catalyst for N-formylation of amines under solvent-free conditions: A novel, practical and convenient 'NOSE' approach
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An expeditious, simple, highly efficient, practical and green protocol for the N-formylation of alkyl/aryl amines and indole derivatives catalyzed by novel nano rod-shaped basic Al2O3 under solvent-free conditions has been developed. The catalyst is efficiently recycled up to the 5th run, an important point in the domain of green chemistry. The methodology provides cleaner conversion, shorter reaction times and high selectivity which makes the protocol attractive. The Royal Society of Chemistry 2012.
- Das, Vijay Kumar,Devi, Rashmi Rekha,Raul, Prasanta Kumar,Thakur, Ashim Jyoti
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supporting information; experimental part
p. 847 - 854
(2012/04/23)
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- Kinetics and mechanism of the oxidation of substituted benzaldehydes with bis(pyridine)silver permanganate
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The oxidation of thirty-six ortho-, meta- and para-substituted benzaldehydes by bis(pyridine)silver permanganate (BPSP) resulted in the formation of the corresponding benzoic acids. The reaction is first order with respect to both BPSP and aldehydes. The reaction is catalyzed by hydrogen ions. The rate of reaction increases with an increase in the amount of acetic acid in the solvent. The correlation analyses of the rate of oxidation of thirty-six aldehydes were performed in terms of Charton's LDR and LDRS equations. The rate of oxidation of meta- and para-substituted benzaldehydes showed excellent correlation with Charton's LDR equation. The rates of ortho-compounds showed excellent correlation with LDRS equation. The oxidation para-compounds is more susceptible to the delocalization effect. The oxidation of ortho- and meta-compounds exhibited a greater dependence on the field effect. The polar reaction constants are negative indicating an electron-deficient centre in the rate-determining step. A mechanism involving a nucleophilic attack on the carbonyl group by a permanganate-oxygen and a subsequent hydride transfer has been proposed.
- Purohit, Trupti,Banerji, Jayshree,Kotai, Laszlo,Sajo,Banerji,Sharma, Pradeep K.
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p. 1045 - 1052
(2013/01/14)
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- Synthesis and evaluation of a photochromic surfactant for organic reactions in aqueous media
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A novel photochromic azobenzene-based surfactant was described for organic chemistry in water. The molecule 4-butylazobenzyl-4′-triazologlucuronic acid sodium salt thus synthesized can be isomerized from its trans to its cis form reversibly in solution by simple light irradiation. That property allowed the recyclability of a model acetylation reaction performed in the surfactant media, compared to the well-known, commercially available sodium dodecyl sulfate surfactant media.
- Drillaud, Nicolas,Banaszak-Léonard, Estelle,Pezron, Isabelle,Len, Christophe
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p. 9553 - 9561
(2013/01/15)
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- Structure-Reactivity correlation in the oxidation of substituted benzaldehydes by tetraethylammonium chlorochromate
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Oxidation of 36 monosubstituted benzaldehydes by tetraethylammonium chlorochromate in dimethyl sulphoxide, leads to the formation of corresponding benzoic acids. The reaction is of first order with respect to chlorochromate and aldehydes. The reaction is promoted by H+; the H+ dependence has the form kobs = a + b[H+]. The oxidation of duteriated benzaldehyde exhibits substantial primary kinetic isotope effect. The reaction was studied in 19 different organic solvents and the effect of solvent was analyzed using Taft's and Swain's multiparametric equations. The rates of the oxidation of para- and meta-substituted benzaldehydes showed excellent correlation in terms of Charton's triparametric LDR equation, whereas the oxidation of ortho-substituted benzaldehydes were correlated well with tetraperametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalized effect than is the oxidation of ortho- and meta- substituted compounds, which display a greater dependence on the field effect. The positive value of h suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the orthosubstituents. A suitable mechanism has been proposed.
- Gehlot,Prasadrao,Sharma
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experimental part
p. 1173 - 1178
(2012/01/05)
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- Synthesis and biological evaluation of Matijing-Su derivatives as potent anti-HBV agents
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A series of Matijing-Su (MTS, N-(N-benzoyl-l-phenylalanyl)-O-acetyl-l- phenylalanol) derivatives were synthesized and evaluated for their anti-hepatitis B virus (HBV) activity in 2.2.15 cells. The IC50 of compounds 14a (0.71 μM), 13c (2.85 μM), 13b (4.37 μM), etc. and the selective index of 13g (161.01), 13c (90.45), 13a (85.09) etc. of the inhibition on the replication of HBV DNA were better than those of the positive control lamivudine (IC50: 82.42 μM, SI: 41.59). Compounds 13o, 13p, and 16a also exhibited significant anti-HBV activity.
- Qiu, Jingying,Xu, Bixue,Huang, Zhengming,Pan, Weidong,Cao, Peixue,Liu, Changxiao,Hao, Xiaojiang,Song, Baoan,Liang, Guangyi
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experimental part
p. 5352 - 5360
(2011/10/12)
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- "Meta elimination," a diagnostic fragmentation in mass spectrometry
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The diagnostic value of the "ortho effect" for unknown identification by mass spectrometry is well known. Here, we report the existence of a novel "meta effect," which adds to the repertoire of useful mass spectrometric fragmentation mechanisms. For example, the meta-specific elimination pathway described in this report enables unequivocal identification of meta isomers from ortho and para isomers of carboxyanilides. The reaction follows a specific path to eliminate a molecule of meta-benzyne, from the anion produced after the initial decarboxylation of the precursor. Consequently, in the CID spectra of carboxyanilides, a peak for the (R-CO-NH)- anion is observed only for the meta isomers. For example, the peaks observed at m/z 58, 86, 120, 128, and 170 from acetamido-, butamido-, benzamido, heptamido-, and decanamido-benzoates, respectively, were specific only to the spectra of meta isomers.
- Attygalle, Athula B.,Nishshanka, Upul,Weisbecker, Carl S.
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experimental part
p. 1515 - 1525
(2012/05/05)
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- Direct hydrogenation of nitroaromatics and one-pot amidation with carboxylic acids over platinum nanowires
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A novel ultrathin platinum nanowire with uniform length and a diameter of 1.5 nm was synthesized by acidic etching of FePt nanowire in methanol. This nanowire was characterized by high-resolution transmission electron microscopy (HRTEM). X-ray diffraction (XRD) data indicated that the main plane is (111). The ability of this nanowire to catalyze the heterogeneous hydrogenation of nitroaromatics to give the corresponding amines has been investigated. The catalyst showed satisfactory activity in various solvents under mild conditions and showed excellent stability. The catalytic performance was also evaluated in the one-pot reduction of nitroaromatics and amidation with carboxylic acids under a hydrogen atmosphere at 100°C. These methods for the hydrogenation of nitroaromatics and the direct amidation of nitroaromatics with carboxylic acids are simple, economical, and environmentally benign, and have practical advantages for the synthesis of amines and amides without the production of toxic byproducts.
- Li, Min,Hu, Lei,Cao, Xueqin,Hong, Haiyan,Lu, Jianmei,Gu, Hongwei
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supporting information; experimental part
p. 2763 - 2768
(2011/04/12)
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- Kinetics and products of the catalytic oxidation of acetamidotoluenes with ozone in acetic acid
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The kinetics of acetamidotoluene oxidation in glacial acetic acid in the presence of cobalt acetate is reported. At 95°C and atmospheric pressure, acetamidotoluenes are oxidized by molecular oxygen very slowly: oxidation is complete in 10-12 h, and the major reaction products are acetamidobenzoic acids (27-36% yield). The introduction of ozone into the reactive gas increases the reaction rate by one order of magnitude. The main role of ozone is to generate the active form of the catalyst.
- Galstyan,Bushuev,Sementsov
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experimental part
p. 516 - 520
(2011/01/07)
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- A green approach to chemoselective N-acetylation of amines using catalytic amount of zinc acetate in acetic acid under microwave irradiation
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It has been found for the first time that zinc acetate alone can act as a selective A'-acetylating agent without any solvent under closed vessel microwave irradiation. It is also observed that the use of a catalytic amount of this reagent in acetic acid is sufficient enough for smooth running of A'-acetylation of a number of structurally diverse amines, and the reaction is chemoselective with respect to phenols, thiols, acids and alcohols. Herein is reported a simple, efficient, cost-effective and environmentally benign alternative method for chemoselective A'-acetylation of amines using catalytic amount of zinc acetate in acetic acid under microwave irradiation. The reaction procedure requires no other solvent, and is rapid with good to excellent yields.
- Brahmachari,Laskar,Sarkar
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experimental part
p. 1274 - 1281
(2010/12/24)
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- Metal acetate/metal oxide in acetic acid: An efficient reagent for the chemoselective N-acetylation of amines under green conditions
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The use of catalytic amount of metal acetate or metal oxide in acetic acid is a new and highly efficient acetylating system for chemoselective N-acetylation of primary and secondary amines in excellent yields under reflux condition. No other solvent is required. The noted features of this method include mild reaction conditions, use of innocuous reagents, excellent yields, convenient work-up, and reuse of catalyst.
- Brahmachari, Goutam,Laskar, Sujay,Sarkar, Sajal
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experimental part
p. 288 - 295
(2010/10/18)
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- Study on the structure-activity relations of pleuromutilin derivatives with an aromatic amide and a thioether group in the C14 side chain
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Nine novel pleuromutilin derivatives having benzamide substituents have been synthesised permitting structureactivity relations of pleuromutilin derivatives with aromatic amide and thioether groups in the C14 side chain to be studied. The results showed that the heterocyclic carboxamide group was necessary to enhance bio-activities.
- Xu, Ke-Ping,Zhang, Yuan-Yuan,Luo, Juan,Chen, Shan-Li,Wang, Yu-Liang
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experimental part
p. 354 - 357
(2010/10/21)
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- Quantitation of folates and their catabolites in blood plasma, erythrocytes, and urine by stable isotope dilution assays
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New stable isotope dilution assays were developed for the simultaneous quantitation of the folates 5-methyltetrahydrofolic acid, 5-formyltetrahydrofolic acid, tetrahydrofolic acid, 10-formylfolic acid, and folic acid as well as for their catabolites para-aminobenzoylglutamate (pABG) and acetyl-para-aminobenzoylglutamate (ApABG) in clinical samples. The methods were based on cleanup by strong anion exchange followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) detection. Deuterated analogues of the folates and [13C5]-labeled isotopologues of the catabolites were applied as the internal standards in stable isotope dilution assays. Extraction in 4-morpholineethanesulfonic acid (MES) buffer at pH 5.0 ensured the optimum stability of folates and, in combination with solid-phase extraction (SPE) based on strong anion exchange, resulted in higher recoveries compared with other combinations of extraction buffers and SPE. The method was sensitive enough to detect pABG in plasma generally and unmetabolized folic acid in the plasma of a volunteer after oral dosage of an aqueous folic acid solution. The sum of folate catabolites increased by a factor of 2 in the urine of the latter volunteer, compared with that resulting when only water was dosed.
- Moench, Sabine,Netzel, Michael,Netzel, Gabriele,Rychlik, Michael
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scheme or table
p. 150 - 160
(2011/12/02)
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- Facile and chemoselective cleavage of allyl carboxylic ester utilizing NaBH4 in DMSO
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A new method for deprotection of allyl carboxylic ester has been observed by using the inexpensive reagent sodium borohydride in dimethyl sulfoxide (DMSO). Aliphatic and aromatic allyl carboxylic ester undergo deprotection smoothly. The allyl ester group can selectively deprotect better than phenol.
- Pawar, Bharati V.,Lokhande, Pradeep D.
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experimental part
p. 2445 - 2453
(2009/12/06)
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- Correlation analysis of reactivity in the oxidation of substituted benzaldehydes by morpholinium chlorochromate
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Oxidation of thirty six monosubstituted benzaldehydes by morpholinium chlorochromate (MCC) in dimethylsulphoxide (DMSO), leads to the formation of corresponding benzoic acids. The reaction is of first order with respect to MCC. A Michaelis-Menten type kinetics is observed with respect to benzaldehydes. The reaction is promoted by hydrogen ions; the hydrogen-ion dependence has the form kobs = a + b [H+]. The oxidation of [2H] benzaidehyde (PhCDO) exhibited a substantial primary kinetic isotope effect. The reaction was studied in nineteen organic solvents and the effect of solvent was analysed using Taft's and Swain's multi-parametric equations. The rates of the oxidation of para- and meta-substituted benzaldehydes showed excellent correlation in terms of Charton's triparametric LDR equation, whereas the oxidation of ortho-substituted benzaldehydes were correlated well with tetraparametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalized effect than is the oxidation of ortho- and meta-substituted compounds, which display a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the ortho-substituents. A suitable mechanism has been proposed.
- Choudhary, Anurag,Malani,Agarwal,Sharma,Sharma, Vinita
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experimental part
p. 927 - 935
(2010/07/16)
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- Study of 4-acetylaminotoluene ozonation in acetic acid
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The reaction of 4-aminotoluene with ozone in acetic acid was studied. It was found that the reaction proceeds at a high rate, giving predominantly tars. The product composition changes after acylation of the amino group: aliphatic peroxides prevailed among the oxidation products and 4-acetylaminobenzoic acid was identified (16%) as well. It was shown that the presence of a catalyst (cobalt(II) acetate) had no substantial effect on the oxidation selectivity for the methyl group (32%) and only the addition of potassium bromide increased the activity of the catalyst; the yield of 4-acetylaminobenzoic acid reached 70%. The mechanism of oxidation in the presence of a cobalt-bromide catalyst explaining the obtained results was discussed.
- Galstyan,Bushuev,Shumilova
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scheme or table
p. 397 - 400
(2010/06/19)
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- Chemoselective acylation of amines, thiols and phenols using 2,4,6-triacyloxy-1,3,5-triazine (TAT) as a new and effective reagent under mild condition
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A facile chemoselective acylation of amines, thiols and phenols using 2,4,6-triacyloxy-1,3,5-triazine (TAT) under mild condition is described. New reagent, high product yield, short reaction time, ease of operation and solvent free reaction condition is the most acceptable feature of the present method.
- Gholap, Somnath S.,Tambe, Ganesh B.,Gill, Charansingh H.
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experimental part
p. 179 - 182
(2010/04/05)
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- Electrochemical nuclear acetamidation of aromatic compounds at the platinum anode
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The electrochemical nuclear acetamidation of aromatic compounds ethylbenzoate, acetophenone, benzoic acid and benzene have been carried out at platinum anode under the process of nuclear oxidation. The removal of electrons from the aromatic π-electron system is achieved by the electrochemical oxidation. The electrolysis is carried out at the constant anode potential in an electrolytic cell assembly containing reaction mixture and electrodes. The products 4-acetamidoethylbenzoate, 4-acetamidoacetophenone, 4-acetamidobenzoic acid and N-phenylacetamide formed during the electrolysis are reported here.
- Sharma, Laxmi Kant,Kumar, Sanjeev,Yadav, Pragati,Singh
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p. 1277 - 1280
(2008/12/23)
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- Microwave-assisted synthesis of amide under solvent-free conditions
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An efficient and environmentally friendly synthetic method for the synthesis of primary amides under microwave irradiation was described, in which the primary amine was directly reacted with acid without any catalytic agents. The reaction took place in 8-12-min, which was much shorter than the traditional synthetic methods, with almost quantitative yields. The influential factor of the reaction was discussed. The tautomerization between the carboxylic acid group and the H atom in α-carbon of L-amino acid was observed, presumably a dehydrated intermediate forming from this tautomerized isomer. Copyright Taylor & Francis Group, LLC.
- Wang, Xiao-Jian,Yang, Qian,Liu, Fei,You, Qi-Dong
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p. 1028 - 1035
(2008/09/18)
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- New, efficient, selective, and one-pot method for acylation of amines
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Hydrazine hydrate with acetic and propionic acids was an efficient reagent for acylation of primary and secondary amines at reflux temperatures. The reported one-pot method is high-yielding, simple, mild, and inexpensive. Copyright Taylor & Francis Group, LLC.
- Basanagouda, Mahantesha,Kulkarni, Manohar V.,Kalkhambkar, Raj G.,Kulkarni, Geeta M.
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p. 2929 - 2940
(2008/12/22)
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- Structure-reactivity correlation in the oxidation of substituted benzaldehydes by 2,2-bipyridinium chlorochromate
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Oxidation of thirty six monosubstituted benzaldchydes by 2,2′-bipyridiniuin chlorochromate (BPCC) in diniethylsulphoxide (DMSO), leads to the formation of corresponding benzoic acids. The reaction is of first order with respect to both BPCC and aldehydes. The reaction is promoted by hydrogen ions; the hydrogen ion dependence has the form kobs= a + b[H+]. The oxidation of [2H]benzaldehyde (PhCDO) exhibited a substantial primary kinetic isotope effect. The reaction was studied in nineteen different organic solvents and the effect of solvent was analysed using Taft's and Swain's multi-parametric equations. The rates of the oxidation of para- and mete-substituted benzaldehydes showed excellent correlation in terms of Charton's triparametric LDR equation, whereas the oxidation of orfAo-substituted benzaldehydes were correlated well with tetraparametric LDRS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalized effect than is the oxidation of ortho- and mem-substituted compounds, which display a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction centre in the rate-determining step. The reaction is subjected to steric acceleration by the ortho-substituents. A suitable mechanism has been proposed.
- Sharma, Pradeep K.
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experimental part
p. 1281 - 1288
(2009/12/31)
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- Oxidation of 4-aminotoluene with ozone in acetic acid solution
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The possibility of preparing 4-aminobenzoic acid by oxidation of 4-aminotoluene with ozone in acetic acid in the presence of cobalt(II) acetate and potassium bromide was examined. The optimal oxidation conditions were found.
- Galstyan,Bushuev,Solomyannyi
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p. 1198 - 1201
(2008/12/23)
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- Kinetics and mechanism of the oxidation of substituted benzaldehydes by tetrabutylammonium tribromide
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The oxidation of thirty-six monosubstituted benzaldehydes by tetrabutylammonium tribromide (TBATB), in aqueous acetic acid solution, leads to the formation of the corresponding benzoic acids. The reaction is first order with respect to both TBATB and aldehydes. The reaction failed to induce the polymerization of acrylonitrile. There is no effect of tetrabutylammonium chloride ions on the reaction rate. The oxidation of [2H]benzaldehyde (PhCDO) indicated the presence of a substantial kinetic isotope effect. The effect of solvent composition indicated that the reaction rate increases with an increase in the polarity of the medium. The rates of oxidation of meta- and para-substituted benzaldehydes showed excellent correlations in terms of Charton's triparametric LDR equation whereas the oxidation of ortho-substituted benzaldehydes correlated well with tetraparametric LDS equation. The oxidation of para-substituted benzaldehydes is more susceptible to the delocalization effect but the oxidation of ortho- and meta-substituted compounds displayed a greater dependence on the field effect. The positive value of η suggests the presence of an electron-deficient reaction center in the rate-determining step. The reaction is subjected to steric acceleration when ortho-substituents are present.
- Chouhan,Sharma, Monica,Sharma, Vinita
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p. 582 - 587
(2008/09/21)
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