- Quantitation of the hydroxyl radical adducts of salicylic acid by micellar electrokinetic capillary chromatography: Oxidizing species formed by a Fenton reaction
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There has been controversy concerning the products formed by a Fenton reaction. We determined the hydroxyl radical (.OH) generated in a Fenton reaction system with no iron chelator using micellar electrokinetic capillary chromatography (MECC). The hydroxyl radical generated in this Fenton system attacked salicylic acid to produce major products of 2,3- and 2,5-dihydroxybenzoic acid (DHB), 2,3-DHB being prominent. Hydroxyl radical scavengers, such as mannitol, ethanol, thiourea and a ferric chelator, Desferal, significantly diminished the peaks for DHBs, showing production of .OH. We compared the MECC method with the electron paramagnetic resonance (EPR) spin trapping technique. The quantity of DHBs obtained by MECC increased dose-dependently up to 1 μM Fe2+ at a fixed concentration of H2O2, whereas that of the spin adduct by EPR showed a bell-shaped curve. This quantitation of .OH adducts by MECC supports the proposal that the oxidizing species formed by a Fenton reaction with no chelator is .OH. The EPR spin trapping method appears to be erroneous, particularly when iron is present at a higher concentration than hydrogen peroxide. The application of this method to the paraquat effect in vitro is demonstrated, and the possibility for analysis of .OH in vivo is also discussed.
- Tomita,Okuyama,Watanabe,Watanabe
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Read Online
- HPLC study on Fenton-reaction initiated oxidation of salicylic acid. Biological relevance of the reaction in intestinal biotransformation of salicylic acid
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Fenton-reaction initiated in vitro oxidation and in vivo oxidative biotransformation of salicylic acid was investigated by HPLC-UV-Vis method. By means of the developed high performance liquid chromatography (HPLC) method salicylic acid, catechol, and all the possible monohydroxylated derivatives of salicylic acid can be separated. Fenton oxidations were performed in acidic medium (pH 3.0) with two reagent molar ratios: (1) salicylic acid: iron: hydrogen peroxide 1:3:1 and (2) 1:0.3:1. The incubation samples were analysed at different time points of the reactions. The biological effect of elevated reactive oxygen species concentration on the intestinal metabolism of salicylic acid was investigated by an experimental diabetic rat model. HPLC-MS analysis of the in vitro samples revealed presence of 2,3- and 2,5-dihydroxybenzoic acids. The results give evidence for nonenzyme catalysed intestinal hydroxylation of xenobiotics.
- Nyúl, Eszter,Kuzma, Mónika,Mayer, Mátyás,Lakatos, Sándor,Almási, Attila,Perjési, Pál
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p. 1040 - 1051
(2018/10/24)
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- Method for producing 2,6-dihydroxybenzoic acid
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The invention discloses a method for producing 2,6-dihydroxybenzoic acid. The method is characterized in that in the carboxylation reaction of 2,6-dihydroxybenzoic acid, self-suction airfoil axial flow stirring is used as the stirring pattern of a carboxylation reactor, so that gas, liquid and solid phases in the reaction system of the carboxylation reaction are fully mixed and contacted; besides,a phase transfer catalyst is added in the carboxylation reaction process, homogenization of the gas-liquid-solid three-phase reaction is improved, and one-time yield of the reaction product is increased. The one-time yield of the reaction product can be increased by 5%-10% with the method.
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Paragraph 0041-0052
(2019/01/16)
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- A promising catalyst for exclusive: Para hydroxylation of substituted aromatic hydrocarbons under UV light
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Herein, we describe a waterborne polymer/carbon dot nanocomposite system as an efficient, resourceful and sustainable photocatalyst for para-selective hydroxylation of substituted aromatic compounds using H2O2 under UV light. The polymer matrix and carbon dot generate a synergistic catalytic system. A unique structural attribute of the functionalities in this catalytic system attracts the aromatic substrates into close proximity and activates them. Additionally, the flexible molecular box-like structure of the hyperbranched polymer provides the ability for favorable three-point interaction with several substrates having various sizes by means of their multiple force networks and the increased accessibility of the active sites. The catalyst can be stored on the bench top for months and is reusable without considerable loss in its activity. The reaction was exclusively selective toward para hydroxylation irrespective of the nature of the substituents (electron donating or electron withdrawing) in the aromatic hydrocarbons. Hence, it is one of the most promising catalysts for selective hydroxylation of substituted aromatic hydrocarbons.
- Das, Vijay Kumar,Gogoi, Satyabrat,Choudary, Boyapati Manoranjan,Karak, Niranjan
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p. 4278 - 4283
(2017/09/29)
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- 6-sulfonate pyrimidyl salicylate compound and preparation method and application thereof
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The invention relates to the field of herbicides and discloses a 6-sulfonate pyrimidyl salicylate compound and a preparation method and application thereof. The compound has a structure as shown in a formula (1). The method for preparing the 6-sulfonate pyrimidyl salicylate compound comprises the steps of (1) carrying out first contact reaction on the compound as shown in a formula (2) and R2SO2Cl to obtain a compound as shown in a formula (3); and (2) carrying out second contact reaction on the compound as shown in the formula (3) and trifluoroacetic acid. The 6-sulfonate pyrimidyl salicylate compound has a good inhibition effect on acetohydroxyacid synthase, and has significant resistance inhibition effect on weeds which are resistant to an acetohydroxyacid synthase inhibitor herbicide, thereby controlling weed resistance plants caused by acetohydroxyacid synthase. The formulas are as shown in the specification.
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Paragraph 0135; 0136; 0137; 0138
(2017/07/19)
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- Metal-Free Dehomologative Oxidation of Arylacetic Acids for the Synthesis of Aryl Carboxylic Acids
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A novel I2-promoted direct conversion of arylacetic acids into aryl carboxylic acids under metal-free conditions has been described. This remarkable transformation involves decarboxylation followed by an oxidation reaction enabled just by using DMSO as the solvent as well as an oxidant. Notably, aryl carboxylic acids are isolated by simple filtration technique and obtained in good to excellent yields. This protocol is free from chromatographic purification, which makes it applicable for large-scale synthesis.
- Kalmode, Hanuman P.,Vadagaonkar, Kamlesh S.,Shinde, Suresh L.,Chaskar, Atul C.
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p. 3781 - 3786
(2017/04/11)
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- [Ru(bpy)3]Cl2-catalyzed aerobic oxidative cleavage β-diketones to carboxylic acids under visible light irradiation
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A mild and highly efficient method for the preparation of carboxylic acids is developed through a visible-light-mediated aerobic oxidative cleavage of β-diketones. This process provides a potential general, practical and scalable protocol for both laboratory synthesis and industrial production of carboxylic acids in a green manner.
- Wang, Xiao-Yan,Shang, Zhen-Peng,Zha, Gao-Feng,Chen, Xiao-Qing,Bukhari, Syed Nasir Abbas,Qin, Hua-Li
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supporting information
p. 5628 - 5631
(2016/11/23)
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- 2, 6-aminodihydroxybenzoic acid manufacturing method
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PROBLEM TO BE SOLVED: To provide a process suitable for industrial production of 2,6-dihydroxybenzoic acid by a reaction of resorcin and carbon dioxide in the presence of an alkali metal compound at a favorable production rate even under mild conditions. SOLUTION: The process for production of 2,6-dihydroxybenzoic acid includes reacting resorcin with carbon dioxide in the presence of the alkali metal compound, wherein the ratio of (A) the total mole number of resorcin and a univalent phenol in the presence or absence of the univalent phenol and (B) the mole number of the alkali metal of the alkali metal compound, (A)/(B), is in a range of 2.2 through 100. COPYRIGHT: (C)2013,JPOandINPIT
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Paragraph 0025
(2016/11/07)
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- PROCESSES FOR THE PREPARATION OF BISPYRIBAC SODIUM AND INTERMEDIATES THEREOF
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The present disclosure relates to a process for the preparation of Bispyribac-sodium by condensing 2,6-dihydroxy benzoic acid with 2-(alkyl sulfonyl)-4,6-dialkoxy pyrimidine in the presence of at least one base and at least one solvent. The present disclosure also relates to processes for the preparation of 2,6-dihydroxy benzoic acid and 2-(alkyl sulfonyl)-4,6- dialkoxy pyrimidine.
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Page/Page column 19
(2014/09/03)
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- Regioselective ortho-carboxylation of phenols catalyzed by benzoic acid decarboxylases: A biocatalytic equivalent to the Kolbe-Schmitt reaction
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The enzyme catalyzed carboxylation of electron-rich phenol derivatives employing recombinant benzoic acid decarboxylases at the expense of bicarbonate as CO2 source is reported. In contrast to the classic Kolbe-Schmitt reaction, the biocatalytic equivalent proceeded in a highly regioselective fashion exclusively at the ortho-position of the phenolic directing group in up to 80% conversion. Several enzymes were identified, which displayed a remarkably broad substrate scope encompassing alkyl, alkoxy, halo and amino- functionalities. Based on the crystal structure and molecular docking simulations, a mechanistic proposal for 2,6-dihydroxybenzoic acid decarboxylase is presented.
- Wuensch, Christiane,Gross, Johannes,Steinkellner, Georg,Lyskowski, Andrzej,Gruber, Karl,Glueck, Silvia M.,Faber, Kurt
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p. 9673 - 9679
(2014/03/21)
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- Inclusion complex containing epoxy resin composition for semiconductor encapsulation
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The invention is an epoxy resin composition for sealing a semiconductor, including (A) an epoxy resin and (B) a clathrate complex. The clathrate complex is one of (b1) an aromatic carboxylic acid compound, and (b2) at least one imidazole compound represented by formula (II): wherein R2 represents a hydrogen atom, C1-C10 alkyl group, phenyl group, benzyl group or cyanoethyl group, and R3 to R5 represent a hydrogen atom, nitro group, halogen atom, C1-C20 alkyl group, phenyl group, benzyl group, hydroxymethyl group or C1-C20 acyl group. The composition has improved storage stability, retains flowability when sealing, and achieves an effective curing rate applicable for sealing delicate semiconductors.
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- Regioselective enzymatic carboxylation of phenols and hydroxystyrene derivatives
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The enzymatic carboxylation of phenol and styrene derivatives using (de)carboxylases in carbonate buffer proceeded in a highly regioselective fashion: Benzoic acid (de)carboxylases selectively formed o-hydroxybenzoic acid derivatives, phenolic acid (de)carboxylases selectively acted at the β-carbon atom of styrenes forming (E)-cinnamic acids.
- Wuensch, Christiane,Glueck, Silvia M.,Gross, Johannes,Koszelewski, Dominik,Schober, Markus,Faber, Kurt
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supporting information; experimental part
p. 1974 - 1977
(2012/06/15)
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- Enzymatic Kolbe-Schmitt reaction to form salicylic acid from phenol: Enzymatic characterization and gene identification of a novel enzyme, Trichosporon moniliiforme salicylic acid decarboxylase
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Salicylic acid decarboxylase (Sdc) can produce salicylic acid from phenol; it was found in the yeast Trichosporon moniliiforme WU-0401 and was for the first time enzymatically characterized, with the sdc gene heterologously expressed. Sdc catalyzed both reactions: decarboxylation of salicylic acid to phenol and the carboxylation of phenol to form salicylic acid without any byproducts. Both reactions were detected without the addition of any cofactors and occurred even in the presence of oxygen, suggesting that this Sdc is reversible, nonoxidative, and oxygen insensitive. Therefore, it is readily applicable in the selective production of salicylic acid from phenol, the enzymatic Kolbe-Schmitt reaction. The deduced amino acid sequence of the gene, sdc, encoding Sdc comprises 350 amino acid residues corresponding to a 40-kDa protein. The recombinant Escherichia coli BL21(DE3) expressing sdc converted phenol to salicylic acid with a 27% (mol/mol) yield at 30 °C for 9 h.
- Kirimura, Kohtaro,Gunji, Hiroaki,Wakayama, Rumiko,Hattori, Takasumi,Ishii, Yoshitaka
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experimental part
p. 279 - 284
(2011/11/14)
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- PROCESS FOR STRAIGHTENING KERATIN FIBRES WITH A HEATING MEANS AND DENATURING AGENTS
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The invention relates to a process for straightening keratin fibres, comprising: (i) a step in which a straightening composition containing at least two denaturing agents is applied to the keratin fibres, (ii) a step in which the temperature of the keratin fibres is raised, using a heating means, to a temperature of between 110 and 250° C.
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- Synergistic compositions for the selective control of tumor tissue
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According to the invention, compositions are made available which have a strong cytotoxic effect which is largely selective on tumor tissue. The invention is based on the fact that certain benzoic acid derivatives have a strong synergistic effect as a mixture and destroy cancer cells selectively in a pH range of 7 or below, such as from 6.5 to 7.
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- Synergistically acting compositions for selectively combating tumor tissue
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According to the invention, compositions are made available which have a strong cytotoxic effect which is largely selective on tumor tissue. The invention is based on the fact that certain benzoic acid derivatives have a strong synergistic effect as a mixture and destroy cancer cells selectively in a pH range of 7 or below, such as from 6.5 to 7.
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- Metabolism of Naphthalenesulfonic Acids by Pseudomonas sp. TA-2
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A 2-naphthylamine-1-sulfonate (tobias acid)-degrading Pseudomonas strain was isolated from soil.This organism degraded 1-naphthalenesulfonate and 2-naphthol-1-sulfonate as well as tobias acid.When the cells grown on a nutrient medium were incubated with tobias acid, 1-naphthalenesulfonate, and 2-naphthol-1-sulfonate, salycilate was temporarily accumulated in the culture medium.A salicylate-degrading enzyme and a gentisate-degrading enzyme were induced by salicylate and gentisate, respectively.On the other hand, the enzymes which degrade sulfonated naphthalenes to salicylate were constitutive.Ammonia, sulfate, and a small amount of sulfite were detected in the course of degradation of tobias acid. 2-Naphthol-8-sulfonate or 1-naphthol-5-sulfonate was converted into 2,4-dihydroxybenzoate or 2,6-dihydroxybenzoate respectively.Both cis-1,2-dihydroxy-1,2-dihydro-3-naphthalenesulfonate and sulfate were formed when the cells were incubated with 2-naphthalenesulfonate.It is suggested that tobias acid was degraded by 1,2-dioxygenation in the initial process of the degradation pathway.
- Ohe, Tatsuhiko,Ohmoto, Takashi,Kobayashi, Yuji,Sato, Akihiro,Watanabe, Yasuto
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p. 669 - 675
(2007/10/02)
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