- Continuous flow metal-free oxidation of picolines using air
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The metal free, direct oxidation of 2-, 3-, and 4-picoline to the corresponding carboxylic acid using either oxygen or air has been developed under continuous flow conditions. Complete conversion for all three substrates was obtained at moderate temperatures and pressures within minutes.
- Hamano, Masaya,Nagy, Kevin D.,Jensen, Klavs F.
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- Bench-scale biosynthesis of isonicotinic acid from 4-cyanopyridine by Pseudomonas putida
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Pseudomonas putida CGMCC3830 harboring nitrilase was used in isonicotinic acid production from 4-cyanopyridine. This nitrilase showed optimum activities towards 4-cyanopyridine at pH 7.5 and 45°C. The half-life of P. putida nitrilase was 93.3 h, 33.9 h, and 9.5 h at 30°C, 38°C, and 45°C, respectively. 4-Cyanopyridine (100 mM) was fully converted into isonicotinic acid within 20 min. The bench-scale production of isonicotinic acid was carried out using 3 mg of resting cells per mL in a 1 L system at 30°C and finally, 123 g L-1 of isonicotinic acid were obtained within 200 min without any by-products. The conversion reaction suffered from the product inhibition effect after the tenth feeding. The volumetric productivity was 36.9 g L -1 h-1. P. putida shows significant potential in nitrile hydrolysis for isonicotinic acid production. This paper is the first report on isonicotinic acid biosynthesis using Pseudomonas putida and it represents the highest isonicotinic acid production reported so far.
- Zhu, Xiao-Yan,Gong, Jin-Song,Li, Heng,Lu, Zhen-Ming,Shi, Jin-Song,Xu, Zheng-Hong
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- Bimetallic cobalt-iron diselenide nanorod modified glassy carbon electrode: an electrochemical sensing platform for the selective detection of isoniazid
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The increasing demand of a sensitive and portable electrochemical sensing platform in pharmaceutical analysis has developed widespread interest in preparing electrode materials possessing remarkable properties for the electrochemical determination of target drug analytes. Herein, we report the synthesis, characterization and application of bimetallic cobalt-iron diselenide (FeCoSe2) nanorods as electrode modifiers for the selective detection of a commonly used anti-tuberculosis drug Isoniazid (INZ). We prepared FeCoSe2nanorods by a simple hydrothermal route and characterized these by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX) and temperature-programmed reduction (TPR) techniques. The electrochemical characterization of FeCoSe2modified GCE was performed by cyclic voltammetry (CV) and square wave anodic stripping voltammetry (SWASV). Under optimized experimental conditions, a linear current-concentration response was obtained for INZ in the range of 0.03-1.0 μM, with very low limit of detection 1.24 × 10?10M. The real applicability of the designed FeCoSe2/GCE sensing platform was adjudicated by the detection of INZ in biological samples.
- Sultan, Sundas,Zulqarnain, Muhammad,Shah, Afzal,Firdous, Naveeda,Nisar, Jan,Ashiq, Muhammad Naeem,Bakhsh, Esraa M.,Khan, Sher Bahadar
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- Assembly of three organic-inorganic hybrid supramolecular materials based on reduced molybdenum(V) phosphates
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Three supramolecular materials based on {P4Mo6} polyoxoanions, (Hbbi)2(H2bbi)[Cu3Mo 12VO24(OH)6(H2O) 6(HPO4)4(H
- Zhang, He,Yu, Kai,Lv, Jing-Hua,Wang, Chun-Mei,Wang, Chun-Xiao,Zhou, Bai-Bin
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- Decoration of copper foam with Ni nanorods and copper oxide nanosheets to produce a high-stability electrocatalyst for the reduction of CO2: Characterization of the electrosynthesis of isonicotinic acid
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CuO–Cu2O (CuxO) nanosheets were coated on a copper foam substrate by the electrochemical anodization method in an alkaline solution. Constant current coulometry was performed to electrodeposit Ni nanorods on the surface of a Cu/CuxO electrode. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) proved that the copper oxide nanosheets were anchored on the copper foam substrate and modified by Ni nanorods (Cu/CuxO/Ni). The process took place via a facile and inexpensive electrodeposition method. As the results indicate, owing to the synergistic effect of adjacent CuxO and Ni sites, a Cu/CuxO/Ni electrode has a very good and stable electrocatalytic activity to reduce CO2. As tested in this study, the product of the electrocatalytic reduction of CO2 (i.e. activated CO2, or CO2 ??) can be used for the electrocarboxylation of pyridine in mild conditions. Once an electron is transferred from CO2 ?? to pyridine, a pyridine radical anion is formed. Based on the EC'C′CC mechanism, this radical anion reacts with CO2 ?? and produces isonicotinic acid as the main product. In addition, two pyridine radical anions react together and produce a 4,4′-bipyridine dimer. The high stability of the electrocatalyst during the electrolysis process and the simplicity of the workup make the proposed modified electrode appropriate for the electrosynthesis of some organic compounds.
- Mohammadzadeh, Safoora,Zare, Hamid R.,Khoshro, Hossein
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- Communication-electrosynthesis of isonicotinic acid via indirect electrochemical reduction of pyridine in the presence of CO2
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The electrocatalytic reduction of CO2 by Schiff base of N, N'-bis(3-hydroxy-2-naphthaldehyde)-1,3-phenylenediimino (NMPD) was studied in an acetonitrile solvent and at room temperature. Indirect electrocatalytic activity of NMPD for reduction of pyridine was empirically demonstrated. It is rational, to view electrocatalytically activated CO2, CO2·-, with a dual activity toward pyridine. The spectral characteristics of the coulometric product indicated that isonicotinic acid is the final product of pyridine reduction in the presence of NMPD and CO2.
- Ghobadi, Kobra,Zare, Hamid R.,Khoshro, Hossein,Gorji, Alireza
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- Kinetics of the highly selective liquid-phase oxidation of side chain alkyl groups in 2-methylpyrazine and picolines by selenium dioxide
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Kinetics of the liquid-phase oxidation of alkyl groups in 2-methylpyrazine and picolines with selenium dioxide at moderate conditions were studied. Thus, 2-methylpyrazine was oxidized to pyrazinoic acid with selenium dioxide in pyridine at 115 °C with 99% selectivity at a 2-methylpyrazine conversion of 100% in 8 h. It was deduced that the reaction follows secondorder kinetics and the activation energy was found to be 35 kcal/mol. The same reaction-scheme was found to hold for picolines oxidation to obtain picolinic acids. The byproduct selenium, formed in the reaction, was converted back to selenium dioxide by nitric acid oxidation with 100% selectivity.
- Mukhopadhyay, Sudip,Chandalia, Sampatraj B.
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- Aerobic oxidation of methylpyridines to pyridinecarboxylic acids catalyzed by N-hydroxyphthalimide
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Selective aerobic oxidation of methylpyridines to pyridinecarboxylic acids was successfully achieved by the use of a radical catalyst, N-hydroxyphthalimide (NHPI), in the presence of Co(II) and/or Mn(II) salts. The oxidation of 3-methylpyridine by NHPI combined with Co(OAc)2 under O2 (1 atm) in AcOH at 100 °C gave 3-pyridinecarboxylic acid (76percent). The reaction was found to be enhanced by addition of a small amount of Mn(OAc)2 to the catalytic system. The reaction with 20 atm of air, catalyzed by NHPI-Co(OAc)2-Mn(OAc)2 at 150 °C for 1 h, gave 3-pyridinecarboxylic acid (85percent). 4-Methylpyridine was much less easily oxidized than 3-methylpyridine. The co-oxidation of 3-methylpyridine and 4-methylpyridine by NHPI-Co(OAc)2-Mn(OAc)2 at 150 °C for 5 h gave results that were better than those obtained from individual oxidations, forming 3-pyridinecarboxylic acid (93percent) and 4-pyridinecarboxylic acid (70percent). The NHPI-catalyzed oxidation of methylpyridines would provide an attractive direct method which has long been desired in the chemical industry for the manufacturing of pyridinecarboxylic acids.
- Shibamoto, Akihiro,Sakaguchi, Satoshi,Ishii, Yasutaka
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- Oxidation of Antitubercular Drug Isoniazid by a Lipopathic Oxidant, Cetyltrimethylammonium Dichromate: A Mechanistic Study
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The oxidation of an antitubercular drug isoniazid by a lipopathic oxidant cetyltrimethylammonium dichromate (CTADC) in a nonpolar medium generates isonicotinic acid both in the presence and the absence of acetic acid. The conventional UV–vis spectrophotometric method is used to study the reaction kinetics. The occurrence of the Michaelis–Menten–type kinetics with respect to isoniazid confirms the binding of oxidant and substrate to form a complex before the rate-determining step. The existence of the inverse solvent kinetic isotope effect, k(H2O)/ k(D2O) = 0.7, in an acid-catalyzed reaction proposes a multistep reaction mechanism. A decrease in the rate constant with an increase in [CTADC] reveals the formation of reverse micellar–type aggregates of CTADC in nonpolar solvents. In the presence of different ionic and nonionic surfactants, CTADC forms mixed aggregates and controls the reaction due to the charge on the interface and also due to partition of oxidant and substrate in two different domains. High negative entropy of activation (ΔS? = –145 and –159 J K?1 mol?1 in the absence and presence of acetic acid) proposes a more ordered and highly solvated transition state than the reactants. Furthermore, the solvent polarity-reactivity relationship reveals (i) the presence of less polar and less ionic transition state compared to the reactants during the oxidation, (ii) differential contribution from nonpolar and dipolar aprotic solvents toward the reaction process, and (iii) the existence of polarity/hydrophobic switch at log P = 0.73. A suitable mechanism has been proposed on the basis of experimental results. These results may provide insight into the mechanism of isoniazid oxidation in hydrophobic environment and may assist in understanding the drug resistance in different location.
- Garnayak, Sarita,Patel, Sabita
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- Thermostable amidase catalyzed production of isonicotinic acid from isonicotinamide
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The biotransformation of isonicotinamide was investigated using thermophilic intracellular amidase produced from Geobacillus subterraneus RL-2a. Various process parameters, including amount of biocatalyst, substrate feeding rate, enzyme-to-substrate ratio and operational thermostability were systematically examined with the aim of achieving complete substrate conversion and high productivity. In 1 L fed batch reaction containing 0.1 M isonicotinamide, in 0.2 M potassium phosphate buffer (pH 6.5, 200 rpm) and 8 U ml-1 amidase activity (12.48 mg dcw ml-1) of whole cells of G. subterraneus RL-2a (as biocatalyst) resulted in a yield of 0.1 M of isonicotinic acid after 50 min reaction time at 70°C and a total of 61.55 g isonicotinic acid was produced at a rate of 1.18 g h-1 g-1 dcw respectively. The volumetric productivity was 14.8 g h-1 l-1.
- Mehta, Praveen Kumar,Bhatia, Shashi Kant,Bhatia, Ravi Kant,Bhalla, Tek Chand
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- Oxidation of isoniazid by N-haloarenesulfonamidates in alkaline medium: A kinetic and mechanistic study
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The kinetics of oxidation of Isoniazid (INH) by sodium N-haloarenesulfonamidates, chloramine-T (CAT), bromamine-T (BAT), chloramine-B (CAB), and bromamine-B (BAB), has been studied in alkaline medium at 303 K. The oxidation reaction follows identical kinetics with a first-order dependence on each [oxidant] and [INH] and an inverse fractional-order on [OH-]. Addition of the reaction product (p-toluenesulfonamide or benzenesulfonamide) had no significant effect on the reaction rate. Variation of ionic strength and addition of halide ions have no influence on the rate. There is a negative effect of dielectric constant of the solvent. Studies of solvent isotope effects using D2O showed a retardation of rate in the heavier medium. The reaction was studied at different temperatures, and activation parameters have been computed from the Arrhenius and Eyring plots. Isonicotinic acid was identified as the oxidation product by GC-MS. A two-pathway mechanism is proposed in which RNHX and the anion RNX- interact with the substrate in the rate-limiting steps. The mechanism proposed and the derived rate laws are consistent with the observed kinetics. The rate of oxidation of INH increases in the order: BAT>BAB>CAT>CAB. This effect is mainly due to electronic factors.
- Puttaswamy,Anuradha,Ramachandrappa,Made Gowda
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- Dual activity of electrocatalytic activated CO2 toward pyridine for synthesis of isonicotinic acid: An EC′C′C mechanism
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The present study demonstrates the indirect electrocatalytic synthesis of isonicotinic acid using a Ni complex, [NiII(Me4-(NO2Bzo)2[14]tetraeneN4)], in an acetonitrile solution at room temperature. The complex was used as an excellent electrocatalyst for the reduction of carbon dioxide. The results indicate that the electrocatalytic reduction product of CO2 (CO2·-) has a dual role in the electrosynthesis of isonicotinic acid. The dual activity of CO2·- involved indirect electrocatalytic reduction of pyridine as well as its radical reaction with pyridine radical anion to form isonicotinic acid. Finally, EC′C′C mechanism was proposed for the synthesis of isonicotinic acid. In contrast, the reaction of pyridine with CO2 in the absence of the complex follows an EC′C mechanism, and the final product is 4,4′-bipyridine.
- Khoshro, Hossein,Zare, Hamid R.,Jafari, Abbas A.,Gorji, Alireza
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- An ESIPT-based colorimetric and fluorescent probe with large Stokes shift for the sensitive detection of hypochlorous acid and its bioimaging in cells
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Hypochlorous acid (HOCl), with a low physiological concentration, plays a vital role in killing the pathogens and anti-inflammation in the human immune system. Deviation from the normal concentration is directly related to the inflammation-associated diseases and even cancer. Thus, it is necessary to sensitively detect the tiny concentration changes of HOCl. However, few of the reported probes could practically work well due to small Stokes shift, high detection of limits, and low SNR. In this study, HBT (2-(2′-Hydroxyphenyl)benzothiazole) was used as the candidate for the ESIPT-based fluorophore and connected to pyridinevia“CC” bonds. The “CC” bonds are the reaction site for HOCl and are activated by the strong electron-withdrawing CN group located on the double-bond carbon atom, resulting in a high sensitivity towards HOCl. Thereby, the probe's emission shifted effectively to the red channel avoiding the interference from biological autofluorescence. The excellent response of the probeJBDtowards HOCl enables it to detect endogenous hypochlorous acid in the cells and provides an ideal molecular tool for exploring the mechanism of hypochlorous acid in oxidative stress and its immune role.
- Ren, Haixian,Huo, Fangjun,Yin, Caixia
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- Metabolism and pharmacokinetics of the cardiotonic agent piroximone and of its major metabolite in dog
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1. Piroximone was administered orally (p.o.) and intravenously (i.v.) to male Beagle dog. In vitro, piroximone was incubated with dog liver microsomes. 2. Piroximone was metabolized in vivo to five metabolites (1-5) representing approximately 20% of the total administered dose. 3. The parent drug and its metabolites were totally eliminated in urine. 4. Reduced piroximone (piroximole), representing approximately 10% of the administered dose, was identified as the major metabolic product in vivo. 5. In vitro, piroximone was metabolized by dog liver microsomes to isonicotinic acid (I) and piroximole (4), with the same ratio as in vivo (1:4 = 0.2). The Michaelis-Menten parameters were determined for piroximole formation and were: K(m app) = 733 μM and V(max app) = 232 pmol/mg protein/min. 6. Comparison of the pharmacokinetics of piroximone and piroximole revealed that both compounds were very well absorbed (F = 93 ± 7 and 89 ± 8% respectively), slightly distributed (V(d app) 0.78 ± 0.4 and 1.02 ± 0.09 l/kg p.o., and 0.95 ± 0.05 and 0.76 ± 0.13 l/kg i.v. respectively) and excreted into urine to the same extent (U(Ex) = 54.7 ± 1.2 and 53.2 ± 12.6% p.o., and 59.1 ± 5.3 and 51.2 ± 5.7% i.v. respectively), except that the clearance of piroximone was two-fold higher than that observed for piroximole (Cl(T) = 7.77 ± 1.35 and 4.12 ± 0.44 ml/min/kg p.o., and 7.68 ± 1.25 and 4.06 ± 0.51 ml/min/kg i.v, respectively).
- Berg-Candolfi,Dulery,Jehl,Haegele
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- SYNTHESIS OF PYRIDYL(TRICHLOROMETHYL)CARBINOLS UNDER INTERPHASE-CATALYSIS CONDITIONS
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The corresponding pyridyl(trichloromethyl)carbinols were obtained by reactions of 2- and 3-formylpyridine and 6-methyl-2-formylpyridine with chloroform in the presence of aqueous or solid alkali and an interphase catalyst.It is shown that carrying out the reaction in a liquid-solid system is more efficient than in a liquid-liquid system.
- Iovel', I. G.,Gol'dberg, Yu. Sh.,Gaukhman, A. P.,Shimanskaya, M. V.
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- Preparation method N-Boc-4 -piperidinecarboxylic acid
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The invention discloses a preparation method of N-Boc-4 - piperidinecarboxylic acid, which comprises the following steps: adding 4 - piperidine formic acid into ethanol, dropwise adding Boc anhydride at room temperature, stirring the reaction to the solution, continuing to react at room temperature to a dot plate without raw materials. The solvent is evaporated till the system is in a viscous state and then stopped, added with water and then filtered to dry the filter cake. Wherein, 4 - piperidinecarboxylic acid, Boc anhydride and ethanol mass ratio 100:169 - 185:450 - 550.4 - piperidinecarboxylic acid is prepared by carrying out enzymatic hydrolysis on 4 - cyanopyridine to obtain pyridine -4 - formic acid. High pressure hydrogenation of pyridine -4 - formic acid to give 4 - piperidinecarboxylic acid.
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Paragraph 0012; 0025-0026
(2021/11/06)
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- Photo-induced deep aerobic oxidation of alkyl aromatics
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Oxidation is a major chemical process to produce oxygenated chemicals in both nature and the chemical industry. Presently, the industrial manufacture of benzoic acids and benzene polycarboxylic acids (BPCAs) is mainly based on the deep oxidation of polyalkyl benzene, which is somewhat suffering from environmental and economical disadvantage due to the formation of ozone-depleting MeBr and corrosion hazards of production equipment. In this report, photo-induced deep aerobic oxidation of (poly)alkyl benzene to benzene (poly)carboxylic acids was developed. CeCl3 was proved to be an efficient HAT (hydrogen atom transfer) catalyst in the presence of alcohol as both hydrogen and electron shuttle. Dioxygen (O2) was found as a sole terminal oxidant. In most cases, pure products were easily isolated by simple filtration, implying large-scale implementation advantages. The reaction provides an ideal protocol to produce valuable fine chemicals from naturally abundant petroleum feedstocks. [Figure not available: see fulltext.].
- Wang, Chang-Cheng,Zhang, Guo-Xiang,Zuo, Zhi-Wei,Zeng, Rong,Zhai, Dan-Dan,Liu, Feng,Shi, Zhang-Jie
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p. 1487 - 1492
(2021/07/10)
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- 1,2-Dibutoxyethane-Promoted Oxidative Cleavage of Olefins into Carboxylic Acids Using O2 under Clean Conditions
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Herein, we report the first example of an effective and green approach for the oxidative cleavage of olefins to carboxylic acids using a 1,2-dibutoxyethane/O2 system under clean conditions. This novel oxidation system also has excellent functional-group tolerance and is applicable for large-scale synthesis. The target products were prepared in good to excellent yields by a one-pot sequential transformation without an external initiator, catalyst, and additive.
- Ou, Jinhua,Tan, Hong,He, Saiyu,Wang, Wei,Hu, Bonian,Yu, Gang,Liu, Kaijian
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p. 14974 - 14982
(2021/10/25)
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- Oxidation of Primary Alcohols and Aldehydes to Carboxylic Acids via Hydrogen Atom Transfer
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The oxidation of primary alcohols and aldehydes to the corresponding carboxylic acids is a fundamental reaction in organic synthesis. In this paper, we report a new chemoselective process for the oxidation of primary alcohols and aldehydes. This metal-free reaction features a new oxidant, an easy to handle procedure, high isolated yields, and good to excellent functional group tolerance even in the presence of vulnerable secondary alcohols and tert-butanesulfinamides.
- Tan, Wen-Yun,Lu, Yi,Zhao, Jing-Feng,Chen, Wen,Zhang, Hongbin
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supporting information
p. 6648 - 6653
(2021/09/08)
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- MOF-Zn-NHC as an efficient N-heterocyclic carbene catalyst for aerobic oxidation of aldehydes to their corresponding carboxylic acids: Via a cooperative geminal anomeric based oxidation
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As an efficient heterogenous N-heterocyclic carbene (NHC) catalyst, MOF-Zn-NHC was used in the aerobic oxidation of aryl aldehydes to their corresponding carbocyclic acids via an anomeric based oxidation. Features such as mild reaction conditions and no need for a co-catalyst or oxidative reagent can be considered as the major advantages of the presented method in this study. This journal is
- Babaee, Saeed,Zarei, Mahmoud,Zolfigol, Mohammad Ali
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p. 36230 - 36236
(2021/12/02)
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- Direct 3-Acylation of Indolizines by Carboxylic Acids for the Practical Synthesis of Red Light-Releasable Caged Carboxylic Acids
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To enhance the practicality of photouncaging system using 3-acyl-2-methoxyindolizines, direct acylation of indolizines with carboxylic acids was developed using condensation reagents, generally used for peptide coupling. This method allowed for caging a broad range of carboxylic acids with indolizines. The method enabled a facile synthesis of water-soluble caged bioactive carboxylic acids having an intramolecular photosensitizer. The efficient release of carboxylic acids from the synthesized caged compounds upon red light irradiation was confirmed in neutral buffered solutions.
- Watanabe, Kenji,Terao, Nodoka,Niwa, Takashi,Hosoya, Takamitsu
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p. 11822 - 11834
(2021/07/31)
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- A decatungstate-based ionic liquid exhibiting a very low dielectric constant suitable for acting as a solvent and a catalyst for the oxidation of organic substrates
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In this contribution, a new POM-based ionic liquid, namely (P6,6,6,14)4[W10O32], was fully characterized. Its viscosity and its very low dielectric constant make this hybrid ionic liquid suitable to be used as a solvent for organic transformations. As a proof of concept, this unique ionic liquid having both solvent and catalyst properties was tested for the catalytic oxidation of various alcohols and alkenes in the presence of H2O2.
- Martinetto, Yohan,Pégot, Bruce,Roch-Marchal, Catherine,Haouas, Mohamed,Cottyn-Boitte, Betty,Camerel, Franck,Jeftic, Jelena,Morineau, Denis,Magnier, Emmanuel,Floquet, Sébastien
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p. 9751 - 9755
(2021/06/15)
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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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- The plant pathogen enzyme AldC is a long-chain aliphatic aldehyde dehydrogenase
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Aldehyde dehydrogenases are versatile enzymes that serve a range of biochemical functions. Although traditionally considered metabolic housekeeping enzymes because of their ability to detoxify reactive aldehydes, like those generated from lipid peroxidation damage, the contributions of these enzymes to other biological processes are widespread. For example, the plant pathogen Pseudomonas syringae strain PtoDC3000 uses an indole-3-acetaldehyde dehydrogenase to synthesize the phytohormone indole-3-acetic acid to elude host responses. Here we investigate the biochemical function of AldC from PtoDC3000. Analysis of the substrate profile of AldC suggests that this enzyme functions as a long-chain aliphatic aldehyde dehydrogenase. The 2.5 ? resolution X-ray crystal of the AldC C291A mutant in a dead-end complex with octanal and NAD1 reveals an apolar binding site primed for aliphatic aldehyde substrate recognition. Functional characterization of site-directed mutants targeting the substrate- and NAD(H)-binding sites identifies key residues in the active site for ligand interactions, including those in the “aromatic box” that define the aldehyde-binding site. Overall, this study provides molecular insight for understanding the evolution of the prokaryotic aldehyde dehydrogenase superfamily and their diversity of function.
- Lee, Soon Goo,Harline, Kate,Abar, Orchid,Akadri, Sakirat O.,Bastian, Alexander G.,Chen, Hui-Yuan S.,Duan, Michael,Focht, Caroline M.,Groziak, Amanda R.,Kao, Jesse,Kottapalli, Jagdeesh S.,Leong, Matthew C.,Lin, Joy J.,Liu, Regina,Luo, Joanna E.,Meyer, Christine M.,Mo, Albert F.,Pahng, Seong Ho,Penna, Vinay,Raciti, Chris D.,Srinath, Abhinav,Sudhakar, Shwetha,Tang, Joseph D.,Cox, Brian R.,Holland, Cynthia K.,Cascella, Barrie,Cruz, Wilhelm,McClerkin, Sheri A.,Kunkel, Barbara N.,Jez, Joseph M.
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p. 13914 - 13926
(2020/12/09)
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- Development of a Novel Chemoenzymatic Process for (S)-1-(Pyridin-4-yl)-1,3-propanediol
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We first developed a novel and efficient chemoenzymatic process to prepare (S)-1-(pyridin-4-yl)-1,3-propanediol, a vital HepDirect prodrug intermediate, from inexpensive and commercially available isonicotinic acid. Through this process, we provide a creative way to obtain the key chiral intermediate, β-hydroxyester, with ketoreductase (KRED) EA. After optimization of the process, we performed the reaction on a 100 g scale with a substrate concentration of up to 150 g/L, a yield of 93%, and an ee value of up to 99.9%. Additionally, we used a simple and effective NaBH4/MgCl2 reduction system to obtain (S)-1-(pyridin-4-yl)-1,3-propanediol with >99.9% ee and an 80% yield. This novel chemoenzymatic process has the potential to be a cost-effective and environmentally friendly process suitable for industrial use.
- Chen, Shao-Xin,Peng, Peng,Tang, Jia-Wei,Wang, Hong-Yi,Yan, Hai-Jun,Zhang, Fu-Li
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p. 2890 - 2897
(2020/12/22)
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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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- Metal-Organic Framework Based on Heptanuclear Cu-O Clusters and Its Application as a Recyclable Photocatalyst for Stepwise Selective Catalysis
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Visible-light driven photoreactions using metal-organic frameworks (MOFs) as catalysts are promising with regard to their environmental friendly features such as the use of renewable and sustainable energy of visible light and potential catalyst recyclability. To develop potential heterogeneous photocatalysts, a family of three copper(II) coordination polymers bearing different Cu-O assemblies have been synthesized with the ligand 4,4-disulfo-[1,1-biphenyl]-2,2-dicarboxylate acid (H4DSDC), namely, {[Cu7(DSDC)2(OH)6(H2O)10]·xH2O}n (1), {[Cu4(DSDC)(4,4-bpy)2(OH)4]·2H2O}n (2), and {Cu2(DSDC)(phen)2(H2O)2}n (3) (4,4-bpy = 4,4-bipyridine and phen = 1,10-phenanthroline). Complex 1 represents a metal-organic framework featuring a NbO type topology constructed from the infinite linkage of heptanuclear [Cu7(μ3-OH)6(H2O)10]8+ clusters by deprotonated DSDC4- ligands, comprising one-dimensional hexagonal channels of a diameter around 11 ? that are filled with water molecules. The infinite waving {[Cu2(OH)2]2+}n ladderlike chains in complex 2 are bridged by DSDC4- and 4,4-bpy ligands into a three-dimensional framework. A two-dimensional layered structure is formed in complex 3 due to the existence of terminal phenanthroline ligands. All of the coordination polymers 1-3 are able to catalyze the visible-light driven oxidation of alcohols at mild conditions using hydrogen peroxide as an oxidant, in which complex 1 demonstrates satisfactory efficiency. Significantly for this photoreaction catalyzed by 1, the extent of oxidation over aryl primary alcohols is fully controllable with time-resolved product selectivity, giving either corresponding aldehydes or carboxylate acids in good yields. It is also remarkable that the photocatalyst could be recovered almost quantitatively on completion of the catalytic cycle without any structure change, and could be recycled for catalytic use for at least five cycles with constant efficiency. This photocatalyst with time-resolved selectivity for different products may provide new insight into the design and development of novel catalytic systems.
- Zhou, Jie,Huang-Fu, Xu,Huang, Yang-Ying,Cao, Chu-Ning,Han, Jie,Zhao, Xiao-Li,Chen, Xu-Dong
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p. 254 - 263
(2019/12/04)
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- SYNTHESIS OF HYPERVALENT IODINE REAGENTS WITH DIOXYGEN
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Methods of synthesis of hypervalent iodine reagents and methods for oxidation of organic compounds are disclosed.
- -
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Paragraph 0157-0160; 0163-0164
(2019/01/15)
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- Kinetics of the Reaction between Cobinamide and Isoniazid in Aqueous Solutions
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Abstract: The kinetics and mechanism of the reaction of diaquacobinamide (Cbi(III)) with isoniazid (iso-nicotinoyl hydrazide (INH)) are studied. It is determined that the composition of the products depends on the ratio between the concentrations of the reactants. Adding excess INH to cobinamide results in the rapid formation of a stable complex of Cbi(III) with two isoniazid molecules. If the concentrations of isoniazid and cobinamide are close, or cobinamide is in excess, then a complex of Cbi(III) with one isoniazid molecule initially forms. There is then a fast inner-sphere electron transfer to yield an unstable complex of reduced Cbi(II) with hydrazyl radical (RN2H2)(Cbi(II)) that decomposes to form reduced cobinamide and the products of the oxidation of isoniazid: isonicotinamide, pyridine-4-carboxaldehyde, and isonicotinic acid (INA). It is concluded that with a 1000% excess of cobinamide, the main product of the oxidation of INH is INA.
- Tumakov,Dereven’kov,Sal’nikov,Makarov
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p. 265 - 270
(2019/06/03)
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- A 4 - chloromethyl pyridine hydrochloride synthetic method
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The invention belongs to the field of organic synthesis, in particular to a 4 - chloromethyl pyridine hydrochloride synthetic method, the method comprises the following steps: (1) to 4 - methyl pyridine as raw materials, takes water as a solvent, the potassium permanganate oxide it to 4 - pyridine carboxylic acid, wherein 4 - methyl pyridine with potassium permanganate in a molar ratio of 1: 2.1 - 2.3, the oxidation temperature is 75 - 80 °C, heating 35 min, the reaction is complete the reaction liquid is adjusted to be acidic, and then cooling and filtering to obtain 4 - pyridine carboxylic acid; (2) 4 - pyridine carboxylic acid with methanol under acidic conditions to produce the 4 - pyridine carboxylic acid methyl ester, wherein the 4 - pyridine carboxylic acid with methanol in a molar ratio of 1: 1.3; (3) reduction of 4 - pyridine carboxylic acid methyl ester for 4 - pyridine methanol; (4) 4 - pyridine methanol with thionyl chloride reaction to obtain the target product 4 - chloromethyl pyridine hydrochloride, 4 - pyridine methanol with thionyl chloride in a molar ratio of 1: 1.1 - 1.3.
- -
-
Paragraph 0016; 0019; 0020; 0024; 0025; 0029; 0030
(2019/06/05)
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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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- Table salt as a catalyst for the oxidation of aromatic alcohols and amines to acids and imines in aqueous medium: Effectively carrying out oxidation reactions in sea water
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A simple, efficient, sustainable and economical method for the oxidation of alcohols and amines has been developed based on chloride, a sea abundant anionic catalyst for the practical synthesis of a wide range of carboxylic acids, ketones and imines. Oxidation of aromatic alcohols was carried out using NaCl (20 mol%) as the catalyst, NaOH (50 mol%) and aq. TBHP (4 equiv.) as the oxidant in 55-92% isolated yields. Oxidation of aromatic amines to imines was achieved by using only 20 mol% of NaCl and aq. TBHP (4 equiv.) in 32-93% isolated yields. The chlorine species formed during the reaction as the active oxidation catalyst has been identified as ClO2- for alcohols and ClO-/ClO2- for amines by control experiments. This method is mostly free from chromatographic purification, which makes it suitable for large-scale synthesis. We have scaled up to 30 gram scale the synthesis of carboxylic acids and imines in good yields and have also carried out efficiently this new method using filtered sea water as the solvent and catalyst.
- Hazra, Susanta,Kushawaha, Ajay Kishor,Yadav, Deepak,Dolui, Pritam,Deb, Mayukh,Elias, Anil J.
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supporting information
p. 1929 - 1934
(2019/04/29)
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- Cobalt/N-Hydroxyphthalimide(NHPI)-Catalyzed Aerobic Oxidation of Hydrocarbons with Ionic Liquid Additive
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A highly efficient and solvent-free system of cobalt/NHPI-catalyzed aerobic oxidation of hydrocarbons was developed using imidazolium-based ionic liquid (IL) as an additive. These amphipathic ILs were found self-assemble at the interface between the organic hydrocarbons and the aqueous phase of catalyst combination (Co/NHPI), with forming a solution of reversed multilamellar vesicles for catalysis. The initial reaction rate was influenced by both the composition of microdomains and the structure of IL launched. Consequently, a proper water content (χH2O) of wet IL was requisite to reach the optimum reactivity. Besides, the interfacial boundary between aqueous and organic phase composed by C2-alkylated imidazolium ILs, such as [bdmim]SbF6 and [C12dmim]SbF6, not only has ternary aggregates (hydrocarbons/IL/H2O) of higher stability but renders O2 a faster diffusion rate and higher concentration, thereby offering a high reactivity of the protocol towards hydrocarbon oxidation.
- Mahmood, Sajid,Xu, Bao-Hua,Ren, Tian-Lu,Zhang, Zhi-Bo,Liu, Xiao-Min,Zhang, Suo-Jiang
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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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- Catalytic Promiscuity of Galactose Oxidase: A Mild Synthesis of Nitriles from Alcohols, Air, and Ammonia
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We report an unprecedented catalytically promiscuous activity of the copper-dependent enzyme galactose oxidase. The enzyme catalyses the one-pot conversion of alcohols into the related nitriles under mild reaction conditions in ammonium buffer, consuming ammonia as the source of nitrogen and dioxygen (from air at atmospheric pressure) as the only oxidant. Thus, this green method does not require either cyanide salts, toxic metals, or undesired oxidants in stoichiometric amounts. The substrate scope of the reaction includes benzyl and cinnamyl alcohols as well as 4- and 3-pyridylmethanol, giving access to valuable chemical compounds. The oxidation proceeds through oxidation from alcohol to aldehyde, in situ imine formation, and final direct oxidation to nitrile.
- Vilím, Jan,Knaus, Tanja,Mutti, Francesco G.
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supporting information
p. 14240 - 14244
(2018/10/15)
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- Bis(methoxypropyl) ether-promoted oxidation of aromatic alcohols into aromatic carboxylic acids and aromatic ketones with O2 under metal- and base-free conditions
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We describe an eco-friendly, practical and operationally simple procedure for the bis(methoxypropyl) ether-promoted oxidation of aromatic alcohols into aromatic carboxylic acids and aromatic ketones with atmospheric dioxygen as the sole oxidant. This chemical process is clean with high conversion and good selectivity, and an external initiator, catalyst, additive and base are not required. The virtue of this reaction is highlighted by its easily available and economical raw materials and excellent functional group tolerance (acid-, base- and oxidant-labile groups).
- Liu, Kai-Jian,Jiang, Si,Lu, Ling-Hui,Tang, Ling-Li,Tang, Shan-Shan,Tang, Hai-Shan,Tang, Zilong,He, Wei-Min,Xu, Xinhua
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supporting information
p. 3038 - 3043
(2018/07/13)
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- Oxidation Catalysis by an Aerobically Generated Dess–Martin Periodinane Analogue
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Hypervalent iodine(V) reagents, such as Dess–Martin periodinane (DMP) and 2-iodoxybenzoic acid (IBX), are broadly useful oxidants in chemical synthesis. Development of strategies to generate these reagents from dioxygen (O2) would immediately enable use of O2 as a terminal oxidant in a broad array of substrate oxidation reactions. Recently we disclosed the aerobic synthesis of I(III) reagents by intercepting reactive oxidants generated during aldehyde autoxidation. In this work, aerobic oxidation of iodobenzenes is coupled with disproportionation of the initially generated I(III) compounds to generate I(V) reagents. The aerobically generated I(V) reagents exhibit substrate oxidation chemistry analogous to that of DMP. The developed aerobic generation of I(V) has enabled the first application of I(V) intermediates in aerobic oxidation catalysis.
- Maity, Asim,Hyun, Sung-Min,Wortman, Alan K.,Powers, David C.
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supporting information
p. 7205 - 7209
(2018/05/29)
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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.
- -
-
Paragraph 0022
(2017/09/01)
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- Simultaneous Voltammetric Determination of Acetaminophen and Isoniazid (Hepatotoxicity-Related Drugs) Utilizing Bismuth Oxide Nanorod Modified Screen-Printed Electrochemical Sensing Platforms
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To overcome the recent outbreaks of hepatotoxicity-related drugs, a new analytical tool for the continuously determination of these drugs in human fluids is required. Electrochemical-based analytical methods offer an effective, rapid, and simple tool for on-site determination of various organic and inorganic species. However, the design of a sensitive, selective, stable, and reproducible sensor is still a major challenge. In the present manuscript, a facile, one-pot hydrothermal synthesis of bismuth oxide (Bi2O2.33) nanostructures (nanorods) was developed. These BiO nanorods were cast onto mass disposable graphite screen-printed electrodes (BiO-SPEs), allowing the ultrasensitive determination of acetaminophen (APAP) in the presence of its common interference isoniazid (INH), which are both found in drug samples. The simultaneous electroanalytical sensing using BiO-SPEs exhibited strong electrocatalytic activity toward the sensing of APAP and INH with an enhanced analytical signal (voltammetric peak) over that achievable at unmodified (bare) SPEs. The electroanalytical sensing of APAP and INH are possible with accessible linear ranges from 0.5 to 1250 μM and 5 to 1760 μM with limits of detection (3σ) of 30 nM and 1.85 μM, respectively. The stability, reproducibility, and repeatability of BiO-SPE were also investigated. The BiO-SPEs were evaluated toward the sensing of APAP and INH in human serum, urine, saliva, and tablet samples. The results presented in this paper demonstrate that BiO-SPEs sensing platforms provide a potential candidate for the accurate determination of APAP and INH within human fluids and pharmaceutical formulations.
- Mahmoud, Bahaa G.,Khairy, Mohamed,Rashwan, Farouk A.,Banks, Craig E.
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p. 2170 - 2178
(2017/08/10)
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- Kinetics and mechanism of oxidation of the anti-tubercular prodrug isoniazid and its analog by iridium(IV) as models for biological redox systems
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A complex reaction mechanism of oxidation of the anti-tubercular prodrug isoniazid (isonicotinic hydrazide, INH) by [IrCl6]2- as a model for redox processes of such drugs in biological systems has been studied in aqueous solution as a function of pH between 0 and 8.5. Similar experiments have been performed with its isomer nicotinic hydrazide (NH). All reactions are overall second-order, first-order in [IrCl6]2- and hydrazide, and the observed second-order rate constants k′ have been determined as a function of pH. Spectrophotometric titrations indicate a stoichiometry of [Ir(iv)]:[hydrazide] = 4:1. HPLC analysis shows that the oxidation product of INH is isonicotinic acid. The derived reaction mechanism, based on rate law, time-resolved spectra and stoichiometry, involves parallel attacks by [IrCl6]2- on all four protolytic species of INH and NH as rate-determining steps, depending on pH. These steps are proposed to generate two types of hydrazyl free radicals. These radicals react further in three rapid consecutive processes, leading to the final oxidation products. Rate constants for the rate-determining steps have been determined for all protolytic species I-IV of INH and NH. They are used to calculate reactivity-pH diagrams. These diagrams demonstrate that for both systems, species IV is ca. 105 times more reactive in the redox process than the predominant species III at the physiological pH of 7.4. Thus, species IV will be the main reactant, in spite of the fact that its concentration at this pH is extremely low, a fact that has not been considered in previous work. The results indicate that pH changes might be an important factor in the activation process of INH in biological systems also, and that in such systems this process most likely is more complicated than previously assumed.
- Dong, Jingran,Ren, Yanli,Sun, Sufang,Yang, Jiao,Nan, Chunxia,Shi, Hongmei,Xu, Jianzhong,Duan, Jie,Shi, Tiesheng,Elding, Lars I.
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supporting information
p. 8377 - 8386
(2017/07/12)
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- Iodine catalyzed oxidation of alcohols and aldehydes to carboxylic acids in water: A metal-free route to the synthesis of furandicarboxylic acid and terephthalic acid
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A metal-free iodine/NaOH-catalyzed oxidation of alcohols and aldehydes has been developed for the practical synthesis of a wide range of carboxylic acids using water as the solvent. This transformation involves dehydrogenation of an alcohol, followed by a fast attack of water on an aldehyde. This method is mostly free from chromatographic purification, which makes it suitable for large-scale synthesis. The iodine species formed during the reaction as the active oxidation catalyst has been deduced as IO2- by control experiments. We also demonstrate a 10 gram scale synthesis of furandicarboxylic acid (FDCA) from HMF in good yield using our method.
- Hazra, Susanta,Deb, Mayukh,Elias, Anil J.
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supporting information
p. 5548 - 5552
(2017/12/06)
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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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- 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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- One-pot oxidative cleavage of olefins to synthesize carboxylic acids by a telescoped ozonolysis-oxidation process
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A mild one-pot ozonolysis-oxidation process of alkenes to synthesize carboxylic acids is described. Conducting the ozonolysis in an aqueous organic solvent eliminates secondary ozonide formation and the intermediates generated are readily converted into a carboxylic acid by adding sodium chlorite. Following a reductive quench, the desired acids are isolated in high purity and high yield by simple extraction.
- Cochran, Brian M.
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supporting information
p. 245 - 248
(2016/01/20)
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- Gem-Diol and Hemiacetal Forms in Formylpyridine and Vitamin-B6-Related Compounds: Solid-State NMR and Single-Crystal X-ray Diffraction Studies
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The gem-diol moieties of organic compounds are rarely isolated or even studied in the solid state. Here, liquid- and solid-state NMR, together with single-crystal X-ray diffraction studies, were used to show different strategies to favor the gem-diol or carbonyl moieties and to isolate hemiacetal structures in formylpyridine and vitamin-B6-related compounds. The change in position of the carbonyl group in pyridine compounds had a clear and direct effect on the hydration, which was enhanced by trifluoroacetic acid addition. Because of their biochemical importance, vitamin-B6-related compounds were studied with emphasis on the elucidation of the gem-diol, cyclic hemiacetal or carbonyl structures that can be obtained in different experimental conditions. In particular, new racemic mixtures for the cyclic hemiacetal structure from pyridoxal are reported in trifluoroacetate and hydrochloride derivatives.
- Crespi, Ayelén Florencia,Vega, Daniel,Chattah, Ana Karina,Monti, Gustavo Alberto,Buldain, Graciela Yolanda,Lázaro-Martínez, Juan Manuel
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p. 7778 - 7785
(2016/10/13)
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- Polyurethane nanomicelles: A novel eco-friendly and efficient polymeric ionic solvent for the Cannizzaro reaction
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Aqueous polyurethane dispersions (APUDs) are commodity synthetic polymers and have a broad range of well-known applications, nevertheless their possible use as a green catalyst or ionic solvent is yet unknown. Here, we demonstrate how a polyurethane dispersion facilitates the progress of the Cannizzaro reaction under very mild alkaline conditions. We introduce anionic polyurethane nanomicelles as an expeditious green polymer ionic solvent for the Cannizzaro reaction. The reusable and novel eco-friendly polymer solvent, excellent yields of the products, low reaction times and low reaction temperatures are the main advantages of this reaction.
- Daemi, Hamed,Barikani, Mehdi,Jahani, Mehdi
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supporting information
p. 2121 - 2125
(2016/03/19)
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- Catalytic hydrolysis of hydrophobic esters on/in water by high-silica large pore zeolites
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Hydrolysis of water-insoluble esters is an industrially important but challenging reaction, because the esters are mostly present in oil droplets on water during the reaction. On the basis of the screening results for hydrolysis of a water-insoluble ester, 3-phenylpropionate, on/in water by 25 types of heterogeneous and homogenous catalysts, we have found that Hβ zeolite with a moderate Si/Al ratio (Si/Al = 75), Hβ-75, is an effective and reusable catalyst for hydrolysis of hydrophobic esters. The hydrolysis of esters with different sizes is studied by Hβ and HZSM5 zeolites with different Si/Al ratios, and the results show the hydrophobicity, pore size and number of Br?nsted acid sites are critical factors affecting the catalytic activity for this system. Kinetic and adsorption studies show that the high yields by Hβ-75 are due to preferential interaction of the hydrophobic zeolite pore with hydrophobic esters over polar molecules (carboxylic acids, water, alcohols) and transfer of the carboxylic acids to the oil droplets on water, both of which inhibit the reverse reaction (esterification of the carboxylic acids).
- Siddiki,Toyao, Takashi,Kon, Kenichi,Touchy, Abeda S.,Shimizu, Ken-ichi
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p. 741 - 748
(2016/12/09)
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- Platinum nanoparticles supported on polymeric ionic liquid functionalized magnetic silica: effective and reusable heterogeneous catalysts for the selective oxidation of alcohols in water
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In this research, the syntheses of core-shell magnetic silica nanostructures, functionalized by a polymeric ionic liquid and immobilization of platinum nanoparticles, are described. Firstly, the magnetic silica nanoparticles were synthesized and modified using an amine-containing organosilane through a single-step process. The synthesized nanostructures were functionalized by the synthesis and polymerization of a pyridinium ionic liquid and a methyl methacrylate monomer, respectively, onto their surfaces. The platinum nanoparticles were immobilized on the functionalized nanoparticles. The obtained functionalized nanostructures have been used in the selective aerobic oxidation, in an aqueous medium, of primary and encumbered secondary aliphatic alcohols, and exhibit high activity at mild temperatures.
- Vessally, Esmail,Ghasemisarabbadeih, Mostafa,Ekhteyari, Zeynab,Hosseinzadeh-Khanmiri, Rahim,Ghorbani-Kalhor, Ebrahim,Ejlali, Ladan
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p. 106769 - 106777
(2016/11/25)
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- Deoxygenation of amine N-oxides using gold nanoparticles supported on carbon nanotubes
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Deoxygenation of a variety of aromatic and aliphatic amine N-oxides has been carried out in excellent yield using dimethylphenylsilane as the reducing agent under the catalytic influence of a carbon nanotube-gold nanohybrid at room temperature. Low catalyst loading, good TON and TOF values, and recyclability of the catalyst are some of the salient features of our methodology.
- Donck, Simon,Gravel, Edmond,Shah, Nimesh,Jawale, Dhanaji V.,Doris, Eric,Namboothiri, Irishi N. N.
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p. 50865 - 50868
(2015/06/25)
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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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- Complexation of tetrakis(acetato)chloridodiruthenium with naphthyridine-2,7-dicarboxylate - Characterization and catalytic activity
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The reaction of calcium naphthyridine-2,7-dicarboxylate (Cadcnp) with Ru2(OAc)4Cl in water resulted in the formation of Ca[Ru2(dcnp)(OAc)3]2 (3). X-ray crystal structural analysis of 3 confirmed its molecular structure and showed that the calcium ion binds to the lateral carboxylate groups of four neighboring anionic units of [Ru2(dcnp)(μ-OAc)3] and two acetone molecules to form a two-dimensional framework. The RuII-RuII valence state of the diruthenium core was supported by superconducting quantum interference device (SQUID) magnetometry [μeff (300 K) = 2.77 μB]. Complex 3 appears to be an efficient catalyst for the oxidative cleavage of olefins in aqueous media under mild conditions. Typically, the reaction of pulegone with NaIO4 in water catalyzed by 3 (1 mol-%) at 45 C afforded 3-methyladipic acid quantitatively. The reaction of calcium naphthyridine-2,7-dicarboxylate (Cadcnp) with Ru2(OAc)4Cl provides Ca[Ru2(dcnp)(OAc)3]2 as the exclusive product. The complex is catalytically active for the oxidative cleavage of olefins in aqueous media.
- Lee, Chia-Han,Wu, Cai-Ling,Hua, Shao-An,Liu, Yi-Hung,Peng, Shie-Ming,Liu, Shiuh-Tzung
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p. 1417 - 1423
(2015/03/18)
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- Ultrasound assisted direct oxidative esterification of aldehydes and alcohols using graphite oxide and Oxone
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A sonochemical procedure for direct oxidative esterification of aldehydes and alcohols using graphite oxide and Oxone in an alcoholic solvent is described. Mild reaction conditions, short reaction times, cost-effectiveness, and facile isolation of the products make the present system as a practical method.
- Mirza-Aghayan, Maryam,Zonoubi, Somayeh,Molaee Tavana, Mahdieh,Boukherroub, Rabah
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p. 359 - 364
(2014/10/16)
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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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- 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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