- Degradation of the antibacterial agents triclosan and chlorophene using hydrodechlorination by Al-based alloys
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Abstract: Triclosan and chlorophene are chlorinated phenols used as antimicrobial agents. Both compounds are ordinarily detected in aquatic environments. The aim of this study is to prove the reactivity of three different metallic alloys used as common re
- Pérko, Jan,Kamenická, Barbora,Weidlich, Tomá?
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Read Online
- Iron-catalyzed arene C-H hydroxylation
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The sustainable, undirected, and selective catalytic hydroxylation of arenes remains an ongoing research challenge because of the relative inertness of aryl carbon-hydrogen bonds, the higher reactivity of the phenolic products leading to over-oxidized by-products, and the frequently insufficient regioselectivity. We report that iron coordinated by a bioinspired L-cystine-derived ligand can catalyze undirected arene carbon-hydrogen hydroxylation with hydrogen peroxide as the terminal oxidant. The reaction is distinguished by its broad substrate scope, excellent selectivity, and good yields, and it showcases compatibility with oxidation-sensitive functional groups, such as alcohols, polyphenols, aldehydes, and even a boronic acid. This method is well suited for the synthesis of polyphenols through multiple carbon-hydrogen hydroxylations, as well as the late-stage functionalization of natural products and drug molecules.
- Cheng, Lu,Wang, Huihui,Cai, Hengrui,Zhang, Jie,Gong, Xu,Han, Wei
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- Method for promoting iron-catalyzed oxidation of aromatic compound carbon - hydrogen bond to synthesize phenol by ligand
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The method comprises the following steps: iron is used as - a catalyst metal; a sulfur-containing amino acid or cystine-derived dipeptide is a ligand; and under the common action of hydrogen peroxide as an oxidizing agent, an aromatic compound is synthesized to prepare a phenol. Under the action of an acid as an accelerant and hydrogen peroxide as an oxidizing agent, the aryl carbon - hydrogen bond is directly hydroxylated to form a phenolic compound, and the method for preparing the phenol by the catalytic oxidation reaction has a plurality of advantages. The reaction raw materials, the oxidant and the promoter are wide in source, low in price, environment-friendly and good in stability. The aromatic compound carbon - hydrogen bonds directly participate in the reaction to react in one step to form phenol. The reaction condition is mild, the functional group compatibility and the application range are wide. The reaction selectivity is good; under the optimized reaction conditions, the target product separation yield can reach 85%.
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Paragraph 0086-0087; 0128
(2021/09/21)
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- CoII Immobilized on Aminated Magnetic-Based Metal–Organic Framework: An Efficient Heterogeneous Nanostructured Catalyst for the C–O Cross-Coupling Reaction in Solvent-Free Conditions
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Abstract: In this paper, we report the synthesis of Fe3O4?AMCA-MIL53(Al)-NH2-CoII NPs based on the metal–organic framework structures as a magnetically separable and environmentally friendly heterogeneous nanocatalyst. The prepared nanostructured catalyst efficiently promotes the C–O cross-coupling reaction in solvent-free conditions without the need for using toxic solvents and/or expensive palladium catalyst. Graphic Abstract: [Figure not available: see fulltext.].
- Mohammadinezhad, Arezou,Akhlaghinia, Batool
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p. 332 - 352
(2020/01/11)
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- Further insights of selenium-containing analogues of WC-9 against Trypanosoma cruzi
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As a continuation of our project aimed at searching for new chemotherapeutic agents against American trypanosomiasis (Chagas disease), new selenocyanate derivatives were designed, synthesized and biologically evaluated against the clinically more relevant dividing form of Trypanosoma cruzi, the etiologic agent of this illness. In addition, in order to establish the role of each part of the selenocyanate moiety, different derivatives, in which the selenium atom or the cyano group were absent, were conceived, synthesized and biologically evaluated. In addition, in order to study the optimal position of the terminal phenoxy group, new regioisomers of WC-9 were synthesized and evaluated against T. cruzi. Finally, the resolution of a racemic mixture of a very potent conformationally rigid analogue of WC-9 was accomplished and further tested as growth inhibitors of T. cruzi proliferation. The results provide further insight into the role of the selenocyanate group in its antiparasitic activity.
- Chao, María N.,Lorenzo-Ocampo, María V.,Szajnman, Sergio H.,Docampo, Roberto,Rodriguez, Juan B.
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p. 1350 - 1361
(2019/02/25)
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- Investigation of Iodonium Trifluoroborate Zwitterions as Bifunctional Arene Reagents
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The synthesis of a new family of iodonium zwitterions, in which the formal anion is a trifluoroborate moiety, is reported. These reagents present very good stability and have high resistance toward benzyne formation. Their structures were confirmed by X-ray crystallographic analysis and were further investigated using DFT calculations. QTAIM analysis supports an ionic, noncovalent, I+···BF3- interaction, in accordance with a true zwitterionic nature. Preliminary results of synthetic applications, the arylation of phenolates and trifluoroborate group functionalization, are reported.
- Robidas, Rapha?l,Guérin, Vincent,Proven?al, Laurent,Echeverria, Marco,Legault, Claude Y.
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supporting information
p. 6420 - 6423
(2017/12/08)
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- Direct oxidation of the C(sp2)-C(sp3) bond from benzyltrimethylsilanes to phenols
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A novel pathway for direct conversion of benzylsilanes to phenols by oxidation with Na2S2O8 and oxygen is efficiently developed under mild and neutral conditions. The reaction shows good functional group tolerance to afford phenols in moderate yields. The possible mechanism is proposed based on the isotopic labeling trials.
- Li, Wei,Gao, Guolin,Gao, Yuan,Yang, Chao,Xia, Wujiong
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supporting information
p. 5291 - 5293
(2017/07/10)
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- Synthesis of SiO2 coated zero-valent iron/palladium bimetallic nanoparticles and their application in a nano-biological combined system for 2,2′,4,4′-tetrabromodiphenyl ether degradation
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Polybrominated diphenyl ethers (PBDEs) are emerging persistent organic pollutants and the degradation of PBDEs is still a significant challenge owing to their extreme persistence and toxicity. In this study, the remediation of 2,2′,4,4′-tetrabromodiphenyl ether (BDE47) was investigated by employing a nano-biological combined system with SiO2-coated zero-valent iron/palladium bimetallic nanoparticles (SiO2-nZVI/Pd) as a reductant and Pseudomonas putida as a biocatalyst. The SiO2-nZVI/Pd exhibited much lower toxicity to the P. putida strain and higher reactivity in debromination than nZVI/Pd. The strain could grow well when the dosage was up to 1.0 g L-1. During the combined process, BDE47 (5 mg L-1) was completely debrominated to diphenyl ether (DE) within 2 h by SiO2-nZVI/Pd (1.0 g L-1) and then DE was completely degraded by P. putida after 4 days in sequential aerobic biodegradation. All the possible intermediates in the whole process were identified by ultra performance liquid chromatography (UPLC) and gas chromatography-mass spectrometer (GC-MS) analyses. The detection of BDE17, BDE7, BDE1 and DE indicated that rapidly stepwise debromination preferentially occurred at para positions in the anaerobic stage. Moreover, during aerobic biodegradation by P. putida, a number of phenolic compounds, such as phenol, catechol and hydroquinone were generated via ring opening by dioxygenation and further mineralized through the tricarboxylic acid cycle (TCA). Importantly, this combined process achieved rapid mineralization of PBDEs and avoided the generation of some highly toxic products like bromophenols and HO-PBDEs, which might have promising application prospects in the remediation of halogenated POPs.
- Lv, Yuancai,Niu, Zhuyu,Chen, Yuancai,Hu, Yongyou
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p. 20357 - 20365
(2016/03/04)
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- Metal-free oxidative aromatization of 2-aryloxycyclohex-2-en-1-ones to 2-aryloxyphenols using DDQ/Amberlyst-15
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Efficient metal-free oxidative aromatization of 2-aryloxycyclohex-2-en-1-ones was achieved by a combination of 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and Amberlyst-15. The conditions for oxidative aromatization are mild and applicable for a variety of substrates, and Amberlyst-15 can be successfully recovered and recycled.
- Jadhav,Samant
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p. 1301 - 1305
(2015/01/08)
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- Ipso-hydroxylation of arylboronic acids and boronate esters by using sodium chlorite as an oxidant in water
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A facile and efficient procedure for the ipso-hydroxylation of arylboronic acids to phenols in water was developed. A series of electron-rich and electron-deficient arylboronic acids were smoothly ipso-hydroxylated with this protocol to afford products in excellent yields. Moreover, the protocol is amenable to boronate esters. In most cases, the phenolic products were obtained in pure form without any chromatographic purification. An efficient procedure for the ipso-hydroxylation of arylboronic acids to phenols in water is reported. A wide range of electronically varied boronic acids are smoothly ipso-hydroxylated with this protocol, which is amenable to boronate esters. The reaction strategy is facile and clean, and the products are obtained in pure form and do not require chromatographic purification. Copyright
- Gogoi, Pranjal,Bezboruah, Pranjal,Gogoi, Junali,Boruah, Romesh C.
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supporting information
p. 7291 - 7294
(2013/11/19)
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- Riccardin C derivatives as anti-MRSA agents: Structure-activity relationship of a series of hydroxylated bis(bibenzyl)s
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Members of a series of macrocyclic bis(bibenzyl) riccardin-class derivatives were found to exhibit antibacterial activity towards methicillin-resistant Staphylococcus aureus (anti-MRSA activity). Structure-activity relationship (SAR) studies were conducted, focusing on the number and position of the hydroxyl groups. The minimum essential structure for anti-MRSA activity was also investigated.
- Sawada, Hiromi,Okazaki, Miki,Morita, Daichi,Kuroda, Teruo,Matsuno, Kenji,Hashimoto, Yuichi,Miyachi, Hiroyuki
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p. 7444 - 7447
(2013/02/21)
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- Design, synthesis, and pharmacological evaluation of azetedine and pyrrolidine derivatives as dual norepinephrine reuptake inhibitors and 5-HT 1A partial agonists
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Compounds with combined norepinephrine reuptake inhibitor (NRI) and serotonin 1A (5-HT1A) partial agonist pharmacology may offer a new therapeutic approach for treating symptoms of neuropsychiatric disorders including ADHD, depression, and anxiety. Herein we describe the design and optimization of novel chemical matter that exhibits favorable dual NRI and 5-HT1A partial agonist activity. Lead compounds in this series were found to be devoid of activity at the dopamine transporter and were shown to be brain penetrant with high receptor occupancy.
- Pettersson, Martin,Campbell, Brian M.,Dounay, Amy B.,Gray, David L.,Xie, Longfei,O'Donnell, Christopher J.,Stratman, Nancy C.,Zoski, Kim,Drummond, Elena,Bora, Gary,Probert, Al,Whisman, Tammy
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scheme or table
p. 865 - 868
(2011/02/27)
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- [4-(Phenoxy)pyridin-3-yl]methylamines: A new class of selective noradrenaline reuptake inhibitors
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[4-(Phenoxy)pyridine-3-yl]methylamines are disclosed as a new series of selective noradrenaline reuptake inhibitors (NRI). Structure-activity relationships established that potent NRI activity could be achieved by appropriate substitution at the 2-position of the phenoxy ring. Compound 31 demonstrated potent NRI activity combined with good selectivity over serotonin and dopamine reuptake and no significant off-target pharmacology.
- Fish, Paul V.,Ryckmans, Thomas,Stobie, Alan,Wakenhut, Florian
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p. 1795 - 1798
(2008/12/21)
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- (Hetero)aryl-bicyclic heteroaryl derivatives, their preparation and their use as protease inhibitors
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The present invention provides novel compounds of the Formula (I): A-B, its prodrug forms, or pharmaceutically acceptable salts thereof, wherein A represents a saturated, unsaturated, or a partially unsaturated bicyclic heterocyclic ring structure, and B represents an aryl or a heteroaryl group. Preferred compounds of the present invention comprise a benzimidazole or indole nucleus. The compounds of this invention are inhibitors of serine proteases, Urokinase (uPA), Factor Xa (FXa), and/or Factor VIIa (FVIIa), and have utility as anti cancer agents and/or as anticoagulants for the treatment or prevention of thromboembolic disorders in mammals.
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Page/Page column 28
(2010/02/11)
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- Inhibition of the Bacterial Enoyl Reductase FabI by Triclosan: A Structure-Reactivity Analysis of FabI Inhibition by Triclosan Analogues
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To explore the molecular basis for the picomolar affinity of triclosan for FabI, the enoyl reductase enzyme from the type II fatty acid biosynthesis pathway in Escherichia coli, an SAR study has been conducted using a series of triclosan analogues. Triclosan (1) is a slow, tight-binding inhibitor of FabI, interacting specifically with the E·NAD+ form of the enzyme with a K1 value of 7 pM. In contrast, 2-phenoxyphenol (2) binds with equal affinity to the E·NAD+ (K1 = 0.5 μM) and E·NADH (K2 = 0.4 μM) forms of the enzyme and lacks the slow-binding step observed for triclosan. Thus, removal of the three triclosan chlorine atoms reduces the affinity of the inhibitor for FabI by 70 000-fold and removes the preference for the E·NAD+ FabI complex. 5-Chloro-2-phenoxyphenol (3) is a slow, tight-binding inhibitor of FabI and binds to the E· NAD+ form of the enzyme (K1 = 1.1 pM) 7-fold more tightly than triclosan. Thus, while the two ring B chlorine atoms are not required for FabI inhibition, replacement of the ring A chlorine increases binding affinity by 450 000-fold. Given this remarkable observation, the SAR study was extended to the 5-fluoro-2-phenoxyphenol (4) and 5-methyl-2-phenoxyphenol (5) analogues to further explore the role of the ring A substituent. While both 4 and 5 are slow, tight-binding inhibitors, they bind substantially less tightly to FabI than triclosan. Compound 4 binds to both E·NAD+ and E·NADH forms of the enzyme with K 1 and K2 values of 3.2 and 240 nM, respectively, whereas compound 5 binds exclusively to the E·NADH enzyme complex with a K 2 value of 7.2 nM. Thus, the ring A substituent is absolutely required for slow, tight-binding inhibition. In addition, pKa measurements coupled with simple electrostatic calculations suggest that the interaction of the ring A substituent with F203 is a major factor in governing the affinity of analogues 3-5 for the FabI complex containing the oxidized form of the cofactor.
- Sivaraman, Sharada,Sullivan, Todd J.,Johnson, Francis,Novichenok, Polina,Cui, Guanglei,Simmerling, Carlos,Tonge, Peter J.
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p. 509 - 518
(2007/10/03)
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- Process for functionalising a phenolic compound carrying an electron-donating group
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The invention concerns a method for functionalizing a phenolic compound bearing an electron-donor group, in said group para position, inter alia a method for the amidoalkylation of a phenolic compound bearing an electron-donor group, and more particularly, a phenolic compound bearing an electron-donor group preferably, in the hydroxyl group ortho position. The method for functionalizing in para position with respect to an electron-donor group carried by a phenolic compound is characterised in that the phenolic compound bearing an electron-donor group is subjected to the following steps: a first step which consists of protecting the hydroxyl group in the form of a sulphonic ester function; a second step which consists in reacting the protected phenolic compound with an electrophilic reagent; optionally, a third step deprotecting the hydroxyl group.
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- Products, rates, and mechanism of the gas-phase condensation of phenoxy radicals between 500-840 K
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Phenols are demonstrated precursors of 'dioxins' - polychlorinated dibenzo-p-dioxins (DDs) and dibenzofurans (DFs) - in thermal processes, especially incineration. Heterogeneous catalysis, depending on conditions, can play an important role, but mere gas-phase combination of phenolic entities to ultimately DD and/or DF is always possible. The present paper addresses the fundamental role of phenol itself. Phenol has long been known to give DF upon pyrolysis and in similar thermal reactions. In the liquid phase under oxidative conditions it yields five condensation products (A-E); this clearly occurs through the dimerization of two phenoxy (PhO) radicals, followed by enolisation/rearomatisation. Our study shows that in the gas phase, at the lower T end, such dimers are also formed, but still with very little DF. That DF, indeed, is almost the only condensation product at elevated temperatures is substantiated by thermochemical-kinetic analysis (favouring the pathway of ortho-C/ortho-C combination of two PhO radicals), as well as by results obtained with two plausible intermediates, viz. 2,2'- dihydroxybiphenyl (A) and 2-phenoxyphenol (C). Mechanisms for the requisite enolisation and dehydration steps leading to DF are discussed.
- Wiater, Izabela,Born, Jan G. P.,Louw, Robert
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p. 921 - 928
(2007/10/03)
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- New preparation of oaryloxyphenols via cyclohexenone oxides
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Reaction of cyclohexenone oxides with phenols under basic two-phase conditions with sonication followed by oxidation represents a new, efficient two-step synthesis of o-aryloxyphenols. I American Chemical Society Arthur C. Cope Scholar, 1995.
- Jung, Michael E.,Starkey, Laurie S.
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p. 7363 - 7366
(2007/10/02)
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- Pair Formation of Phenol in the Vicinity of an Aqueous Solution Surface Studied by Means of Liquid Beam Multiphoton Ionization Mass Spectrometry
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An aqueous solution of phenol was introduced into vacuum as a continuous liquid flow (liquid beam) and was irradiated with a laser beam at a wavelength of 272 nm.Ions produced by multiphoton ionization in the liquid beam and ejected from it were analyzed by a time-of-flight mass spectrometer.The mass spectrum of ions ejected from the liquid beam exhibits peaks assignable to C6H5OH+(H2O)n, H3O+(H2O)n, and C6H5O+C6H5OH.The ions C6H5OH+ and H3O+ are considered to be produced in the liquid beam by multiphoton ionization of phenol and proton transfer from phenol to a water molecule, respectively; these ions are ejected into vacuum with the solvent water molecules.On the other hand, C6H5O+C6H5OH is considered to be produced mainly from a pair of phenol molecules in the vicinity of the solution surface.This ion is regarded as the precursor for formation of phenoxyphenol, C6H5OC6H4OH, which is known as a product of the ion-molecule reaction of C6H5O+ + C6H5OH in the liquid.An abrupt rise in the abundance of C6H5O+C6H5OH above 0.55 M indicates that the surface structure starts to change at this concentration to a new one where two phenol molecules are paired.
- Mafune, Fumitaka,Hashimoto, Yuichiro,Hashimoto, Mitsuo,Kondow, Tamotsu
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p. 13814 - 13818
(2007/10/02)
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- An umpoled synthon approach to the synthesis of 2-aryloxyphenols
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A convenient three-step method for the preparation of 2-aryloxyphenols from phenols and 2-fluorobenzaldehyde is described. Condensation of phenols with 2-fluorobenzaldehyde produces the intermediate 2-aryloxybenzaldehydes in 83-95% yield. These products rapidly undergo meta-chloroperbenzoic acid (m-CPBA) promoted Baeyer-Villiger oxidation to yield the corresponding 2-aryloxyphenyl formates which are hydrolyzed, without isolation, to give the desired 2-aryloxyphenols in 79-96% yield.
- Yeager,Schissel
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- Biotransformation of diphenyl ether by the yeast Trichosporon beigelii SBUG 752
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Trichosporon beigelii SBUG 752 was able to transform diphenyl ether. By TLC, HPLC, GC, GC-MS, NMR- and UV-spectroscopy, several oxidation products were identified. The primary attack was initiated by a monooxygenation step, resulting in the formation of 4-hydroxydiphenyl ether, 2-hydroxydiphenyl ether and 3-hydroxydiphenyl ether (48:47:5). Further oxidation led to 3,4-dihydroxydiphenyl ether. As a characteristic product resulting from the cleavage of an aromatic ring, the lactone of 2-hydroxy-4-phenoxymuconic acid was identified. The possible mechanism of ring cleavage to yield this metabolite is discussed.
- Schauer, Frieder,Henning, Kirsten,Pscheidl, Helmut,Wittich, Rolf M.,Fortnagel, Peter,et al.
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p. 173 - 180
(2007/10/03)
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- Imidazole 5-position substituted angiotensin II antagonists
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Novel substituted imidazoles of Formula (III), which are useful as angiotensin-II antagonists, are disclosed: STR1 These compounds, exemplified by the compound 1-((2'-((i-Amyloxycarbonylamino)sulfonyl)-3-fluoro-(1,1'-biphenyl)-4-yl)methyl)-5-[2-(N-butyryl-N-pyridin-3-ylamino) ethylcarbonyl]-4-ethyl-2-propyl-1H-imidazole, are useful as antihypertensive agents.
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- Products of oxidative coupllng of phenol by horseradish peroxidase
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The oxidation and coupling of phenol by horseradish peroxidase in the presence of hydrogen peroxide yielded dimers trimers and higher molecular weight polymers which are mostly insoluble in water, so the products may be removed by centrifugation. However we discovered some products, such as dimers o,o'-biphenol, p,p'-biphenol, o,p'-biphenol, o-phenoxyphenol and p-phenoxyphenol, even though trimer 4-(4-phenoxyphenoxy)phenol were present in the aqueous phase at a very low concentration.
- Huixian,Taylor
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p. 1807 - 1817
(2007/10/03)
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- Photochemistry of Dibenzo-1,4-dioxin: Formation of 2,2'-Biphenylquinone as an Observable Intermediate
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Photolysis of dibenzo-1,4-dioxin 1, which is parent ring system of the well-known environmental contaminant 'dioxin' an 2,3,7,8-tetramethyldibenzo-1,4-dioxin 2, in aqueous solution results in an novel intramolecular rearrangement, giving rise to intermedi
- Guan, Bing,Wan, Peter
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p. 409 - 410
(2007/10/02)
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- KINETICS AND MECHANISM OF THE REACTION OF OZONE WITH PHENOL IN ALKALINE MEDIA
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The kinetics of the reaction of O3 with PhOH in alkaline medium has been studied.The rate of oxidation of phenol by ozone is directly proportional to the concentrations of reactants and increases in a complex manner with increase in alkali content in aque
- Konstantinova, M. L.,Razumovskii, S. D.,Zaikov, G. E.
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p. 266 - 270
(2007/10/02)
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- Multiphoton Ionization of Phenol in Nonaqueous Solutions: Characterization of the Cation and Ion-Molecule Chemistry
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The phenoxy cation has been generated in polar and nonpolar solutions by two-photon ionization of phenol by using 2.5-ns pulses of 266 nm light.The ions have been characterized by pulsed conductivity (ion mobility) measurements and transient absorption spectroscopy with λmax = 290 - 300 nm and an estimated extinction coefficient of 1300 M-1 cm-1.The involvement of the phenoxy ion in ion-molecule chemistry with either neutral solute or solvent molecules has been observed.The kinetics of these processes as well as a proposed reaction mechanism are presented.
- Siuzdak, G.,North, S.,BelBruno, J. J.
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p. 5186 - 5190
(2007/10/02)
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- SECOND-ORDER COMBINATION REACTION OF PHENOXYL RADICALS
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Phenoxy radicals, when produced pulse radiolytically at concentrations > 1E-4 M, combine in second-order processes to give 2,2'-, 2,4', and 4,4'-dihydroxybiphenyl as the predominant products.The ratios of these products observed under a variety of conditi
- Ye, Mingyu,Schuler, Robert H.
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p. 1898 - 1902
(2007/10/02)
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- ARENE COMPLEXES OF TRANSITION METALS IN REACTIONS WITH NUCLEOPHILIC REAGENTS. XI. SYNTHESIS OF HETEROCYCLIC COMPOUNDS BY NUCLEOPHILIC SUBSTITUTION OF CHLORINE ATOMS IN η6-o-DICHLOROBENZENECHROMIUM TRICARBONYL
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A method was developed for the synthesis of dibenzo-1,4-dioxin, phenoxazine, and phenoxathiin and also their chromium tricarbonyl complexes by the reaction of η6-o-dichlorobenzenechromium tricarbonyl with the alkali-metal salts of pyrocatechol, o-aminophenol, and o-mercaptophenol in HMPTA.The composition of the reaction products and the yield of the heterocyclic compounds depend significantly on the nature of the solvent, the nucleophile, the condensing agent, and the reaction conditions.
- Litvak, V. V.,Goryunov, L. I.,Shteingarts, V. D.
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p. 138 - 144
(2007/10/02)
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- Cyclodienones. X. Reaction of Halo-cyclohexadien-1-ones with Phenols in the Presence of α-Picoline and Preparation of 4-Hydroxy- and 2-Hydroxyphenyl Aryl Ethers
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Reaction of 4-halocyclohexadienones such as 4-bromo-(1a), 4-chloro-2,4,6-tri-t-butyl-(1b), 2,4-dichloro-4,6-di-t-butyl-2,5-cyclohexadien-1-one, and 2,4-dichloro-2,6-di-t-butyl-3,5-cyclohexadien-1-one with phenols in the presence of α-picoline was carried out under various conditions.The reaction of 1a and 1b with phenols afforded the corresponding 2-aryloxy-4,6-di-t-butyl phenols together with various by-products.The AlCl3 catalyzed trans-t-butylation of 2-aroxy-4,6-di-t-butyl-phenols, which were obtained by the above reaction, afforded the corresponding 2-hydroxyphenyl aryl ethers.The similar reaction of 4-aroxy-2,4,6-tri-t-butyl-2,5-cyclohexadien-1-ones also afforded the corresponding 4-hydroxyphenyl aryl ethers.
- Tashiro, Masashi,Itoh, Takashi,Fukata, Gouki
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p. 416 - 420
(2007/10/02)
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- THE ROLE OF STEREOELECTRONIC FACTORS IN THE OXIDATION OF PHENOLS
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The oxidative coupling of both 3,5-dimethylphenol and phenol leads to the ortho-ortho and ortho-para coupled products as the predominant C-C dimers: stereoelectronic factors determine the preferred mode of approach of the phenoxyl radicals.
- Armstrong, David R.,Breckenridge, Robin J.,Cameron, Colin,Nonhebel, Derek C.,Pauson, Peter L.,Perkins, Peter G.
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p. 1071 - 1074
(2007/10/02)
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- Oxidativ Coupling of Phenols. Part 6. A Study of the Role of Spin Density Factors on the Product Composition in the Oxidations of 3,5-Dimethylphenol and Phenol
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Oxidations of both 3,5-dimethyphenol and phenol with di-t-butyl peroxide at 140 degC gave as the major product the ortho-ortho-C-C coupled dimer, while oxidations with di-t-butyl peroxyoxalate at room temperature give much more of the ortho-para-C-C dimer.The results are not consistent either with the spin density distribution in the phenoxyl radical intermediates or with steric effects being the major factor which determines the product composition.It is proposed that the two phenoxyl radicals involved in coupling preferentially approach each other in a 'sandwich like' manner with the oxigens in a 1,3-relationship.
- Armstrong, David R.,Cameron, Colin,Nonhebel, Derek C.,Perkins, Peter G.
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p. 563 - 568
(2007/10/02)
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- Method for manufacture of dihydric phenols
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Dihydric phenols are produced preferentially in high yields by having monohydric phenols or phenyl ethers oxidized by an organic peracid using, as a catalyst, at least one member selected from the group consisting of peracid stabilizers, polycarboxylic acids containing N or OH and possessed of a structure from which heavy metal ion-chelating property can theoretically be assumed, magnesium salts, sodium salts and potassium salts thereof, sodium salt, potassium salt and lower alkyl esters of phosphoric acid, and sodium salt and lower alkyl esters of pyrophosphoric acid.
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