- Electrochemical Properties of Hydroxyphenazine-Coated Electrodes
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Glass carbon and gold electrodes were coated with 1-hydroxyphenazine, and the electrochemical properties of these electrodes were tested using them as a rotating disc electrode to reduce Ru(bipy)33+, Fe3+, quinoxaline, O2, and to oxidize Eu2+.The fixed redox couple can be reversibly reduced and oxidized, and acts as an intermediate medium for the electron transfer.For example the Ru(bipy)33+ (E1/2= 1010 mV vs.SCE. (saturated calomel electrode) on a glassy carbon electrode in 1M H2SO4) is only reduced at 50 mV, whereas the oxidation of Eu2+( E1/2= -460 mV vs.SCE. on a Hg-electrode in 1M HCl) takes place at -100 mV.The heterogeneous rate constant depends on the second order reaction between the attached coating and the redox couple in solution.Depending on this rate constant, selectivity of the electrode is observed.
- Haas, Otto,Zumbrunnen, Hans-Rudolf
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Read Online
- Synthesis of 1-substituted phenazines as novel antichlamydial agents
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A novel series of 1-substituted phenazines 4a-4l were designed and synthesized via Palladium-catalyzed reactions from 1-phenazine trifluoromethanesulfonate. These phenazines showed antichlamydial activity with IC50 values from 1 to 10 μM. Among them, compounds 4c and 4i exhibited the best antichlamydial activity with IC50 values from 2.06 to 2.74 μM without apparent cytotoxicity to host cells.
- Bao, Xiao-Feng,Jiang, He,Liu, Zi-Yi,Xie, Wen-Xia,Zhao, Yu,Zhu, Li,Zhu, Yi-Xin
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- Design, synthesis and biological evaluations of diverse Michael acceptor-based phenazine hybrid molecules as TrxR1 inhibitors
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A series of novel phenazine derivatives (1~27) containing the Michael acceptor scaffolds were designed and synthesized in this study. Some compounds exhibited selective cytotoxicity against Bel-7402 cancer cell line in vitro, in which compound 26 were found to have the best antiproliferative activity. Meanwhile, compound 26 showed no obvious cell toxicity against human normal liver epithelial L02 cells, which means this compound possessed a better safety potential. In the following research, compound 26 was verified to inhibit TrxR1 enzyme activity, ultimately resulting in cellular molecular mechanism events of apoptosis including growth of intracellular ROS level, depletion of reduced Trx1, liberation of ASK1 and up-regulation of p38, respectively. Together, all these evidences implicated that compound 26 acted as the TrxR1 inhibitor against Bel-7402 cells, and could activate apoptosis through the ROS-Trx-ASK1-p38 pathway.
- Zhong, Yucheng,Liu, Jing,Cheng, Xiangyu,Zhang, Hao,Zhang, Chunhua,Xia, Zhuolu,Wu, Zhongxi,Zhang, Lu,Zheng, Yuting,Gao, Zhanyu,Jiang, Zhidong,Wang, Zhixiang,Huang, Dechun,Lu, Yuanyuan,Jiang, Feng
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- BIOMARKER PANEL TARGETED TO DISEASES DUE TO MULTIFACTORIAL ONTOLOGY OF GLYCOCALYX DISRUPTION
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The present disclosure provides biomarkers useful as companion diagnostics for detecting glycocalyx-based disease that is amenable to treatment using compounds designed for improving the condition of the glycocalyx and/or reducing inflammation and/or oxidative damage, as well as related compositions, kits, and methods.
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Paragraph 0291; 0305
(2021/04/02)
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- Synthesis of phenazines from ortho-bromo azo compounds via sequential Buchwald-Hartwig amination under micellar conditions and acid promoted cyclization
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Non-symmetric phenazines were synthesized via the Buchwald-Hartwig amination of ortho-bromoazobenzenes with anilines under micellar conditions, using the commercially available surfactant Kolliphor EL in water, followed by an acid-promoted 6π-electrocyclization-aromatization process. Two different synthetic pathways to obtain the ortho-bromo azo intermediates were explored, namely the palladium catalysed selective ortho bromination of azobenzenes and the diazo coupling of ortho-bromo diazonium salts with N,N-dimethylaniline, imidazole, phenol, sodium methanesulfinate and ethyl chloroformate.
- Yousif, Dawod,Monti, Mauro,Papagni, Antonio,Vaghi, Luca
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supporting information
(2020/10/19)
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- A Simple and Efficient Flow Preparation of Pyocyanin a Virulence Factor of Pseudomonas aeruginosa
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The synthesis of the naturally occurring toxin pyocyanin has been realized in a short 4 step sequence. The key photochemical reaction and isolation of the final product have been facilitated by the use of flow chemistry techniques and immobilised reagents. Using these procedures gram quantities of pyocyanin were easily prepared in high yield and purity.
- Mortzfeld, Frederik B.,Pietruszka, J?rg,Baxendale, Ian R.
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p. 5424 - 5433
(2019/06/13)
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- Functional and Structural Analysis of Phenazine O -Methyltransferase LaPhzM from Lysobacter antibioticus OH13 and One-Pot Enzymatic Synthesis of the Antibiotic Myxin
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Myxin is a well-known antibiotic that had been used for decades. It belongs to the phenazine natural products that exhibit various biological activities, which are often dictated by the decorating groups on the heteroaromatic three-ring system. The three rings of myxin carry a number of decorations, including an unusual aromatic N5,N10-dioxide. We previously showed that phenazine 1,6-dicarboxylic acid (PDC) is the direct precursor of myxin, and two redox enzymes (LaPhzS and LaPhzNO1) catalyze the decarboxylative hydroxylation and aromatic N-oxidations of PDC to produce iodinin (1.6-dihydroxy-N5,N10-dioxide phenazine). In this work, we identified the LaPhzM gene from Lysobacter antibioticus OH13 and demonstrated that LaPhzM encodes a SAM-dependent O-methyltransferase converting iodinin to myxin. The results further showed that LaPhzM is responsible for both monomethoxy and dimethoxy formation in all phenazine compounds isolated from strain OH13. LaPhzM exhibits relaxed substrate selectivity, catalyzing O-methylation of phenazines with non-, mono-, or di-N-oxide. In addition, we demonstrated a one-pot biosynthesis of myxin by in vitro reconstitution of the three phenazine-ring decorating enzymes. Finally, we determined the X-ray crystal structure of LaPhzM with a bound cofactor at 1.4 ? resolution. The structure provided molecular insights into the activity and selectivity of the first characterized phenazine O-methyltransferase. These results will facilitate future exploitation of the thousands of phenazines as new antibiotics through metabolic engineering and chemoenzymatic syntheses.
- Jiang, Jiasong,Guiza Beltran, Daisy,Schacht, Andrew,Wright, Stephen,Zhang, Limei,Du, Liangcheng
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p. 1003 - 1012
(2018/04/30)
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- Haptenes and Conjugates Derived from Pyocyanin, Antibodies Thereof, and Immunichemical Method for Detecting Infections Caused by Pseudomonas Aeruginosa
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The present invention relates to a compound of general formula I and to the use thereof as a hapten. An object of the present invention is also a conjugate of said compound I with a carrier protein or fragment thereof, with a detectable labelling agent, or with a polymer or support, and to the use thereof for producing antibodies. Furthermore, the present invention also relates to a method for the detection and/or quantification of 1-hydroxyphenazine and/or pyocyanin using said antibodies and conjugates for the detection of infections caused by Pseudomonas aeruginosa.
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Paragraph 0200; 0201
(2016/02/22)
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- PHENAZINE DERIVATIVES AS ANTIMICROBIAL AGENTS
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The present invention provides novel phenazine derivatives, such as compounds of Formula (I) and (II), and pharmaceutically acceptable salts thereof. The compounds of the invention are expected to be anitmicrobial agents and may act by a microbial warfare strategy (e.g., a reactive oxygen species (ROS)-based competition strategy). The present invention also provides pharmaceutical compositions, kits, uses, and methods that involve the compounds of the invention and may be useful in preventing or treating a microbial infection (e.g., a bacterial infection) in a subject, inhibiting the growth and/or reproduction of a microorganism (e.g., a bacterium), killing a microorganism (e.g., a bacterium), inhibiting the formation and/or growth of a biofilm, or reducing or clearing a biofilm.
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Paragraph 00302-00305
(2015/07/15)
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- Phenazine antibiotic inspired discovery of potent bromophenazine antibacterial agents against Staphylococcus aureus and Staphylococcus epidermidis
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Nearly all clinically used antibiotics have been (1) discovered from microorganisms (2) using phenotype screens to identify inhibitors of bacterial growth. The effectiveness of these antibiotics is attributed to their endogenous roles as bacterial warfare agents against competing microorganisms. Unfortunately, every class of clinically used antibiotic has been met with drug resistant bacteria. In fact, the emergence of resistant bacterial infections coupled to the dismal pipeline of new antibacterial agents has resulted in a global health care crisis. There is an urgent need for innovative antibacterial strategies and treatment options to effectively combat drug resistant bacterial pathogens. Here, we describe the implementation of a Pseudomonas competition strategy, using redox-active phenazines, to identify novel antibacterial leads against Staphylococcus aureus and Staphylococcus epidermidis. In this report, we describe the chemical synthesis and evaluation of a diverse 27-membered phenazine library. Using this microbial warfare inspired approach, we have identified several bromophenazines with potent antibacterial activities against S. aureus and S. epidermidis. The most potent bromophenazine analogue from this focused library demonstrated a minimum inhibitory concentration (MIC) of 0.78-1.56 μM, or 0.31-0.62 μg mL-1, against S. aureus and S. epidermidis and proved to be 32- to 64-fold more potent than the phenazine antibiotic pyocyanin in head-to-head MIC experiments. In addition to the discovery of potent antibacterial agents against S. aureus and S. epidermidis, we also report a detailed structure-activity relationship for this class of bromophenazine small molecules.
- Borrero, Nicholas V.,Bai, Fang,Perez, Cristian,Duong, Benjamin Q.,Rocca, James R.,Jin, Shouguang,Huigens Iii, Robert W.
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supporting information
p. 881 - 886
(2014/02/14)
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- Unusual friedlander reactions: A route to novel quinoxaline-based heterocycles
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Acid catalyzed Friedlander reactions of a number of 2,3-dihydro-1H- cyclopenta[b]quinoxaline-1-ones with 2-aminobenzaldehyde yield, unexpectedly, 8H-indolo[3,2-a]phenazine and quinolino[2,3-c]cyclopentadienone[2,3-b] quinoxalines, the structures of derivatives of which were confirmed by X-ray crystallography. Easy routes to novel quinoxaline-based indoles, quinolones, and quinoxaline-1,4-dioxides are reported, and proposed mechanisms for the unexpected products are discussed.
- Shoker, Tharallah A.,Ghattass, Khaled I.,Fettinger, James C.,Kurth, Mark J.,Haddadin, Makhluf J.
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supporting information; experimental part
p. 3704 - 3707
(2012/09/21)
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- Potential chemopreventive agents based on the structure of the lead compound 2-bromo-1-hydroxyphenazine, isolated from streptomyces species, strain CNS284
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The isolation of 2-bromo-1-hydroxyphenazine from a marine Streptomyces species, strain CNS284, and its activity against NF-κB, suggested that a short and flexible route for the synthesis of this metabolite and a variety of phenazine analogues should be developed. Numerous phenazines were subsequently prepared and evaluated as inducers of quinone reductase 1 (QR1) and inhibitors of quinone reductase 2 (QR2), NF-κB, and inducible nitric oxide synthase (iNOS). Several of the active phenazine derivatives displayed IC50 values vs QR1 induction and QR2 inhibition in the nanomolar range, suggesting that they may find utility as cancer chemopreventive agents.
- Conda-Sheridan, Martin,Marler, Laura,Park, Eun-Jung,Kondratyuk, Tamara P.,Jermihov, Katherine,Mesecar, Andrew D.,Pezzuto, John M.,Asolkar, Ratnakar N.,Fenical, William,Cushman, Mark
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experimental part
p. 8688 - 8699
(2011/02/28)
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- Palladium-catalyzed synthesis of quinoxaline derivatives
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A palladium-catalyzed reductive N-heteroannulation of enamines derived from 2-nitrobenzenamines forming mixtures of 1,2-dihydroquinoxalines and 3,4-dihydroquinoxalin-2-ones is described. The reactions are performed using bis(dibenzylideneacetone)palladium(0), 1,3-bis(diphenylphosphino)propane, and 1,10-phenanthroline in DMF under 6 atm of carbon monoxide at 70 °C.
- Wallace, Jeffery M.,S?derberg, Bj?rn C.G.,Tamariz, Joaquín,Akhmedov, Novruz G.,Hurley, Mathew T.
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p. 9675 - 9684
(2008/12/22)
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- Investigation on the photoreactions of nitrate and nitrite ions with selected azaarenes in water
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The photoreactions of selected azaarenes with nitrate and nitrite ions were investigated under irradiation at λ = 313 nm. The excitation of both anions leads to several photochemical reactions forming mainly hydroxyl radicals and nitrogen oxides. The purification capability of natural waters i.e. the oxidation of inorganic and organic substances results from the formation of hydroxyl radicals. Nitrated isomers of azaarenes were found among the main products of the investigated photoreactions. The nitrogen oxides were responsible for the production of nitrated derivatives which possess a high toxic potential. Their formation was explained by the parallel occurance of two mechanism, a molecular and a radical one. The molecular mechanism became more important with increasing ionisation potentials of the azaarenes. The spectrum of oxidized products corresponded to the one got in the photoreactions of azaarenes with hydrogen peroxide. The formation of several oxidation and nitration products of the pyridine ring with its low electron density was explained by the reaction of excited states of azaarenes. The photoreactions with nitrite ions only led to the formation of oxidized and nitrated products. Nitroso products were not formed. The reactivity of nitrogen monoxide is too low for its reaction with the azaarenes.
- Beitz, Toralf,Bechmann, Wolfgang,Mitzner, Rolf
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p. 351 - 361
(2007/10/03)
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