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Sample records for quinoxalines

  1. Quinoxaline ozonation in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Andreozzi, R.; Caprio, V.; D' Amore, M.G.; Insola, A. (Universita di Napoli (Italy))

    The oxidation of quinoxaline by ozone in aqueous solution is investigated. The chemical and kinetic evolution of the oxidation process at varying pH are followed by means of semi-batch and batch ozonation experiments. Results indicate that quinoxaline ozonation can develop according to both radical and ionic mechanisms whose relative occurrence can be varied by means of addition to the reacting system of radical scavengers or ozone decomposition promoters. It is shown that each mechanism involves an initial attack of ozone to both the homocyclic and heterocyclic rings of quinoxaline. Pyrazinedicarboxylic acid is formed as a stable final product in ionic ozonation, whereas it appears as an intermediate still reactive towards ozone in radical ozonation. Despite this, the radical ozonation of quinoxaline appears to be more selective than ionic ozonation with respect to production of pyrazinedicarboxylic acid. Reaction schemes are proposed to account for the observed kinetic behaviors and product formations. Oxidation experiments have also been extended to pyrazine, and its sensitivity to only radical ozonation is shown.

  2. Ugi-based approaches to quinoxaline libraries.

    Science.gov (United States)

    Azuaje, Jhonny; El Maatougui, Abdelaziz; García-Mera, Xerardo; Sotelo, Eddy

    2014-08-11

    An expedient and concise Ugi-based unified approach for the rapid assembly of quinoxaline frameworks has been developed. This convergent and versatile method uses readily available commercial reagents, does not require advanced intermediates, and exhibits excellent bond-forming efficiency, thus exemplifying the operationally simple synthesis of quinoxaline libraries.

  3. Quinoxaline-Based Cyclo(oligophenylenes).

    Science.gov (United States)

    Marin, Lidia; Kudrjasova, Julija; Verstappen, Pieter; Penxten, Huguette; Robeyns, Koen; Lutsen, Laurence; Vanderzande, Dirk J M; Maes, Wouter

    2015-02-20

    A series of fully conjugated quinoxaline-based oligophenylene macrocycles is synthesized by Ni(0)-mediated Yamamoto-type diaryl homocoupling of (fluorinated) 2,3-bis(4'-bromophenyl)quinoxaline precursors. Cyclotrimers and cyclotetramers are obtained as the dominant reaction products. The cyclooligomers are fully characterized, including single-crystal X-ray structures, and their optoelectronic properties are analyzed with respect to possible applications in host-guest chemistry and organic electronics.

  4. Two Dimensional Aggregation Behaviors of Quinoxaline Dendrimers.

    Science.gov (United States)

    Choi, Soyoung; Lee, Hoik; Kim, Hwan Kyu; Lee, Sang Uck; Sohn, Daewon

    2015-02-01

    This study focuses on the molecular behavior of two dendrimers containing a hydrophilic core group (carboxyl group) and hydrophobic branches (quinoxaline and methoxyphenyl groups), 2,3-bis(4-(2,3- bis(4-methoxyphenyl)quinoxalin-6-yloxy)phenyl)quinoxaline-6-carb-oxylic acid (G2) and 2,3-bis(4-(2,3-bis(4-(2,3-bis(4-methoxyphenyl)quinoxalin-6-yloxy)phe-nyl)quinoxalin-6-y-oxy)phenyl) quin oxaline-6-carboxylic acid (G3) at the air-water interface. To understand the mechanism of the self-assembly of these molecules, we measured the surface pressure-area (III-A) isotherm and investigated the surface morphology of Langmuir-Blodgett films transferred onto hydrophilic silicon wafers using atomic force microscopy (AFM). Upon compression, G2 molecules stand up and steadily make close-packed monolayer whereas G3 molecules form circular domains and gradually make aggregates of domains. These results were confirmed by the X-ray Reflectivity (XRR) profiles of G2 and G3 monolayers transferred onto silicon substrates.

  5. Nucleophilic Substitution on 2-Monosubstituted Quinoxalines Giving 2,3-Disubstituted Quinoxalines: Investigating the Effect of the 2-Substituent

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    Ndumiso Thamsanqa Ndlovu

    2016-09-01

    Full Text Available An investigation on the effect of substituent at the 2-position of mono-substituted quinoxalines in the synthesis of di-substituted quinoxaline derivatives via nucleophilic substitution reactions, is reported. Di-substituted quinoxalines bearing aryl-alky, aryl-aryl, aryl-heteroaryl, aryl-alkynyl, and amino-alkyl substituents were prepared in moderate to good yields. 2-Monosubstituted quinoxalines bearing a phenyl and butyl substituent reacted readily with alkyl-, aryl-, heteroaryl- and alkynyl- nucluephiles, giving di-substituted quinoxalines. 2-Monosubstituted quinoxalines bearing an amine and alkynyl substituent only reacted with alkyl nucleophiles. Oxidative rearomatization to give 2,3-disubstituted quinoxaline products occurred in atmospheric O2.

  6. AgNO2-mediated direct nitration of the quinoxaline tertiary benzylic C-H bond and direct conversion of 2-methyl quinoxalines into related nitriles.

    Science.gov (United States)

    Wu, Degui; Zhang, Jian; Cui, Jianhai; Zhang, Wei; Liu, Yunkui

    2014-09-25

    A unique method for AgNO2-mediated direct nitration of the quinoxaline tertiary C-H bond and direct conversion of 2-methyl quinoxalines into 2-quinoxaline nitriles under oxidative conditions has been developed. This protocol provides an efficient way to access quinoxaline containing nitroalkanes and nitriles depending on different substrate selection.

  7. Antimicrobial Evaluation and Synthesis of Some Phenylpyrazolo benzothiazolo quinoxaline Derivatives

    OpenAIRE

    2009-01-01

    2,3-Diphenyl quinoxaline (SI) was fused with 2-amino benzothiazoles (SII) by a methylene bridge, which was then allowed for acetylation. The acetylated product (SIV) was made to react with different aromatic aldehydes to give chalcones (SV1-SV5). Chalcones refluxed with substituted acid hydrazides to afford different phenyl pyrazolo benzothiazolo quinoxaline derivatives (SVI1-SVI15). The structure of chalcones and phenyl pyrazolo benzothiazolo quinoxaline derivatives were confirmed by M.P, TL...

  8. Recent advances in design of potential quinoxaline anti-infectives.

    Science.gov (United States)

    Jampilek, Josef

    2014-01-01

    Antimicrobial diazanaphthalenes are indispensable in the treatment of various infections. The quinoxaline scaffold possesses unique physicochemical properties and provides a possibility of a great number of targeted modifications. Quinoxaline-based compounds have a wide range of promising biological properties; therefore a special attention is paid to them for research and designing of new drugs. In fact, quinoxaline can be considered as a privileged structure. The scaffold can be easily and rapidly constructed, which emphasizes the significance of this favourable structure. The review is focused on recently reported potential antibacterial, antimycobacterial, antifungal and antiprotozoal agents derived from the quinoxaline scaffold, their mechanism of action and structure-activity relationships. A brief classification of synthetic pathways of quinoxaline derivatives is provided too.

  9. Present status of quinoxaline motifs: excellent pathfinders in therapeutic medicine.

    Science.gov (United States)

    Ajani, Olayinka Oyewale

    2014-10-01

    Quinoxalines belong to a class of excellent heterocyclic scaffolds owing to their wide biological properties and diverse therapeutic applications in medicinal research. They are complementary in shapes and charges to numerous biomolecules they interact with, thereby resulting in increased binding affinity. The pharmacokinetic properties of drugs bearing quinoxaline cores have shown them to be relatively easy to administer either as intramuscular solutions, oral capsules or rectal suppositories. This work deals with recent advances in the synthesis and pharmacological diversities of quinoxaline motifs which might pave ways for novel drugs development.

  10. Antimicrobial Evaluation and Synthesis of Some Phenylpyrazolo benzothiazolo quinoxaline Derivatives

    Directory of Open Access Journals (Sweden)

    CH. Sridevi

    2009-01-01

    Full Text Available 2,3-Diphenyl quinoxaline (SI was fused with 2-amino benzothiazoles (SII by a methylene bridge, which was then allowed for acetylation. The acetylated product (SIV was made to react with different aromatic aldehydes to give chalcones (SV1-SV5. Chalcones refluxed with substituted acid hydrazides to afford different phenyl pyrazolo benzothiazolo quinoxaline derivatives (SVI1-SVI15. The structure of chalcones and phenyl pyrazolo benzothiazolo quinoxaline derivatives were confirmed by M.P, TLC and spectral data. All the synthesized compounds were screened for their antimicrobial activities.

  11. Synthesis of quinoxaline derivatives catalyzed by PEG-400

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Polyethylene glycol(PEG) was found to be an effective catalyst for the condensation of 1,2-diamines with 1,2-dicarbonyl compounds to afford the corresponding quinoxaline derivatives in excellent yields under mild reaction conditions.

  12. Synthesis of tetrazolo(1,5-a)quinoxalines with antimicrobial activity

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ho Sik; Kim, Tong Eun [Catholic University of Taegu, Gyongsan (Korea, Republic of); Kurasawa, Yoshihisa [Kitasato Univ., Tokyo (Japan)

    2001-08-01

    The 4-substituted tetrazolo(1,5-a)quinoxalines were synthesized from 4-chlorotetrazolo-(1,5-a)quinoxaline(8) or 4-hydrazinotetrazolo(1,5-a)quinoxaline(9). Refluxing of the tetrazolo(1,5-a)quinoxaline(12) in N,N-dimethylformamide gave the 1,2,4-triazolo(3,4-c)tetrazolo(1,5-a)quinoxaline(13), which was also obtained by the reaction of compound 9 with ethyl chloroformate in N,N-dimethylformamide. The reaction of compound 9 with isothiocyanates in ethanol provided the tetrazolo(1,5-a)quinoxalines(14), whose reaction with dimethyl acetylenedicarboxylate afforded the tetrazolo(1,5-a)quinoxalines(15). The tetrazolo(1,5-a)quinoxalines(18) were obtained by the reaction of compound 9 with alkyl (ethoxymethylene)cyanoacetates. Some of the compounds showed antibacterial, antifungal or algicidal activities against some strains.

  13. Structures, stabilization energies, and binding energies of quinoxaline···(H2O)(n), quinoxaline dimer, and quinoxaline···Cu complexes: a theoretical study.

    Science.gov (United States)

    Kabanda, Mwadham M; Ebenso, Eno E

    2013-02-21

    Quinoxaline is a parent structure for a broad class of N-heteroaromatic compounds, many of which exhibit various biological activities. The interaction of quinoxaline with explicit water molecules or metal ions and the formation of quinoxaline dimer play an important role in many of the biological activities of quinoxaline. This study investigates the structures, stabilization, and binding energies of quinoxaline complexes with water, transition metal ions, and quinoxaline dimer to provide information on the preferred geometries, interaction energies, and type of noncovalent interactions accounting for the stability of the complexes. The investigations are performed in vacuo and in water solution using MP2 and DFT methods. The results of the study on the quinoxaline···(H(2)O)(n) show that the preferred adducts in vacuo involve one, two, or three water molecules hydrogen bonded to the N atom and the neighboring H atom of the C(sp2)-H group. The results in water solution show a preference for water-water clustering. The dimers of quinoxaline are stabilized by either π-π stacking or weak C-H···N intermolecular hydrogen bonds. The relative stability of the quinoxaline···Cu complexes depends on the site on which the Cu ion binds and the binding strength depends on both the nature of the cation and the binding site.

  14. Quinoxaline derivatives: novel and selective butyrylcholinesterase inhibitors.

    Science.gov (United States)

    Zeb, Aurang; Hameed, Abdul; Khan, Latifullah; Khan, Imran; Dalvandi, Kourosh; Choudhary, M Iqbal; Basha, Fatima Z

    2014-01-01

    Alzheimer's disease (AD) is a progressive brain disorder which occurs due to lower levels of acetylcholine (ACh) neurotransmitters, and results in a gradual decline in memory and other cognitive processes. Acetycholinesterase (AChE) and butyrylcholinesterase (BChE) are considered to be primary regulators of the ACh levels in the brain. Evidence shows that AChE activity decreases in AD, while activity of BChE does not change or even elevate in advanced AD, which suggests a key involvement of BChE in ACh hydrolysis during AD symptoms. Therefore, inhibiting the activity of BChE may be an effective way to control AD associated disorders. In this regard, a series of quinoxaline derivatives 1-17 was synthesized and biologically evaluated against cholinesterases (AChE and BChE) and as well as against α- chymotrypsin and urease. The compounds 1-17 were found to be selective inhibitors for BChE, as no activity was found against other enzymes. Among the series, compounds 6 (IC50 = 7.7 ± 1.0 µM) and 7 (IC50 = 9.7 ± 0.9 µM) were found to be the most active inhibitors against BChE. Their IC50 values are comparable to the standard, galantamine (IC50 = 6.6 ± 0.38 µM). Their considerable BChE inhibitory activity makes them selective candidates for the development of BChE inhibitors. Structure-activity relationship (SAR) of this new class of selective BChE inhibitors has been discussed.

  15. New and modified classical methods for the synthesis of quinoxalines

    Energy Technology Data Exchange (ETDEWEB)

    Saifina, D F; Mamedov, Vakhid A [A.E. Arbuzov Institute of Organic and Physical Chemistry, Kazan Scientific Centre of the Russian Academy of Sciences, Kazan (Russian Federation)

    2010-07-13

    Published data on the synthesis of quinoxalines are generalized and described systematically; the key attention is given to the sources published in the last 10-15 years. Modifications of the classical synthetic routes and new methods little known to wide circles of chemists are considered.

  16. Quinoxaline-Based Scaffolds Targeting Tyrosine Kinases and Their Potential Anticancer Activity.

    Science.gov (United States)

    El Newahie, Aliya M S; Ismail, Nasser S M; Abou El Ella, Dalal A; Abouzid, Khaled A M

    2016-05-01

    Quinoxaline derivatives, also called benzopyrazines, are an important class of heterocyclic compounds. Quinoxalines have drawn great attention due to their wide spectrum of biological activities. They are considered as an important basis for anticancer drugs due to their potential activity as protein kinase inhibitors. In this review, we focus on the chemistry of the quinoxaline derivatives, the strategies for their synthesis, their potential activities against various tyrosine kinases, and on the structure-activity relationship studies reported to date.

  17. Synthesis and biological activity of some heterocyclic compounds containing quinoxaline and coumarin moieties

    OpenAIRE

    M. E. ABD EL-FATTAH; I. M. EL-DEEN

    2000-01-01

    2,3-Dichloroquinoxaline (2) condensed with 7,8-dihydroxy-4-methylcoumarin to give the 1,4-dioxane derivative 4. 2.3-Dichloroquinoxaline (2) reacted with 4-hydroxycoumarin, 7-hydroxy-4-methylcoumarin and acyl hydrazide 13 to give either the 2,3-(dicoumarin-4-yloxy)quinoxaline (6) or the 2,3-di-(4-methylcoumarin-7-yloxy)quinoxaline (7) or the 2-chloro-3-(coumarin-4-yloxy)quinoxaline (8) or the 2-chloro-3-(4-methylcoumarin-7-yloxy) quinoxaline (9) or the ditriazoloquinoxaline 14 or the oxa-diazi...

  18. New Conjugates of Quinoxaline as Potent Antitubercular and Antibacterial Agents

    Directory of Open Access Journals (Sweden)

    Ramalingam Peraman

    2016-01-01

    Full Text Available Considering quinoxaline as a privileged structure for the design of potent intercalating agents, some new sugar conjugates of quinoxaline were synthesized and characterized by IR, 1HNMR, 13C NMR, and mass spectral data. In vitro testing for antitubercular and antimicrobial activities was performed against Mycobacterium tuberculosis H37Rv and some pathogenic bacteria. Results revealed that conjugate containing ribose moiety demonstrated the most promising activity against Mycobacteria and bacteria with minimum inhibitory concentrations (MIC of 0.65 and 2.07 μM, respectively. Other conjugates from xylose, glucose, and mannose were moderately active whilst disaccharides conjugates were found to be less active. In silico docking analysis of prototype compound revealed that ATP site of DNA gyrase B subunit could be a possible site for inhibitory action of these synthesized compounds.

  19. New Conjugates of Quinoxaline as Potent Antitubercular and Antibacterial Agents.

    Science.gov (United States)

    Peraman, Ramalingam; Kuppusamy, Rajendran; Killi, Sunil Kumar; Reddy, Y Padmanabha

    2016-01-01

    Considering quinoxaline as a privileged structure for the design of potent intercalating agents, some new sugar conjugates of quinoxaline were synthesized and characterized by IR, (1)HNMR, (13)C NMR, and mass spectral data. In vitro testing for antitubercular and antimicrobial activities was performed against Mycobacterium tuberculosis H 37 Rv and some pathogenic bacteria. Results revealed that conjugate containing ribose moiety demonstrated the most promising activity against Mycobacteria and bacteria with minimum inhibitory concentrations (MIC) of 0.65 and 2.07 μM, respectively. Other conjugates from xylose, glucose, and mannose were moderately active whilst disaccharides conjugates were found to be less active. In silico docking analysis of prototype compound revealed that ATP site of DNA gyrase B subunit could be a possible site for inhibitory action of these synthesized compounds.

  20. Synthesis of quinoxalines in the presence of heteropoly acids

    Directory of Open Access Journals (Sweden)

    Fatemeh Hakimia

    2013-04-01

    Full Text Available Efficient synthesis of quinoxaline derivatives from the reaction of α-diketones and o-phenylenediamines in the presence of Keggin-type heteropolyacids (HPA such as H3PMo12O40, H4SiW12O40, K7PMo2W9O40, H3PW12O40.SiO2 and H3PW12O40 in high yields and short reaction times, and at room temperature is introduced.

  1. Synthesis, Biological Evaluation and Structure-Activity Relationships of New Quinoxaline Derivatives as Anti-Plasmodium falciparum Agents

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    Ana Gil

    2014-02-01

    Full Text Available We report the synthesis and antimalarial activities of eighteen quinoxaline and quinoxaline 1,4-di-N-oxide derivatives, eight of which are completely novel. Compounds 1a and 2a were the most active against Plasmodium falciparum strains. Structure-activity relationships demonstrated the importance of an enone moiety linked to the quinoxaline ring.

  2. Synthesis, biological evaluation and structure-activity relationships of new quinoxaline derivatives as anti-Plasmodium falciparum agents.

    Science.gov (United States)

    Gil, Ana; Pabón, Adriana; Galiano, Silvia; Burguete, Asunción; Pérez-Silanes, Silvia; Deharo, Eric; Monge, Antonio; Aldana, Ignacio

    2014-02-18

    We report the synthesis and antimalarial activities of eighteen quinoxaline and quinoxaline 1,4-di-N-oxide derivatives, eight of which are completely novel. Compounds 1a and 2a were the most active against Plasmodium falciparum strains. Structure-activity relationships demonstrated the importance of an enone moiety linked to the quinoxaline ring.

  3. Synthesis, Biological Evaluation and Structure-Activity Relationships of New Quinoxaline Derivatives as Anti-Plasmodium falciparum Agents

    OpenAIRE

    Ana Gil; Adriana Pabón; Silvia Galiano; Asunción Burguete; Silvia Pérez-Silanes; Eric Deharo; Antonio Monge; Ignacio Aldana

    2014-01-01

    We report the synthesis and antimalarial activities of eighteen quinoxaline and quinoxaline 1,4-di-N-oxide derivatives, eight of which are completely novel. Compounds 1a and 2a were the most active against Plasmodium falciparum strains. Structure-activity relationships demonstrated the importance of an enone moiety linked to the quinoxaline ring.

  4. Antitumor Activity of New Quinoxaline Analogues and Its Complexes

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    A. A. Ismaeel

    2013-12-01

    Full Text Available This study shows synthesis of a new quinoxaline derivatives (LH and preparation of copper (Cu-LH and cobalt (Co-LH complexes and studying the effect of these compounds on the activity of lactate dehydrogenase (LDH a primary enzyme to the process of anaerobic glycolysis which is the source of energy in tumor cell. This study included of 40 women with recently diagnosed of malignancies Breast cancer; (20 subject women in stage I&(20subject women in stage II who were admitted to Medical City Hospital with age ranged (37-45 years and 30 apparently healthy woman matched for age served as controls. Serum LDH activity was assayed on the time of the diagnosis in all cases and after addition of different concentrations (10-1, 10-2, 10-3 of quinoxalin derivatives and transition metals complexes in vitro. The results revealed an inhibitory effect of LH and its complexes with Cu and Co in all concentrations used in this study on LDH activity. The inhibition percent’s increased with increase concentration for LH and its complexes. Also the results reveal that the inhibitory effect of LH in all concentrations used were more than inhibitory effect of its complexes. Moreover the inhibitory effect of LH-Co complex was more than inhibitory effect of LH-Cu complex in all concentrations used. The inhibition ability of quinoxaline derivative and its complexes on the enzyme lactate dehydrogenase leads to the fact that these compounds can be characterized as an active anti –cancer substances for one of the metabolic enzymes necessary to feed the cancer cells.

  5. Synthesis of highly functionalized polycyclic quinoxaline derivatives using visible-light photoredox catalysis.

    Science.gov (United States)

    He, Zhi; Bae, Minwoo; Wu, Jie; Jamison, Timothy F

    2014-12-22

    A mild and facile method for preparing highly functionalized pyrrolo[1,2-a]quinoxalines and other nitrogen-rich heterocycles, each containing a quinoxaline core or an analogue thereof, has been developed. The novel method features a visible-light-induced decarboxylative radical coupling of ortho-substituted arylisocyanides and radicals generated from phenyliodine(III) dicarboxylate reagents and exhibits excellent functional group compatibility. A wide range of quinoxaline heterocycles have been prepared. Finally, a telescoped preparation of these polycyclic compounds by integration of the in-line isocyanide formation and photochemical cyclization has been established in a three-step continuous-flow system.

  6. Synthesis of Some Phenylpyrazolo Benzimidazolo Quinoxaline Derivatives as Potent Antihistaminic Agents

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    C. H. Sridevi

    2010-01-01

    Full Text Available 2,3-Diphenyl quinoxaline (NI was fused with benzimidazole (NII by a methylene bridge, which was then allowed for acetylation. The acetylated product (NIV was made to react with different aromatic aldehydes to give chalcones (NV1-NV5. Chalcones refluxed with substituted acid hydrazides to afford different phenyl pyrazolo benzimidazole quinoxaline derivatives (NVI 1-NVI 15. The structure of chalcones and phenyl pyrazolo benzimidazole quinoxaline derivatives were confirmed by m.p, TLC and spectral data. All the synthesized compounds were screened for their antihistaminic activity. Compounds NVI-3, NVI-12, NVI-13, NVI-14 and NVI-15 were shown good % protection of antihistamic activity.

  7. Aromatic quinoxaline as corrosion inhibitor for bronze in aqueous chloride solution

    Indian Academy of Sciences (India)

    N Saoudi; A Bellaouchou; A Guenbour; A Ben Bachir; E M Essassi; M El Achouri

    2010-06-01

    A new corrosion inhibitor, viz. 3-ethyl-6-méthyl-quinoxalin-2-one, 1-benzyl-6-methyl-quinoxalin- 2-one, 2-benzyloxy-3,6-dimethyl-quinoxaline, 1-benzyl-3-methyl-quinoxalin-2-one, were synthesized in the laboratory. Their influence on the inhibition on corrosion of bronze in aqueous chloride solution (3% NaCl) was studied by electrochemical polarization methods and weight-loss measurements. The impact of temperature on the effectiveness of the substances mentioned above has been determined between 20 and 60°C. The results showed that the corrosion resistance was greatly enhanced in the presence of inhibitor and that the effectiveness depends on some physicochemical properties of the molecule, related to its functional groups. These compounds act through the formation of a protective film on the surface of the alloy.

  8. Synthesis and Characterization of Quinoxaline-Based Low-Bandgap Copolymers for Bulk Heterojunction Solar Cells

    Science.gov (United States)

    Lee, Yoonkyoo; Jo, Won Ho

    2011-03-01

    A series of low-bandgap alternating copolymers consisting of quinoxaline derivatives and electron-donating carbazole or fluorene were synthesized via the Suzuki coupling reaction. For the purpose to improve the molecular packing of polymer chains and to enhance the charge carrier mobility in the packing direction, a new quinoxaline derivative, 5,8-dithien-2-yl-dibenzophenazine which has perfectly planar polycyclic structure, was synthesized and introduced as a new building block for alternating copolymers instead of frequently-used 5,8-dithien-2-yl-2,3-diphenylquinoxaline. The use of planar quinoxaline derivative exhibited better optical, electrochemical, and structural properties of the resulting copolymers as compared to those of polymers with less planar quinoxaline derivatives. Charge transport and photovoltaic properties of these two classes of copolymers are compared and discussed.

  9. Quinoxaline, its derivatives and applications: A State of the Art review.

    Science.gov (United States)

    Pereira, Joana A; Pessoa, Ana M; Cordeiro, M Natália D S; Fernandes, Rúben; Prudêncio, Cristina; Noronha, João Paulo; Vieira, Mónica

    2015-06-01

    Quinoxaline derivatives are an important class of heterocycle compounds, where N replaces some carbon atoms in the ring of naphthalene. Its molecular formula is C8H6N2, formed by the fusion of two aromatic rings, benzene and pyrazine. It is rare in natural state, but their synthesis is easy to perform. In this review the State of the Art will be presented, which includes a summary of the progress made over the past years in the knowledge of the structure and mechanism of the quinoxaline and quinoxaline derivatives, associated medical and biomedical value as well as industrial value. Modifying quinoxaline structure it is possible to obtain a wide variety of biomedical applications, namely antimicrobial activities and chronic and metabolic diseases treatment.

  10. Phenanthro[4,5-fgh]quinoxaline-Fused Subphthalocyanines: Synthesis, Structure, and Spectroscopic Characterization.

    Science.gov (United States)

    Pan, Houhe; Liu, Wenbo; Wang, Chiming; Wang, Kang; Jiang, Jianzhuang

    2016-07-01

    A series of four phenanthro[4,5-fgh]quinoxaline-fused subphthalocyanine derivatives 0-3 containing zero, one, two, and three phenanthro[4,5-fgh]quinoxaline moieties, respectively, were isolated from the mixed cyclotrimerization reaction of 2,9-di-tert-butylphenanthro[4,5-fgh]quinoxaline-5,6-dicarbonitrile with 4,5-bis(2,6-diisopropylphenoxy)phthalonitrile and characterized by a series of spectroscopic methods including MALDI-TOF mass, (1) H NMR, electronic absorption, magnetic circular dichroism (MCD), and fluorescence spectroscopy. The molecular structures for the compounds 0 and 2 were clearly revealed on the basis of single-crystal X-ray diffraction analysis. Their electrochemical properties were also studied by cyclic voltammetry. In particular, theoretical calculations in combination with the electronic absorption and electrochemical analyses revealed the significant influence of the fused-phenanthro[4,5-fgh]quinoxaline units on the electronic structures.

  11. A quinoxaline-fused tetrathiafulvalene-based sensitizer for efficient dye-sensitized solar cells.

    Science.gov (United States)

    Amacher, Anneliese; Yi, Chenyi; Yang, Jiabao; Bircher, Martin Peter; Fu, Yongchun; Cascella, Michele; Grätzel, Michael; Decurtins, Silvio; Liu, Shi-Xia

    2014-06-21

    A new quinoxaline-fused tetrathiafulvalene-based sensitizer has been prepared and characterized. The resulting power conversion efficiency of 6.47% represents the best performance to date for tetrathiafulvalene-sensitized solar cells.

  12. Nano-TiO2: An eco-friendly alternative for the synthesis of quinoxalines

    Institute of Scientific and Technical Information of China (English)

    Bi Bi Fatemeh Mirjalili; Ali Akbari

    2011-01-01

    Nano-TiO2 as an eco-friendly and efficient nanocatalyst was applied for quinoxaline preparation with improved yield. In this protocol, diketones and 1.2-diamines were condensed in the presence of catalyst at room temperature.

  13. Thiamine hydrochloride: An efficient catalyst for one-pot synthesis of quinoxaline derivatives at ambient temperature

    Indian Academy of Sciences (India)

    Omprakash B Pawar; Fulchand R Chavan; Venkat S Suryawanshi; Vishnu S Shinde; Narayan D Shinde

    2013-01-01

    Quinoxaline derivatives have been synthesized in high to excellent yields in the presence of thiamine hydrochloride (VB1) as an inexpensive, non-toxic and metal ion free catalyst at ambient temperature.

  14. Fast and green synthesis of biologically important quinoxalines with high yields in water

    Directory of Open Access Journals (Sweden)

    Hossein Ghafuri

    2014-06-01

    Full Text Available Optimal method were developed for the green synthesis of quinoxaline derivatives based on the highly efficient and simple condensation reaction of various aromatic 1,2-diketones and 1,2-diamines in nearly quantitative yields in water. In this method we did not use any catalyst. The very mild reaction conditions, the high yields of the products, and the absence of any catalyst make this methodology an efficient and green route for synthesis of quinoxalines.

  15. BF{sub 3}-promoted electrochemical properties of quinoxaline in propylene carbonate.

    Energy Technology Data Exchange (ETDEWEB)

    Carino, Emily V.; Diesendruck, Charles E.; Moore, Jeffrey S.; Curtiss, Larry A.; Assary, Rajeev S.; Brushett, Fikile R.

    2015-01-01

    Electrochemical and density functional studies demonstrate that coordination of electrolyte constituents to quinoxalines modulates their electrochemical properties. Quinoxalines are shown to be electrochemically inactive in most electrolytes in propylene carbonate, yet the predicted reduction potential is shown to match computational estimates in acetonitrile. We find that in the presence of LiBF4 and trace water, an adduct is formed between quinoxaline and the Lewis acid BF3, which then displays electrochemical activity at 1-1.5 V higher than prior observations of quinoxaline electrochemistry in non-aqueous media. Direct synthesis and testing of a bis-BF3 quinoxaline complex further validates the assignment of the electrochemically active species, presenting up to a similar to 26-fold improvement in charging capacity, demonstrating the advantages of this adduct over unmodified quinoxaline in LiBF4-based electrolyte. The use of Lewis acids to effectively "turn on" the electrochemical activity of organic molecules may lead to the development of new active material classes for energy storage applications.

  16. Synthesis and stereochemistry of long-chain quinoxaline metallocyclophanes.

    Science.gov (United States)

    Howard, Mark J; Heirtzler, Fenton R; Dias, Sandra I G

    2008-04-04

    Condensation of 1,2-diamino-4,5-bis(n-alkoxy)arenes with an oligopyridyl-type alpha-diketone afforded a series of long-chain pyridine-quinoxaline hybrids. These were evaluated for their ability to self-assemble with tetrahedral Cu(I) and Ag(I) to form dimeric, double-decker amphiphillic complexes having a flattened metallocyclophane topology. Detailed NOESY and T1 relaxation time experimentation showed that the configuration of the dicopper(I) complexes corresponds to inversion (meso) symmetry, which leads to an extended molecular shape, wherein the alkoxy chains of the individual ligand components lie on opposite sides of the metallocyclophane core, as opposed to the same side. Preliminary measurements show that the disilver(I) complexes having nC12H25 and nC18H37 chains exhibit reversible melting processes and undergo two endothermic transitions each, at 189/237 and 59/80 degrees C, respectively.

  17. Synthesis, biological evaluation and structure-activity relationships of new quinoxaline derivatives as anti-Plasmodium falciparum agents

    OpenAIRE

    Gil, Ana Gloria; Pabón, Adriana; Galiano, Silvia; Burguete, M. Isabel; Pérez-Silanes, Silvia; Deharo, Eric; Monge, Antonio; Aldana Ignacio

    2014-01-01

    We report the synthesis and antimalarial activities of eighteen quinoxaline and quinoxaline 1,4-di-N-oxide derivatives, eight of which are completely novel. Compounds 1a and 2a were the most active against Plasmodium falciparum strains. Structure-activity relationships demonstrated the importance of an enone moiety linked to the quinoxaline ring. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

  18. An Efficient Protocol for the Synthesis of Quinoxaline Derivatives at Room Temperature Using Recyclable Alumina-Supported Heteropolyoxometalates

    Directory of Open Access Journals (Sweden)

    Diego M. Ruiz

    2012-01-01

    Full Text Available We report a suitable quinoxaline synthesis using molybdophosphovanadates supported on commercial alumina cylinders as catalysts. These catalysts were prepared by incipient wetness impregnation. The catalytic test was performed under different reaction conditions in order to know the performance of the synthesized catalysts. The method shows high yields of quinoxaline derivatives under heterogeneous conditions. Quinoxaline formation was obtained using benzyl, o-phenylenediamine, and toluene as reaction solvent at room temperature. The CuH2PMo11VO40 supported on alumina showed higher activity in the tested reaction. Finally, various quinoxalines were prepared under mild conditions and with excellent yields.

  19. Simultaneous determination of five quinoxaline-1,4-dioxides in animal feeds using an immunochromatographic strip.

    Science.gov (United States)

    Le, Tao; Zhu, Liqian; Shu, Lihui; Zhang, Lei

    2016-01-01

    An immunochromatographic (ICG) strip was developed for the simultaneous quantitative determination of five quinoxaline-1,4-dioxides in animal feed. For this purpose, polyclonal antibodies (PcAb) with group-specific quinoxaline-1,4-dioxides were conjugated to colloidal gold particles as the detection reagent for ICG strips to test for quinoxaline-1,4-dioxides. This method achieved semi-quantitative detection of quinoxaline-1,4-dioxides within 5-10 min. The visual lower detection limits of the strip for quinocetone, cyadox, carbadox, mequindox and olaquindox were 10, 15, 15, 20 and 20 ng ml(-1), respectively. Using an ICG strip reader, the 50% inhibitions (IC50 values) were calculated to be 9.1, 13.5, 16.6, 20.2 and 21.3 ng ml(-1) for quinocetone, cyadox, carbadox, mequindox and olaquindox, respectively. When used to analyse samples of animal feed, acceptable recovery rates of 77.5-99.5% and coefficients of variation (CVs) of 4.3-10.7% were obtained. Levels measured with the ICG strip for 10 spiked samples were confirmed by HPLC with a high correlation coefficient of 0.9965 (n = 10). In conclusion, the method was rapid and accurate for simultaneous determination of five quinoxaline-1,4-dioxides antibiotics in animal feed.

  20. Design and synthesis of novel quinoxaline derivatives as potential candidates for treatment of multidrug-resistant and latent tuberculosis.

    Science.gov (United States)

    Santivañez-Veliz, Mery; Pérez-Silanes, Silvia; Torres, Enrique; Moreno-Viguri, Elsa

    2016-05-01

    Twenty-four quinoxaline derivatives were evaluated for their antimycobacterial activity using BacTiter-Glo microbial cell viability assay. Five compounds showed MIC values quinoxaline derivatives could be considered for making further advances in the future development of antimycobacterial agents.

  1. Magnetic dilution in the cadmium-doped spin ladder compound Cdx Cu1 - x (quinoxaline) Br2

    Science.gov (United States)

    Keith, Brian; Landee, Chris; Turnbull, Mark

    2011-03-01

    Both Cu (quinoxaline) (Br2) and Cu (quinoxaline) (Cl2) are examples of molecule-based magnets where the CuX4 dimers are linked into ladders by quinoxaline molecules, where X is either Cl or Br. The rung exchange occurs through the bridging halides while the rail exchange occurs through the quinoxaline rings. Introducing random rung interactions into the system [ Cu (quinoxaline) (Br2)1-x (Cl2)x ] has caused the spin gap to close, in contrast with the gapped pure spin ladder parents. Crystal growth of non-magnetic-doped molecular magnets, CdxCu1 - x (2 , 3 - dimethylpyrazine)Br2 , have been performed for several values of the nominal conentration, x, and have been confirmed. The magnetizations and susceptibilities of the magnetically diluted ladder assemblage are presented along with a comparison of the effects of dilution from the pure case (x=0).

  2. The Benzyl Moiety in a Quinoxaline-Based Scaffold Acts as a DNA Intercalation Switch.

    Science.gov (United States)

    Mahata, Tridib; Kanungo, Ajay; Ganguly, Sudakshina; Modugula, Eswar Kalyan; Choudhury, Susobhan; Pal, Samir Kumar; Basu, Gautam; Dutta, Sanjay

    2016-06-27

    Quinoxaline antibiotics intercalate dsDNA and exhibit antitumor properties. However, they are difficult to synthesize and their structural complexity impedes a clear mechanistic understanding of DNA binding. Therefore design and synthesis of minimal-intercalators, using only part of the antibiotic scaffold so as to retain the key DNA-binding property, is extremely important. Reported is a unique example of a monomeric quinoxaline derivative of a 6-nitroquinoxaline-2,3-diamine scaffold which binds dsDNA by two different modes. While benzyl derivatives bound DNA in a sequential fashion, with intercalation as the second event, nonbenzyl derivatives showed only the first binding event. The benzyl intercalation switch provides important insights about molecular architecture which control specific DNA binding modes and would be useful in designing functionally important monomeric quinoxaline DNA binders and benchmarking molecular simulations.

  3. Synthesis, photochemistry, DNA cleavage/binding and cytotoxic properties of fluorescent quinoxaline and quinoline hydroperoxides.

    Science.gov (United States)

    Chowdhury, Nilanjana; Gangopadhyay, Moumita; Karthik, S; Pradeep Singh, N D; Baidya, Mithu; Ghosh, S K

    2014-01-01

    Novel fluorescent quinoxaline and quinoline hydroperoxides were shown to perform dual role as both fluorophores for cell imaging and photoinduced DNA cleaving agents. Photophysical studies of newly synthesized quinoxaline and quinoline hydroperoxides showed that they all exhibited moderate to good fluorescence. Photolysis of quinoxaline and quinoline hydroperoxides in acetonitrile using UV light above 350nm resulted in the formation of corresponding ester compounds via γ-hydrogen abstraction by excited carbonyl chromophore. Single strand DNA cleavage was achieved on irradiation of newly synthesized hydroperoxides by UV light (⩾350nm). Both hydroxyl radicals and singlet oxygen were identified as reactive oxygen species (ROS) responsible for the DNA cleavage. Further, we showed quinoline hydroperoxide binds to ct-DNA via intercalative mode. In vitro biological studies revealed that quinoline hydroperoxide has good biocompatibility, cellular uptake property and cell imaging ability. Finally, we showed that quinoline hydroperoxide can permeate into cells efficiently and may cause cytotoxicity upon irradiation by UV light.

  4. A green protocol for the synthesis of quinoxaline derivatives catalyzed by polymer supported sulphanilic acid

    Directory of Open Access Journals (Sweden)

    Umesh P. Tarpada

    2017-05-01

    Full Text Available Polymer supported sulphanilic acid was found to be an effective heterogeneous catalyst for one pot synthesis of various quinoxaline derivatives from the condensation reaction between 1,2-diamines and 1,2-dicarbonyl compounds in ethanol. Synthesis was attempted under reflux as well as at room temperature using ethanol as the solvent to afford excellent yields. Heterogeneity of the catalyst allowed its recycling for five times with almost retention in catalytic activity. Prepared quinoxaline derivatives were also tested for their antioxidant activity by the FRAP assay method.

  5. Application of quinoxaline based diimidazolium salt in palladium catalyzed cross-coupling reactions

    Indian Academy of Sciences (India)

    Mujahuddin M Siddiqui; Mohammed Waheed; Sajad A Bhat; Maravanji S Balakrishna

    2015-05-01

    The reaction of 2,3-bis(bromomethyl)quinoxaline with imidazole afforded the quinoxaline bridged diimidazolium salt (1) in good yield. Diimidazolium salt (1) in conjunction with Pd(OAc)2 was employed as a catalyst for C–C cross-coupling reactions. The diimidazolium salt was found to be efficient in catalyzing Suzuki-Miyaura cross-coupling reaction in ethanol under ambient conditions. Moderate to good selectivity of the trans product was observed in the Heck cross-coupling reaction. The molecular structure of 1 was confirmed by single crystal X-ray diffraction study.

  6. Synthesis and tautomerism of pyrazoles and N-phenylethanamides with quinoxaline ring

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ho Sik; Choi, Kyung Ok; Lee, Hyong Choul [Catholic University of Taegu, Gyongsan (Korea, Republic of); Kwag, Sam Tag [Pukyong National Univ., Pusan (Korea, Republic of); Kurasawa, Yoshihisa [Kitasato Univ., Tokyo (Japan)

    2001-10-01

    The reaction of 3-methoxycarbonylmethylene-2-oxo-1,2,3,4-tetrahydroquinoxaline(7) with hydrazine hydrate gave 3-hydrazinocarbonylmethylene-2-oxo-1,2,3,4-tetrahydroquinoxaline(8). The reaction of compound 8 with alkyl (ethoxymethylene)cyanoacetates gave the ((quinoxalin-2-ylidene)ethanoyl)-1H-pyra-zoles(9). The reaction of compound 9b with N-alkylanilines provided the N-alkyl-(quinoxalin-2-ylidene)-N-phenylethanamides(10). Compounds 9 and 10 showed the tautomerism between the enamine and methylene imine forms in solution. The tautomer ratios were determined by the {sup 1}H NMR.

  7. Quinoxaline Nucleus: A Promising Scaffold in Anti-cancer Drug Discovery.

    Science.gov (United States)

    Pinheiro, Alessandra C; Mendonça Nogueira, Thais C; de Souza, Marcus V N

    2016-01-01

    Heterocyclic compounds are a class of substances, which play a critical role in modern drug discovery being incorporated in the structure of a large variety of drugs used in many different types of diseases. Quinoxaline is an important heterocyclic nucleus with a wide spectrum of biological activities, and recently much attention has been found on anticancer drug discovery based on this class. Owing to the importance of this system, the aim of this review is to provide an update on the synthesis and anticancer activity of quinoxaline derivatives covering articles published between 2010 and 2015.

  8. Indolizino[5,6-b]quinoxaline Derivatives: Intramolecular Charge Transfer Characters and NIR Fluorescence.

    Science.gov (United States)

    Kojima, Mitsuru; Hayashi, Hironobu; Aotake, Tatsuya; Ikeda, Shinya; Suzuki, Mitsuharu; Aratani, Naoki; Kuzuhara, Daiki; Yamada, Hiroko

    2015-11-01

    Indolizino[5,6-b]quinoxaline derivatives (1 a and 1 b) with a push-pull structure were prepared to show intramolecular charge-transfer properties. Compounds 1 a and 1 b are strongly fluorescent in aprotic solvents while symmetrical derivatives (2 a and 2 b) were non-fluorescent. The π-expanded α-α linked dimer (10) of indolizino[5,6-b]quinoxaline 1 b was serendipitously obtained to show NIR absorption over 800 nm and the fluorescence edge reached to 1400 nm.

  9. SYNTHESIS AND MICROBIAL ACTIVITY OF NOVEL QUINOXALINE DERIVATIVES SYNTHESE UND mikrobielle Aktivität NOVEL Chinoxalin DERIVATE

    Directory of Open Access Journals (Sweden)

    Vijay V. Dabholkar and Sunil R.Patil,Rajesh V. Pandey

    2012-01-01

    Full Text Available Quinoxaline-2,3(1H,4H-dione 1 was chlorinated by using SOCl2/DMF, to form 2,3- dichloroquinoxaline 2, The dichloro compound 2 was subjected to reaction with Substituted Triazole, 1,10-diaminonaphthalene, 2-aminothiophenol, o-phenylenediamine, 1,2- diaminoethane,Sodim azide, thiocarbohydrazones and thiosemicarbazones to furnish 3'- substituted-(1',2',4' triazolo [5,6-b] [quinoxalo (2,3-e]-1,3,4-thiadiazine 3a-c, Quinoxalino [1,4- b]-1,4-dihydronaphto[18-ef][1,4]-diazepine 4, 7-substituted-1,4-benzothiazino[2,3-b]- quinoxalines 5a-c, benzopiperazino[2,3-b]-quinoxalines 6 , piperazino[2,3-b]-quinoxalines 7, bis-triazo-[4,5-a/c]-quinoxalines 8, 2-(benzylidine-hyrazino-1,3,4-thiadiazino [ 5,6-b]- quinoxalines 9 and 2-(benzylidine-imino-1,3,3-thiadiazino [ 5,6-b]-quinoxalines 10 respectively. Representative samples were screened for their anti-microbial activity against gram-negative bacteria, E coli and Paeruginosa and gram-positive bacteria, S aureus, and C diphtheriae using disc diffusion method. The structures of the products were confirmed by IR,1H, 13 C NMR and elemental analysis.

  10. Comparison of the structure of (E)-2-(2-benzylidenehydrazinylidene)quinoxaline with those of its chloro- and bromobenzylidene analogues.

    Science.gov (United States)

    Gomes, Ligia Rebelo; Low, John Nicolson; Rodrigues, Ana S M C; Wardell, James L; de Souza, Marcus V N; Noguiera, Thais C M; Pinheiro, Alessandra C

    2013-08-01

    (E)-2-(2-Benzylidenehydrazinylidene)quinoxaline, C₁₅H₁₂N₄, crystallized with two molecules in the asymmetric unit. The structures of six halogen derivatives of this compound were also investigated: (E)-2-[2-(2-chlorobenzylidene)hydrazinylidene]quinoxaline, C₁₅H₁₁ClN₄; (E)-2-[2-(3-chlorobenzylidene)hydrazinylidene]quinoxaline, C₁₅H₁₁ClN₄; (E)-2-[2-(4-chlorobenzylidene)hydrazinylidene]quinoxaline, C₁₅H₁₁ClN₄; (E)-2-[2-(2-bromobenzylidene)hydrazinylidene]quinoxaline, C₁₅H₁₁BrN₄; (E)-2-[2-(3-bromobenzylidene)hydrazinylidene]quinoxaline, C₁₅H₁₁BrN₄; (E)-2-[2-(4-bromobenzylidene)hydrazinylidene]quinoxaline, C₁₅H₁₁BrN₄. The 3-Cl and 3-Br compounds are isomorphous, as are the 4-Cl and 4-Br compounds. In all of these compounds, it was found that the supramolecular structures are governed by similar predominant patterns, viz. strong intermolecular N-H...N(pyrazine) hydrogen bonds supplemented by weak C-H∙∙∙N(pyrazine) hydrogen-bond interactions in the 2- and 3-halo compounds and by C-H∙∙∙Cl/Br interactions in the 4-halo compounds. In all compounds, there are π-π stacking interactions.

  11. An Efficient Approach to 6, 7-Disubstituted-1H-quinoxalin-2-ones

    Institute of Scientific and Technical Information of China (English)

    Xun LI; Qing Ping HU; Xue Gui CUI; Dong Hua WANG

    2004-01-01

    A novel approach to the synthesis of 6, 7-disubstituted-1H-quinoxalin-2-ones is described.The title compounds were regioselectively prepared by starting from substituted phenylamines and chloroacetyl chloride through the efficient sequence ofacylation, nitration, reduction, intramolecular alkylation, and oxidation.

  12. Synthesis and Physicochemical Study of a Quinoxaline Derivative with Potencial Antineoplasic or Anti-HIV Activity

    Directory of Open Access Journals (Sweden)

    Gabriela A. Rodrigo

    2000-03-01

    Full Text Available Kinetics of the synthesis of 3-[3-quinoxaline(1H-one]propionic acid (I were performed. This compound was achieved from reaction between o-phenylenediamine and α-ketoglutaric acid under different experimental conditions, and it was sent to the National Cancer Institute (USA for its pharmacological evaluation.

  13. Synthesis of Quinoxaline Derivatives via Tandem Oxidative Azidation/Cyclization Reaction of N-Arylenamines.

    Science.gov (United States)

    Ma, Haichao; Li, Dianjun; Yu, Wei

    2016-02-19

    A new method was developed for the synthesis of quinoxalines. This method employs N-arylenamines and TMSN3 as the starting materials and implements two oxidative C-N bond-forming processes in a tandem pattern by using (diacetoxyiodo)benzene as the common oxidant. The present reaction conditions are mild and simple and thus are useful in practical synthesis.

  14. Striking antitumor activity of a methinium system with incorporated quinoxaline unit obtained by spontaneous cyclization.

    Science.gov (United States)

    Bříza, T; Králová, J; Dolenský, B; Rimpelová, S; Kejík, Z; Ruml, T; Hajdúch, M; Džubák, P; Mikula, I; Martásek, P; Poučková, P; Král, V

    2015-03-01

    A novel pentamethinium salt was synthesized with an unforeseen expanded conjugated quinoxaline unit directly incorporated into a pentamethinium chain. The compound exhibited high fluorescence intensity, selective mitochondrial localization, high cytotoxicity, and selectivity toward malignant cell lines, and resulted in remarkable in vivo suppression of tumor growth in mice.

  15. An Efficient Solid Acid Promoted Synthesis of Quinoxaline Derivatives at Room Temperature

    Institute of Scientific and Technical Information of China (English)

    AHMAD,Shaabani; ALI,Maleki

    2007-01-01

    Quinoxaline derivatives have been synthesized in a very short time with excellent yields by the condensation of 1,2-diamines with aliphatic or aromatic 1,2-dicarbonyl compounds or benzilmonoxime in the presence of silica sul-furic acid as a very inexpensive solid acid catalyst at room temperature. The recovery and reuse of the catalyst are also satisfactory.

  16. Microwave assisted synthesis of fluorene-based copolymers with different conjugate degreed quinoxaline segments from reactive polymer

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jixin; Song, Xiaohui; Feng, Ying [School of Petrochemical Engineering, Shenyang University of Technology, 30 Guanghua Street, Liaoyang 111003 (China); Wang, Zhiming, E-mail: wangzm2011@yahoo.com.cn [School of Petrochemical Engineering, Shenyang University of Technology, 30 Guanghua Street, Liaoyang 111003 (China); State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Avenue, Changchun 130012 (China); Zhang, Xiaojuan [School of Petrochemical Engineering, Shenyang University of Technology, 30 Guanghua Street, Liaoyang 111003 (China); Shen, Fangzhong; Lu, Ping [State Key Laboratory of Supramolecular Structure and Materials, Jilin University, 2699 Qianjin Avenue, Changchun 130012 (China)

    2013-10-31

    In this work, we prepared three fluorene-based copolymers with different conjugate degreed quinoxaline segments from one reactive polymer by microwave assisted method. The obtained quinoxaline-based copolymers exhibited different bright color emissions, high photoluminescence quantum, low electron affinity and electron injection barrier. This approach not only simplified the steps of similar-structure polymers, but also avoided the monomer solubility problem. - Highlights: • Quinoxaline-based copolymers were prepared in microwave-assisted synthesis. • Polymer-synthesis containing different acceptors was simplified from reactive polymer. • Multi-functions were tuned by controlling reactive monomer structures.

  17. Quinoxaline N-oxide containing potent angiotensin II receptor antagonists: synthesis, biological properties, and structure-activity relationships.

    Science.gov (United States)

    Kim, K S; Qian, L; Bird, J E; Dickinson, K E; Moreland, S; Schaeffer, T R; Waldron, T L; Delaney, C L; Weller, H N; Miller, A V

    1993-08-01

    A series of novel quinoxaline heterocycle containing angiotensin II receptor antagonist analogs were prepared. This heterocycle was coupled to the biphenyl moiety via an oxygen atom linker instead of a carbon atom. Many of these analogs exhibit very potent activity and long duration of effect. Interestingly, the N-oxide quinoxaline analog was more potent than the nonoxidized quinoxaline as in the comparison of compounds 5 vs 30. In order to improve oral activity, the carboxylic acid function of these compounds was converted to the double ester. This change did result in an improvement in oral activity as represented by compound 44.

  18. Synthesis and biological evaluation of quinoxaline-5,8-diones that inhibit vascular smooth muscle cell proliferation.

    Science.gov (United States)

    Chung, Hwa-Jin; Jung, Ok-Jai; Chae, Mi Jin; Hong, Sung-Yu; Chung, Kwang-Hoe; Lee, Sang Kook; Ryu, Chung-Kyu

    2005-07-15

    A series of 6-arylamino-2,3-bis(pyridin-2-yl)-7-chloro-quinoxaline-5,8-diones were synthesized and evaluated for their inhibitory activity on the rat aortic smooth muscle cell (RAoSMC) proliferation. The quinoxaline-5,8-diones exhibited a potent antiproliferative activity. Further mechanistic study revealed that the inhibitory effect of one representative quinoxaline-5,8-dione on SMC proliferation was mediated by modulation of the extracellular signal-regulated kinase 1/2 signaling pathway in the RAoSMCs.

  19. Iodinated (Perfluoro)alkyl Quinoxalines by Atom Transfer Radical Addition Using ortho-Diisocyanoarenes as Radical Acceptors.

    Science.gov (United States)

    Leifert, Dirk; Studer, Armido

    2016-09-12

    A simple method for the preparation of functionalized quinoxalines is reported. Starting from readily accessible ortho-diisocyanoarenes and (perfluoro)alkyl iodides, the quinoxaline core is constructed during (perfluoro)alkylation by atom transfer radical addition (ATRA), resulting in 2-iodo-3-(perfluoro)alkylquinoxalines. The radical cascades are readily initiated either with visible light or by using α,α'-azobisisobutyronitrile (AIBN). The heteroarene products are obtained in high yields (up to 94 %), and the method can be readily scaled up. Useful follow-up chemistry documents the value of the novel radical quinoxaline synthesis.

  20. Design, synthesis and anti-HIV activity of novel quinoxaline derivatives.

    Science.gov (United States)

    Patel, Saloni B; Patel, Bhumika D; Pannecouque, Christophe; Bhatt, Hardik G

    2016-07-19

    In order to design novel anti-HIV agents, pharmacophore modelling, virtual screening, 3D-QSAR and molecular docking studies were performed. Pharmacophore model was generated using 17 structurally diverse molecules using DISCOtech followed by refinement with GASP module of Sybyl X. The best model containing four features; two donor sites, one acceptor atom and one hydrophobic region; was used as a query for virtual screening in NCI database and 6 compounds with Qfit value ≥98 were retrieved. The quinoxaline ring which is the bio-isostere of pteridine ring, retrieved as a hit in virtual screening, was selected as a core moiety. 3D-QSAR was carried on thirty five 5-hydroxy-6-oxo-1,6-dihydropyrimidine-4-carboxamide derivatives. Contour map analysis of best CoMFA and CoMSIA model suggested incorporation of hydrophobic, bulky and electronegative groups to increase potency of the designed compounds. 50 quinoxaline derivatives with different substitutions were designed on basis of both ligand based drug design approaches and were mapped on the best pharmacophore model. From this, best 32 quinoxaline derivatives were docked onto the active site of integrase enzyme and in-silico ADMET properties were also predicted. From this data, synthesis of top 7 quinoxaline derivatives was carried out and were characterized using Mass, (1)H-NMR and (13)C-NMR spectroscopy. Purity of compounds were checked using HPLC. These derivatives were evaluated for anti-HIV activity on III-B strain of HIV-1 and cytotoxicity studies were performed on VERO cell line. Two quinoxaline derivatives (7d and 7e) showed good results, which can be further explored to develop novel anti-HIV agents.

  1. Quinoxaline N,N'-dioxide derivatives and related compounds as growth inhibitors of Trypanosoma cruzi. Structure-activity relationships.

    Science.gov (United States)

    Aguirre, Gabriela; Cerecetto, Hugo; Di Maio, Rossanna; González, Mercedes; Alfaro, María Elena Montoya; Jaso, Andrés; Zarranz, Belén; Ortega, Miguel Angel; Aldana, Ignacio; Monge-Vega, Antonio

    2004-07-16

    Quinoxaline derivatives presented good inhibitor activity of growth of Trypanosoma cruzi in in vitro assays. The 50% inhibitory doses were of the same order of that of Nifurtimox. Derivative 13, a quinoxaline N,N'-dioxide derivative, and the reduced derivatives 19 and 20 were the most cytotoxic compounds against the protozoan. Structural requirements for optimal activity were studied by computational methods. From statistical analysis we could establish a multiple correlation between activity and lipophilic properties and LUMO energy.

  2. One-pot three-component synthesis of quinoxaline and phenazine ring systems using Fischer carbene complexes

    Directory of Open Access Journals (Sweden)

    Priyabrata Roy

    2010-05-01

    Full Text Available One-pot three-component coupling of o-alkynylheteroaryl carbonyl derivatives with Fischer carbene complexes and dienophiles leading to the synthesis of quinoxaline and phenazine ring systems has been investigated. This involves the generation of furo[3,4-b]pyrazine and furo[3,4-b]quinoxaline as transient intermediates, which were trapped with Diels–Alder dienophiles. This is the first report on furo[3,4-b]pyrazine intermediates.

  3. Highly efficient synthesis of quinoxaline derivatives from 1,2-benzenediamine and α-aminoxylated 1,3-dicarbonyl compounds.

    Science.gov (United States)

    Yan, Jianwei; Xu, Yanhong; Zhuang, Fangfang; Tian, Jie; Zhang, Guisheng

    2016-05-01

    Simple and efficient synthetic procedures for the preparation of quinoxaline, pyrazine, pyridopyrazine, and benzoxazin-2-one derivatives were developed. The one-pot cascade process involves the acidic elimination of α-aminoxylated dicarbonyl compounds to generate 1,2,3-tricarbonyl compounds and subsequent condensation with 1,4-N,N or -N,O dinucleophiles to afford quinoxaline, pyrazine, pyridopyrazine, and benzoxazin-2-one scaffolds. All the proposed processes do not need extra catalysts, dry solvents, or harsh reaction conditions.

  4. Synthesis, Characterization and Biological Evaluation of Some Quinoxaline Derivatives: A Promising and Potent New Class of Antitumor and Antimicrobial Agents

    OpenAIRE

    Al-Marhabi, Aisha; Abbas, Hebat-Allah; Ammar, Yousry

    2015-01-01

    the present work deals with the synthesis of some novel tetrazolo[1,5-a]quinoxalines, N-pyrazoloquinoxalines, the corresponding Schiff bases, 1,2,4-triazinoquinoxalines and 1,2,4-triazoloquinoxalines. These compounds were synthesized via the reaction of the key intermediate hydrazinoquinoxalines with various reagents and evaluated for anticancer and antimicrobial activity. The results indicated that tetrazolo[1,5-a]quinoxaline derivatives showed the best result, with the highest inhibitory ef...

  5. A quinoxaline based N-heteroacene interfacial layer for efficient hole-injection in quantum dot light-emitting diodes

    Science.gov (United States)

    Bai, Linyi; Yang, Xuyong; Ang, Chung Yen; Nguyen, Kim Truc; Ding, Tao; Bose, Purnandhu; Gao, Qiang; Mandal, Amal Kumar; Sun, Xiao Wei; Demir, Hilmi Volkan; Zhao, Yanli

    2015-07-01

    A series of N-heterocyclic quinoxaline derivatives was successfully synthesized and applied as hole transport layers in quantum dot light-emitting diodes (QLEDs). By inducing sp2 N-atoms into the quinoxaline backbone, the electron affinity of the obtained material was enhanced, and its optical properties and bandgap became tunable. Quinoxaline based N-heteroacenes show a narrow bandgap, high thermal stability, and aligned film morphology. The resulting N-heteroacene polymer based QLED exhibits superior performance to poly(9-vinylcarbazole) based QLED. This study presents a strategy towards the design of novel N-rich molecules for the fabrication of QLEDs with improved performance.A series of N-heterocyclic quinoxaline derivatives was successfully synthesized and applied as hole transport layers in quantum dot light-emitting diodes (QLEDs). By inducing sp2 N-atoms into the quinoxaline backbone, the electron affinity of the obtained material was enhanced, and its optical properties and bandgap became tunable. Quinoxaline based N-heteroacenes show a narrow bandgap, high thermal stability, and aligned film morphology. The resulting N-heteroacene polymer based QLED exhibits superior performance to poly(9-vinylcarbazole) based QLED. This study presents a strategy towards the design of novel N-rich molecules for the fabrication of QLEDs with improved performance. Electronic supplementary information (ESI) available: Synthesis and characterization details. See DOI: 10.1039/c5nr03197d

  6. 6H-Indolo[2,3-b]quinoxalines: DNA and protein interacting scaffold for pharmacological activities.

    Science.gov (United States)

    Moorthy, N S Hari Narayana; Manivannan, E; Karthikeyan, C; Trivedi, Piyush

    2013-08-01

    6H-Indolo[2,3-b]quinoxaline, a planar fused heterocyclic compound exhibits a wide variety of pharmacological activities. The mechanism of pharmacological action exerted by these compounds is predominantly DNA intercalation. The thermal stability of the intercalated complex (DNA and 6H-indolo[2,3-b]quinoxaline derivatives) is an important parameter for the elucidation of anticancer, antiviral and other activities. This thermal stability of the 6H-indolo[2,3- b]quinoxaline-DNA complex depends on the type of substituents and side chains attached to the 6H-indolo[2,3- b]quinoxaline nucleus and also the orientation of the side chain towards the GC rich minor groove of the DNA. Highly active 6H-indolo[2,3-b]quinoxaline derivatives such as NCA0424, B-220 and 9-OH-B-220 have shown good binding affinity to DNA as evident from high thermal stability of compound-DNA complex. Interestingly, these compounds possessed poor inhibitory activity on topoisomerase II enzyme but have significant MDR modulating activity. This review establishes '6H-indolo[2,3-b]quinoxaline' as a valuable template for design and development of novel molecules with different biological activities.

  7. Anti-Mycobacterium tuberculosis agents derived from quinoxaline-2-carbonitrile and quinoxaline-2-carbonitrile 1,4-di-N-oxide.

    Science.gov (United States)

    Ortega, Miguel Angel; Sainz, Yolanda; Montoya, María Elena; Jaso, Andrés; Zarranz, Belén; Aldana, Ignacio; Monge, Antonio

    2002-01-01

    In this paper new quinoxaline derivatives with different substituents in positions 3, 6, 7 and 8 are reported. Their biological activities against Mycobacterium tuberculosis have been assessed and most of the 1,4-di-N-oxide derivatives have been shown to strongly inhibit the bacteria growth in the first in vitro screening. One of these N-oxides (4) is a promising candidate due to its good Selectivity Index (7.95). On the other hand, those compounds without N-oxide moieties showed no or very low activity (growth inhibition: 17% and 39%).

  8. Relationship between electronic properties and drug activity of seven quinoxaline compounds: A DFT study

    Science.gov (United States)

    Behzadi, Hadi; Roonasi, Payman; Assle taghipour, Khatoon; van der Spoel, David; Manzetti, Sergio

    2015-07-01

    The quantum chemical calculations at the DFT/B3LYP level of theory were carried out on seven quinoxaline compounds, which have been synthesized as anti-Mycobacterium tuberculosis agents. Three conformers were optimized for each compound and the lowest energy structure was found and used in further calculations. The electronic properties including EHOMO, ELUMO and related parameters as well as electron density around oxygen and nitrogen atoms were calculated for each compound. The relationship between the calculated electronic parameters and biological activity of the studied compounds were investigated. Six similar quinoxaline derivatives with possible more drug activity were suggested based on the calculated electronic descriptors. A mechanism was proposed and discussed based on the calculated electronic parameters and bond dissociation energies.

  9. Synthesis and biological evaluation of some new amide moiety bearing quinoxaline derivatives as antimicrobial agents.

    Science.gov (United States)

    Abu Mohsen, U; Yurttaş, L; Acar, U; Özkay, Y; Kaplacikli, Z A; Karaca Gencer, H; Cantürk, Z

    2015-05-01

    In this study, we aimed to synthesize some new quinoxaline derivatives bearing amide moiety and to evaluate their antimicrobial activity. A set of 16 novel compounds of N-[2,3-bis(4-methoxy/methylphenyl)quinoxalin-6-yl]-substituted benzamide derivatives were synthesized by reacting 2,3-bis(4-methoxyphenyl)-6-aminoquinoxaline or 2,3-bis(4-methylphenyl)-6-aminoquinoxaline with benzoyl chloride derivatives in tetrahydrofuran and investigated for their antimicrobial activity. The structures of the obtained final compounds were confirmed by spectral data (IR, (1)H-NMR, (13)C-NMR and MS). The antimicrobial activity of the compounds were determined by using the microbroth dilution method. Antimicrobial activity results revealed that synthesized compounds exhibited remarkable activity against Candida krusei (ATCC 6258) and Candida parapsilosis (ATCC 22019).

  10. Quinoxaline 1,4-di-N-oxide and the potential for treating tuberculosis.

    Science.gov (United States)

    Vicente, Esther; Villar, Raquel; Pérez-Silanes, Silvia; Aldana, Ignacio; Goldman, Robert C; Mong, Antonio

    2011-04-01

    New drugs active against drug-resistant tuberculosis are urgently needed to extend the range of TB treatment options to cover drug resistant infections. Quinoxaline derivatives show very interesting biological properties (antibacterial, antiviral, anticancer, antifungal, antihelmintic, insecticidal) and evaluation of their medicinal chemistry is still in progress. In this review we report the properties and the recent developments of quinoxaline 1,4-di-N-oxide derivatives as potential anti-tuberculosis agents. Specific agents are reviewed that have excellent antitubercular drug properties, are active on drug resistant strains and non-replicating mycobacteria. The properties of select analogs that have in vivo activity in the low dose aerosol infection model in mice will be reviewed.

  11. Novel quinoxaline 1,4-di-N-oxide derivatives as new potential antichagasic agents.

    Science.gov (United States)

    Torres, Enrique; Moreno-Viguri, Elsa; Galiano, Silvia; Devarapally, Goutham; Crawford, Philip W; Azqueta, Amaia; Arbillaga, Leire; Varela, Javier; Birriel, Estefanía; Di Maio, Rossanna; Cerecetto, Hugo; González, Mercedes; Aldana, Ignacio; Monge, Antonio; Pérez-Silanes, Silvia

    2013-08-01

    As a continuation of our research and with the aim of obtaining new agents against Chagas disease, an extremely neglected disease which threatens 100 million people, eighteen new quinoxaline 1,4-di-N-oxide derivatives have been synthesized following the Beirut reaction. The synthesis of the new derivatives was optimized through the use of a new and more efficient microwave-assisted organic synthetic method. The new derivatives showed excellent in vitro biological activity against Trypanosoma cruzi. Compound 17, which was substituted with fluoro groups at the 6- and 7-positions of the quinoxaline ring, was the most active and selective in the cytotoxicity assay. The electrochemical study showed that the most active compounds, which were substituted by electron-withdrawing groups, possessed a greater ease of reduction of the N-oxide groups.

  12. Synthesis and in vitro antitumor activity of substituted quinazoline and quinoxaline derivatives: search for anticancer agent.

    Science.gov (United States)

    Noolvi, Malleshappa N; Patel, Harun M; Bhardwaj, Varun; Chauhan, Ankit

    2011-06-01

    The synthesis of some 2-furano-4(3H)-quinazolinones, diamides (open ring quinazolines), quinoxalines and their biological evaluation as antitumor agents using National Cancer Institute (NCI) disease oriented antitumor screen protocol are investigated. Among the synthesize compounds, seventeen compounds were granted NSC code and screened at National Cancer Institute (NCI), USA for anticancer activity at a single high dose (10(-5) M) in full NCI 60 cell panel. Among the selected compounds, 3-(2-chloro benzylideneamine)-2-(furan-2-yl) quinazoline-4(3h)-one 21 was found to be the most active candidate of the series at five dose level screening against Ovarian OVCAR-4 and Non-small cell lung cancer NCI-H522 with GI50 1.82 & 2.14 μM respectively. Rational approach and QSAR techniques enabled the understanding of the pharmacophoric requirement for quinazoline, diamides and quinoxaline derivatives.

  13. Quinoxaline 1,4-dioxide: a versatile scaffold endowed with manifold activities.

    Science.gov (United States)

    Carta, A; Corona, P; Loriga, M

    2005-01-01

    Since 1940s, Quinoxaline 1,4-dioxides (QdNO's) are known as potent antibacterial agents, and subtherapeutic levels have been used to promote growth and improve efficiency of feed conversion in animal feed. They have also shown a selective cytotoxicity against hypoxic cells present in solid tumours. Furthermore, recent studies have put in evidence that QdNO's are endowed with antitubercular, antiprotozoal and anticandida activities. On the other hand, several authors have reported about photoallergic and mutagenic effects of some derivatives. QdNO's may also cause the development of antibiotic-resistant bacteria and influence the horizontal transfer of virulence genes between bacteria. In this review article we report the biological properties, the mode of action and Structure Activity Relationship (SAR) studies of the QdNO derivatives. Furthermore, some cytogenetic and genotoxic effects, classical and more recent method of synthesis, the quinoxaline 1,4-dioxides, and some of their most important reactions, were also reported.

  14. Tautomerism in quinoxalines derived from the 1,4-naphthoquinone nucleus: acid mediated synthesis, X-ray molecular structure of 5-chlorobenzo[f]quinoxalin-6-ol and density functional theory calculations

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, Javier A.G.; Lage, Mateus R.; Carneiro, Jose Walkimar de M.; Resende, Jackson A.L.C.; Vargas, Maria D., E-mail: mdvargas@vm.uff.br, E-mail: walk@vm.uff.br [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Instituto de Quimica

    2013-02-15

    The reaction of tert-butyl 2-(3-chloro-1,4-dioxo-1,4-dihydronaphthalen-2-ylamino) ethylcarbamate with CF{sub 3}COOH/CH{sub 2}Cl{sub 2} yields 5-chloro-3,4-dihydrobenzo[f]quinoxalin-6(2H)-one which undergoes acid-promoted dehydrogenation in the presence of water to give novel 5-chlorobenzo[f]quinoxalin-6-ol. The molecular structure of 5-chlorobenzo[f]quinoxalin-6-ol in the solid state, determined by an X-ray diffraction (XRD) study, and the solution data confirm that it exists as the enol-imine tautomer, both in the solid state and in solution, differently from 5-chloro-3,4-dihydrobenzo[f]quinoxalin-6(2H)-one, which exhibits the keto-amine arrangement. Density functional theory (DFT) calculations confirmed the preference of 5-chlorobenzo[f]quinoxalin-6-ol and of the derivatives containing H and CH{sub 3} groups in place of the Cl atom for the enol-imine tautomer. It is suggested that the enol-imine structure is preferred for 5-chlorobenzo[f]quinoxalin-6-ol as a consequence of the higher aromatic character of this structure in comparison with the keto-amine form. DFT calculations carried out on the two tautomers of the benzo[a]phenazin-5(7H)-ones analogous to the benzo[f]quinoxalin-6(4H)-ones showed that the relative stabilities are dominated by solvation effects in the first case and the degree of aromaticity, in the latter. (author)

  15. Polyethylene glycol in water: A simple, efficient and green protocol for the synthesis of quinoxalines

    Indian Academy of Sciences (India)

    Hemant V Chavan; Laxman K Adsul; Babasaheb P Bandgar

    2011-07-01

    A variety of biologically important quinoxaline derivatives has been efficiently synthesized in excellent yields under extremely mild conditions using PEG-600 and water. This inexpensive, non-toxic, ecofriendly and readily available system efficiently condensed several aromatic as well as aliphatic 1,2-diketones with aromatic and aliphatic 1,2-diamines to afford the products in excellent yield. Polyethylene glycol (PEG) can be recovered and recycled.

  16. An Efficient and Recyclable Nanoparticle-Supported Cobalt Catalyst for Quinoxaline Synthesis.

    Science.gov (United States)

    Rajabi, Fatemeh; Alves, Diego; Luque, Rafael

    2015-11-19

    The syntheses of quinoxalines derived from 1,2-diamine and 1,2-dicarbonyl compounds under mild reaction conditions was carried out using a nanoparticle-supported cobalt catalyst. The supported nanocatalyst exhibited excellent activity and stability and it could be reused for at least ten times without any loss of activity. No cobalt contamination could be detected in the products by AAS measurements, pointing to the excellent activity and stability of the Co nanomaterial.

  17. Synthesis and biological evaluation of quinoxaline di-N-oxide derivatives with in vitro trypanocidal activity.

    Science.gov (United States)

    Pérez-Silanes, Silvia; Torres, Enrique; Arbillaga, Leire; Varela, Javier; Cerecetto, Hugo; González, Mercedes; Azqueta, Amaya; Moreno-Viguri, Elsa

    2016-02-01

    We report the synthesis and in vitro activity against Trypanosoma cruzi epimastigotes of 15 novel quinoxaline derivatives. Ten of the derivatives presented IC50 values lower than the reference drugs Nfx and Bzn; four of them standed out with IC50 values lower than 1.5 μM. Moreover, unspecific cytotoxicity and genotoxicity studies are also reported. Compound 14 showed a SI higher than 24, whereas compound 10 was the only one that was negative in the genotoxicity screening.

  18. Keggin type heteropolyacids-catalyzed synthesis of quinoxaline derivatives in water

    Institute of Scientific and Technical Information of China (English)

    Tai Kun Huang; Lin Shi; Rui Wang; Xing Zhou Guo; Xiao Xia Lu

    2009-01-01

    Keggin type heteropolyacids was found to be an efficient and reusable catalyst for the synthesis of biologically active quinoxaline derivatives from the condensation of 1,2-diamine with 1,2-dicarbonyl compounds in excellent yields in water.This method provides a new and efficient protocol in terms of small quantity of catalyst,a wide scope of substrates,and simple work-up procedure.

  19. Synthesis and biological activity of new quinoxaline antibiotics of echinomycin analogues.

    Science.gov (United States)

    Kim, Yun Bong; Kim, Yong Hae; Park, Ju Youn; Kim, Soo Kie

    2004-01-19

    Novel quinoxaline antibiotics having the methylenedithioether bridge as an analogue of echinomycin have been synthesized by insertion of methylene moiety between -S-S- bond. The compound 1a shows remarkable cytotoxicities against human tumor various cell lines, and is active VRE (vancomycin-resistant enterococci) within MIC range 0.5-8 microg/mL. According to the eukaryotic or prokaryotic data, 1a might be a first analogue to replace echinomycin.

  20. Catalyst-free and solvent-free method for the synthesis of quinoxalines under microwave irradiation

    Institute of Scientific and Technical Information of China (English)

    Jian Feng Zhou; Gui Xia Gong; Kun Bao Shi; San Jun Zhi

    2009-01-01

    A facile procedure for the synthesis.of quinoxalines is being reported starting from benzil and 1,2-diaminobenzene. Thereactions were carried out catalyst-free, solvent-free and under microwave irradiation conditions in high yield (84-98%) with short time (3-6 rain) and environmental benign, as well as convenient operation. The structures of all the compounds have been confirmed on the basis of their IR, 1H NMR, and/or 13C NMR, mass spectral data.

  1. Quinoxaline 1,4-di-N-Oxides: Biological Activities and Mechanisms of Actions

    OpenAIRE

    Cheng, Guyue; Sa, Wei; Cao, Chen; Guo, Liangliang; Hao, Haihong; Liu, Zhenli; Wang, Xu; Yuan, Zonghui

    2016-01-01

    Quinoxaline 1,4-di-N-oxides (QdNOs) have manifold biological properties, including antimicrobial, antitumoral, antitrypanosomal and antiinflammatory/antioxidant activities. These diverse activities endow them broad applications and prospects in human and veterinary medicines. As QdNOs arouse widespread interest, the evaluation of their medicinal chemistry is still in progress. In the meantime, adverse effects have been reported in some of the QdNO derivatives. For example, genotoxicity and ba...

  2. Synthesis and biological evaluation of quinoxaline di-N-oxide derivatives with in vitro trypanocidal activity

    OpenAIRE

    Perez-Silanes, S. (Silvia); Torres, E; L. Arbillaga; Varela, J; H. Cerecetto; Gonzalez, M.; Azqueta, A.; Moreno-Viguri, E. (Elsa)

    2016-01-01

    Abstract: We report the synthesis and in vitro activity against T. cruzi epimastigotes of 15 novel quinoxaline derivatives. Ten of the derivatives presented IC50 values lower than the reference drugs Nfx and Bzn; four of them standed out with IC50 values lower than 1.5 M. Moreover, unspecific cytotoxicity and genotoxicity studies are also reported. Compound 14 showed a SI higher than 24, whereas compound 10 was the only one that was negative in the genotoxicity screening.

  3. An Efficient and Recyclable Nanoparticle-Supported Cobalt Catalyst for Quinoxaline Synthesis

    Directory of Open Access Journals (Sweden)

    Fatemeh Rajabi

    2015-11-01

    Full Text Available The syntheses of quinoxalines derived from 1,2-diamine and 1,2-dicarbonyl compounds under mild reaction conditions was carried out using a nanoparticle-supported cobalt catalyst. The supported nanocatalyst exhibited excellent activity and stability and it could be reused for at least ten times without any loss of activity. No cobalt contamination could be detected in the products by AAS measurements, pointing to the excellent activity and stability of the Co nanomaterial.

  4. On application of constitutional descriptors for merging of quinoxaline data sets using linear statistical methods.

    Science.gov (United States)

    Ghosh, Payel; Vracko, Marjan; Chattopadhyay, Asis Kumar; Bagchi, Manish C

    2008-08-01

    The present paper is an attempt for unifying two different quinoxaline data sets with a wide range of substituents in 2, 3, 7, and 8 positions having excellent antitubercular activities with a view to developing robust and reliable structure-activity relationships. The merging has been performed for these two sets of quinoxaline 1,4-di-N-oxides derivatives comprising 29 and 18 compounds, respectively, on the basis of constitutional descriptors, which denotes the structural characterization of the molecules. Principal component analysis was performed to see the distribution of the compounds from two data sets for the constitutional descriptors. The distribution of compounds in score plot based on constitutional descriptors suggests unification of quinoxaline data sets which is useful for the model development. Outlier detection was performed from the standpoint of residual analysis of the partial least squares regression models. The superiority of the constitutional descriptors over other calculated molecular descriptors has been established from the standpoint of leave-one-out cross-validation technique associated with partial least squares regression analysis. Internal validation through the leave-many-out methodology was also performed with good results, assuring the stability of the models. The results obtained from linear partial least squares regression analysis lead to a statistically significant and robust quantitative structure-activity relationship modeling.

  5. New quinoxaline 1,4-di-N-oxides. Part 1: Hypoxia-selective cytotoxins and anticancer agents derived from quinoxaline 1,4-di-N-oxides.

    Science.gov (United States)

    Amin, Kamelia M; Ismail, Magda M F; Noaman, Eman; Soliman, Dalia H; Ammar, Yousry A

    2006-10-15

    Hypoxic cells which are common feature of solid tumors are resistant to both anticancer drugs and radiation therapy. Thus, the identification of drugs with the selective toxicity toward hypoxic cells is an important target in anticancer chemotherapy. Tirapazamine has been shown to be an efficient and selective cytotoxin after bioreductive activation in hypoxic cells which is thought to be due to the presence of the 1,4-di-N-oxide. A new series of quinoxaline 1,4-di-N-oxides and fused quinoxaline di-N-oxides were synthesized and evaluated for hypoxic-cytotoxic activity on EAC cell line. Compound 10a was the most potent cytotoxin IC(50) 0.9 microg/mL, potency 75 microg/mL, and was approximately 15 times more selective cytotoxin (HCR>111) than 3-aminoquinoxaline-2-carbonitrile which has been used as a standard (HCR>7.5). Compounds 4 and 3a,b were more selective than the standard. In addition, antitumor activity against Hepg2 (liver) and U251 (brain) human cell lines was evaluated, compounds 9c and 8a were the most active against Hepg2 with IC(50) values 1.9 and 2.9 microg/mL, respectively, however, all the tested compounds were nontoxic against U251 cell line.

  6. Synthesis and characterization of quinoxaline-based polymers for bulk-heterojunction polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Bathula, Chinna [Energy Materials Research Center, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 305–600 (Korea, Republic of); Song, Chang Eun [Department of Materials Science and Engineering, Korea Advanced Instituted of Science and Technology, Daejeon 305–701 (Korea, Republic of); Lee, Woo-Hyung [Department of Chemistry, The Catholic University of Korea, Bucheon, Gyeonggi-do 420–743 (Korea, Republic of); Lee, Jaemin; Badgujar, Sachin; Koti, Rajesh [Energy Materials Research Center, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 305–600 (Korea, Republic of); Kang, In-Nam [Department of Chemistry, The Catholic University of Korea, Bucheon, Gyeonggi-do 420–743 (Korea, Republic of); Shin, Won Suk [Energy Materials Research Center, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 305–600 (Korea, Republic of); Ahn, Taek, E-mail: taekahn@ks.ac.kr [Department of Chemistry, Kyungsung University, Busan 608–736 (Korea, Republic of); Lee, Jong-Cheol [Energy Materials Research Center, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 305–600 (Korea, Republic of); Moon, Sang-Jin, E-mail: moonsj@krict.re.kr [Energy Materials Research Center, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 305–600 (Korea, Republic of); Lee, Sang Kyu, E-mail: skyulee@krict.re.kr [Energy Materials Research Center, Korea Research Institute of Chemical Technology (KRICT), 141 Gajeong-ro, Yuseong-gu, Daejeon 305–600 (Korea, Republic of)

    2013-06-30

    A series of quinoxaline (Qx)-based copolymers, poly[2,7-(9,9-bis(2-ethylhexyl)dibenzosilole)-alt-5,5-(5′, 8′-di-2-thienyl-2,3-bis(4-octyloxyl)phenyl)quinoxaline] (P1), poly[4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b′]dithiophene-alt-5,5-(5′, 8′-di-2-thienyl-2,3-bis(4-octyloxyl)phenyl)quinoxaline] (P2), and poly[4,4′-bis(2-ethylhexyl)-dithieno[3,2-b:2′,3′-d]silole-alt-5,5-(5′, 8′-di-2-thienyl-2,3-bis(4-octyloxyl)phenyl)quinoxaline] (P3), were synthesized and characterized for use in polymer solar cells (PSCs). We describe the effects of the various donor segments on the optical, electrochemical, field-effect carrier mobilities, and photovoltaic characteristics of the resulting Qx-based copolymers. The results indicated that the donor units in the copolymers significantly influenced the band gap, electronic energy levels, carrier mobilities, and photovoltaic properties of the copolymers. The band gaps of the copolymers were 1.71–2.03 eV. Under optimized conditions, the Qx-based polymers showed power conversion efficiencies for the PSCs of 0.87–2.15% under AM 1.5 illumination (100 mW/cm{sup 2}). Among the studied Qx-based copolymers, P2, which contained a benzo[1,2-b:4,5-b′]dithiophene unit, showed a power conversion efficiency of 2.15% with a short circuit current of 7.06 mA/cm{sup 2}, an open-circuit voltage of 0.67 V, and a fill factor of 0.46, under AM 1.5 illumination (100 mW/cm{sup 2}). - Highlights: • A series of quinoxaline (Qx)-based copolymers were synthesized. • We described the effects of the donor segments on photovoltaic characteristics. • The Qx-based polymers showed power conversion efficiencys in the range 0.87–2.15%.

  7. Binding Mode of an α-Amino Acid-Linked Quinoxaline-2,3-dione Analogue at Glutamate Receptor Subtype GluK1

    DEFF Research Database (Denmark)

    Demmer, Charles S; Møller, Charlotte; Brown, Patricia M G E;

    2015-01-01

    Two α-amino acid-functionalized quinoxalines, 1a (CNG-10301) and 1b (CNG-10300), of a quinoxaline moiety coupled to an amino acid moiety were designed, synthesized, and characterized pharmacologically. While 1a displayed low affinity at native AMPA, KA, and NMDA receptors, and at homomeric GluK1,...

  8. A quinoxaline derivative as a potent chemotherapeutic agent, alone or in combination with benznidazole, against Trypanosoma cruzi.

    Directory of Open Access Journals (Sweden)

    Jean Henrique da Silva Rodrigues

    Full Text Available BACKGROUND: Chagas' disease is a condition caused by the protozoan Trypanosoma cruzi that affects millions of people, mainly in Latin America where it is considered endemic. The chemotherapy for Chagas disease remains a problem; the standard treatment currently relies on a single drug, benznidazole, which unfortunately induces several side effects and it is not successful in the cure of most of the chronic patients. In order to improve the drug armamentarium against Chagas' disease, in the present study we describe the synthesis of the compound 3-chloro-7-methoxy-2-(methylsulfonyl quinoxaline (quinoxaline 4 and its activity, alone or in combination with benznidazole, against Trypanosoma cruzi in vitro. METHODOLOGY/PRINCIPAL FINDINGS: Quinoxaline 4 was found to be strongly active against Trypanosoma cruzi Y strain and more effective against the proliferative forms. The cytotoxicity against LLCMK2 cells provided selective indices above one for all of the parasite forms. The drug induced very low hemolysis, but its anti-protozoan activity was partially inhibited when mouse blood was added in the experiment against trypomastigotes, an effect that was specifically related to blood cells. A synergistic effect between quinoxaline 4 and benznidazole was observed against epimastigotes and trypomastigotes, accompanied by an antagonistic interaction against LLCMK2 cells. Quinoxaline 4 induced several ultrastructural alterations, including formations of vesicular bodies, profiles of reticulum endoplasmic surrounding organelles and disorganization of Golgi complex. These alterations were also companied by cell volume reduction and maintenance of cell membrane integrity of treated-parasites. CONCLUSION/SIGNIFICANCE: Our results demonstrated that quinoxaline 4, alone or in combination with benznidazole, has promising effects against all the main forms of T. cruzi. The compound at low concentrations induced several ultrastructural alterations and led the

  9. Skeletally Diverse Synthesis of Innovative [2,1-c]-1,4-Oxazepine and [1,4]-Quinoxaline Systems.

    Science.gov (United States)

    Lee, Chia-Hsin; Wu, Wen-Chun; Dangate, Prasad S; Shen, Li-Ching; Chung, Wen-Sheng; Sun, Chung-Ming

    2015-10-12

    An efficient, innovative synthesis of [2,1-c]-1, 4-oxazepine and [1,4]-quinoxaline heterocycles along with the embodied pyrimido-pyrrolo motifs was established. Initially, the pyrrole ring was installed using microwave irradiation through an intramolecular base-catalyzed cyclization between acetyl bromomethyl pyrimidine dione and o-amino phenyl methanol or o-phenylenediamine methyl benzoates. Furthermore, oxazepine, and quinoxaline scaffolds were constructed by an acid-catalyzed condensation with a variety of aldehydes by an unconventional Pictet-Spengler reaction strategy. An important aspect of this work is to build novel heterocyclic ring systems with potential medicinal interest.

  10. Antimicrobial activity of quinoxaline 1,4-dioxide with 2- and 3-substituted derivatives.

    Science.gov (United States)

    Vieira, Mónica; Pinheiro, Cátia; Fernandes, Rúben; Noronha, João Paulo; Prudêncio, Cristina

    2014-04-01

    Quinoxaline is a chemical compound that presents a structure that is similar to quinolone antibiotics. The present work reports the study of the antimicrobial activity of quinoxaline N,N-dioxide and some derivatives against bacterial and yeast strains. The compounds studied were quinoxaline-1,4-dioxide (QNX), 2-methylquinoxaline-1,4-dioxide (2MQNX), 2-methyl-3-benzoylquinoxaline-1,4-dioxide (2M3BenzoylQNX), 2-methyl-3-benzylquinoxaline-1,4-dioxide (2M3BQNX), 2-amino-3-cyanoquinoxaline-1,4-dioxide (2A3CQNX), 3-methyl-2-quinoxalinecarboxamide-1,4-dioxide (3M2QNXC), 2-hydroxyphenazine-N,N-dioxide (2HF) and 3-methyl-N-(2-methylphenyl)quinoxalinecarboxamide-1,4-dioxide (3MN(2MF)QNXC). The prokaryotic strains used were Staphylococcus aureus ATCC 6538, S. aureus ATCC 6538P, S. aureus ATCC 29213, Escherichia coli ATCC 25922, E. coli S3R9, E. coli S3R22, E. coli TEM-1 CTX-M9, E. coli TEM-1, E. coli AmpC Mox-2, E. coli CTX-M2 e E. coli CTX-M9. The Candida albicans ATCC 10231 and Saccharomyces cerevisiae PYCC 4072 were used as eukaryotic strains. For the compounds that presented activity using the disk diffusion method, the minimum inhibitory concentration (MIC) was determined. The alterations of cellular viability were evaluated in a time-course assay. Death curves for bacteria and growth curves for S. cerevisiae PYCC 4072 were also accessed. The results obtained suggest potential new drugs for antimicrobial activity chemotherapy since the MIC's determined present low values and cellular viability tests show the complete elimination of the bacterial strain. Also, the cellular viability tests for the eukaryotic model, S. cerevisiae, indicate low toxicity for the compounds tested.

  11. Microwave-Assisted Synthesis of Some Quinoxaline-Incorporated Schiff Bases and Their Biological Evaluation

    Directory of Open Access Journals (Sweden)

    L. Achutha

    2013-01-01

    Full Text Available Quinoxaline-incorporated Schiff bases (4a–j were synthesized by the condensation of 2-[(3-methylquinoxalin-2-yloxy]acetohydrazide (3 with indole-3-carbaldehyde, furfuraldehyde, 5-(4-nitrophenyl-2-furfuraldehyde, and substituted benzaldehydes under conventional and microwave irradiation methods. The microwave method was found to be remarkably successful with higher yields, less reaction time, and environmentally friendly compared to conventional heating method. The chemical structures of the synthesized compounds have been confirmed by analytical and spectral data. All the compounds have been evaluated for antitubercular and anti-inflammatory activities.

  12. An efficient catalyst-free protocol for the synthesis of quinoxaline derivatives under ultrasound irradiation

    OpenAIRE

    Guo,Wen-Xue; Jin,Hui-Le; Chen,Jiu-Xi; Chen, Fan; Ding,Jin-Chang; Wu,Hua-Yue

    2009-01-01

    A highly efficient and facile method has been described for the synthesis of quinoxaline derivatives in good to excellent yields (80-99%) by condensation reaction of heterocyclic as well as aliphatic 1,2-diketones (R¹COCOR¹, R¹ = Et, Ph, p-MeC6H5, p-MeOC6H5, Furyl) with 1,2-diamines (1,2-(NH2)2C6H3R², R² = H, Br, NO2, PhCO). A systematic study was carried out to examine the influence of reaction media and electronic factors of the substrates on the reaction results.

  13. A facile synthesis of phenazine and quinoxaline derivatives using magnesium sulfate heptahydrate as a catalyst

    Directory of Open Access Journals (Sweden)

    BAHADOR KARAMI

    2011-09-01

    Full Text Available Convenient and simple procedures for the synthesis of phenazine and quinoxaline derivatives were developed via a reaction of o-phenylenediamines and 1,2-dicarbonyl compounds. In addition, the synthesis of two new 1,4-benzodiazine derivatives and the catalytic activity of magnesium sulfate heptahydrate (MgSO4·7H2O in the room temperature condensation of o-phenylenediamines and 1,2-dicarbonyl compounds in ethanol as solvent are reported. This method has many appealing attributes, such as excellent yields, short reaction times, and simple work-up procedures.

  14. Synthesis and biological activity of some heterocyclic compounds containing quinoxaline and coumarin moieties

    Directory of Open Access Journals (Sweden)

    M. E. ABD EL-FATTAH

    2000-02-01

    Full Text Available 2,3-Dichloroquinoxaline (2 condensed with 7,8-dihydroxy-4-methylcoumarin to give the 1,4-dioxane derivative 4. 2.3-Dichloroquinoxaline (2 reacted with 4-hydroxycoumarin, 7-hydroxy-4-methylcoumarin and acyl hydrazide 13 to give either the 2,3-(dicoumarin-4-yloxyquinoxaline (6 or the 2,3-di-(4-methylcoumarin-7-yloxyquinoxaline (7 or the 2-chloro-3-(coumarin-4-yloxyquinoxaline (8 or the 2-chloro-3-(4-methylcoumarin-7-yloxy quinoxaline (9 or the ditriazoloquinoxaline 14 or the oxa-diazinoquinoxaline 16, depending on the relative ratios of the reactants and the reaction conditions.

  15. Synthesis and biological activities of pyrazolo[3,4-g]quinoxaline derivatives.

    Science.gov (United States)

    Gavara, Laurent; Saugues, Emmanuelle; Alves, Georges; Debiton, Eric; Anizon, Fabrice; Moreau, Pascale

    2010-11-01

    The synthesis of new pyrazolo[3,4-g]quinoxaline derivatives, as well as their Pim kinases (Pim-1, Pim-2, Pim-3) inhibitory potencies and in vitro antiproliferative activities toward a human fibroblast primary culture and three human solid cancer cell lines (PA1, PC3 and DU145) are described. The results obtained in this preliminary structure-activity relationship study have pointed out that most of the compounds in this series exhibited interesting in vitro Pim-3 kinase inhibitory potencies. Moreover, some of the tested compounds have demonstrated favorable antiproliferative potencies.

  16. The effect of rotational isomerism on the first hyperpolarizability of chromophores with divinyl quinoxaline conjugated bridge

    Science.gov (United States)

    Levitskaya, A. I.; Kalinin, A. A.; Fominykh, O. D.; Balakina, M. Yu.

    2017-08-01

    The effect of rotational isomerism on the values of first hyperpolarizability is studied by the example of two chromophores 7-DMA-VQV-TCP and 3-DMA-VQonV-TCP with quinoxaline and quinoxalinone moieties in the π-electron bridge. At the isomers formation the rotations about three single bonds are considered, thus providing eight possible conformers for each chromophore. The analysis of the results of DFT calculations demonstrates the presence of one lowest-energy conformer characterized by dominating probability for each chromophore. The calculations show that for both chromophores all rotational isomers are characterized by the first hyperpolarizability values rather close (within 8% and 11%) to statistically averaged ones.

  17. 4-Chlorotetrazolo[1,5-a]quinoxaline inhibits activation of Syk kinase to suppress mast cells in vitro and mast cell-mediated passive cutaneous anaphylaxis in mice

    Energy Technology Data Exchange (ETDEWEB)

    Park, Kui Lea [Center for Drug Development Assistance, National Institute of Food Drug Safety Evaluation (NIFDS), KFDA, Cheongwon-gun (Korea, Republic of); Ko, Na Young; Lee, Jun Ho; Kim, Do Kyun; Kim, Hyuk Soon; Kim, A-Ram; Her, Erk; Kim, Bokyung [Department of Immunology and physiology, College of Medicine, Konkuk University, Chungju (Korea, Republic of); Kim, Hyung Sik [College of Pharmacy, Pusan National University, Busan (Korea, Republic of); Moon, Eun-Yi [Department of Bioscience and Biotechnology, College of Biological Science, Sejong University, Seoul (Korea, Republic of); Kim, Young Mi [College of Pharmacy, Duksung Women' s University, Seoul (Korea, Republic of); Kim, Hang-Rae, E-mail: hangrae2@snu.ac.kr [Department of Anatomy, Seoul National University College of Medicine, Seoul (Korea, Republic of); Choi, Wahn Soo, E-mail: wahnchoi@kku.ac.kr [Department of Immunology and physiology, College of Medicine, Konkuk University, Chungju (Korea, Republic of)

    2011-12-15

    4-Chlorotetrazolo[1,5-a]quinoxaline is a quinoxaline derivative. We aimed to study the effects of 4-chlorotetrazolo[1,5-a]quinoxaline on activation of mast cells in vitro and in mice. 4-Chlorotetrazolo[1,5-a]quinoxaline reversibly inhibited degranulation of mast cells in a dose-dependent manner, and also suppressed the expression and secretion of TNF-{alpha} and IL-4 in mast cells. Mechanistically, 4-chlorotetrazolo[1,5-a]quinoxaline inhibited activating phosphorylation of Syk and LAT, which are crucial for early Fc{epsilon}RI-mediated signaling events, as well as Akt and MAP kinases, which play essential roles in the production of various pro-inflammatory cytokines in mast cells. Notably, although 4-chlorotetrazolo[1,5-a]quinoxaline inhibited the activation of Fyn and Syk, minimal inhibition was observed in mast cells in the case of Lyn. Furthermore, consistent with its in vitro activity, 4-chlorotetrazolo[1,5-a]quinoxaline significantly suppressed mast cell-mediated passive cutaneous anaphylaxis in mice. In summary, the results from this study demonstrate that 4-chlorotetrazolo[1,5-a]quinoxaline shows an inhibitory effect on mast cells in vitro and in vivo, and that this is mediated by inhibiting the activation of Syk in mast cells. Therefore, 4-chlorotetrazolo[1,5-a]quinoxaline could be useful in the treatment of mast cell-mediated allergic diseases. -- Highlights: Black-Right-Pointing-Pointer 4-chlorotetrazolo[1,5-a]quinoxaline is a quinoxaline derivative. Black-Right-Pointing-Pointer The effect of 4-chlorotetrazolo[1,5-a]quinoxaline on mast cells was investigated. Black-Right-Pointing-Pointer 4-chlorotetrazolo[1,5-a]quinoxaline reversibly inhibited Syk activation. Black-Right-Pointing-Pointer 4-chlorotetrazolo[1,5-a]quinoxaline could be useful for IgE-mediated allergy.

  18. Pyrazolo[3,4-b]quinoxalines. A new class of cyclin-dependent kinases inhibitors.

    Science.gov (United States)

    Ortega, Miguel A; Montoya, María E; Zarranz, Belén; Jaso, Andrés; Aldana, Ignacio; Leclerc, Sophie; Meijer, Laurent; Monge, Antonio

    2002-07-01

    Protein kinases are involved in most physiological processes and in numerous diseases. Therefore, inhibitors of protein kinases have therefore a wide therapeutic potential. While screening for inhibitors of cyclin-dependent kinases (CDK's) and glycogen synthase kinase-3 (GSK-3), we identified pyrazolo[3,4-b]quinoxalines as sub-micromolar inhibitors of CDK1/cyclin B. A preliminary structure-activity relationship study suggests that this family of compounds can be optimized to inhibit CDK's and GSK-3. Compounds were tested for their anti-proliferative activity and the results show that several of them displayed a significant inhibitory effect on CDK1/cyclin B. The most active compound (1) was also tested against the brain kinases CDK5/p25 and GSK-3, and proved to be a good inhibitor of both of them. On the contrary, none of the compounds showed any activity in the CDC25 phosphatase assay. As an additional approach, affinity chromatography on immobilized pyrazolo[3,4-b]quinoxalines will be used to identify the intracellular targets of this family of compounds.

  19. QSAR modeling for quinoxaline derivatives using genetic algorithm and simulated annealing based feature selection.

    Science.gov (United States)

    Ghosh, P; Bagchi, M C

    2009-01-01

    With a view to the rational design of selective quinoxaline derivatives, 2D and 3D-QSAR models have been developed for the prediction of anti-tubercular activities. Successful implementation of a predictive QSAR model largely depends on the selection of a preferred set of molecular descriptors that can signify the chemico-biological interaction. Genetic algorithm (GA) and simulated annealing (SA) are applied as variable selection methods for model development. 2D-QSAR modeling using GA or SA based partial least squares (GA-PLS and SA-PLS) methods identified some important topological and electrostatic descriptors as important factor for tubercular activity. Kohonen network and counter propagation artificial neural network (CP-ANN) considering GA and SA based feature selection methods have been applied for such QSAR modeling of Quinoxaline compounds. Out of a variable pool of 380 molecular descriptors, predictive QSAR models are developed for the training set and validated on the test set compounds and a comparative study of the relative effectiveness of linear and non-linear approaches has been investigated. Further analysis using 3D-QSAR technique identifies two models obtained by GA-PLS and SA-PLS methods leading to anti-tubercular activity prediction. The influences of steric and electrostatic field effects generated by the contribution plots are discussed. The results indicate that SA is a very effective variable selection approach for such 3D-QSAR modeling.

  20. Synthesis and in vivo diuretic activity of some new benzothiazole sulfonamides containing quinoxaline ring system.

    Science.gov (United States)

    Husain, Asif; Madhesia, Diwakar; Rashid, Mohd; Ahmad, Aftab; Khan, Shah Alam

    2016-12-01

    A series of new 6-substituted-N-[3-{2-(substituted phenyl)-ethenyl} quinoxaline-2(1H)-ylidene]-1,3-benzothiazole-2-amine (4a-f) were designed and synthesized by condensing 2-amino-benzothiazole-6-sulfonic acid amide (1) with chalcones of quinoxaline-2-one (3a-f) in a hope to obtain promising and a new class of diuretic agents. Structures of all the newly synthesized compounds were characterized by spectral data and elemental analysis. The pharmacological studies in experimental rats indicates that compound 4c possesses excellent in vivo diuretic activity of 1.13 and appears to be a better diuretic agent than the reference drugs, acetazolamide (1.0) and urea (0.88). Insight of the binding mode of the synthesized compounds (ligand) into the binding sites of carbonic anhydrase enzyme (PDF code: 4KUV) was provided by docking studies, performed with the help of Maestro 9.0 docking software. Further pharmacokinetic and toxicological studies are needed to confirm the safety of compound 4c which emerged as a lead diuretic compound.

  1. in Silico investigation of the structural requirements for the AMPA receptor antagonism by quinoxaline derivatives.

    Science.gov (United States)

    Azam, Faizul; Abugrain, Ismaiel Mohamed; Sanalla, Mohamed Hussin; Elnaas, Radwan Fatahalla; Rajab, Ibrahim Abdassalam Ibn

    2013-01-01

    Glutamate receptors have been implicated in various neurological disorders and their antagonism offers a suitable approach for the treatment of such disorders. The field of drug design and discovery aims to find best medicines to prevent, treat and cure diseases quickly and efficiently. In this regard, computational tools have helped medicinal chemists modify and optimize molecules to potent drug candidates with better pharmacokinetic profiles, and guiding biologists and pharmacologists to explore new disease genes as well as novel drug targets. In the present study, to understand the structural requirements for AMPA receptor antagonism, molecular docking study was performed on 41 structurally diverse antagonists based on quinoxaline nucleus. Lamarckian genetic algorithm methodology was employed for docking simulations using AutoDock 4.2 program. The results obtained signify that the molecular docking approach is reliable and produces a good correlation coefficient (r(2) = 0.6) between experimental and docking predicted AMPA receptor antagonistic activity. The aromatic moiety of quinoxaline core has been proved to be vital for hydrophobic contacts exhibiting - interactions in docked conformations. However, polar moieties such as carboxylic group and 1,2,4-triazole moieties were noted to be sites for hydrophilic interactions in terms of hydrogen bonding with the receptor. These analyses can be exploited to design and develop novel AMPA receptor antagonists for the treatment of different neurological disorders.

  2. Electrochemical Behavior of Quinoxalin-2-one Derivatives at Mercury Electrodes and Its Analytical Use

    Directory of Open Access Journals (Sweden)

    Milan Zimpl

    2012-01-01

    Full Text Available Derivatives of quinoxalin-2-one are interesting compounds with potential pharmacological activity. From this point of view, understanding of their electrochemical behavior is of great importance. In the present paper, a mechanism of electrochemical reduction of quinoxalin-2-one derivatives at mercury dropping electrode was proposed. Pyrazine ring was found to be the main electroactive center undergoing a pH-dependent two-electron reduction process. The molecule protonization of nitrogen in the position 4 precedes the electron acceptance forming a semiquinone radical intermediate which is relatively stable in acidic solutions. Its further reduction is manifested by separated current signal. A positive mesomeric effect of the nonprotonized amino group in the position 7 of the derivative III accelerates the semiquinone reduction yielding a single current wave. The suggested reaction mechanism was verified by means of direct current polarography, differential pulse, cyclic and elimination voltammetry, and coulometry with subsequent GC/MS analysis. The understanding of the mechanism was applied in developing of analytical method for the determination of the studied compounds.

  3. Silica Bonded S-Sulfonic Acid: A Recyclable Catalyst for the Synthesis of Quinoxalines at Room Temperature

    Directory of Open Access Journals (Sweden)

    Khodabakhsh Niknam

    2009-05-01

    Full Text Available The reaction of 3-mercaptopropylsilica (MPS and chlorosulfonic acid in chloroform afforded silica bonded S-sulfonic acid (SBSSA, which was used as a catalyst for the room temperature synthesis of quinoxaline derivatives from 1,2-diamino compounds and 1,2-dicarbonyl compounds. The catalyst could be recycled and reused several times without any loss of efficiency.

  4. Synthesis of New Quinoxalines Containing an Oxirane Ring by the TDAE Strategy and in Vitro Evaluation in Neuroblastoma Cell Lines

    Directory of Open Access Journals (Sweden)

    Marc Montana

    2014-09-01

    Full Text Available Neuroblastoma is an aggressive pediatric malignancy with significant chemotherapeutic resistance. In order to obtain new compounds active on neuroblastoma cell lines, we investigated the reactivity of carbanion formed via TDAE in quinoxaline series. The new synthesized compounds were tested for their anti-proliferative activity on two neuroblastoma cell lines, and seven oxirane derivatives obtained interesting activities.

  5. C-shaped diastereomers containing cofacial thiophene-substituted quinoxaline rings: synthesis, photophysical properties, and X-ray crystallography.

    Science.gov (United States)

    DeBlase, Catherine R; Finke, Ryan T; Porras, Jonathan A; Tanski, Joseph M; Nadeau, Jocelyn M

    2014-05-16

    Synthesis and characterization of two diastereomeric C-shaped molecules containing cofacial thiophene-substituted quinoxaline rings are described. A previously known bis-α-diketone was condensed with an excess of 4-bromo-1,2-diaminobenzene in the presence of zinc acetate to give a mixture of two C-shaped diastereomers with cofacial bromine-substituted quinoxaline rings. After chromatographic separation, thiophene rings were installed by a microwave-assisted Suzuki coupling reaction, resulting in highly emissive diastereomeric compounds that were studied by UV-vis, fluorescence, and NMR spectroscopy, as well as X-ray crystallography. The unique symmetry of each diastereomer was confirmed by NMR spectroscopy. NMR data indicated that the syn isomer has restricted rotation about the bond connecting the thiophene and quinoxaline rings, which was also observed in the solid state. The spectroscopic properties of the C-shaped diastereomers were compared to a model compound containing only a single thiophene-substituted quinoxaline ring. Ground state intramolecular π-π interactions in solution were detected by NMR and UV-vis spectroscopy. Red-shifted emission bands, band broadening, and large Stokes shifts were observed, which collectively suggest excited state π-π interactions that produce excimer-like emissions, as well as a remarkable positive emission solvatochromism, indicating charge-transfer character in the excited state.

  6. Synthesis and biological evaluation of novel 2,3-disubstituted quinoxaline derivatives as antileishmanial and antitrypanosomal agents.

    Science.gov (United States)

    Cogo, Juliana; Kaplum, Vanessa; Sangi, Diego Pereira; Ueda-Nakamura, Tânia; Corrêa, Arlene Gonçalves; Nakamura, Celso Vataru

    2015-01-27

    Quinoxalines belong to the N-containing heterocyclic compounds that stand out as having promising biological activity due to their privileged scaffold. In this work, we report the synthesis, antileishmanial, and antitrypanosomal properties of 46 new 2,3-disubstituted quinoxaline and 40 previously reported derivatives. Among all of the compounds screened for in vitro activity against epimastigotes and trypomastigotes of Trypanosoma cruzi and promastigotes of Leishmania amazonensis as well as mammalian toxicity on LLCMK2 cells and J774 macrophages, analogues from series 5, 6, 7, 9, 12, and 13 displayed high activity at micromolar IC50 and EC50 concentrations. Sixteen quinoxaline derivatives were selected and evaluated on T. cruzi and/or L. amazonensis amastigotes. The most active compounds were 6a-b and 7d-e, on all evolutive forms of L. amazonensis and T. cruzi evaluated with IC50 values 0.1-0.8 μM on promastigotes and epimastigotes 1.4-8.6 on amastigotes. Compounds 5k, 12b and 13a were the most selective (SI = 19.5-38.4) on amastigotes of T. cruzi. In general their activity was directly related to the methylsulfoxyl, methylsulfonyl, and amine groups as well as the presence of chorine or bromine in the molecules. The current results indicate that these quinoxaline derivatives are novel and promising agents for further development towards a treatment for Chagas' disease and leishmaniasis.

  7. Quinoxaline-Based Polymer Dots with Ultrabright Red to Near-Infrared Fluorescence for In Vivo Biological Imaging.

    Science.gov (United States)

    Liu, Hong-Yi; Wu, Pei-Jing; Kuo, Shih-Yu; Chen, Chuan-Pin; Chang, En-Hao; Wu, Chang-Yi; Chan, Yang-Hsiang

    2015-08-19

    This article describes the design and synthesis of quinoxaline-based semiconducting polymer dots (Pdots) that exhibit near-infrared fluorescence, ultrahigh brightness, large Stokes shifts, and excellent cellular targeting capability. We also introduced fluorine atoms and long alkyl chains into polymer backbones and systematically investigated their effect on the fluorescence quantum yields of Pdots. These new series of quinoxaline-based Pdots have a fluorescence quantum yield as high as 47% with a Stokes shift larger than 150 nm. Single-particle analysis reveals that the average per-particle brightness of the Pdots is at least 6 times higher than that of the commercially available quantum dots. We further demonstrated the use of this new class of quinoxaline-based Pdots for effective and specific cellular and subcellular labeling without any noticeable nonspecific binding. Moreover, the cytotoxicity of Pdots were evaluated on HeLa cells and zebrafish embryos to demonstrate their great biocompatibility. By taking advantage of their extreme brightness and minimal cytotoxicity, we performed, for the first time, in vivo microangiography imaging on living zebrafish embryos using Pdots. These quinoxaline-based NIR-fluorescent Pdots are anticipated to find broad use in a variety of in vitro and in vivo biological research.

  8. Convenient Synthesis of Substituted Quinoxalines and 2H-Benzo[b][1,4]oxazines in Water

    Institute of Scientific and Technical Information of China (English)

    DING Chang-jiang; WANG Yan; ZHANG Wei-wei; LIU Li; LIANG Yong-jiu; DONG De-wen

    2009-01-01

    A facile and convenient synthesis method has been developed for substituted quinoxalines and 2H-benzo[b][1,4]oxazines from the reactions of α-bromoketones with benzene-1,2-diamine and 2-aminophenol,respectively,which were catalyzed by tetrabutylammonium bromide(TBAB) in aqueous basic media.

  9. Citric acid: An efficient and green catalyst for rapid one pot synthesis of quinoxaline derivatives at room temperature

    Institute of Scientific and Technical Information of China (English)

    Radhakrishnan Mahesh; Arghya Kusum Dhar; Tara Sasank T.V.N.V.; Sappanimuthu Thirunavukkarasu; Thangaraj Devadoss

    2011-01-01

    The condensation of o-phenylenediamines with 1,2-dicarbonyl compounds in the presence of citric acid afforded the corresponding quinoxaline derivatives in higher yields at room temperature in ethanol, and most of the reactions were completed in less than 1 min.

  10. Quinoxaline derivatives as corrosion inhibitors for mild steel in hydrochloric acid medium: Electrochemical and quantum chemical studies

    Science.gov (United States)

    Olasunkanmi, Lukman O.; Kabanda, Mwadham M.; Ebenso, Eno E.

    2016-02-01

    The corrosion inhibition potential of four quinoxaline derivatives namely, 1-[3-(4-methylphenyl)-5-(quinoxalin-6-yl)-4,5-dihydropyrazol-1-yl]butan-1-one (Me-4-PQPB), 1-(3-(4-methoxyphenyl)-5-(quinoxalin-6-yl)-4,5-dihydropyrazol-1-yl)butan-1-one (Mt-4-PQPB), 1-[3-(3-methoxyphenyl)-5-(quinoxalin-6-yl)-4,5-dihydropyrazol-1-yl]butan-1-one (Mt-3-PQPB) and 1-[3-(2H-1,3-benzodioxol-5-yl)-5-(quinoxalin-6-yl)-4,5-dihydropyrazol-1-yl]butan-1-one (Oxo-1,3-PQPB) was studied for mild steel corrosion in 1 M HCl solution using electrochemical, spectroscopic techniques and quantum chemical calculations. The results of both potentiodynamic polarization and electrochemical impedance spectroscopic studies revealed that the compounds are mixed-type inhibitors and the order of corrosion inhibition efficiency at 100 ppm is Me-4-PQPB>Mt-3-PQPB>Oxo-1,3-PQPB>Mt-4-PQPB. Fourier transform infrared (FTIR) and ultraviolet-visible (UV-vis) spectroscopic analyses confirmed the presence of chemical interactions between the inhibitors and mild steel surface. The adsorption of the inhibitor molecules on mild steel surface was found to be both physisorption and chemisorption but predominantly chemisorption. The experimental data obey Langmuir adsorption isotherm. Scanning electron microscopy studies revealed the formation of protective films of the inhibitors on mild steel surface. Quantum chemical parameters obtained from density functional theory (DFT) calculations support experimental results.

  11. Radiation-induced reduction of quinoxalin-2-one derivatives in aqueous solutions

    Science.gov (United States)

    Skotnicki, Konrad; De la Fuente, Julio R.; Cañete, Alvaro; Bobrowski, Krzysztof

    2016-07-01

    Quinoxaline-2-one derivatives have been proposed as potential drugs in treatments of various diseases since some of them showed a variety of pharmacological properties. The kinetics and spectral characteristics of the transients formed in the reactions of hydrated electrons (eaq-) with quinoxalin-2-(1H)-one (Q) and its methyl derivative, 3-methyl quinoxalin-2-(1H)-one (3-MeQ) were studied by pulse radiolysis in aqueous solutions at pH ranging from 5 to 14. The transient absorption spectra recorded in the reactions of (eaq-) with Q and 3-MeQ at pH 7 consisted of a broad, almost flat band in the range 390-450 nm and were assigned to the respective protonated radical anions (QH•/3-MeQH•) at N4 atom in a pyrazin-2-one ring. On the other hand, the transient absorption spectra recorded in the reactions of (eaq-) with Q and 3-MeQ at pH 13 are characterized by a broad band with a much better pronounced maximum at λmax=390 nm and higher intensity (in comparison to that at pH 7) and were assigned to the respective radical anions (Q•-/3-MeQ•-). Both forms are involved in the prototropic equilibrium with the pKa located at pH≥13.5. The rate constants of the reactions of (eaq-) with Q and 3-MeQ were found to be at pH 7 (2.6±0.1)×1010 M-1 s-1 and (2.1±0.1)×1010 M-1 s-1 and at pH 13 (1.6±0.1)×1010 M-1 s-1 and (1.3±0.1)×1010 M-1 s-1, respectively. Semi-empirical quantum mechanical calculations reproduce fairly well the spectral features of the experimental absorption spectra and show that protonated radical anions at nitrogen atom (N4) in both molecules are the most stable hydrogenated radicals.

  12. Ga(ClO4)3-catalyzed Reaction of 1,2-Diamines and α-Bromoketones: Synthesis of 2-Substituted Quinoxalines

    Institute of Scientific and Technical Information of China (English)

    JI Yun-fei; CHEN Tang-ming; MAO Hai-feng; ZOU Jian-ping

    2012-01-01

    Ga(ClO4)3-catalyzed reaction of 1,2-aryldiamines and a-bromoketones to afford 2-substituted quinoxalines in good yields is described.The reaction proceeded via grinding process with 10%(molar fraction) catalyst under solvent-free conditions at room temperature.For unsymmetrical o-phenylenediamines bearing electron-withdrawing groups,regio-selective quinoxalines were obtained.

  13. Synthesis, Photophysical, Electrochemical and Thermal Studies of Triarylamines based on benzo[]quinoxalines

    Indian Academy of Sciences (India)

    Azam M Shaikh; Bharat K Sharma; Rajesh M Kamble

    2015-09-01

    A series of novel dipolar and nonplanar compounds featuring electron acceptor benzo[]quinoxaline and various electron donor triarylamine units have been synthesized in good yields and fully characterized. The photophysical, electrochemical and thermal properties of the synthesized compounds are described. The photoluminescence properties of the synthesized molecules are influenced by peripheral amines. The derivatives have high Stokes shifts, low band gap and the Commission Internationale de l’Eclairage (CIE) coordinates are positioned in the green–yellow region of the chromaticity diagram. The ionization potentials and electron affinity were found to be in the range of 5.11–5.60 eV and 2.77–2.93 eV and are comparable to the commonly used hole transporters. Thermal studies also reveal that these synthesized molecules have good thermal stability with 5% and 10% weight loss temperature ranging from 200 to 355°C and 268 to 442°C, respectively.

  14. Genotoxicity of quinoxaline 1,4-dioxide derivatives in Escherichia coli and Salmonella typhimurium.

    Science.gov (United States)

    Nunoshiba, T; Nishioka, H

    1989-05-01

    The mutagenicities of 5 quinoxaline 1,4-dioxide (QdO) derivatives were tested by 2 bacterial assays using forward mutation with Escherichia coli WP2uvrA/pKM101 and reverse mutation with Salmonella typhimurium TA100 and TA98. Potent mutagenic activities of all QdOs tested were observed in both mutation assays. Mutagenicities of these compounds were varied by addition of S9 mix. Their SOS-inducing activities were examined with a 'Rec-lac test' that has been newly developed by us for detecting genotoxins. A high level of SOS-inducing activity was observed in all samples tested. These results suggest that the mutagenicity of QdOs results from the error-prone repair involved in SOS responses.

  15. Fourier transform microwave and millimeter wave spectroscopy of quinazoline, quinoxaline, and phthalazine

    Science.gov (United States)

    McNaughton, Don; Godfrey, Peter D.; Jahn, Michaela K.; Dewald, David A.; Grabow, Jens-Uwe

    2011-04-01

    The pure rotational spectra of the bicyclic aromatic nitrogen heterocycle molecules, quinazoline, quinoxaline, and phthalazine, have been recorded and assigned in the region 13-87 GHz. An analysis, guided by ab initio molecular orbital predictions, of frequency-scanned Stark modulated, jet-cooled millimeter wave absorption spectra (48-87 GHz) yielded a preliminary set of rotational and centrifugal distortion constants. Subsequent spectral analysis at higher resolution was carried out with Fourier transform microwave (FT-MW) spectroscopy (13-18 GHz) of a supersonic rotationally cold molecular beam. The high spectral resolution of the FT-MW instrument provided an improved set of rotational and centrifugal distortion constants together with nitrogen quadrupole coupling constants for all three species. Density functional theory calculations at the B3LYP/6-311+G** level of theory closely predict rotational constants and are useful in predicting quadrupole coupling constants and dipole moments for such species.

  16. Quinoxaline-based inhibitors of Ebola and Marburg VP40 egress.

    Science.gov (United States)

    Loughran, H Marie; Han, Ziying; Wrobel, Jay E; Decker, Sarah E; Ruthel, Gordon; Freedman, Bruce D; Harty, Ronald N; Reitz, Allen B

    2016-08-01

    We prepared a series of quinoxalin-2-mercapto-acetyl-urea analogs and evaluated them for their ability to inhibit viral egress in our Marburg and Ebola VP40 VLP budding assays in HEK293T cells. We also evaluated selected compounds in our bimolecular complementation assay (BiMC) to detect and visualize a Marburg mVP40-Nedd4 interaction in live mammalian cells. Antiviral activity was assessed for selected compounds using a live recombinant vesicular stomatitis virus (VSV) (M40 virus) that expresses the EBOV VP40 PPxY L-domain. Finally selected compounds were evaluated in several ADME assays to have an early assessment of their drug properties. Our compounds had low nM potency in these assays (e.g., compounds 21, 24, 26, 39), and had good human liver microsome stability, as well as little or no inhibition of P450 3A4.

  17. Evaluation of kinetic parameters and redox mechanism of quinoxaline at glassy carbon electrode

    Directory of Open Access Journals (Sweden)

    Aleksić Mara M.

    2014-01-01

    Full Text Available The electrochemical behavior of a biologically important heterocyclic compound quinoxaline (QUI was investigated by cyclic voltammetry (CV in solutions of differing pH, using a glassy carbon electrode (GCE. The reduction of QUI occurs as a quasi-reversible reaction in acid medium, reaching reversibility in alkaline solutions. The kinetic parameters of the electrode process such as αnα, diffusion coefficient (D and heterogeneous rate constant (ks, were evaluated and discussed. Redox mechanism of QUI was proposed on the basis of experimental results. Reduction process involves a transfer of two electrons and two protons at the pyrazine ring of QUI forming a dihydro-derivative. In acid solutions, the product of QUI reduction undergoes irreversible oxidation in a one-electron process. The electrode processes was found to be diffusion controlled. [Projekat Ministarstva nauke Republike Srbije, br. 172033

  18. Photovoltaic and photophysical properties of a novel bis-3-hexylthiophene substituted quinoxaline derivative

    Energy Technology Data Exchange (ETDEWEB)

    Guenes, Serap [Linz Institute for Organic Solar Cells (LIOS), Johannes Kepler University Linz, Physical Chemistry, Altenberger Strasse 69, A-4040 Linz (Austria); Yildiz Technical University, Faculty of Arts and Science, Department of Physics, Davutpasa Campus, 34210 Esenler, Istanbul (Turkey); Baran, Derya; Guenbas, Goerkem; Oezyurt, Funda; Toppare, Levent [Middle East Technical University, Faculty of Arts and Science, Department of Chemistry, 06531 Ankara (Turkey); Fuchsbauer, Anita; Sariciftci, Niyazi Serdar [Linz Institute for Organic Solar Cells (LIOS), Johannes Kepler University Linz, Physical Chemistry, Altenberger Strasse 69, A-4040 Linz (Austria)

    2008-09-15

    We report on the photophysical properties and photovoltaic performance of a polythiophene derivative, poly-2,3-bis(4-tert-butylphenyl)-5,8-bis(4-hexylthiophen-2-yl)quinoxaline (PHTQ) as an electron donor in bulk heterojunction solar cells blended with the acceptor 1-(3-methoxycarbonyl)propyl-1-phenyl-[6,6]-methanofullerene (PCBM). Devices were composed of PHTQ and varying amounts of PCBM (1:1, 1:2, 1:3, 1:4 w-w ratio). The components were spin cast from ortho-dichlorobenzene (ODCB) and characterized by measuring current-voltage characteristics under simulated AM 1.5 conditions. Efficiencies up to 0.3% have been reached. Incident photon to current efficiency (IPCE) is reported and the nanoscale morphology was investigated with atomic force microscopy (AFM). Photoinduced absorption spectroscopy confirms the photoinduced charge transfer in such donor acceptor blends. (author)

  19. A novel quinoxaline bearing electroactive monomer: Pyrrole as the donor moiety

    Energy Technology Data Exchange (ETDEWEB)

    Taskin, Asli Tuba; Balan, Abidin; Epik, Bugra; Yildiz, Ersin [Middle East Technical University, Department of Chemistry, 06531, Ankara (Turkey); Udum, Yasemin Arslan [Gazi University, Institute of Science and Technology, Department of Advanced Technologies, 06570, Ankara (Turkey); Toppare, Levent [Middle East Technical University, Department of Chemistry, 06531, Ankara (Turkey)], E-mail: toppare@metu.edu.tr

    2009-09-30

    A novel electroactive monomer 5,8-di(1H-pyrrol-2-yl)-2,3-di(thiophen-2-yl)quinoxaline (PTQ) was successfully synthesized and its electrochromic properties were reported. Nuclear magnetic resonance ({sup 1}H NMR-{sup 13}C NMR) and mass spectroscopy were used to characterize the monomer. The monomer was electrochemically polymerized in the presence of tetrabutylammonium perchlorate (TBAP) as supporting electrolyte in dichloromethane. Monomer reveals relatively low oxidation potential at +0.70 V. Spectroelectrochemical behaviors and switching ability of homopolymer were investigated by UV-vis spectroscopy and cyclic voltammetry. Two {pi}-{pi}* transitions were observed at 400 and 815 nm with a low band gap, 1.0 eV. Polymer possesses 66% optical contrast in the Near IR region, which may be promising in NIR electrochromic device applications.

  20. Design, synthesis and biological evaluation of type-II VEGFR-2 inhibitors based on quinoxaline scaffold.

    Science.gov (United States)

    Shahin, Mai I; Abou El Ella, Dalal A; Ismail, Nasser S M; Abouzid, Khaled A M

    2014-10-01

    In an effort to develop ATP-competitive VEGFR-2 selective inhibitors, a series of new quinoxaline-based derivatives was designed and synthesized. The target compounds were biologically evaluated for their inhibitory activity against VEGFR-2. The design of the target compounds was accomplished after a profound study of the structure activity relationship (SAR) of type-II VEGFR-2 inhibitors. Among the synthesized compounds, 1-(2-((4-methoxyphenyl)amino)-3-oxo-3,4 dihydroquinoxalin-6-yl)-3-phenylurea (VIIa) displayed the highest inhibitory activity against VEGFR-2. Molecular modeling study involving molecular docking and field alignment was implemented to interpret the variable inhibitory activity of the newly synthesized compounds.

  1. An efficient catalyst-free protocol for the synthesis of quinoxaline derivatives under ultrasound irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Wen-Xue; Jin, Hui-Le; Chen, Jiu-Xi; Chen, Fan; Wu, Hua-Yue [Wenzhou University, Wenzhou (China). Coll. of Chemistry and Materials Engineering; Ding, Jin-Chang [Wenzhou Vocational and Technical College, Wenzhou (China)

    2009-07-01

    A highly efficient and facile method has been described for the synthesis of quinoxaline derivatives in good to excellent yields (80-99%) by condensation reaction of heterocyclic as well as aliphatic 1,2-diketones (R{sup 1}COCOR{sup 1}, R{sup 1} = Et, Ph, p-MeC{sub 6}H{sub 5}, p-MeOC{sub 6}H{sub 5}, Furyl) with 1,2-diamines (1,2-(NH{sub 2}){sub 2}C{sub 6}H{sub 3}R{sup 2}, R{sup 2} = H, Br, NO{sub 2}, PhCO). A systematic study was carried out to examine the influence of reaction media and electronic factors of the substrates on the reaction results. (author)

  2. Synthesis and Neuropharmacological Evaluation of Some Novel Quinoxaline 2, 3-Dione Derivatives

    Directory of Open Access Journals (Sweden)

    Selvaraj Jubie

    2012-01-01

    Full Text Available Quinoxaline-2, 3-dione obtained from cyclocondensation reaction of o-phenylene diamine with oxalic acid was reacted with three different ketones and formaldehyde to give the corresponding Mannich bases in satisfactory yield. Their structures were confirmed by using 1H NMR, IR, and mass analysis. In pharmacological evaluation, the synthesized compounds showed its curative effect against ethidium-bromide-induced demyelination in rats. For the purpose, different screening methods such as open field exploratory behavior test, rota rod test, grip strength test, beam walk test, and photo actometer test were performed. Ethidium bromide induction showed muscle weakness; muscle discoordination; loss of locomotor activity, and so forth, the synthesized drugs reversed all the above-mentioned neuromuscular disorders caused by ethidium bromide administration.

  3. In Vitro and In Vivo Activities of 2,3-Diarylsubstituted Quinoxaline Derivatives against Leishmania amazonensis.

    Science.gov (United States)

    Kaplum, Vanessa; Cogo, Juliana; Sangi, Diego Pereira; Ueda-Nakamura, Tânia; Corrêa, Arlene Gonçalves; Nakamura, Celso Vataru

    2016-06-01

    Leishmaniasis is endemic in 98 countries and territories worldwide. The therapies available for leishmaniasis have serious side effects, thus prompting the search for new therapies. The present study investigated the antileishmanial activities of 2,3-diarylsubstituted quinoxaline derivatives against Leishmania amazonensis The antiproliferative activities of 6,7-dichloro-2,3-diphenylquinoxaline (LSPN329) and 2,3-di-(4-methoxyphenyl)-quinoxaline (LSPN331) against promastigotes and intracellular amastigotes were assessed, and the cytotoxicities of LSPN329 and LSPN331 were determined. Morphological and ultrastructural alterations were examined by electron microscopy, and biochemical alterations, reflected by the mitochondrial membrane potential (ΔΨm), mitochondrial superoxide anion (O2·(-)) concentration, the intracellular ATP concentration, cell volume, the level of phosphatidylserine exposure on the cell membrane, cell membrane integrity, and lipid inclusions, were evaluated. In vivo antileishmanial activity was evaluated in a murine cutaneous leishmaniasis model. Compounds LSPN329 and LSPN331 showed significant selectivity for promastigotes and intracellular amastigotes and low cytotoxicity. In promastigotes, ultrastructural alterations were observed, including an increase in lipid inclusions, concentric membranes, and intense mitochondrial swelling, which were associated with hyperpolarization of ΔΨm, an increase in the O2·(-) concentration, decreased intracellular ATP levels, and a decrease in cell volume. Phosphatidylserine exposure and DNA fragmentation were not observed. The cellular membrane remained intact after treatment. Thus, the multifactorial response that was responsible for the cellular collapse of promastigotes was based on intense mitochondrial alterations. BALB/c mice treated with LSPN329 or LSPN331 showed a significant decrease in lesion thickness in the infected footpad. Therefore, the antileishmanial activity and mitochondrial mechanism of

  4. Discovery of indeno[1,2-b]quinoxaline derivatives as potential anticancer agents.

    Science.gov (United States)

    Tseng, Chih-Hua; Chen, You-Ren; Tzeng, Cherng-Chyi; Liu, Wangta; Chou, Chon-Kit; Chiu, Chien-Chih; Chen, Yeh-Long

    2016-01-27

    We have synthesized certain indeno[1,2-b]quinoxaline derivatives for antiproliferative evaluation. Among them, 11-{[3-(dimethylamino)propoxy]imino}-N-[3-(dimethylamino) propyl]-11H-indeno[1,2-b]quinoxaline-6-carboxamide (10a) was active against the growth of MDA-MB231, PC-3, and Huh-7 with IC50 values of 0.87 (selectivity index, SI = 36.22), 0.82 (SI = 38.43), and 0.64 μM (SI = 49.23) respectively. Compound 10a was inactive against the growth of normal human fetal lung fibroblast cell line (MRC-5) with an IC50 value of 31.51 μM. Its analogs, 10b and 10c, were also active against the growth of MB231, PC-3, and Huh-7 with IC50 values of <1.0 μM in each case. Our results have also indicated compounds 10a-10c exhibited comparable inhibitory activities against topo I and topo II with the positive compound 2 at a concentration of 10 μM. Mechanism studies indicated that compound 10a induced cell cycle arrest at S phase via activation of caspase-3, -7 and an increase in the protein expression of Bad and Bax but a decrease in expression of Bcl-2 and PARP, which consequently cause cell death. In addition, compound 10a attenuated the levels of phosphorylated Src, Akt-1, and Akt-2 protein levels but did not affect the total protein expression of Akt. We have also implanted human hepatocellular carcinoma cells into the yolk sac of zebrafish larvae and incubated larvae with various concentrations of 10a. Our results of the zebrafish xenograft assay confirmed the anti-tumor effect of 10ain vivo.

  5. Synthesis and characterization of polyesters from 2,3-bis (4'-hydroxy phenyl) quinoxaline and 2,3-bis (2'-hydroxynaphthalene-6'-yl) quinoxaline

    Energy Technology Data Exchange (ETDEWEB)

    Patil, V.B.; Medhi, M. [Chemistry Department, Solapur University, Pune-Solapur high way, Kegaon, Solapur 413255, Maharashtra (India); Bhairamadgi, N.S.; Wadgaonkar, P.P. [Polymer Science and Engineering Division, National Chemical Laboratory, Pune 411008 (India); Maldar, N.N., E-mail: maldar_nn@rediffmail.co [Chemistry Department, Solapur University, Pune-Solapur high way, Kegaon, Solapur 413255, Maharashtra (India)

    2010-04-15

    Two bisphenols containing pendant, quinoxaline moiety; 2,3-bis (4'-hydroxy phenyl) quinoxaline (BHPQ) and 2,3-bis (2'-hydroxynaphthalene-6'-yl) quinoxaline (BHNQ) were synthesized and characterized by FT-IR, {sup 1}H, {sup 13}C NMR and mass spectrometry. Aromatic polyesters and copolyesters were prepared by interfacial polymerization from BHPQ or BHNQ and isophthaloyl chloride or terephthaloyl chloride or a mixture of different mole proportions of (IPC + TPC). These polyesters and copolyesters were characterized by spectroscopic technique, viscosity measurement, solubility, thermal stability, DSC and XRD. Polymers had moderate to high molecular weights as evidenced by the inherent viscosities in the range 0.35-0.78 dL/g for BHPQ series and 0.27-0.52 dL/g for BHNQ series. BHPQ polyesters and copolyesters dissolved in m-cresol, NMP and conc. H{sub 2}SO{sub 4} whereas, BHNQ polyesters and copolyesters were readily soluble in NMP, DMAc, (TCE + phenol) and partly soluble in solvent like CHCl{sub 3}, pyridine, etc. Wide angle X-ray diffraction (WAXD) results showed that introduction of quinoxaline moiety into polymer chain and aromatic phenyl/rigid naphthyl structures lead to crystalinity. Differentional scanning calorimetry of BHNQ polyesters showed the glass transition temperatures in the range of 131-151 deg. C. BHPQ polyesters did not show any weight loss below 330 deg. C and retained 27-55% weight at 900 deg. C when investigated by TGA under nitrogen atmosphere demonstrating good thermal stability BHNQ derived polyesters showed initial decomposition temperatures in range 211-234 deg. C. The structure-property relationships for the mentioned polyesters are analyzed, as these polyesters are of interest as materials for electronics, microelectronics and membrane separation.

  6. A sensitive and selective imprinted solid phase extraction coupled to HPLC for simultaneous detection of trace quinoxaline-2-carboxylic acid and methyl-3-quinoxaline-2-carboxylic acid in animal muscles.

    Science.gov (United States)

    Duan, Zhenjuan; Yi, Jianghua; Fang, Guozhen; Fan, Lipeng; Wang, Shuo

    2013-08-15

    A new molecularly imprinted polymer (MIP), selective for major metabolites of quinoxaline-1,4-dioxides, was prepared through bulk polymerisation using quinoxaline-2-carboxylic acid (QCA) as template, diethylaminoethylmethacrylate as functional monomer and ethylene glycol dimethacrylate as cross-linker in tetrahydrofuran. The synthesised MIP was characterised by Fourier transform infrared and adsorption experiments. MIP exhibited high affinity, fast kinetics for QCA and good selectivity for QCA and methyl-3-quinoxaline-2-carboxylic acid (MQCA). MIP obtained was used as a selective sorbent for molecularly imprinted solid phase extraction (MISPE) coupled with HPLC to detect QCA and MQCA. Under the optimal conditions, the limits of detection (S/N=3) of porcine, chicken and fish muscles were 0.1, 0.3, 0.1 μg/kg for QCA and 0.2, 0.3, 0.1 μg/kg for MQCA, respectively and good recoveries were obtained in the range from 60.0 to 119.4%. These results indicated the MISPE-HPLC procedure could be successfully used for the determination QCA and MQCA in animal muscles.

  7. A new approach to construct a fused 2-ylidene chromene ring: highly regioselective synthesis of novel chromeno quinoxalines.

    Science.gov (United States)

    Kumar, K Shiva; Rambabu, D; Prasad, Bagineni; Mujahid, Mohammad; Krishna, G Rama; Rao, M V Basaveswara; Reddy, C Malla; Vanaja, G R; Kalle, Arunasree M; Pal, Manojit

    2012-06-28

    Regioselective construction of a fused 2-ylidene chromene ring was achieved for the first time by using AlCl(3)-induced C-C bond formation followed by Pd/C-Cu mediate coupling-cyclization strategy. A number of chromeno[4,3-b]quinoxaline derivatives were prepared by using this strategy. Single crystal X-ray diffraction study of a representative compound e.g. 6-(2,2-dimethylpropylidene)-4-methyl-6H-chromeno[4,3-b]quinoxalin-3-ol confirmed the presence of an exocyclic C-C double bond with Z-geometry. The crystal structure analysis and hydrogen bonding patterns of the same compound along with its structure elaboration via propargylation followed by Sonogashira coupling of the resulting terminal alkyne is presented. A probable mechanism for the formation of 2-ylidene chromene ring is discussed. Some of the compounds synthesized showed anticancer properties when tested in vitro.

  8. 2,3-Bifunctionalized Quinoxalines: Synthesis, DNA Interactions and Evaluation of Anticancer, Anti-tuberculosis and Antifungal Activity

    Directory of Open Access Journals (Sweden)

    Tom Ellis

    2002-08-01

    Full Text Available A variety of 2,3-bifunctionalized quinoxalines (6-14 have been prepared by the condensation of 1,6-disubstituted-hexan-1,3,4,6-tetraones (1-4 with o-phenylenediamine, (R,R-1,2-diaminocyclohexane and p-nitro-o-phenylenediamine. It is concluded that strong intramolecular N-H----O bonds in the favoured keto-enamine form may be responsible for the minimal biological activities observed in DNA footprinting, antitubercular, anti-fungal and anticancer tests with these hyper π-conjugated quinoxaline derivatives. However, subtle alteration by addition of a nitro group affecting the charge distribution confers significant improvements in biological effects and binding to DNA.

  9. In Silico Studies of Quinoxaline-2-Carboxamide 1,4-di-N-Oxide Derivatives as Antimycobacterial Agents

    Directory of Open Access Journals (Sweden)

    Awwad A. Radwan

    2014-02-01

    Full Text Available Molecular modelling studies were performed on some previously reported novel quinoxaline-2-carboxamide 1,4-di-N-oxide derivatives (series 1–9. Using the LigandScout program, a pharmacophore model was developed to further optimize the antimycobacterial activity of this series of compounds. Using the Dock6 program, docking studies were performed in order to investigate the mode of binding of these compounds. The molecular modeling study allowed us to confirm the preferential binding mode of these quinoxaline-2-carboxamide 1,4-di-N-oxide derivatives inside the active site. The obtained binding mode was as same as that of the novobiocin X-ray structure.

  10. Quinoxaline-based π-conjugated donor polymer for highly efficient organic thin-film solar cells

    Science.gov (United States)

    Kitazawa, Daisuke; Watanabe, Nobuhiro; Yamamoto, Shuhei; Tsukamoto, Jun

    2009-08-01

    A quinoxaline-based π-conjugated donor polymer, poly[2,7-(9,9-dioctylfluorene)-alt-5,5-(5',8'-di-2-thienyl-2',3'-diphenylquinoxaline)] (N-P7), was synthesized to achieve a high power conversion efficiency (PCE) of bulk heterojunction (BHJ)-based solar cells. The optical band-gap and highest occupied molecular orbital level of N-P7 were 1.95 and -5.37 eV, respectively. BHJ-based solar cells using N-P7 as a donor and phenyl C71 butyric acid methyl ester as an acceptor gave a PCE as high as 5.5% under AM 1.5G 100 mW/cm2 illumination. We also investigated the effects of substituent groups of quinoxaline-based polymers on the morphology of the BHJ layer.

  11. An improved understanding of the reaction of bis(bromomethyl)quinoxaline 1-N-oxides with amines using substituent effects.

    Science.gov (United States)

    Evans, Kathryn M; Slawin, Alexandra M Z; Lebl, Tomas; Philp, Douglas; Westwood, Nicholas J

    2007-04-27

    The reaction of bis(bromomethyl)quinoxaline N-oxides with amines is interesting from a reaction mechanism perspective and due to the reported biological activity of compounds in this general class. The complex mechanism of this reaction (particularly in the case of primary amines) is complicated further when C6 or C7 substituted mono-N-oxides are considered. In this study, the synthesis and subsequent characterization of a series of 2,3-bis(bromomethyl)quinoxaline 1-N-oxides is reported. Experimental and computational evidence is used to show that the observed product ratios from the reaction with diethylamine reflect the influence of both the C6/C7 substituent and the N-oxide functional group on the initial nucleophilic substitution reaction.

  12. Synthesis and biological activity of 7H-benzo[4,5]indolo[2,3-b]-quinoxaline derivatives.

    Science.gov (United States)

    Shibinskaya, Marina O; Karpenko, Alexander S; Lyakhov, Sergey A; Andronati, Sergey A; Zholobak, Nadezhda M; Spivak, Nikolay Ya; Samochina, Natalia A; Shafran, Lev M; Zubritsky, Mykhail Ju; Galat, Valerij F

    2011-02-01

    New 7-(2-aminoethyl)-7H-benzo[4,5]indolo[2,3-b]quinoxalines (13-20) were synthesized with high yields starting from 3H-benzo[e]indole-1,2-dione. These compounds were screened for the cytotoxicity, anti-viral activity, interferon inducing ability and DNA affinity compared with the corresponding 6-(2-aminoethyl)-6H-indolo[2,3-b]quinoxaline derivatives (1-12). It was shown, that compounds 13-20 bind to DNA stronger (lg Кa=6.23-6.87) than compounds 1-12 (lg Кa=5.57-5.89). Anti-viral activity is significantly reduced with annulations of benzene ring in Indoloquinoxaline moiety 13-20.

  13. One-pot efficient green synthesis of 1,4-dihydro-quinoxaline-2,3-dione derivatives

    Indian Academy of Sciences (India)

    Harjyoti Thakuria; Gopal Das

    2006-09-01

    An efficient synthesis of the potential pharmacophore 1,4-dihydro-quinoxaline-2,3-dione (1) has been achieved in a one-pot reaction at room temperature from substituted -phenylene diamine and oxalic acid under solvent-free conditions by a simple grinding method with unsurpassed atom economy. Thermal and powder X-ray diffraction analysis was carried out for some hydrated crystals.

  14. A simple strategy to the side chain functionalization on the quinoxaline unit for efficient polymer solar cells.

    Science.gov (United States)

    Yuan, Jun; Qiu, Lixia; Zhang, Zhiguo; Li, Yongfang; He, Yuehui; Jiang, Lihui; Zou, Yingping

    2016-05-25

    A new tetrafluoridequinoxaline electron accepting block from a quinoxaline core, which is substituted with a fluorine atom onto its backbone and side chains, was designed. A new copolymer (PBDTT-ffQx) was synthesized from tetrafluoridequinoxaline and benzodithiophene. The copolymer was characterized in detail. The photovoltaic properties were well investigated. A high PCE of 8.6% based on the single junction device was obtained.

  15. Molecular modeling studies and synthesis of novel quinoxaline derivatives with potential anticancer activity as inhibitors of c-Met kinase.

    Science.gov (United States)

    Abbas, Hebat-Allah S; Al-Marhabi, Aisha R; Eissa, Sally I; Ammar, Yousry A

    2015-10-15

    In an effort to develop potent anti-cancer agents, we have synthesized some substituted quinoxaline derivatives. Reaction of 6-bromo-3-methylquinoxalin-2(1H)-one 1 with aromatic aldehydes furnished the styryl derivatives 2a-e. Alkylation of 1 with ethyl chloroacetate produced the N-alkyl derivatives 3. Hydrazinolysis of the ester derivative 3 with hydrazine hydrate afforded the hydrazide derivative 4. In addition, chlorination of 1 with phosphorus oxychloride afforded the 2-chloro derivative 5 which was used as a key intermediate for the synthesis of substituted quinoxaline derivatives 6-8, N-pyrazole derivative 9, tetrazolo[1,5-a]quinoxaline derivative 10 and Schiff base derivatives 13, 15 via reaction with several nucleophiles reagents. Docking methodologies were used to predict their binding conformation to explain the differences of their tested biological activities. All the tested compounds were screened in vitro for their cytotoxic effect on three tumor cell lines. Some new quinoxaline derivatives were studied as inhibitors of c-Met kinase, a receptor associated with high tumor grade and poor prognosis in a number of human cancers. Compounds 2e, 4, 7a, 12a, 12b and 13 showed the highest binding affinity with CDOCKER energy score, while showed the lowest IC50 values against three types of cancer cell lines. It is worth to mention that, compounds 2e, 7a, 12b and 13 showed comparable inhibition activity to the reference drug, while compounds 4 and 12a showed a more potent inhibition activity than Doxorubicin.

  16. Synthesis, Characterization and Biological Evaluation of Some Quinoxaline Derivatives: A Promising and Potent New Class of Antitumor and Antimicrobial Agents.

    Science.gov (United States)

    Al-Marhabi, Aisha R; Abbas, Hebat-Allah S; Ammar, Yousry A

    2015-11-03

    In continuation of our endeavor towards the development of potent and effective anticancer and antimicrobial agents; the present work deals with the synthesis of some novel tetrazolo[1,5-a]quinoxalines, N-pyrazoloquinoxalines, the corresponding Schiff bases, 1,2,4-triazinoquinoxalines and 1,2,4-triazoloquinoxalines. These compounds were synthesized via the reaction of the key intermediate hydrazinoquinoxalines with various reagents and evaluated for anticancer and antimicrobial activity. The results indicated that tetrazolo[1,5-a]quinoxaline derivatives showed the best result, with the highest inhibitory effects towards the three tested tumor cell lines, which were higher than that of the reference doxorubicin and these compounds were non-cytotoxic to normal cells (IC50 values > 100 μg/mL). Also, most of synthesized compounds exhibited the highest degrees of inhibition against the tested strains of Gram positive and negative bacteria, so tetrazolo[1,5-a]quinoxaline derivatives show dual activity as anticancer and antimicrobial agents.

  17. Synthesis, Characterization and Biological Evaluation of Some Quinoxaline Derivatives: A Promising and Potent New Class of Antitumor and Antimicrobial Agents

    Directory of Open Access Journals (Sweden)

    Aisha R. Al-Marhabi

    2015-11-01

    Full Text Available In continuation of our endeavor towards the development of potent and effective anticancer and antimicrobial agents; the present work deals with the synthesis of some novel tetrazolo[1,5-a]quinoxalines, N-pyrazoloquinoxalines, the corresponding Schiff bases, 1,2,4-triazinoquinoxalines and 1,2,4-triazoloquinoxalines. These compounds were synthesized via the reaction of the key intermediate hydrazinoquinoxalines with various reagents and evaluated for anticancer and antimicrobial activity. The results indicated that tetrazolo[1,5-a]quinoxaline derivatives showed the best result, with the highest inhibitory effects towards the three tested tumor cell lines, which were higher than that of the reference doxorubicin and these compounds were non-cytotoxic to normal cells (IC50 values > 100 μg/mL. Also, most of synthesized compounds exhibited the highest degrees of inhibition against the tested strains of Gram positive and negative bacteria, so tetrazolo[1,5-a]quinoxaline derivatives show dual activity as anticancer and antimicrobial agents.

  18. Synthesis of new pyrrolo[1,2-a]quinoxaline derivatives as potential inhibitors of Akt kinase.

    Science.gov (United States)

    Desplat, Vanessa; Geneste, Ambre; Begorre, Marc-Antoine; Fabre, Solene Belisle; Brajot, Stephane; Massip, Stephane; Thiolat, Denis; Mossalayi, Djavad; Jarry, Christian; Guillon, Jean

    2008-10-01

    Akt kinases are attractive targets for small molecule drug discovery because of their key role in tumor cell survival/proliferation and their overexpression/activation in many human cancers. Recent efforts in the development and biological evaluation of small molecule inhibitors of Akt have led to the identification of novel Akt kinase inhibitors, based on a quinoxaline or pyrazinone scaffold. A series of new substituted pyrrolo[1,2-a]quinoxaline derivatives, structural analogues of these active quinoxaline or pyrazinone pharmacophores, was synthesized from various substituted 2-nitroanilines or 1,2-phenylenediamine via multistep heterocyclization process. These new compounds were tested for their in vitro ability to inhibit the proliferation of the human leukemic cell lines K562, U937 and HL60, and the breast cancer cell line MCF7. Three of these human cell lines (K562, U937 and MCF7) exhibited an active phosphorylated Akt form. The most promising active pyrroloquinoxalines were found to be 1a that inhibited K562 cell line proliferation with an IC(50) of 4.5 microM, and 1h that inhibited U937 and MCF7 cell lines with IC(50) of 5 and 8 microM, respectively. These two candidates exhibited more potent activities than the reference inhibitor A6730.

  19. Synthesis and in vitro evaluation of 4-trichloromethylpyrrolo[1,2-a]quinoxalines as new antiplasmodial agents.

    Science.gov (United States)

    Primas, Nicolas; Suzanne, Peggy; Verhaeghe, Pierre; Hutter, Sébastien; Kieffer, Charline; Laget, Michèle; Cohen, Anita; Broggi, Julie; Lancelot, Jean-Charles; Lesnard, Aurélien; Dallemagne, Patrick; Rathelot, Pascal; Rault, Sylvain; Vanelle, Patrice; Azas, Nadine

    2014-08-18

    Thanks to a preliminary in vitro screening of several CCl3-substituted-nitrogen containing heterocycles belonging to our chemical library, the 2-trichloromethylquinoxaline scaffold appeared to be of potential interest for developing new antiplasmodial agents. Then, combining these experimental results to the antimalarial properties reported for various pyrrolo[1,2-a]quinoxaline derivatives, an original series of fifteen 7-substituted-4-trichoromethylpyrrolo[1,2-a]quinoxalines was synthesized in a 4 to 5 reaction steps pathway. All molecules were evaluated in vitro toward both their antiplasmodial activity on the K1 multi-resistant Plasmodium falciparum strain and their cytotoxicity on the HepG2 human cell line. Thus, 3 hit molecules were identified, displaying IC50 values in the micromolar range and low cytotoxicity values, reaching good selectivity indexes, in comparison with the reference drugs chloroquine and doxycycline. Structure-activity relationship studies showed that the pyrrolo[1,2-a]quinoxaline scaffold can support selective antiplasmodial activity when substituted at position 4 by a CCl3 group. However, substitution at position 7 of the same scaffold is neither beneficial for cytotoxicity nor favourable for the solubility in the biological media.

  20. Simple and selective spectrophotometric determination of ruthenium after solid phase extraction with some quinoxaline dyes into microcrystalline p-dichlorobenzene

    Science.gov (United States)

    Amin, Alaa S.

    2002-07-01

    A simple selective and highly sensitive extraction method has been developed for the determination of ruthenium spectrophotometrically after extraction of its 2,3-dichloro-6-(3-carboxy-2-hydroxy-1-naphthylazo)quinoxaline (I), 2,3-dichloro-6-(2-hydroxy-3,5-dinitrophenylazo)quinoxaline (II) and 2,3-dichloro-6-(2,7-dihydroxy-naphthylazo)quinoxaline (III) complexes into microcrystalline p-dichlorobenzene. The optimization of experimental conditions for the procedure is studied. The solid p-dichlorobenzene containing the ruthenium-reagent (I-III) complexes is separated by filtration and dissolved in N, N-dimethylformamide. The absorbance is measured at λmax 622, 518 and 542 nm against reagents I, II and III, respectively, as blank. Beer's law is obeyed upto 2.5 μg ml -1 of ruthenium. The molar absorptivity, Sandell sensitivity, detection and quantification limits are calculated, when compared with those parameters without using solid phase extraction method. The interference of various ions has been studied in detail and the statistical evaluation of the experimental results is reported. The proposed methods have been successfully applied for the determination of trace amount of ruthenium in seawater, ore and metallurgy products.

  1. Synthesis of Three Novel Poly (aryl ether quinoxaline)s%3种新型聚苯基醚喹(噁)啉的合成

    Institute of Scientific and Technical Information of China (English)

    赵秋堂; 陈慧; 花慧

    2013-01-01

    用4,4′-二氟代二苯甲酰与双酚A的溶液缩聚制得聚醚苯偶酰(PEB),经邻苯二胺改性后,通过两步法得到聚苯基醚喹(噁)啉(PEQ-1).在PEB的改性反应中加入质量分数分别为1.0%和1.3%的3,3′,4,4′-四胺基二苯醚,可有效增加聚苯基醚喹(噁)啉的相对分子质量,得到PEQ-2和PEQ-3(总收率≥90%),其质均相对分子质量分别为7.492×104和1.486×105.并用IR、NMR等对这些聚合物进行了表征.该法操作简便,具有潜在的应用价值.%Novel poly(aryl ether quinoxaline)s(PEQs) were prepared via a new two-step procedure.First,poly (ether benzil) (PEB) was synthesized by the polycondensation of 4,4′-difluorobenzil and 4,4′-isopropylidenediphenol.Then,PEQ-1 was synthesized through chemical modification of PEB by 1,2-diaminobenzene.The mass average relative molecular mass of the PEQs could be adjusted easily as 7.492 × 104 and 1.486 × 105 by the addition of 1.0% and 1.3% mass fraction of 4,4′-oxydibenzene-1,2-diamine,respectively.The total yield of this two-step method is above 90%.The polymers were characterized by IR,NMR and other measurements.The method is simple and has a potential application value.

  2. Quinoxaline 1, 4-di-N-oxides: Biological activities and mechanisms of actions

    Directory of Open Access Journals (Sweden)

    Guyue eCheng

    2016-03-01

    Full Text Available Quinoxaline 1, 4-di-N-oxides (QdNOs have manifold biological properties, including antimicrobial, antitumoral, antitrypanosomal and antiinflammatory/antioxidant activities. These diverse activities endow them broad applications and prospects in human and veterinary medicines. As QdNOs arouse widespread interest, the evaluation of their medicinal chemistry is still in progress. In the meantime, adverse effects have been reported in some of the QdNO derivatives. For example, genotoxicity and bacterial resistance have been found in QdNO antibacterial growth promoters, conferring urgent need for discovery of new QdNO drugs. However, the modes of actions of QdNOs are not fully understood, hindering the development and innovation of these promising compounds. Here, QdNOs are categorized based on the activities and usages, among which the antimicrobial activities are consist of antibacterial, antimycobacterial and anticandida activities, and the antiprotozoal activities include antitrypanosomal, antimalarial, antitrichomonas and antiamoebic activities. The structure-activity relationship and the mode of actions of each type of activity of QdNOs are summarized, and the toxicity and the underlying mechanisms are also discussed, providing insight for the future research and development of these fascinating compounds.

  3. Spectroscopic properties and the catalytic activity of new organo-lead supramolecular coordination polymer containing quinoxaline

    Science.gov (United States)

    Etaiw, Safaa El-din H.; Abdou, Safaa N.

    2015-01-01

    The 3D-supramolecular coordination polymer (SCP) 3∞[ Cu2(CN)3(Me3Pb)(qox)], 1, as the first example of the CuCN SCP containing the (Me3Pb) fragment, was explored to investigate its catalytic and photo-catalytic activities. The structure of 1 contains two chemically identical but crystallographically different [Cu2(CN)3ṡMe3Pbṡqox]2 units with four Cu(I) sites assuming distorted TP-3 geometry. Two non-linear chains of equal abundance are formed producing corrugated parallel chains which are connected laterally by quinoxaline creating 2D-layers which are arranged parallel in an (AB⋯AB⋯AB)n fashion forming 3D-network. IR, mass, electronic absorption and fluorescence spectra are also investigated. The SCP 1 is diamagnetic and exhibits good catalytic and photo-catalytic activities for the degradation of methylene blue (MB). The reaction is first order with respect to MB dye. The irradiation of the reaction with UV-light enhanced the rate of MB mineralization. The efficiency of recycled the 1 and the mechanism of degradation of MB dye were investigated.

  4. Further investigations into the genotoxicity of quinoxaline-di-N-oxides and their primary metabolites.

    Science.gov (United States)

    Liu, Qianying; Zhang, Jianwu; Luo, Xun; Ihsan, Awais; Liu, Xianglian; Dai, Menghong; Cheng, Guyue; Hao, Haihong; Wang, Xu; Yuan, Zonghui

    2016-07-01

    Quinoxaline-di-N-oxides (QdNOs) are potential antibacterial agents with a wide range of biological properties. Quinocetone (QCT), carbadox (CBX), olaquindox (OLA), mequindox (MEQ) and cyadox (CYA) are classical QdNOs. Though the genotoxicity of parent drugs has been evaluated, the genotoxicity of their primary N → O reduced metabolites remains unclear. In the present study, a battery of four different short-term tests, mouse lymphoma assay (MLA), Ames test, chromosomal aberration assay in vitro and bone marrow erythrocyte micronucleus assay in vivo was carried out to investigate the genotoxicity of the six primary N → O reduced metabolites. Additionally, the genotoxicity of five parent drugs was evaluated by the MLA. Strong genotoxicity of N1-MEQ, B-MEQ and B-CBX was found in three of the assays but not in the Ames assay, and the rank order was N1-MEQ>B-MEQ>B-CBX that is consistent with prototype QdNOs. Negative results for the five QdNOs were noted in the MLA. We present for the first time a comparison of the genotoxicity of primary N → O reduced metabolites, and evaluate the ability of five QdNOs to cause mutations in the MLA. The present study demonstrates that metabolites are involved in genetic toxicity mediated by QdNOs, and improve the prudent use of QdNOs for public health.

  5. Design, synthesis, antifungal, and antioxidant activities of (E)-6-((2-phenylhydrazono)methyl)quinoxaline derivatives.

    Science.gov (United States)

    Zhang, Mao; Dai, Zhi-Cheng; Qian, Shao-Song; Liu, Jun-Yan; Xiao, Yu; Lu, Ai-Min; Zhu, Hai-Liang; Wang, Jian-Xin; Ye, Yong-Hao

    2014-10-01

    Different substituted phenylhydrazone groups were linked to the quinoxaline scaffold to provide 26 compounds (6a-6z). Their structures were confirmed by (1)H and (13)C NMR, MS, elemental analysis, and X-ray single-crystal diffraction. The antifungal activities of these compounds against Rhizoctonia solani were evaluated in vitro. Compound 6p is the most promising one among all the tested compounds with an EC50 of 0.16 μg·mL(-1), more potent than the coassayed positive control fungicide carbendazim (EC50: 1.42 μg·mL(-1)). In addition, these compounds were subjected to antioxidant assay by employing diphenylpicrylhydrazyl (DPPH) and mice microsome lipid peroxidation (LPO) methods. Most of these compounds are potent antioxidants. The strongest compounds are 6e (EC50: 7.60 μg·mL(-1), DPPH) and 6a (EC50: 0.96 μg·mL(-1), LPO), comparative to or more potent than the positive control Trolox [EC50: 5.90 μg·mL(-1) (DPPH) and 18.23 μg·mL(-1) (LPO)]. The structure and activity relationships were also discussed.

  6. A physiologically based pharmacokinetic model for quinoxaline-2-carboxylic acid in rats, extrapolation to pigs.

    Science.gov (United States)

    Yang, X; Zhou, Y-F; Yu, Y; Zhao, D-H; Shi, W; Fang, B-H; Liu, Y-H

    2015-02-01

    A multi-compartment physiologically based pharmacokinetic (PBPK) model to describe the disposition of cyadox (CYX) and its metabolite quinoxaline-2-carboxylic acid (QCA) after a single oral administration was developed in rats (200 mg/kg b.w. of CYX). Considering interspecies differences in physiology and physiochemistry, the model efficiency was validated by pharmacokinetic data set in swine. The model included six compartments that were blood, muscle, liver, kidney, adipose, and a combined compartment for the rest of tissues. The model was parameterized using rat plasma and tissue concentration data that were generated from this study. Model simulations were achieved using a commercially available software program (ACSLXL ibero version 3.0.2.1). Results supported the validity of the model with simulated tissue concentrations within the range of the observations. The correlation coefficients of the predicted and experimentally determined values for plasma, liver, kidney, adipose, and muscles in rats were 0.98, 0.98, 0.98, 0.99, and 0.95, respectively. The rat model parameters were then extrapolated to pigs to estimate QCA disposition in tissues and validated by tissue concentration of QCA in swine. The correlation coefficients between the predicted and observed values were over 0.90. This model could provide a foundation for developing more reliable pig models once more data are available.

  7. Quinoxaline 1,4-di-N-Oxides: Biological Activities and Mechanisms of Actions.

    Science.gov (United States)

    Cheng, Guyue; Sa, Wei; Cao, Chen; Guo, Liangliang; Hao, Haihong; Liu, Zhenli; Wang, Xu; Yuan, Zonghui

    2016-01-01

    Quinoxaline 1,4-di-N-oxides (QdNOs) have manifold biological properties, including antimicrobial, antitumoral, antitrypanosomal and antiinflammatory/antioxidant activities. These diverse activities endow them broad applications and prospects in human and veterinary medicines. As QdNOs arouse widespread interest, the evaluation of their medicinal chemistry is still in progress. In the meantime, adverse effects have been reported in some of the QdNO derivatives. For example, genotoxicity and bacterial resistance have been found in QdNO antibacterial growth promoters, conferring urgent need for discovery of new QdNO drugs. However, the modes of actions of QdNOs are not fully understood, hindering the development and innovation of these promising compounds. Here, QdNOs are categorized based on the activities and usages, among which the antimicrobial activities are consist of antibacterial, antimycobacterial and anticandida activities, and the antiprotozoal activities include antitrypanosomal, antimalarial, antitrichomonas, and antiamoebic activities. The structure-activity relationship and the mode of actions of each type of activity of QdNOs are summarized, and the toxicity and the underlying mechanisms are also discussed, providing insight for the future research and development of these fascinating compounds.

  8. A quinoxaline urea analog uncouples inflammatory and pro-survival functions of IKKβ.

    Science.gov (United States)

    Maroni, Dulce; Rana, Sandeep; Mukhopadhyay, Chandrani; Natarajan, Amarnath; Naramura, Mayumi

    2015-12-01

    Activation of the NF-κB pathway is causally linked to initiation and progression of diverse cancers. Therefore, IKKβ, the key regulatory kinase of the canonical NF-κB pathway, should be a logical target for cancer treatment. However, existing IKKβ inhibitors are known to induce paradoxical immune activation, which limits their clinical usefulness. Recently, we identified a quinoxaline urea analog 13-197 as a novel IKKβ inhibitor that delays tumor growth without significant adverse effects in xenograft tumor models. In the present study, we found that 13-197 had little effect on LPS-induced NF-κB target gene induction by primary mouse macrophages while maintaining considerable anti-proliferative activities. These characteristics may explain absence of inflammatory side effects in animals treated with 13-197. Our data also demonstrate that the inflammation and proliferation-related functions of IKKβ can be uncoupled, and highlight the utility of 13-197 to dissect these downstream pathways.

  9. ANTI INFLAMMATORY ACTIVITY OF SOME NEW THIO-ETHER DERIVATIVES OF QUINOXALINE

    Directory of Open Access Journals (Sweden)

    Singh, Dharmchand Prasad

    2010-12-01

    Full Text Available A series of thioether derivatives of 2-Chloro-3-methylquinoxaline have been synthesized by reacting 3- methylquinoxalin-2-thiosodium with 2-chloro-N-(substituted aryl/alkyl-acetamides. The synthesis was initiated with the reaction of o-phenylenediamine (1 with ethyl pyruvate in n-butanol to yield 2-hydroxy-3-methyl quinoxaline (2, which on treatment with POCl3 ,yielded 2-chloro-3-methylquinoxaline(3.A mixture of the compound(3 and sodium sulphide in DMF was refluxed to yield 3-methylquinoxalin-2-thiosodium(4,which on treatment with different Nsubstituted chloroacetamides afforded the one pot synthesis of 2-(2-methylquinoxalin-3-ylthio-N-substitutedaryl/ alkyl-acetamides(5a-k. 2-chloro-N-substituted acetamides were prepared by treating substituted anilines in glacial acetic acid with chloroacetylchloride, warming on the water bath for half an hour and then precipitating, 2- chloro-N-substituted acetamides by addition of saturated aqueous solution of anhydrous sodium acetate. A compound 2-(benzylthio-3-methylquinoxaline 5l was also prepared. The newly synthesized compounds have been characterized by IR, and 1HNMR spectra, analysis. All compounds (5a-l were screened for their in vivo anti inflammatory activity by carrageenan induced rat paw edema method. Compounds 5a, 5b, 5d, 5e, 5g and 5k have been found to possess good anti inflammatory activity.

  10. N,N′-Bis(pyridin-2-ylbenzene-1,4-diamine–quinoxaline (2/1

    Directory of Open Access Journals (Sweden)

    Barbara Wicher

    2011-12-01

    Full Text Available The asymmetric unit of the title compound, 2C16H14N4·C8H6N2, consits of one molecule of N,N′-bis(pyridin-2-ylbenzene-1,4-diamine (PDAB and one half-molecule of quinoxaline (QX that is located around an inversion centre and disordered over two overlapping positions. The PDAB molecule adopts a non-planar conformation with an E configuration at the two partially double exo C...;N bonds of the 2-pyridylamine units. In the crystal, these self-complementary units are N—H...N hydrogen bonded via a cyclic R22(8 motif, creating tapes of PDAB molecules extending along [010]. Inversion-related tapes are arranged into pairs through π–π stacking interactions between the benzene rings [centroid–centroid distance = 3.818 (1 Å] and the two symmetry-independent pyridine groups [centroid–centroid distance = 3.760 (1 Å]. The QX molecules are enclosed in a cavity formed between six PDAB tapes.

  11. Synthesis and biological evaluation of novel substituted pyrrolo[1,2-a]quinoxaline derivatives as inhibitors of the human protein kinase CK2.

    Science.gov (United States)

    Guillon, Jean; Le Borgne, Marc; Rimbault, Charlotte; Moreau, Stéphane; Savrimoutou, Solène; Pinaud, Noël; Baratin, Sophie; Marchivie, Mathieu; Roche, Séverine; Bollacke, Andre; Pecci, Adali; Alvarez, Lautaro; Desplat, Vanessa; Jose, Joachim

    2013-07-01

    Herein we describe the synthesis and properties of substituted phenylaminopyrrolo[1,2-a]quinoxaline-carboxylic acid derivatives as a novel class of potent inhibitors of the human protein kinase CK2. A set of 15 compounds was designed and synthesized using convenient and straightforward synthesis protocols. The compounds were tested for inhibition of human protein kinase CK2, which is a potential drug target for many diseases including inflammatory disorders and cancer. New inhibitors with IC50 in the micro- and sub-micromolar range were identified. The most promising compound, the 4-[(3-chlorophenyl)amino]pyrrolo[1,2-a]quinoxaline-3-carboxylic acid 1c inhibited human CK2 with an IC50 of 49 nM. Our findings indicate that pyrrolo[1,2-a]quinoxalines are a promising starting scaffold for further development and optimization of human protein kinase CK2 inhibitors.

  12. Synthesis and Application of Isopropyl-Quinoxaline%2-异丙基喹喔啉衍生物的合成及应用

    Institute of Scientific and Technical Information of China (English)

    崔建海; 张剑; 刘运奎

    2014-01-01

    以邻苯二胺化合物和α-溴代酮类化合物为原料,经过串联环化反应合成喹喔啉类化合物。部分未知的喹喔啉衍生物经过质谱和核磁分析加以确证。同时研究了2-异丙基喹喔啉在过渡金属Ag参与下的sp3 C-H键硝化反应。%Using o-phenylenediamine compounds and α-bromo ketones as raw material, the quinoxaline was synthesized via cyclization reaction. The partly unknown quinoxaline derivatives were confirmed by mass spectrometry and nuclear magnetic. The sp3 C-H bond nitrification of quinoxaline under the transition metal Ag were studied.

  13. Disposition and metabolism of the food mutagen 2-amino-3,8-dimethylimidazo(4,5-f)quinoxaline (MeIQx) in rats

    Energy Technology Data Exchange (ETDEWEB)

    Sjoedin, P.W.; Wallin, H.; Alexander, J.; Jaegerstad, M.

    1989-07-01

    The disposition and metabolism of a common food mutagen, 2-amino-3,8-dimethylimidazo(4,5-f)quinoxaline (MeIQx), was studied in rats. Five rats of both sexes were given a single oral dose of /sup 14/C-labeled MeIQx (3-4 mg/kg body wt). The male rats excreted 36% of the radioactivity and 15% of the mutagenic activity of the dose given in the urine collected during the first 24 h. In the females the corresponding urine contained 41% of the radioactivity and 12% of the mutagenicity. During the next 48 h only 1-3% of the radioactive dose was excreted in urine. The remaining dose was excreted in the feces except of less than 1% that was retained by the tissues after 72 h. The liver and kidney retained more radioactivity than other organs. In a separate study the metabolites of bile, urine and feces of both sexes were investigated. After a single oral dose of 20 mg /sup 14/C-labeled MeIQx/kg body wt, three major non-mutagenic metabolites were identified. These were 2-amino-4(or 5)-(beta-D-glucuronopyranosyloxy)-3,8-dimethylimidazo(4,5-f) quinoxaline, 2-amino-3,8-dimethylimidazo(4,5-f)quinoxalin-4(or 5)-yl sulfate and N-(3,8-dimethylimidazo(4,5-f)quinoxalin-2-yl) sulfamate. Another two metabolites present in bile, urine and feces were 2-(beta-D-glucuronopyranosylamino)-3,8-dimethylimidazo(4,5-f ) quinoxaline and 2-amino-8-hydroxymethyl-3-methylimidazo(4,5-f)quinoxalin-4 (or 5)yl sulfate. All metabolites were essentially non-mutagenic. Most of the mutagenicity still present in bile, urine and feces could be explained by unchanged MeIQx. Unchanged MeIQx was the most abundant form excreted in urine.

  14. Synthesis of quinoxaline 1,4-di-n-oxide derivatives on solid support using room temperature and microwave-assisted solvent-free procedures

    Energy Technology Data Exchange (ETDEWEB)

    Gomez-Caro, Lilia C.; Sanchez-Sanchez, Mario; Bocanegra-Garcia, Virgilio; Rivera, Gildardo [Universidad Autonoma de Tamaulipas, Reynosa (Mexico). Dept. de Farmacia y Quimica Medicinal; Monge, Antonio [Universidad de Navarra, Pamplona (Spain). Centro de Investigacion en Farmacobiologia Aplicada. Unidad de Investigacion y Desarrollo de Medicamentos

    2011-07-01

    We describe the synthesis of 12 new ethyl and methyl quinoxaline-7-carboxylate 1,4-di-N-oxide derivatives on solid supports with room temperature and microwave-assisted solvent-free procedures. Results show that solid supports have good catalytic activity in the formation of quinoxaline 1,4-di-N-oxide derivatives. We found that florisil and montmorillonite KSF and K10 could be used as new, easily available, inexpensive alternatives of catalysts. Additionally, room temperature and microwave-irradiation solvent-free synthesis was more efficient than a conventional procedure (Beirut reaction), reducing reaction time and increasing yield. (author)

  15. A Combined Experimental and Theoretical Study of the Ammonium Bifluoride Catalyzed Regioselective Synthesis of Quinoxalines and Pyrido[2,3-b]pyrazines

    OpenAIRE

    Lassagne, Frédéric; Chevallier, Floris; Roisnel, Thierry; Dorcet, Vincent; Mongin, Florence; Domingo, Luis .R.

    2015-01-01

    International audience; Ammonium bifluoride was efficiently used (at a 0.5 mol % loading) to catalyze the cyclocondensation between 1,2-arylenediamines and 1,2-dicarbonyl compounds at room temperature in methanol-water, affording quinoxalines and pyrido[2,3-b]pyrazines in excellent yields. Importantly, 2,8-disubstituted quinoxalines and 3-substituted pyrido[2,3-b]pyrazines were regioselectively formed by reacting aryl glyoxals with 3-methyl-1,2-phenylenediamine and 2,3-diaminopyridine, respec...

  16. Crystal and molecular structure of 2,2'-(quinoxaline-2,3-diyl)dipyridinium dinitrate (H2 L)(NO3)2

    Science.gov (United States)

    Egorova, O. A.; Polyakova, I. N.; Sergienko, V. S.; Davydov, V. V.

    2016-07-01

    The crystal structure of 2,2'-(quinoxaline-2,3-diyl)dipyridinium dinitrate (H2 L)(NO3)2 is studied by X-ray diffraction ( T = 150 K, R1 = 0.0467). The H2 L 2+ cation is located on the twofold rotation axis and connected with two NO3 - anions by strong N-H···O hydrogen bonds. Planar quinoxaline fragments of cations form stacks with the interplanar spacing of 3.308 Å. The structure of the diprotonated H2 L 2+ cation is compared with those of the monoprotonated H2 L 2+ cation and neutral L molecule.

  17. Design, synthesis and study of quinoxaline-2- carboxamide 1,4-DI-N-Oxide derivatives as anti-tuberculosis agents

    OpenAIRE

    Moreno-Viguri, E. (Elsa); Monge, A; Perez-Silanes, S. (Silvia)

    2013-01-01

    The experimental work presented in this memory is based on the hypothesis that quinoxalines di-N-oxide, considered to be the core of the structure, which present a carboxamide moiety on position two and aliphatic linker between this group and an aromatic system, can be proposed as potent anti-tuberculosis agents. The main purpose of this project is the synthesis of new quinoxaline di-N-oxide derivatives as anti-tuberculosis agents. The strategy consists of the design and synthesis of several ...

  18. Substitutions of Fluorine Atoms and Phenoxy Groups in the Synthesis of Quinoxaline 1,4-di-N-oxide Derivatives

    Directory of Open Access Journals (Sweden)

    Antonio Monge

    2008-01-01

    Full Text Available The unexpected substitution of fluorine atoms and phenoxy groups attached toquinoxaline or benzofuroxan rings is described. The synthesis of 2-benzyl- and 2-phenoxy-3-methylquinoxaline 1,4-di-N-oxide derivatives was based on the classical Beirut reaction.The tendency of fluorine atoms linked to quinoxaline or benzofuroxan rings to be replacedby a methoxy group when dissolved in an ammonia saturated solution of methanol wasclearly demonstrated. In addition, 2-phenoxyquinoxaline 1,4-di-N-oxide derivativesbecame 2-aminoquinoxaline 1,4-di-N-oxide derivatives in the presence of gaseousammonia.

  19. Syntheses of Benzimidazoles, Quinoxalines and 3,3-Dihydro 1 H-1,5-benzodiazepines Starting from o-Phenylenediamine

    Institute of Scientific and Technical Information of China (English)

    CUI Yong; TANG Xiu-Bo; SHAO Chang-Xing; LI Ji-Tai; SUN Wen-Hua

    2005-01-01

    A series of benzo-fused heteroaromatic compounds with 5-, 6- and 7-membered rings, such as benzimidazole,quinoxaline and 1H-1,5-benzodiazepine derivatives, were synthesized through condensation reaction of o-phenyl-enediamine with aryl aldehydes or ketones. The experimental conditions were carefully examined, and the products were characterized by 1H NMR, 13C NMR, MS, IR and elemental analyses. In addition, the structure of a benzodiazaepine derivative with 7-membered ring was confirmed by single crystal X-ray diffraction analysis.

  20. Radical Chemistry and Cytotoxicity of Bioreductive 3-Substituted Quinoxaline Di-N-Oxides.

    Science.gov (United States)

    Anderson, Robert F; Yadav, Pooja; Shinde, Sujata S; Hong, Cho R; Pullen, Susan M; Reynisson, Jóhannes; Wilson, William R; Hay, Michael P

    2016-08-15

    The radical chemistry and cytotoxicity of a series of quinoxaline di-N-oxide (QDO) compounds has been investigated to explore the mechanism of action of this class of bioreductive drugs. A series of water-soluble 3-trifluoromethyl (4-10), 3-phenyl (11-19), and 3-methyl (20-21) substituted QDO compounds were designed to span a range of electron affinities consistent with bioreduction. The stoichiometry of loss of QDOs by steady-state radiolysis of anaerobic aqueous formate buffer indicated that one-electron reduction of QDOs generates radicals able to initiate chain reactions by oxidation of formate. The 3-trifluoromethyl analogues exhibited long chain reactions consistent with the release of the HO(•), as identified in EPR spin trapping experiments. Several carbon-centered radical intermediates, produced by anaerobic incubation of the QDO compounds with N-terminal truncated cytochrome P450 reductase (POR), were characterized using N-tert-butyl-α-phenylnitrone (PBN) and 5-(diethoxyphosphoryl)-5-methyl-1-pyrroline-N-oxide (DEPMPO) spin traps and were observed by EPR. Experimental data were well simulated for the production of strongly oxidizing radicals, capable of H atom abstraction from methyl groups. The kinetics of formation and decay of the radicals produced following one-electron reduction of the parent compounds, both in oxic and anoxic solutions, were determined using pulse radiolysis. Back oxidation of the initially formed radical anions by molecular oxygen did not compete effectively with the breakdown of the radical anions to form oxidizing radicals. The QDO compounds displayed low hypoxic selectivity when tested against oxic and hypoxic cancer cell lines in vitro. The results from this study form a kinetic description and explanation of the low hypoxia-selective cytotoxicity of QDOs against cancer cells compared to the related benzotriazine 1,4-dioxide (BTO) class of compounds.

  1. Tetrathiafulvalene-fused porphyrins via quinoxaline linkers: symmetric and asymmetric donor-acceptor systems.

    Science.gov (United States)

    Jia, Hongpeng; Schmid, Belinda; Liu, Shi-Xia; Jaggi, Michael; Monbaron, Philippe; Bhosale, Sheshanath V; Rivadehi, Shadi; Langford, Steven J; Sanguinet, Lionel; Levillain, Eric; El-Khouly, Mohamed E; Morita, Ysushi; Fukuzumi, Shunichi; Decurtins, Silvio

    2012-10-08

    A tetrathiafulvalene (TTF) donor is annulated to porphyrins (P) via quinoxaline linkers to form novel symmetric P-TTF-P triads 1 a-c and asymmetric P-TTF dyads 2 a,b in good yields. These planar and extended π-conjugated molecules absorb light over a wide region of the UV/Vis spectrum as a result of additional charge-transfer excitations within the donor-acceptor assemblies. Quantum-chemical calculations elucidate the nature of the electronically excited states. The compounds are electrochemically amphoteric and primarily exhibit low oxidation potentials. Cyclic voltammetric and spectroelectrochemical studies allow differentiation between the TTF and porphyrin sites with respect to the multiple redox processes occurring within these molecular assemblies. Transient absorption measurements give insight into the excited-state events and deliver corresponding kinetic data. Femtosecond transient absorption spectra in benzonitrile may suggest the occurrence of fast charge separation from TTF to porphyrin in dyads 2 a,b but not in triads 1 a-c. Clear evidence for a photoinduced and relatively long lived charge-separated state (385 ps lifetime) is obtained for a supramolecular coordination compound built from the ZnP-TTF dyad and a pyridine-functionalized C(60) acceptor unit. This specific excited state results in a (ZnP-TTF)(⋅+) ⋅⋅⋅(C(60) py)(⋅-) state. The binding constant of Zn(II) ⋅⋅⋅py is evaluated by constructing a Benesi-Hildebrand plot based on fluorescence data. This plot yields a binding constant K of 7.20×10(4)  M(-1), which is remarkably high for bonding of pyridine to ZnP. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. In vitro and in vivo anti-glioma activity of a chalcone-quinoxaline hybrid.

    Science.gov (United States)

    Loch-Neckel, Gecioni; Bicca, Maíra Assunção; Leal, Paulo César; Mascarello, Alessandra; Siqueira, Jarbas Mota; Calixto, João B

    2015-01-27

    Chalcones are important compounds that exhibit multiple biological activities, including anti-inflammatory, antimitotic and antibacterial properties. In the present study, we have analyzed the potential anti-cancer activity of a chalcone named N9 (a hybrid chalcone-quinoxaline compound) using in vitro and in vivo experimental glioma models. Here, we report N9-induced inhibition of cell proliferation and also N9-induced cell death in a concentration-dependent manner in U87-MG glioma cells. These effects of N9 appear to be associated with its ability to inhibit the expression of cell cycle-associated proteins, and also the augmentation in the expression of the p21 (p21/Cip1) protein, a cyclin-dependent kinase inhibitor. Additionally, N9 also potentiates the production of the pro-apoptotic markers Bax and p53 via inhibition of MDM2. Moreover, our results show that N9 also significantly enhanced apoptosis of U87-MG cells with disruption of mitochondrial membrane potential, generation of ROS and caspase-9 activation. In vivo experiments carried out in a murine xenograft model of U87-MG revealed that N9 produced a significant reduction of tumors volume when compared to vehicle treated mice. Collectively, data demonstrate that N9 possess in vitro and in vivo anti-cancer activity, an effect that seems to involve the induction of p53 and p21 proteins, as well as, the activation of mitochondrial apoptosis pathway associated with the inhibition of protein MDM2. Overall, this study suggests N9 is affecting a variety of intracellular pathways related to tumor apoptosis. Perhaps N9 or derivate molecules could represent new potential drugs for cancer therapeutics.

  3. Synthesis of new quinoxaline-2-carboxylate 1,4-dioxide derivatives as anti-Mycobacterium tuberculosis agents.

    Science.gov (United States)

    Jaso, Andrés; Zarranz, Belén; Aldana, Ignacio; Monge, Antonio

    2005-03-24

    Twenty-nine new 6(7)-substituted quinoxaline-2-carboxylate 1,4-dioxide derivatives were synthesized and evaluated for in vitro antituberculosis activity. In general, the in vitro activity is significantly affected by substituents on the quinoxaline nucleus. It has been observed that the presence of a chloro, methyl, or methoxy group in position 7 of the benzene moiety reduces the MIC and IC(50) values. However, antituberculosis activity principally depends on the substituents in the carboxylate group, improving in the following order: benzyl > ethyl > 2-methoxyethyl > allyl > tert-butyl. Fourteen compounds have been selected for macrophage assay, and the results show that ethyl and benzyl 3-methylquinoxaline-2-carboxylate 1,4-dioxide derivatives with the chlorine group in position 7 of the benzene moiety (compounds 10 and 26) and the unsubstituted derivatives (compounds 11 and 27) have good antitubercular activity, including activity in macrophages. In addition, compounds 7 and 28 (the only ones tested up to now) are active against drug-resistant strains of M. tuberculosis H(37)Rv. In conclusion, the potency, selectivity, and low cytotoxicity of these compounds make them valid leads for synthesizing new compounds that possess better activity.

  4. Identification of phenylsulfone-substituted quinoxaline (WYE-672) as a tissue selective liver X-receptor (LXR) agonist.

    Science.gov (United States)

    Hu, Baihua; Unwalla, Rayomand J; Goljer, Igor; Jetter, James W; Quinet, Elaine M; Berrodin, Thomas J; Basso, Michael D; Feingold, Irene B; Nilsson, Annika Goos; Wilhelmsson, Anna; Evans, Mark J; Wrobel, Jay E

    2010-04-22

    A series of phenyl sulfone substituted quinoxaline were prepared and the lead compound 13 (WYE-672) was shown to be a tissue selective LXR Agonist. Compound 13 demonstrated partial agonism for LXRbeta in kidney HEK-293 cells but did not activate Gal4 LXRbeta fusion proteins in huh-7 liver cells. Although 13 showed potent binding affinity to LXRbeta (IC(50) = 53 nM), it had little binding affinity for LXRalpha (IC(50) > 1.0 microM) and did not recruit any coactivator/corepressor peptides in the LXRalpha multiplex assay. However, compound 13 showed good agonism in THP-1 cells with respect to increasing ABCA1 gene expression and good potency on cholesterol efflux in THP-1 foam cells. In an eight-week lesion study in LDLR -/- mice, compound 13 showed reduction of aortic arch lesion progression and no plasma or hepatic triglyceride increase. These results suggest quinoxaline 13 may have an improved biological profile for potential use as a therapeutic agent.

  5. One novel quinoxaline derivative as a potent human cyclophilin A inhibitor shows highly inhibitory activity against mouse spleen cell proliferation.

    Science.gov (United States)

    Li, Jian; Chen, Jing; Zhang, Li; Wang, Feng; Gui, Chunshan; Zhang, Li; Qin, Yu; Xu, Qiang; Liu, Hong; Nan, Fajun; Shen, Jingkang; Bai, Donglu; Chen, Kaixian; Shen, Xu; Jiang, Hualiang

    2006-08-15

    Cyclophilin A (CypA) is a ubiquitous cellular enzyme playing critical roles in many biological processes, and its inhibitor has been reported to have potential immunosuppressive activity. In this work, we reported a novel quinoxaline derivative, 2,3-di(furan-2-yl)-6-(3-N,N-diethylcarbamoyl-piperidino)carbonylamino quinoxaline (DC838, 3), which was confirmed to be a potent inhibitor against human CypA. By using the surface plasmon resonance (SPR) and fluorescence titration techniques, the kinetic analysis of CypA/DC838 interaction was quantitatively performed. CypA peptidyl prolyl cis-trans isomerase (PPIase) activity inhibition assay showed that DC838 demonstrated highly CypA PPIase inhibitory activity. In vivo assay results showed that DC838 could inhibit mouse spleen cell proliferation induced by concanavalin A (Con A). Molecular docking simulation further elucidated the specific DC838 binding to CypA at the atomic level. The current work should provide useful information in the discovery of immunosuppressor based on CypA inhibitor.

  6. Poly(,'-dibromo--ethyl-benzene-1,3-disulphonamide) and ,,','-tetrabromobenzene-1,3-disulphonamide as novel catalysts for synthesis of quinoxaline derivatives

    Indian Academy of Sciences (India)

    Ramin Ghorbani-Vaghei; Somaye Hajinazari

    2013-03-01

    Poly(,'-dibromo--ethyl-benzene-1,3-disulphonamide) [PBBS] and ,,','-tetrabromobenzene-1,3-disulphonamide [TBBDA] were used as efficient catalysts for the synthesis of quinoxaline derivatives in excellent yields from 1,2-diamines and 1,2-dicarbonyls under aqueous and solvent-free conditions.

  7. Quinoxaline-2-carboxamide as a carrier ligand in two new platinum(ii) compounds: Synthesis, crystal structure, cytotoxic activity and DNA interaction

    NARCIS (Netherlands)

    Marques Gallego, P.; Amparo Gamiz-Gonzalez, M.; Fortea-Pérez, F. R.; Lutz, M.; Spek, A.L.; Pevec, A.; Kozlevar, B.; Reedijk, J.

    2010-01-01

    The search for platinum compounds structurally different from cisplatin has led to two new platinum(II) compounds containing quinoxaline-2-carboxamide as a carrier ligand, i.e. cis-[Pt(qnxca)(MeCN)Cl2] (1) and the [Pt(qnxca−H)(dmso)Cl] (2). Both compounds have been synthesized and characterized usin

  8. One-pot synthesis of 7-bromo-1-[4-(1-cyano- 1-methylethyl)]-phenyl-[1,2,4]-triazole-[4,3-a]-quinoxalin

    Institute of Scientific and Technical Information of China (English)

    Yan Yang; Hong Gang Hu; Qing Jie Zhao; Shi Chong Yu; Zhi Gang Dan; Yan Zou; Qiu Ye Wu

    2009-01-01

    [1,2,4]-Triazole-[4,3-a]-quinoxaline is an important component of many drugs. The yield of the reported methods for triazole cyclization step was usually as low as 20%. In this article, the triazole cyclization step was successfully done by using microwave method with a high yield of 75% for the first time.

  9. Microwave-assisted synthesis of 5,6-dihydroindolo[1,2-a]quinoxaline derivatives through copper-catalyzed intramolecular N-arylation

    Directory of Open Access Journals (Sweden)

    Fei Zhao

    2013-11-01

    Full Text Available An efficient and practical protocol has been developed to synthesize 5,6-dihydroindolo[1,2-a]quinoxaline derivatives by CuI-catalyzed intramolecular N-arylation under microwave irradiation. This method rapidly afforded the tetracyclic products with good to excellent yields (83–97% in short reaction times (45–60 min.

  10. One-Pot Synthesis of Pyrrolo[1,2-a]quinoxaline Derivatives via a Copper-Catalyzed Aerobic Oxidative Domino Reaction.

    Science.gov (United States)

    Liu, Huanhuan; Duan, Tiantian; Zhang, Zeyuan; Xie, Caixia; Ma, Chen

    2015-06-19

    A copper-catalyzed process for the synthesis of pyrrolo[1,2-a]quinoxalines from readily available α-amino acids and 1-(2-halophenyl)-1H-pyrroles is described. Different functional groups were well tolerated to give the corresponding products.

  11. Pressure-dependent helix inversion of poly(quinoxaline-2,3-diyl)s containing chiral side chains in non-aqueous solvents.

    Science.gov (United States)

    Nagata, Yuuya; Takeda, Ryohei; Suginome, Michinori

    2015-06-30

    Poly(quinoxaline-2,3-diyl)s with chiral (S)-2-butoxymethyl side chains dissolved in 1,2-dichloroethane experience a reversible pressure-dependent helix inversion from P- to M-helical structures between 0.1 MPa and 200 MPa.

  12. Synthesis and characterization of different zinc(II) oxide nano-structures from two new zinc(II)-Quinoxaline coordination polymers

    Science.gov (United States)

    Molaei, Fatemeh; Bigdeli, Fahime; Morsali, Ali; Joo, Sang Woo; Bruno, Giuseppe; Rudbari, Hadi Amiri

    2015-09-01

    Two new zinc(II) coordination polymers, [Zn(Quinoxaline)(NO3)2(H2O)2]nṡQuinoxaline·H2O (1) and [Zn(Quinoxaline)2(Br)2]n (2), Quinoxaline = Benzopyrazine, have been synthesized and characterized by IR spectroscopy. Compounds 1 and 2 were structurally characterized by single crystal X-ray diffraction and are one-dimensional coordination polymers with coordination environment of octahedral and tetrahedral respectively. Nanostructures of zinc(II) oxide were obtained by thermolyses of compound 1 in oleic acid, calcination of compound 1 at 500 °C under air atmosphere and sol-gel processes. Also, nanopowders of zinc(II) oxide were obtained by calcination of compound 2 at 450 and 550 °C. The nanomaterials were characterized by scanning electron microscopy and X-ray powder diffraction (XRD). The thermal stability of compounds 1 and 2 both their bulk were studied by thermo-gravimetric (TGA) and differential thermal analyses (DTA). This study demonstrates the coordination polymers may be suitable precursors for the preparation of nanoscale materials.

  13. Ferrocene-quinoxaline Y-shaped chromophores as fascinating second-order NLO building blocks for long lasting highly active SHG polymeric films.

    Science.gov (United States)

    Senthilkumar, Kabali; Thirumoorthy, Krishnan; Dragonetti, Claudia; Marinotto, Daniele; Righetto, Stefania; Colombo, Alessia; Haukka, Matti; Palanisami, Nallasamy

    2016-07-26

    The first example of a Y-shaped ferrocene quinoxaline derivative with a surprisingly high and stable second harmonic generation (SHG) response in composite polymeric films is reported. The interesting quadratic hyperpolarizability values of different substituted Y-shaped chromophores are also investigated in solution by the EFISH technique.

  14. 1 H-pyrazolo[3,4- b]quinoline and 1 H-pyrazolo[3,4- b]quinoxaline derivatives as promising materials for optoelectronic applications

    Science.gov (United States)

    Danel, Andrzej; Gondek, Ewa; Kityk, Iwan

    2009-12-01

    A review of recent studies of pyrazoloquinoline and quinoxaline derivative chromophore used as organic light emitting diodes and photovoltaic elements is done. We present both the principal ways of modifications of these materials as well as a possible chemical modifications to achieve more suitable technological parameters.

  15. Ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br: a green and neutral reaction media for the efficient, catalyst-free synthesis of quinoxaline derivatives

    Directory of Open Access Journals (Sweden)

    MAASOOMEH KHEDRI

    2010-10-01

    Full Text Available Quinoxaline derivatives were produced in excellent yields and short reaction times via the condensation of 1,2-diamines with 1,2-diketones in the neutral ionic liquid 1-butyl-3-methylimidazolium bromide ([bmim]Br under catalyst-free and microwave irradiation conditions.

  16. Development of quinoxaline 1, 4-dioxides resistance in Escherichia coli and molecular change under resistance selection.

    Directory of Open Access Journals (Sweden)

    Wentao Guo

    Full Text Available Quinoxaline 1, 4-dioxides (QdNOs has been used in animals as antimicrobial agents and growth promoters for decades. However, the resistance to QdNOs in pathogenic bacteria raises worldwide concern but it is barely known. To explore the molecular mechanism involved in development of QdNOs resistance in Escherichia coli, 6 strains selected by QdNOs in vitro and 21 strains isolated from QdNOs-used swine farm were subjected to MIC determination and PCR amplification of oqxA gene. A conjugative transfer was carried out to evaluate the transfer risk of QdNOs resistant determinant. Furthermore, the transcriptional profile of a QdNOs-resistant E. coli (79O4-2 selected in vitro with its parent strain 79-161 was assayed with a prokaryotic suppression subtractive hybridization (SSH PCR cDNA subtraction. The result showed that more than 95% (20/21 clinical isolates were oqxA positive, while all the 6 induced QdNOs-resistant strains carried no oqxA gene and exhibited low frequency of conjugation. 44 fragments were identified by SSH PCR subtraction in the QdNOs-resistant strain 79O4-2. 18 cDNAs were involved in biosynthesis of Fe-S cluster (narH, protein (rpoA, trmD, truA, glyS, ileS, rplFCX, rpsH, fusA, lipoate (lipA, lipid A (lpxC, trehalose (otsA, CTP(pyrG and others molecular. The 11 cDNAs were related to metabolism or degradation of glycolysis (gpmA and pgi and proteins (clpX, clpA, pepN and fkpB. The atpADG and ubiB genes were associated with ATP biosynthesis and electron transport chain. The pathway of the functional genes revealed that E. coli may adapt the stress generated by QdNOs or develop specific QdNOs-resistance by activation of antioxidative agents biosynthesis (lipoate and trehalose, protein biosynthesis, glycolysis and oxidative phosphorylation. This study initially reveals the possible molecular mechanism involved in the development of QdNOs-resistance in E. coli, providing with novel insights in prediction and assessment of the emergency

  17. [Determination of the residues of 3-methyl-quinoxaline-2-carboxylic acid and quinoxaline-2-carboxylic acid in animal origin foods by high performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Zheng, Ling; Wu, Yujie; Li, Yong; Li, Lihua

    2012-07-01

    A high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/ MS) method was developed for the simultaneous quantitative determination of 3-methyl-quinoxaline-2-carboxylic acid (MQCA) and quinoxaline-2-carboxylic acid (QCA) as the marker residues for carbadox (CBX) and olaquindox (OLA), respectively, in the muscles and livers of porcine and chicken and in the muscles of fish and shrimp. The MQCA and QCA were deproteinated with 5% metaphosphoric acid in 10% methanol followed by liquid-liquid extraction. Further clean-up was performed by solid phase extraction (SPE) through mixed mode anion-exchange columns (Oasis MAX SPE). The separation of the compounds was carried on a Waters Xterra MS C18 column (150 mm x 2.1 mm, 5 microm) by a gradient elution using methanol and 0.2% formic acid as mobile phases. The analytes were detected by tandem mass spectrometry in multiple reaction monitoring (MRM) mode with positive electrospray ionization. The MQCA and QCA were quantified by internal standard method. The linear ranges were 1.0-20.0 microg/L and the correlation coefficients were not less than 0.9996. The average recoveries and relative standard deviations ranged from 62.4%-118% and 1.48%-28.1% respectively at the spiked levels of 0.1, 0.2 and 1.0 microg/kg for the both markers. The limit of quantitation (LOQ) was 0.1 microg/kg. The method is sensitive, accurate and suitable for the determination and confirmation of MQCA and QCA in animal origin foods.

  18. Functionalization of Carboxylated Multi-Wall Nanotubes with Derivatives of N1-(11H-Indeno[1,2-b]quinoxalin-11-ylidenebenzene-1,4-diamine

    Directory of Open Access Journals (Sweden)

    Javad Azizian

    2013-01-01

    Full Text Available Quinoxaline derivatives are compounds with pharmaceutical applications. In this study, derivatives of N1-(11H-indeno[1,2-b]quinoxalin-11-ylidenebenzene-1,4-diamine were synthesized and attached to carboxylated multi-wall nanotubes (MWNT–COOH. Functionalized carbon nanotubes were characterized by scanning electron microscopy (SEM to study the shape of structures, transmission electron microscopy (TEM, fast Fourier transform infrared (FT-IR, Raman spectroscopy, and elemental analysis.

  19. Synthesis and antimycobacterial activity of new quinoxaline-2-carboxamide 1,4-di-N-oxide derivatives.

    Science.gov (United States)

    Zarranz, Belén; Jaso, Andrés; Aldana, Ignacio; Monge, Antonio

    2003-05-15

    As a continuation of our research and with the aim of obtaining new antituberculosis agents which can improve the current chemotherapeutic antituberculosis treatments, new series of quinoxaline-2-carboxamide 1,4-di-N-oxide derivatives were synthesized and evaluated for in vitro antituberculosis activity against Mycobacterium tuberculosis strain H(37)Rv, using the radiometric BACTEC 460-TB methodology. Active compounds were also screened by serial dilution to assess toxicity to a VERO cell line. The results indicate that some compounds exhibited a good antituberculosis activity and the arylcarboxamide analogues 3, 8, and 9 were the most active compounds (EC(90)/MIC1). Also, the cytotoxic effects indicate that these compounds have a good Selectivity Index (SI).

  20. Synthesis, crystal structure, property research, and DFT calculation of 2,3-diphenylfuro[3,2-b]quinoxaline

    Science.gov (United States)

    Yao, Qi-Chao; Wu, Ding-Er; Xia, Min

    2013-06-01

    The title compound is obtained via the intramolecular condensation of 3-(2-oxo-1,2-diphenylethyl)quinoxalin-2(1H)-one in the presence of excessive boron trifluoride etherate and characterized by 1H NMR, 13C NMR, IR, and EI-MS. The solution-based and solid-state fluorescence along with the electrochemical property are studied in detail. The unique herring-bone arrangement which is revealed by the X-ray crystallography should account for the intense solid-state fluorescence. The theoretic calculations are employed to clarify the origin of the large Stokes shift and the positive solvatochromism in view of the geometric relaxation and the transition feature.

  1. Synthesis, characterization and antimicrobial activity of 3d transition metal complexes of a biambidentate ligand containing quinoxaline moiety

    Science.gov (United States)

    Anantha Lakshmi, P. V.; Reddy, P. Saritha; Raju, V. Jayatyaga

    2009-09-01

    A new series of oxovanadium(IV), chromium(III), manganese(II), iron(III), cobalt(II), nickel(II), and copper(II) complexes of the 3-hydrazino quinoxaline-2-one (HQO) were prepared and characterized. The ligand exhibits biambidenticity. It behaves as a bidentate ON donor in oxovanadium(IV), iron(III) and copper(II) complexes and as a bis bidentate ONNN donor in chromium(III), manganese(II), cobalt(II) and nickel(II) complexes. The nature of bonding and the stereochemistry of the complexes have been deduced from elemental analyses, thermal, infrared, 1H NMR, electronic spectra, magnetic susceptibility and conductivity measurements. An octahedral geometry was suggested for all the complexes. All the complexes show subnormal magnetic moments. The ligand, HQO, and its complexes were tested against one strain Gram +ve bacteria ( Staphylococcus aureus), Gram -ve bacteria ( Escherichia coli). The prepared metal complexes exhibited higher antimicrobial activities than the parent ligand.

  2. Dibenzo[f,h]thieno[3,4-b] quinoxaline-fullerene heterojunction bilayer solar cells with complementary spectrum coverage

    Energy Technology Data Exchange (ETDEWEB)

    Kekuda, Dhananjaya [Research Center for Applied Sciences, Academia Sinica, Nankang, Taipei (China); Huang, Jen-Shien [Department of Chemical Engineering, National Taiwan University (China); Velusamy, Marappan; Lin, Jiann T. [Institute of Chemistry, Academia Sinica, Nankang, Taipei (China); Chu, Chih-Wei [Research Center for Applied Sciences, Academia Sinica, Nankang, Taipei (China); Department of Photonics, National Chio-Tung University, Hsinchu 30013 (China)

    2010-10-15

    In the present article, potential of a bilayer organic solar cell has been investigated. We utilize newly synthesized small molecules, namely dibenzo[f,h]thieno[3,4-b]quinoxaline as electron donors for solar cells in heterojunction bilayer configuration. These small molecules with a narrow absorption band in the range 400-450 nm provide a complementary spectrum for the fullerene C{sub 70}, thereby leading to an overall power conversion efficiency of 2.6{+-}0.2% under 100 mW/cm{sup 2} incident radiation. Thermal annealing seems to impact the charge separation at the donor-acceptor interface, which eventually affects device performance. This work demonstrates that carefully optimized bilayer devices are comparable to the bulk heterojunction counterparts. (author)

  3. High-performance fluorescence sensing of lanthanum ions (La(3+)) by a polydentate pyridyl-based quinoxaline derivative.

    Science.gov (United States)

    Zhao, Qiang; Liu, Xiu-Ming; Li, Huan-Rong; Zhang, Ying-Hui; Bu, Xian-He

    2016-06-28

    A polydentate pyridyl derivative, 2,3,6,7,10,11-hexa(2-pyridyl)-dipyrazino [2,3-f:2',3'-h]quinoxaline (HPDQ), exhibits a high-performance fluorescence response to La(3+) with an ∼65 nm redshifted emission wavelength and 38 fold enhanced intensity, in contrast to its weakened emission for other lanthanide ions. The final La(3+) coordination complex in solution has a stoichiometric ratio of 1 : 3 of ligand-to-metal, as testified by the Job's plot and single crystal structure analyses. The red shift of the luminescence emission as well as UV-vis absorption was rationalized in terms of the change of the electron structure as indicated by nuclear magnetic titration, electrochemical experiment and density functional theoretical calculation, while the significant enhancement of emission was attributed to the enhanced π conjugated extent of HPDQ caused by La(3+) coordination.

  4. Discovery and Optimization of Macrocyclic Quinoxaline-pyrrolo-dihydropiperidinones as Potent Pim-1/2 Kinase Inhibitors.

    Science.gov (United States)

    Cee, Victor J; Chavez, Frank; Herberich, Bradley; Lanman, Brian A; Pettus, Liping H; Reed, Anthony B; Wu, Bin; Wurz, Ryan P; Andrews, Kristin L; Chen, Jie; Hickman, Dean; Laszlo, Jimmy; Lee, Matthew R; Guerrero, Nadia; Mattson, Bethany K; Nguyen, Yen; Mohr, Christopher; Rex, Karen; Sastri, Christine E; Wang, Paul; Wu, Qiong; Wu, Tian; Xu, Yang; Zhou, Yihong; Winston, Jeffrey T; Lipford, J Russell; Tasker, Andrew S; Wang, Hui-Ling

    2016-04-14

    The identification of Pim-1/2 kinase overexpression in B-cell malignancies suggests that Pim kinase inhibitors will have utility in the treatment of lymphoma, leukemia, and multiple myeloma. Starting from a moderately potent quinoxaline-dihydropyrrolopiperidinone lead, we recognized the potential for macrocyclization and developed a series of 13-membered macrocycles. The structure-activity relationships of the macrocyclic linker were systematically explored, leading to the identification of 9c as a potent, subnanomolar inhibitor of Pim-1 and -2. This molecule also potently inhibited Pim kinase activity in KMS-12-BM, a multiple myeloma cell line with relatively high endogenous levels of Pim-1/2, both in vitro (pBAD IC50 = 25 nM) and in vivo (pBAD EC50 = 30 nM, unbound), and a 100 mg/kg daily dose was found to completely arrest the growth of KMS-12-BM xenografts in mice.

  5. 1,2,4-Triazolo[1,5-a]quinoxaline derivatives: synthesis and biological evaluation as adenosine receptor antagonists.

    Science.gov (United States)

    Catarzi, Daniela; Colotta, Vittoria; Varano, Flavia; Filacchioni, Guido; Martini, Claudia; Trincavelli, Letizia; Lucacchini, Antonio

    2004-02-01

    Since most of the reported adenosine receptor antagonists are 2-(hetero)aryl-substituted tricyclic heteroaromatic derivatives, in the present study we report the synthesis and the biological evaluation of a new set of 4-amino-1,2,4-triazolo[1,5-a]quinoxalines containing at position-2 an ethyl carboxylate group or a hydrogen atom. The structure-activity relationships on these compounds were in accordance with those of a previously reported series of analogous size and shape, thus suggesting a similar A(1)-binding mode. In particular, the binding data indicate that alkylation of the 4-amino group of these derivatives lead to potent A(1)-receptor antagonists. Moreover, as new results, this study has pointed out that the ethyl 2-carboxylate group can advantageously replace the 2-(hetero)aryl ring of previously reported triazoloquinoxaline derivatives, affording an ameliorated interaction with the A(1)-receptor subtype.

  6. Comparative acute systemic toxicity of several quinoxaline 1,4-di-N-oxides in Wistar rats.

    Science.gov (United States)

    Azqueta, Amaya; Gil, Ana Gloria; García-Rodríguez, Alba; García-Jalón, Jose Antonio; Cia, Felipe; Zarranz, Belén; Monge, Antonio; de Cerain, Adela López

    2007-01-01

    The acute toxicity of six quinoxaline 1,4-di-N-oxides has been evaluated in an attempt to determine: a) the feasibility of testing systemic toxicity of these compounds in a very preliminary phase without an adequate formulation for in vivo administration, b) the LD50 range and the toxic target organ of these compounds in order to have an approximation of the structure-activity relationship. Quinoxaline 1,4-di-N-oxides have shown a great variety of biological activities with potential therapeutic application in cancer, malaria, etc. Problems of toxicity hinder the progression of these compounds to clinical phases. The compounds dissolved in DMSO at their solubility limit were administered i.v. to female Wistar rats (8 weeks, 160 g), using an infusion pump (300 microL; 20 microl/min). Animals were observed for a period of 14 days. This dose of the vehicle (1.7 ml/kg) was well tolerated by the animals. The LD50 could not be determined, but a marked hypoactivity was induced by the treatment. The same compounds were also injected intraperitoneally, suspended in 0.01% Tween 80/0.09 % saline, and the animals that did not die were observed for a period of 14 days. The LD50 could be estimated to be in a range between 30 and 120 mg/kg, except for one of the compounds. A decrease in the evolution of body weight and hypoactivity were the principal symptoms induced by the treatment. In both assays, histopathologic study of heart, liver, kidney, lung, spleen and ovaries indicated that the target organs may be heart and spleen. In conclusion, the i.v. route is not adequate for estimating the LD50 of these compounds due to solubility problems; by i.p. route, the LD50 interval is between 30 and 120 mg/kg. The data did not permit the deduction of any specific structure-activity relationship.

  7. Quinoxaline chemistry. Part 16. 4-substituted anilino and 4-substituted phenoxymethyl pyrrolo[1,2-a]quinoxalines and N-[4-(pyrrolo[1,2-a]quinoxalin-4-yl)amino and hydroxymethyl]benzoyl glutamates. Synthesis and evaluation of in vitro biological activity.

    Science.gov (United States)

    Alleca, Sergio; Corona, Paola; Loriga, Mario; Paglietti, Giuseppe; Loddo, Roberta; Mascia, Valeria; Busonera, Bernardetta; La Colla, Paolo

    2003-09-01

    Twenty eight pyrrolo[1,2-a]quinoxalines bearing at position 4 various substituents related to the moieties present in classical and non classical antifolic agents were prepared and evaluated in vitro for antiproliferative activity. In an in vitro screening performed at NCI, several compounds emerged as potent antiproliferative agents at concentrations ranging between 10 and 100 microM. Interestingly, some of these compounds proved active also against bovine and murine DHFR (Farmaco 53 (1998) 480). More recently, a compound of classical antifolate type has been reported to be a potent inhibitor of hDHFR in vitro (Farmaco 58 (2003) 51). We then synthesized new derivatives that, in our hands, were endowed with in vitro antiproliferative activities as low as 3.4 microM against a panel of cell lines derived from hematological and solid tumours. In addition, a complete screening of cytotoxicity, antiretroviral HIV-1 and antimicrobial activity has been carried out.

  8. Microwave-assisted Solvent-free Synthesis and in Vitro Antibacterial Screening of Quinoxalines and Pyrido[2, 3b]pyrazines

    Directory of Open Access Journals (Sweden)

    Javier Peralta-Cruz

    2012-05-01

    Full Text Available We report herein the microwave assisted synthesis, without solvents and catalysts, of 6-substituted quinoxalines and 7-substituted pyrido[2,3b]pyrazines. The compounds were obtained in good yields and short reaction times using the mentioned procedure and two new structures are reported. A complete 1H- and 13C-NMR assignment was performed using 1D and 2D-NMR. Additionally, an in vitro screening was performed on Gram-positive and Gram-negative bacteria using amoxicillin as positive reference. Compounds bearing a pyridyl group tended to have higher antibacterial activity, but the best activity against Bacillus subtilis and Proteus mirabilis was observed with quinoxaline derivatives.

  9. Synthesis, 3D-QSAR analysis and biological evaluation of quinoxaline 1,4-di-N-oxide derivatives as antituberculosis agents.

    Science.gov (United States)

    Pan, Yuanhu; Li, Panpan; Xie, Shuyu; Tao, Yanfei; Chen, Dongmei; Dai, Menghong; Hao, Haihong; Huang, Lingli; Wang, Yulian; Wang, Liye; Liu, Zhenli; Yuan, Zonghui

    2016-08-15

    A series of quinoxaline 1,4-di-N-oxide derivatives variously substituted at C-2 position were synthesized and evaluated for in vitro antimycobacterial activity. Seventeen compounds exhibited potential activity (MIC ⩽6.25μg/mL) against Mycobacterium tuberculosis (H37Rv), in particular the compounds 3d and 3j having an MIC value of 0.39μg/mL. None of the compounds exhibited cytotoxicity when using an MTT assay in VERO cells. To further investigate the structure-activity relationship, CoMFA (q(2)=0.507, r(2)=0.923) and CoMSIA (q(2)=0.665, r(2)=0.977) models were performed on the basis of antimycobacterial activity data. The 3D-QSAR study of these compounds can provide useful information for further rational design of novel quinoxaline 1,4-di-N-oxides for treatment of tuberculosis.

  10. Design, synthesis, and biological evaluation of 3-vinyl-quinoxalin-2(1H)-one derivatives as novel antitumor inhibitors of FGFR1

    Science.gov (United States)

    Liu, Zhiguo; Yu, Shufang; Chen, Di; Shen, Guoliang; Wang, Yu; Hou, Leping; Lin, Dan; Zhang, Jinsan; Ye, Faqing

    2016-01-01

    FGFR1 is well known as a molecular target in anticancer drug design. TKI258 plays an important role in RTK inhibitors. Utilizing TKI258 as a lead compound that contains a quinazolinone nucleus, we synthesized four series of 3-vinyl-quinoxalin-2(1H)-one derivatives, a total of 27 compounds. We further evaluated these compounds for FGFR1 inhibition ability as well as cytotoxicity against four cancer cell lines (H460, B16-F10, Hela229, and Hct116) in vitro. Some compounds displayed good-to-excellent potency against the four tested cancer cell lines compared with TKI258. Structure–activity relationship analyses indicated that small substituents at the side chain of the 3-vinyl-quinoxalin-2(1H)-one were more effective than large substituents. Lastly, we used molecular docking to obtain further insight into the interactions between the compounds and FGFR1. PMID:27217720

  11. Studies on Log Po/w of Quinoxaline di-N-Oxides: A Comparison of RP-HPLC Experimental and Predictive Approaches

    Directory of Open Access Journals (Sweden)

    James A. Platts

    2011-09-01

    Full Text Available As reported in our previous papers, a series of quinoxaline-2-carboxamide 1,4-di-N-oxide derivatives were synthesized and studied as anti-tuberculosis agents. Here, the capability of the shake-flask method was studied and the retention time (expressed as log K of 20 compounds were determined by RP-HPLC analysis. We found that the prediction of log P by the RP-HPLC analysis can result in a high accuracy and can replace the shake-flask method avoiding the experimental problems presented by quinoxaline di-N-oxides. The studied compounds were subjected to the ALOGPS module with the aim of comparing experimental log Po/w values and predicted data. Moreover, a preliminary in silico screening of the QSAR relationship was made confirming the influence of reduction peak potential, lipophilicity, H-bond donor capacity and molecular dimension descriptors on anti-tuberculosis activity.

  12. Design, synthesis, and biological evaluation of 3-vinyl-quinoxalin-2(1H)-one derivatives as novel antitumor inhibitors of FGFR1.

    Science.gov (United States)

    Liu, Zhiguo; Yu, Shufang; Chen, Di; Shen, Guoliang; Wang, Yu; Hou, Leping; Lin, Dan; Zhang, Jinsan; Ye, Faqing

    2016-01-01

    FGFR1 is well known as a molecular target in anticancer drug design. TKI258 plays an important role in RTK inhibitors. Utilizing TKI258 as a lead compound that contains a quinazolinone nucleus, we synthesized four series of 3-vinyl-quinoxalin-2(1H)-one derivatives, a total of 27 compounds. We further evaluated these compounds for FGFR1 inhibition ability as well as cytotoxicity against four cancer cell lines (H460, B16-F10, Hela229, and Hct116) in vitro. Some compounds displayed good-to-excellent potency against the four tested cancer cell lines compared with TKI258. Structure-activity relationship analyses indicated that small substituents at the side chain of the 3-vinyl-quinoxalin-2(1H)-one were more effective than large substituents. Lastly, we used molecular docking to obtain further insight into the interactions between the compounds and FGFR1.

  13. Synthesis of Quinoxaline 1,4-di-N-Oxide Analogues and Crystal Structure of 2-Carbomethoxy-3-hydroxyquinoxaline-di-N-oxide

    Directory of Open Access Journals (Sweden)

    Minmin Zhang

    2011-08-01

    Full Text Available A series of quinoxaline 1,4-di-N-oxide analogues were prepared from benzofurazan N-oxide derivatives and β-diketone ester compounds by the improved Beirut reaction. The structures of the target products were characterized by NMR, MS, IR and elemental analysis measurements, and that of 2-carbomethoxy-3-hydroxyquinoxaline- di-N-oxide was further confirmed by single-crystal X-ray diffraction. Its crystal structure belongs to the monoclinic system, space group C2/c with a = 14.4320 (12 Å, b = 10.7514 (9 Å, c = 13.2728 (11 Å, V = 1958.5 (3 Å 3, Z = 8. The X-ray crystallographic analysis reveals that quinoxaline 1,4-di-N-oxide displays acyloin-endiol tautomerism.

  14. Single-layer electroluminescent devices based on fluorene-1H-pyrazolo[3,4-b]quinoxaline co-polymers

    Science.gov (United States)

    Pokladko-Kowar, Monika; Danel, Andrzej; Chacaga, Łukasz

    2013-11-01

    A fluorene based copolymer was synthesized for electroluminescent application. To the main chain of polymer the nitrogen heterocyclic, 1H-pyrazolo[3,4-b]quinoxaline, unit was introduced. The incorporation of this derivative tuned the emission from the blue to yellow-green one. A simple, single layered device was fabricated with the configuration ITO/PEDOT/co-poly-FLU-PQX/Ca/Mg.

  15. Efficient solvent-free synthesis of pyridopyrazine and quinoxaline derivatives using copper-DiAmSar complex anchored on SBA-15 as a reusable catalyst

    Institute of Scientific and Technical Information of China (English)

    Marzieh Mohammadi; Ghasem Rezanejade Bardajee; Nader Noroozi Pesyan

    2015-01-01

    A catalytic system comprising mesoporous silica functionalized with Cu(II)-DiAmSar was synthe-sized. This was demonstrated as an efficient heterogeneous catalyst for the synthesis of biologically useful pyridopyrazine and quinoxaline heterocycles under solvent-free conditions. X-ray diffraction, transmission electron microscopy, N2 adsorption-desorption, Fourtier transformation infrared spectroscopy, and thermogravimetric analysis were used to characterize the catalyst and investi-gate the texture of SBA-15 during the grafting process.

  16. A Double Activation Method for the Conversion of Vinyl Epoxides into vic-Amino Alcohols and Chiral Benzoxazine/Quinoxaline Derivatives.

    Science.gov (United States)

    Srikanth, Gourishetty; Ramakrishna, Kallaganti V S; Sharma, Gangavaram V M

    2015-09-18

    A new method for the synthesis of 1,2-syn-vic amino alcohols (with double inversion of configuration) from vinyl epoxides, by the amination of a π-allyl palladium-borate complex generated by using Pd(0) and phenyl-o-phenylene borate (a double activation technique), is reported. Further, this new method with broad functional group compatibility was extended to a one-pot/two-step synthesis of chiral benzoxazine and quinoxaline derivatives.

  17. New 1,4-di-N-oxide-quinoxaline-2-ylmethylene isonicotinic acid hydrazide derivatives as anti-Mycobacterieum tuberculosis agents

    OpenAIRE

    Torres, E; Moreno-Viguri, E. (Elsa); Ancizu, S. (Saioa); Barea, C. (Carlos); Aldana, I.; Monge, A; Perez-Silanes, S. (Silvia)

    2011-01-01

    The increase in the prevalence of drug-resistant tuberculosis cases demonstrates the need of discovering new and promising compounds with antimycobacterial activity. As a continuation of our research and with the aim of identifying new antitubercular drugs candidates, a new series of quinoxaline 1,4-di-N-oxide derivatives containing isoniazid was synthesized and evaluated for in vitro anti-tuberculosis activity against Mycobacterium tuberculosis H37Rv strain. Moreover, various drug-like prope...

  18. 1,4-Di-N-oxide quinoxaline-2-carboxamide: Cyclic voltammetry and relationship between electrochemical behavior, structure and anti-tuberculosis activity

    OpenAIRE

    Moreno-Viguri, E. (Elsa); Perez-Silanes, S. (Silvia); Gouravaram, S. (S.); Macharam, A. (Abinav); Ancizu, S. (Saioa); Torres, E; Aldana, I.; Monge, A; Crawford, P.W. (Philip W.)

    2011-01-01

    To gain insight into the mechanism of action, the redox properties of 37 quinoxaline-2-carboxamide 1,4-di-N-oxides with varying degrees of anti-tuberculosis activity were studied in dimethylformamide (DMF) using cyclic voltammetry and first derivative cyclic voltammetry. For all compounds studied, electrochemical reduction in DMF is consistent with the reduction of the N-oxide functionality to form a radical anion. The influence of molecular structure on reduction potential is addressed and i...

  19. Structure-activity relationship study of anticancer thymidine-quinoxaline conjugates under the low radiance of long wavelength ultraviolet light for photodynamic therapy.

    Science.gov (United States)

    Zhang, Dejun; Liu, Huaming; Wei, Qiong; Zhou, Qibing

    2016-01-01

    Thymidine quinoxaline conjugate (dT-QX) is a thymidine analog with selective cytotoxicity against different cancer cells. In this study, the structure activity relationship study of dT-QX analogs was carried out under the low radiance of black fluorescent (UVA-1) light. Significantly enhanced cytotoxicity was observed under UVA-1 activation among analogs containing both thymidine and quinoxaline moieties with different length of the linker, stereochemical configuration and halogenated substituents. Among these analogs, the thymidine dichloroquinoxaline conjugate exhibited potent activity under UVA-1 activation as the best candidate with EC50 at 0.67 μM and 1.3 μM against liver and pancreatic cancer cells, respectively. In contrast, the replacement of thymidine moiety with a galactosyl residue or the replacement of quinoxaline moiety with a fluorescent pyrenyl residue or a simplified diketone structure resulted in the full loss of activity. Furthermore, it was revealed that the low radiance of UVA-1 at 3 mW/cm(2) for 20 min was sufficient enough to induce the full cytotoxicity of thymidine dichloroquinoxaline conjugate and that the cytotoxic mechanism was achieved through a rapid and steady production of reactive oxygen species.

  20. Design, synthesis and biological evaluation of novel 4-alkapolyenylpyrrolo[1,2-a]quinoxalines as antileishmanial agents--part III.

    Science.gov (United States)

    Ronga, Luisa; Del Favero, Marco; Cohen, Anita; Soum, Claire; Le Pape, Patrice; Savrimoutou, Solène; Pinaud, Noël; Mullié, Catherine; Daulouede, Sylvie; Vincendeau, Philippe; Farvacques, Natacha; Agnamey, Patrice; Pagniez, Fabrice; Hutter, Sébastien; Azas, Nadine; Sonnet, Pascal; Guillon, Jean

    2014-06-23

    A series of new 4-alkapolyenylpyrrolo[1,2-a]quinoxaline derivatives, original and structural analogues of alkaloid chimanine B and of previously described 4-alkenylpyrrolo[1,2-a]quinoxalines, was synthesized in good yields using efficient palladium-catalyzed Suzuki-Miyaura cross-coupling reactions. These new compounds were tested for in vitro antiparasitic activity upon three Leishmania spp. strains. Biological results showed activity against the promastigote forms of L. major, L. mexicana and L. donovani with IC50 ranging from 1.2 to 14.7 μM. In attempting to investigate if our pyrrolo[1,2-a]quinoxaline derivatives are broad-spectrum antiprotozoal compounds activities toward one Trypanosoma brucei brucei strain and the W2 and 3D7 Plasmodium falciparum strains were also investigated. In parallel, the in vitro cytotoxicity of these molecules was assessed on the murine J774 and human HepG2 cell lines. Structure-activity relationships of these new synthetic compounds are here discussed.

  1. Design, synthesis, and biological evaluation of 3-vinyl-quinoxalin-2(1H-one derivatives as novel antitumor inhibitors of FGFR1

    Directory of Open Access Journals (Sweden)

    Liu Z

    2016-05-01

    Full Text Available Zhiguo Liu,1,* Shufang Yu,1,* Di Chen,1 Guoliang Shen,1 Yu Wang,1 Leping Hou,2 Dan Lin,1 Jinsan Zhang,1 Faqing Ye1 1School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, 2Second Affiliated Hospital of Zhejiang University School of Medicine, Hangzhou, People’s Republic of China *These authors contributed equally to this work Abstract: FGFR1 is well known as a molecular target in anticancer drug design. TKI258 plays an important role in RTK inhibitors. Utilizing TKI258 as a lead compound that contains a quinazolinone nucleus, we synthesized four series of 3-vinyl-quinoxalin-2(1H-one derivatives, a total of 27 compounds. We further evaluated these compounds for FGFR1 inhibition ability as well as cytotoxicity against four cancer cell lines (H460, B16-F10, Hela229, and Hct116 in vitro. Some compounds displayed good-to-excellent potency against the four tested cancer cell lines compared with TKI258. Structure–activity relationship analyses indicated that small substituents at the side chain of the 3-vinyl-quinoxalin-2(1H-one were more effective than large substituents. Lastly, we used molecular docking to obtain further insight into the interactions between the compounds and FGFR1. Keywords: FGFR1, synthesis, quinoxaline, antitumor activity, kinase inhibitor

  2. Metabolism of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline in human hepatocytes: 2-amino-3-methylimidazo[4,5-f]quinoxaline-8-carboxylic acid is a major detoxification pathway catalyzed by cytochrome P450 1A2.

    Science.gov (United States)

    Langouët, S; Welti, D H; Kerriguy, N; Fay, L B; Huynh-Ba, T; Markovic, J; Guengerich, F P; Guillouzo, A; Turesky, R J

    2001-02-01

    Metabolic pathways of the mutagen 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) remain incompletely characterized in humans. In this study, the metabolism of MeIQx was investigated in primary human hepatocytes. Six metabolites were characterized by UV and mass spectroscopy. Novel metabolites were additionally characterized by 1H NMR spectroscopy. The carcinogenic metabolite, 2-(hydroxyamino)-3,8-dimethylimidazo[4,5-f]quinoxaline, which is formed by cytochrome P450 1A2 (P450 1A2), was found to be transformed into the N(2)-glucuronide conjugate, N(2)-(beta-1-glucosiduronyl)-2-(hydroxyamino)-3,8-dimethylimidazo[4,5-f]quinoxaline. The phase II conjugates N(2)-(3,8-dimethylimidazo[4,5-f]quinoxalin-2-yl)sulfamic acid and N(2)-(beta-1-glucosiduronyl)-2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, as well as the 7-oxo derivatives of MeIQx and N-desmethyl-MeIQx, 2-amino-3,8-dimethyl-6-hydro-7H-imidazo[4,5-f]quinoxalin-7-one (7-oxo-MeIQx), and 2-amino-6-hydro-8-methyl-7H-imidazo[4,5-f]quinoxalin-7-one (N-desmethyl-7-oxo-MeIQx), thought to be formed exclusively by the intestinal flora, were also identified. A novel metabolite was characterized as 2-amino-3-methylimidazo[4,5-f]quinoxaline-8-carboxylic acid (IQx-8-COOH), and it was the predominant metabolite formed in hepatocytes exposed to MeIQx at levels approaching human exposure. IQx-8-COOH formation is catalyzed by P450 1A2. This metabolite is a detoxication product and does not induce umuC gene expression in Salmonella typhimurium strain NM2009. IQx-8-COOH is also the principal oxidation product of MeIQx excreted in human urine [Turesky, R., et al. (1998) Chem. Res. Toxicol. 11, 217-225]. Thus, P450 1A2 is involved in both the metabolic activation and detoxication of this procarcinogen in humans. Analogous metabolism experiments were conducted with hepatocytes of untreated rats and rats pretreated with the P450 inducer 3-methylcholanthrene. Unlike human hepatocytes, the rat cell preparations did not produce IQx-8

  3. Systematic and Molecular Basis of the Antibacterial Action of Quinoxaline 1,4-Di-N-Oxides against Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Guyue Cheng

    Full Text Available Quinoxaline 1,4-di-N-oxides (QdNOs are widely known as potent antibacterial agents, but their antibacterial mechanisms are incompletely understood. In this study, the transcriptomic and proteomic profiles of Escherichia coli exposed to QdNOs were integratively investigated, and the results demonstrated that QdNOs mainly induced an SOS response and oxidative stress. Moreover, genes and proteins involved in the bacterial metabolism, cellular structure maintenance, resistance and virulence were also found to be changed, conferring bacterial survival strategies. Biochemical assays showed that reactive oxygen species were induced in the QdNO-treated bacteria and that free radical scavengers attenuated the antibacterial action of QdNOs and DNA damage, suggesting an oxidative-DNA-damage action of QdNOs. The QdNO radical intermediates, likely carbon-centered and aryl-type radicals, as identified by electron paramagnetic resonance, were the major radicals induced by QdNOs, and xanthine oxidase was one of the QdNO-activating enzymes. This study provides new insights into the action of QdNOs in a systematic manner and increases the current knowledge of bacterial physiology under antibiotic stresses, which may be of great value in the development of new antibiotic-potentiating strategies.

  4. The Solvent Extraction of Cadmium From Phosphoric Acid Solution By3-Methyl-Quinoxaline-2-Thione in Toluene Diluent

    Directory of Open Access Journals (Sweden)

    anae Baki Senhaji

    2016-12-01

    Full Text Available The solvent extraction of cadmium (II from phosphoric acid 2.5M by 3-methyl-2 (1H-quinoxaline-thione Vol32No6_SOLV_SANA_for1 is investigated in various experimental conditions. Obtained results show a variation of extraction of Cd with pH, and Vol32No6_SOLV_SANA_for2 concentration. The conventional methods of slope analysis can’t be performed successfully for understanding interaction mechanisms. A technique combining slope analysis with the variation of overall extraction constant with pH is performed in this case. There is no predominant removal mechanism, cadmium is extracted as complexes in Vol32No6_SOLV_SANA_for3 stoichiometry varying between 1:1:0 and 1:3:3. The extraction reaction is a complex process including ion exchange-ion pair formation,organic and inorganic complexation, H3PO4deprotonation and solvatation phenomena. A best recovery of 43 to 60% is achieved in acidic conditions with CLH = 0.26M

  5. Metal coordination polymers of 2,3-bis(benzimidazol-1-ylmethyl)quinoxaline: Syntheses, crystal structures and luminescent properties

    Science.gov (United States)

    Du, Jian-Long; Wei, Zi-Zhang; Hu, Tong-Liang

    2011-06-01

    Two new metal-organic frameworks, {[Cu LI]·CHCl 3} ∞( 1) and {[Hg L(Br) 2] 4·2CH 2Cl 2} ∞ ( 2) have been prepared by reacting CuI and HgBr 2 with the new flexible ligand L [ L = 2,3-Bis(benzimidazol-1-ylmethyl)quinoxaline]. Both complexes have been characterized by elemental analysis, IR, TGA, XRPD, and single crystal X-ray diffraction determination. In 1, the Cu(I) ion takes tetrahedral coordination geometry, and the flexible ligands bridge dinuclear units (Cu 2I 2) to form a one dimensional (1D) double chain structure. While in 2, the Hg(II) coordinates to two bromine ions and two nitrogen donors of L to form a 1D coordination polymer. The structure differences of the two complexes mainly depend on the geometry of the metal ions and the influence of anions. The coordination features of the ligand have also been primarily investigated by density functional theory (DFT) calculations. In addition, the fluorescent properties of the complexes and free ligand L have been investigated in the solid state at room temperature.

  6. Assembly of Cu/Ag-quinoxaline-polyoxotungstate hybrids: Influence of Keggin and Wells-Dawson polyanions on the structure

    Science.gov (United States)

    Chi, Ying-Nan; Cui, Feng-Yun; Lin, Zheng-Guo; Xu, Yan; Ma, Xiao-Yu; Shen, Pan-Pan; Huang, Kun-Lin; Hu, Chang-Wen

    2013-03-01

    In order to investigate the influence of Keggin and Wells-Dawson polyoxometalates on the resultant structure, four new organic-inorganic hybrid compounds [Cu4(qx)5(SiW12O40)] (1), [Cu6(qx)6(P2W18O62)(H2O)1.5]·4.5H2O (2), [Ag4(qx)4(SiW12O40)(H2O)]·H2O (3), [Ag6(qx)6(P2W18O62)]·8H2O (4) (qx=quinoxaline) were synthesized and structurally characterized by single-crystal X-ray diffraction. In 1, the 2D layers are linked by the SiW12O404- (SiW12) anions to construct a 3D framework. When the Wells-Dawson type P2W18O626- (P2W18) is used, 2 is prepared, in which the 1D helical chains are connected by P2W18 to form a 3D network. In 3, two kinds of 1D metal-organic chains are connected by SiW12 clusters to construct a 3D framework. In 4, there are also two kinds of 1D chains one kind of 1D chain combines with P2W18 by the AgO weak interaction and the other kind is just metal-organic chain. In addition, the electrochemistry properties of compounds 1-4 have been studied.

  7. Spectral characterization, electrochemical and anticancer studies on some metal(II) complexes containing tridentate quinoxaline Schiff base

    Science.gov (United States)

    Chellaian, Justin Dhanaraj; Johnson, Jijo

    2014-06-01

    Co(II), Ni(II), Cu(II) and Zn(II) complexes of a tridentate ONO donor Schiff base ligand derived from 3-(2-aminoethylamino)quinoxalin-2(1H)-one were synthesized. The ligand and its metal complexes were characterized using elemental analysis, molar conductance, IR, 1H NMR, mass, magnetic susceptibility, electronic spectra and ESR spectral studies. Electrochemical behavior of the synthesized compounds was studied using cyclic voltammetry. The grain size of the synthesized compounds was determined by powder XRD. The Schiff base and its complexes have been screened for their antimicrobial activities against the bacterial species E. coli, K. pneumoniae, P. aeruginosa and S. aureus; fungal species include, A. niger, and C. albicans by disc diffusion method. The results show that the complexes have higher activity than the free ligand. The interaction of the complexes with calf thymus DNA (CT DNA) has been investigated by electronic absorption method. Furthermore, the DNA cleavage activity of the complexes was studied using agarose gel electrophoresis. In vitro anticancer studies of the ligand and its complexes using MTT assay was also done.

  8. Synthesis, characterization, electrochemical and biological studies on some metal(II) Schiff base complexes containing quinoxaline moiety

    Science.gov (United States)

    Justin Dhanaraj, Chellaian; Johnson, Jijo

    2014-01-01

    Novel Co(II), Ni(II), Cu(II) and Zn(II) complexes of Schiff base derived from quinoxaline-2,3-(1,4H)-dione and 4-aminoantipyrine (QDAAP) were synthesized. The ligand and its complexes were characterized by elemental analyses, molar conductance, magnetic susceptibility measurements, FTIR, UV-Vis., mass and 1H NMR spectral studies. The X band ESR spectrum of the Cu(II) complex at 300 and 77 K were also recorded. Thermal studies of the ligand and its complexes show the presence of coordinated water in the Ni(II) and Zn(II) complexes. The coordination behavior of QDAAP is also discussed. All the complexes are mono nuclear and tetrahedral geometry was found for Co(II) complex. For the Ni(II) and Zn(II) complexes, octahedral geometry was assigned and for the Cu(II) complex, square planar geometry has been suggested. The grain size of the complexes was estimated using powder XRD. The surface morphology of the compounds was studied using SEM analysis. Electrochemical behavior of the synthesized complexes in DMF at room temperature was investigated by cyclic voltammetry. The in vitro biological screening of QDAAP and its metal complexes were tested against bacterial species Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. The fungal species include Aspergillus niger, Aspergillus flavus and Candida albicans. The DNA cleavage activity of QDAAP and its complexes were also discussed.

  9. Cosensitization of D-A-π-A quinoxaline organic dye: efficiently filling the absorption valley with high photovoltaic efficiency.

    Science.gov (United States)

    Pei, Kai; Wu, Yongzhen; Li, Hui; Geng, Zhiyuan; Tian, He; Zhu, Wei-Hong

    2015-03-11

    In the efficient cosensitization, the pure organic sensitizers with high molecular extinction coefficients and long wavelength response are highly preferable since the dye loading amount for each dye in cosensitization is decreased with respect to single dye sensitization. A D-A-π-A featured quinoxaline organic sensitizer IQ21 is specifically designed. The high conjugation building block of 4H-cyclopenta[2,1-b:3,4-b']dithiophene (CPDT) is introduced as the π bridge, instead of the traditional thiophene unit, especially in realizing high molecular extinction coefficients (up to 66 600 M(-1) cm(-1)) and extending the light response wavelength. With respect to the reference dye IQ4, the slightly lower efficiency of IQ21 (9.03%) arises from the decrease of VOC, which offsets the gain in JSC. While cosensitized with a smaller D-π-A dye S2, the efficiency in IQ21 is further improved to 10.41% (JSC = 19.8 mA cm(-2), VOC = 731 mV, FF = 0.72). The large improvement in efficiency is attributed to the well-matched molecular structures and loading amounts of both dyes in the cosensitization system. We also demonstrated that coabsorbent dye S2 can distinctly compensate the inherent drawbacks of IQ21, not only enhancing the response intensity of IPCE, making up the absorption defects around low wavelength region of IPCE, but also repressing the charge recombination rate to some extent.

  10. Photo-degradation in air of the active layer components in a thiophene-quinoxaline copolymer:fullerene solar cell.

    Science.gov (United States)

    Hansson, Rickard; Lindqvist, Camilla; Ericsson, Leif K E; Opitz, Andreas; Wang, Ergang; Moons, Ellen

    2016-04-28

    We have studied the photo-degradation in air of a blend of [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) and poly[2,3-bis-(3-octyloxyphenyl)quinoxaline-5,8-diyl-alt-thiophene-2,5-diyl] (TQ1), and how the photo-degradation affects the solar cell performance. Using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy, changes to the electronic structure of TQ1 and PCBM caused by illumination in ambient air are investigated and compared between the pristine materials and the blend. The NEXAFS spectra show that the unoccupied molecular orbitals of TQ1 are not significantly changed by the exposure of pristine TQ1 to light in air, whereas those of PCBM are severely affected as a result of photo-induced degradation of PCBM. Furthermore, the photo-degradation of PCBM is accelerated by blending it with TQ1. While the NEXAFS spectrum of TQ1 remains unchanged upon illumination in air, its valence band spectrum shows that the occupied molecular orbitals are weakly affected. Yet, UV-Vis absorption spectra demonstrate photo-bleaching of TQ1, which is attenuated in the presence of PCBM in blend films. Illumination of the active layer of TQ1:PCBM solar cells prior to cathode deposition causes severe losses in electrical performance.

  11. Synthesis and biological evaluation of 1-(6-methylpyridin-2-yl)-5-(quinoxalin-6-yl)-1,2,3-triazoles as transforming growth factor-β type 1 receptor kinase inhibitors.

    Science.gov (United States)

    Li, Fei; Park, Yunjeong; Hah, Jung-Mi; Ryu, Jae-Sang

    2013-02-15

    A series of 1-(6-methylpyridin-2-yl)-5-(quinoxalin-6-yl)-1,2,3-triazoles has been synthesized and evaluated for their ALK5 inhibitory activity. The 1-(6-methylpyridin-2-yl)-1,2,3-triazoles were assembled by Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition. Following this, quinoxaline was introduced through Pd-catalyzed direct arylation. The synthesized 1-(6-methylpyridin-2-yl)-5-(quinoxalin-6-yl)-1,2,3-triazoles revealed significant selectivity differences with respect to p38α MAP kinase. In particular, 12k showed 80.8% ALK5 inhibitory activity at a concentration of 10 μM and IC(50) value of 4.69 μM, but did not show p38α MAP kinase inhibitory activity (-1.94% inhibition at a concentration of 10 μM).

  12. Anti-leishmanial and structure-activity relationship of ring substituted 3-phenyl-1-(1,4-di-N-oxide quinoxalin-2-yl-2-propen-1-one derivatives

    Directory of Open Access Journals (Sweden)

    Asunción Burguete

    2008-12-01

    Full Text Available A series of ring substituted 3-phenyl-1-(1,4-di-N-oxide quinoxalin-2-yl-2-propen-1-one derivatives were synthesized and tested for in vitro leishmanicidal activity against amastigotes of Leishmania amazonensis in axenical cultures and murine infected macrophages. Structure-activity relationships demonstrated the importance of a radical methoxy at position R3', R4' and R5'. (2E-3-(3,4,5-trimethoxy-phenyl-1-(3,6,7-trimethyl-1,4-dioxy-quinoxalin-2-yl-propenone was the most active. Cytotoxicity on macrophages revealed that this product was almost six times more active than toxic.

  13. Binding mode of an α-amino acid-linked quinoxaline-2,3-dione analogue at glutamate receptor subtype GluK1.

    Science.gov (United States)

    Demmer, Charles S; Møller, Charlotte; Brown, Patricia M G E; Han, Liwei; Pickering, Darryl S; Nielsen, Birgitte; Bowie, Derek; Frydenvang, Karla; Kastrup, Jette S; Bunch, Lennart

    2015-06-17

    Two α-amino acid-functionalized quinoxalines, 1a (CNG-10301) and 1b (CNG-10300), of a quinoxaline moiety coupled to an amino acid moiety were designed, synthesized, and characterized pharmacologically. While 1a displayed low affinity at native AMPA, KA, and NMDA receptors, and at homomeric GluK1,3 receptors, the affinity for GluK2 was in the midmicromolar range (Ki = 136 μM), 1b displayed low to midmicromolar range binding affinity at all the iGluRs (Ki = 9-126 μM). In functional experiments (outside-out patches excised from transfected HEK293T cells), 100 μM 1a partially blocked GluK1 (33% peak response), while GluK2 was unaffected (96% peak response). Furthermore, 1a was shown not to be an agonist at GluK1 and GluK2 at 100 μM. On the other hand, 100 μM 1b fully antagonized GluK1 (8% peak response) but only partially blocked GluK2 (33% peak response). An X-ray structure at 2.3 Å resolution of 1b in the GluK1-LBD (ligand-binding domain) disclosed an unexpected binding mode compared to the predictions made during the design phase; the quinoxaline moiety remains to act as an amino acid bioisostere, but the amino acid moiety is oriented into a new area within the GluK1 receptor. The structure of the GluK1-LBD with 1b showed a large variation in domain openings of the three molecules from 25° to 49°, demonstrating that the GluK1-LBD is capable of undergoing major domain movements.

  14. Formation of one-dimensional helical columns and excimerlike excited states by racemic quinoxaline-fused [7]carbohelicenes in the crystal.

    Science.gov (United States)

    Sakai, Hayato; Shinto, Sho; Araki, Yasuyuki; Wada, Takehiko; Sakanoue, Tomo; Takenobu, Taishi; Hasobe, Taku

    2014-08-01

    A series of quinoxaline-fused [7]carbohelicenes (HeQu derivatives) was designed and synthesized to evaluate their structural and photophysical properties in the crystal state. The quinoxaline units were expected to enhance the light-emitting properties and to control the packing structures in the crystal. The electrochemical and spectroscopic properties and excited-state dynamics of these compounds were investigated in detail. The first oxidation potentials of HeQu derivatives are approximately the same as that of unsubstituted reference [7]carbohelicene (Heli), whereas their first reduction potentials are shifted to the positive by about 0.7 V. The steady-state absorption, fluorescence, and circular dichroism spectra also became redshifted compared to those of Heli. The molecular orbitals and energy levels of the HOMO and LUMO states, calculated by DFT methods, support these trends. Moreover, the absolute fluorescence quantum yields of HeQu derivatives are about four times larger than that of Heli. The structural properties of the aggregated states were analyzed by single-crystal analysis. Introduction of appropriate substituents (i.e., 4-methoxyphenyl) in the HeQu unit enabled the construction of one-dimensional helical columns of racemic HeQu derivatives in the crystal state. Helix formation is based on intracolumn π-stacking between two neighboring [7]carbohelicenes and intercolumn CH⋅⋅⋅N interaction between a nitrogen atom of a quinoxaline unit and a hydrogen atom of a helicene unit. The time-resolved fluorescence spectra of single crystals clearly showed an excimerlike delocalized excited state owing to the short distance between neighboring [7]carbohelicene units.

  15. Crystal structures of two 2,3-di­ethyl­naphtho­[2,3-g]quinoxaline-6,11-dione derivatives

    Science.gov (United States)

    Forsyth, Craig M.

    2017-01-01

    Two new 5,12-disubstituted 2,3-di­ethyl­naphtho­[2,3-g]quinoxaline-6,11-dione compounds were readily synthesized from the commercial dye quinizarin. For 2,3-diethyl-5,12-di­hydroxy­naphtho­[2,3-g]quinoxaline-6,11-dione, (II), C20H16N2O4, the mol­ecule displays a near planar conformation and both hy­droxy groups participate in intra­molecular O—H⋯O(carbon­yl) hydrogen bonds. In the crystal, π–π ring inter­actions [minimum ring centroid separation = 3.5493 (9) Å] form stacks of co-planar mol­ecules down the c axis, while only minor inter­molecular C—H⋯O inter­actions are present. In contrast, in 2,3-diethyl-5,12-bis­(piperidin-1-yl)naphtho­[2,3-g]quinoxaline-6,11-dione, (IV), C30H34N4O2, which contains two independent, but similar, mol­ecules in the asymmetric unit, the polycyclic cores have a significant twist, with dihedral angles of 29.79 (6) and 29.31 (7)° between the terminal rings and only minor inter­molecular C—H⋯O hydrogen-bonding inter­actions are present. Electron density associated with additional solvent mol­ecules disordered about a fourfold axis was accounted for using the SQUEEZE procedure in PLATON [Spek (2015 ▸). Acta Cryst. C71, 9–18]. PMID:28932420

  16. Rapid, efficient and eco-friendly procedure for the synthesis of quinoxalines under solvent-free conditions using sulfated polyborate as a recyclable catalyst

    Indian Academy of Sciences (India)

    KRISHNA S INDALKAR; CHETAN K KHATRI; GANESH U CHATURBHUJ

    2017-02-01

    An efficient and inexpensive sulfated polyborate catalyst was applied for the rapid synthesis of quinoxaline derivatives from various substituted o-phenylenediamines and 1,2-diketones/α-hydroxy ketones using sulfated polyborate is described. The catalyst has the advantage of Lewis as well as Bronsted acidity and recyclability without significant loss in catalytic activity. The key advantages of the present method are high yields, short reaction times, solvent-free condition, easy workup, and ability to tolerate a variety of functional groups, which give economical as well as ecological rewards.

  17. Synthesis of new 2-acetyl and 2-benzoyl quinoxaline 1,4-di-N-oxide derivatives as anti-Mycobacterium tuberculosis agents.

    Science.gov (United States)

    Jaso, Andrés; Zarranz, Belén; Aldana, Ignacio; Monge, Antonio

    2003-09-01

    A series of 2-acetyl and 2-benzoyl-6(7)-substituted quinoxaline 1,4-di-N-oxide derivatives were synthesized and evaluated for in vitro antituberculosis activity. The results show that 2-acetyl-3-methylquinoxaline 1,4-di-N-oxide derivatives with chlorine, methyl or methoxy group in position 7 of the benzene moiety (compounds 2, 4 and 6, respectively) and unsubstituted (3) have good antitubercular activity, exhibiting EC(90)/MIC values between 0.80 and 4.29. In conclusion, the potency, selectivity and low cytotoxicity of these compounds make them valid leads for synthesizing new compounds that possess better activity.

  18. Mechanochemical solid-state synthesis of 2-aminothiazoles, quinoxalines and benzoylbenzofurans from ketones by one-pot sequential acid- and base-mediated reactions.

    Science.gov (United States)

    Nagarajaiah, Honnappa; Mishra, Abhaya Kumar; Moorthy, Jarugu Narasimha

    2016-04-26

    α-Chloroketones - obtained by the atom-economical chlorination of ketones with trichloroisocyanuric acid (TCCA) in the presence of p-TSA under ball-milling conditions - were set up for a sequential base-mediated condensation reaction with thiourea/thiosemicarbazides, o-phenylenediamine and salicylaldehyde to afford 2-aminothiazoles, 2-hydrazinylthiazoles, quinoxalines and benzoylbenzofurans, respectively, in respectable yields. The viability of one-pot sequential acid- and base-mediated reactions in the solid state under ball-milling conditions is thus demonstrated.

  19. Synthesis, characterization and DNA-binding studies of ruthenium(II) mixed-ligand complexes containing dipyrido[1,2,5]oxadiazolo[3,4-b]quinoxaline

    Science.gov (United States)

    Peng, Bin; Chen, Xiang; Du, Ke-Jie; Yu, Bo-Le; Chao, Hui; Ji, Liang-Nian

    2009-11-01

    A novel ligand dipyrido[1,2,5]oxadiazolo[3,4-b]quinoxaline (dpoq) and its complexes [Ru(bpy) 2(dpoq)] 2+ and [Ru(phen) 2(dpoq)] 2+ (bpy = 2,2'-bipyridine; phen = 1,10-phenanthroline) have been synthesized and characterized by elemental analysis, electrospray mass spectra and 1H NMR. The interaction of Ru(II) complexes with calf thymus DNA (CT-DNA) was investigated by absorption spectroscopy, fluorescence spectroscopy, thermal denaturation and viscosity measurements. Results suggest that two Ru(II) complexes bind to DNA via an intercalative mode.

  20. Achieving a balance between small singlet-triplet energy splitting and high fluorescence radiative rate in a quinoxaline-based orange-red thermally activated delayed fluorescence emitter.

    Science.gov (United States)

    Yu, Ling; Wu, Zhongbin; Xie, Guohua; Zhong, Cheng; Zhu, Zece; Cong, Hengjiang; Ma, Dongge; Yang, Chuluo

    2016-09-21

    A new orange-red thermally activated delayed fluorescence (TADF) emitter is designed and synthesized by incorporating a fluorine-substituted quinoxaline as an electron-acceptor and a phenoxazine as an electron-donor. The rational molecular design enables small singlet-triplet energy splitting (ΔEST) and high fluorescence radiative rate (k) for long-wavelength TADF emitters. The organic light emitting diodes (OLEDs) employing the new TADF emitter achieve maximum external quantum efficiencies (EQEs) of 13.9% and 9.0% for the vacuum- and solution-processed OLEDs, respectively.

  1. Hypervalent iodine(iii)-promoted N-incorporation into N-aryl vinylogous carbamates to quinoxaline diesters: access to 1,4,5,8-tetraazaphenanthrene.

    Science.gov (United States)

    Sagar, A; Vidaycharan, Shinde; Shinde, Anand H; Sharada, Duddu S

    2016-04-26

    A novel oxidative N-incorporation strategy for synthesis of quinoxaline diesters under metal-free conditions is described for the first time. The mild reaction conditions allow for this transformation via the formation of two C(sp(2))-N bonds utilizing cheaply available NaN3 as the N-atom source. N-Aryl vinylogous carbamates in this study undergo azidation at enamino C(sp(2))-H selectively. The robustness of this strategy is further demonstrated by the synthesis of a valuable 1,4,5,8-tetraazaphenanthrene derivative using a mild and convenient approach.

  2. New 1,4-di-N-oxide-quinoxaline-2-ylmethylene isonicotinic acid hydrazide derivatives as anti-Mycobacterium tuberculosis agents.

    Science.gov (United States)

    Torres, Enrique; Moreno, Elsa; Ancizu, Saioa; Barea, Carlos; Galiano, Silvia; Aldana, Ignacio; Monge, Antonio; Pérez-Silanes, Silvia

    2011-06-15

    The increase in the prevalence of drug-resistant tuberculosis cases demonstrates the need of discovering new and promising compounds with antimycobacterial activity. As a continuation of our research and with the aim of identifying new antitubercular drugs candidates, a new series of quinoxaline 1,4-di-N-oxide derivatives containing isoniazid was synthesized and evaluated for in vitro anti-tuberculosis activity against Mycobacterium tuberculosis H37Rv strain. Moreover, various drug-like properties of new compounds were predicted. Taking into account the biological results and the promising drug-likeness profile of these compounds, make them valid leads for further experimental research.

  3. A Ferrocene-Quinoxaline Derivative as a Highly Selective Probe for Colorimetric and Redox Sensing of Toxic Mercury(II Cations

    Directory of Open Access Journals (Sweden)

    Antonio Caballero

    2010-12-01

    Full Text Available A new chemosensor molecule 3 based on a ferrocene-quinoxaline dyad recognizes mercury (II cations in acetonitrile solution. Upon recognition, an anodic shift of the ferrocene/ferrocenium oxidation peaks and a progressive red-shift (Δλ = 140 nm of the low-energy band, are observed in its absorption spectrum. This change in the absorption spectrum is accompanied by a colour change from orange to deep green, which can be used for a “naked-eye” detection of this metal cation.

  4. Synthesis and structural studies of first row transition metal complexes of N-(2-nitro-benzilidine-3-hydrazino quinoxaline-2-one

    Directory of Open Access Journals (Sweden)

    P.V. Anantha Lakshmi

    2008-12-01

    Full Text Available Cr(III, Mn(II, Fe(III, Co(II, Ni(II and Cu(II complexes of N-(2-nitro-benzilidene-3-hydrazino quinoxaline-2-one (NBHQO have been synthesized and characterized by elemental analysis, conductance, thermal, spectral and magnetic data. NBHQO acts as a bidentate ON donor in all the complexes except in Ni(II complex in which it acts as a tridentate ONO donor. Octahedral geometries have been proposed for all the complexes except for Cu(II complex to which the square planar geometry is assigned.

  5. Mechanisms of antibacterial action of Quinoxaline 1,4-di-N-oxides against Clostridium perfringens and Brachyspira hyodysenteriae

    Directory of Open Access Journals (Sweden)

    Fanfan Xu

    2016-12-01

    Full Text Available Quinoxaline 1,4-di-N-oxides (QdNOs are a class of bioreductive compounds, however their antibacterial mechanisms are still unclarified. The aim of this study was to assess the ability of two representative QdNO drugs, cyadox (CYA and olaquindox (OLA, to produce reactive oxide species (ROS in Gram-positive anaerobe Clostridium perfringens CVCC1125 and Gram-negative anaerobe Brachyspira hyodysenteriae B204. In addition, the effects of QdNOs on the integrity of bacterial cell walls and membranes as well as the morphological alterations and DNA oxidative damage in C. perfringens and B. hyodysenteriae were analyzed. It was demonstrated that under anaerobic conditions, QdNOs were metabolized into the reduced products which did not show any antibacterial activity. A significant dose-related increase of intracellular ROS level and intracellular hydroxyl radicals were evident in bacteria exposed to QdNOs. The result of biochemical assay showed that the cell walls and membranes of the bacteria treated with QdNOs were damaged. After exposure to 1/2MIC to 4MIC of CYA and OLA, C. perfringens and B. hyodysenteriae became elongated and filamentous. Morphological observation with scanning and transmission electron microscopes revealed rupture, loss of cytoplasmic material and cell lysis in QdNO-treated bacteria, indicating serious damage of cells. There was an increase of 8-OHdG in the two strains treated by QdNOs, but it was lower in Gram-positive than in Gram-negative bacteria. Agarose gel electrophoresis showed the degradation of chromosomal DNA in both of the two anaerobes treated by QdNOs. The results suggest that QdNOs may kill C. perfringens and B. hyodysenteriae via the generation of ROS and hydroxyl radicals from the bacterial metabolism of QdNOs, which cause oxidative damage in bacteria under anaerobic conditions.

  6. Mechanisms of Antibacterial Action of Quinoxaline 1,4-di-N-oxides against Clostridium perfringens and Brachyspira hyodysenteriae.

    Science.gov (United States)

    Xu, Fanfan; Cheng, Guyue; Hao, Haihong; Wang, Yulian; Wang, Xu; Chen, Dongmei; Peng, Dapeng; Liu, Zhenli; Yuan, Zonghui; Dai, Menghong

    2016-01-01

    Quinoxaline 1,4-di-N-oxides (QdNOs) are a class of bioreductive compounds, however, their antibacterial mechanisms are still unclarified. The aim of this study was to assess the ability of two representative QdNO drugs, cyadox (CYA) and olaquindox (OLA), to produce reactive oxide species (ROS) in Gram-positive anaerobe Clostridium perfringens CVCC1125 and Gram-negative anaerobe Brachyspira hyodysenteriae B204. In addition, the effects of QdNOs on the integrity of bacterial cell walls and membranes as well as the morphological alterations and DNA oxidative damage in C. perfringens and B. hyodysenteriae were analyzed. It was demonstrated that under anaerobic conditions, QdNOs were metabolized into the reduced products which did not show any antibacterial activity. A significant dose-related increase of intracellular ROS level and intracellular hydroxyl radicals were evident in bacteria exposed to QdNOs. The result of biochemical assay showed that the cell walls and membranes of the bacteria treated with QdNOs were damaged. After exposure to 1/2MIC to 4MIC of CYA and OLA, C. perfringens and B. hyodysenteriae became elongated and filamentous. Morphological observation with scanning and transmission electron microscopes revealed rupture, loss of cytoplasmic material and cell lysis in QdNO-treated bacteria, indicating serious damage of cells. There was an increase of 8-OHdG in the two strains treated by QdNOs, but it was lower in C. perfringens CVCC1125 than in B. hyodysenteriae B204. Agarose gel electrophoresis showed the degradation of chromosomal DNA in both of the two anaerobes treated by QdNOs. The results suggest that QdNOs may kill C. perfringens and B. hyodysenteriae via the generation of ROS and hydroxyl radicals from the bacterial metabolism of QdNOs, which cause oxidative damage in bacteria under anaerobic conditions.

  7. Assessing the reactivity of sodium alkyl-magnesiates towards quinoxaline: single electron transfer (SET) vs. nucleophilic alkylation processes.

    Science.gov (United States)

    Livingstone, Zoe; Hernán-Gómez, Alberto; Baillie, Sharon E; Armstrong, David R; Carrella, Luca M; Clegg, William; Harrington, Ross W; Kennedy, Alan R; Rentschler, Eva; Hevia, Eva

    2016-04-14

    By exploring the reactivity of sodium butyl-magnesiate (1) supported by the bulky chelating silyl(bisamido) ligand {Ph2Si(NAr*)2}(2-) (Ar* = 2,6-iPr2-C6H3) towards Quinoxaline (Qx), the ability of this bimetallic system to effectively promote SET processes has been disclosed. Thus 1 executes the single-electron reduction of Qx affording complex (2) whose structure in the solid state contains two quinaxolyl radical anions Qx˙ stabilised within a dimeric magnesiate framework. Combining multinuclear NMR and EPR measurements with DFT calculations, new insights into the constitution of 2 in solution and its magnetic behaviour have been gained. Further evidence on the SET reactivity of 1 was found when it was reacted with nitroxyl radical TEMPO which furnished contacted ion pair sodium magnesiate [(Ph2Si(NAr*)2)Mg(TEMPO(-))Na(THF)3] (4) where both metals are connected by an alkoxide bridge, resulting from reduction of TEMPO. The role that the different ligands present in 1 can play in these new SET reactions has also been assessed. Using an amination approach, the Bu group in 1 can be replaced by the more basic amide TMP allowing the isolation of (3) which was characterised by multinuclear NMR and X-ray crystallography. (1)H NMR monitoring of the reaction of 3 with Qx showed its conversion to 2, leaving the hydrogen atoms of the heterocycle untouched. Contrastingly, using sodium homoalkyl magnesiate [NaMg(CH2SiMe3)3] (5) led to the chemoselective C2 alkylation of this heterocycle, suggesting that the presence of the steric stabiliser {Ph2Si(NAr*)2}(2-) on the mixed-metal reagent is required in order to facilitate the Qx reduction.

  8. Studies on some metal complexes of quinoxaline based unsymmetric ligand: Synthesis, spectral characterization, in vitro biological and molecular modeling studies.

    Science.gov (United States)

    Dhanaraj, Chellaian Justin; Johnson, Jijo

    2016-08-01

    Mononuclear Co(II), Ni(II), Cu(II) and Zn(II) complexes of an unsymmetric Schiff base ligand, 3-(-(3-(-3,5-dichloro-2-hydroxybenzylideneamino)propylimino)methyl)quinoxalin-2(1H) -one (L) were synthesized and characterized by various analytical and spectral techniques. The molar conductance values of metal complexes indicate non-electrolytic behavior of the metal complexes. The Schiff base act as tetra dentate ONNO donor ligand in Co(II), Ni(II), Zn(II) complexes and tridentate NNO donor in Cu(II) complex. Thermal stabilities of the newly synthesized compounds were determined by thermal analysis. Crystallinity, average grain size and unit cell parameters were determined from powder X-ray diffraction study. Electrochemical behaviors of the compounds were examined by cyclic voltammetry technique. The Schiff base and its complexes have been screened for their in vitro antimicrobial activities against some bacterial and fungal strains by disc diffusion method. The interaction of the compounds with calf thymus DNA (CT DNA) has been investigated by electronic absorption spectral titration and viscosity measurement (hydrodynamic) methods. Furthermore, the pUC18 DNA cleavage activities of the complexes have been explored. The compounds were also subjected to in vitro antioxidant, anticancer activity screening, druglikeness and bioactivity predictions using Molinspiration software. Molecular docking studies of the present compounds were carried out against B-DNA dodecamer d(CGCGAATTCGCG)2 and vascular endothelial growth factor receptor (VEGFR-2) kinase. Quantum chemical calculations were done with DFT method to determine the optimum geometry of the ligand and its metal complexes. From the quantum chemical parameters, the reactivity parameters of the compounds were established.

  9. Experimental and Quantum chemical studies on the inhibition potential of some Quinoxaline derivatives for mild steel in acid media

    Directory of Open Access Journals (Sweden)

    Saranya.J

    2014-12-01

    Full Text Available The inhibition potential of four Quinoxaline derivatives namely 1,4-dihydroquinoxaline-2,3-dione, (3E-3-hydrazinylidene-3,4-dihydroquinoxalin-2(1H-one, 1-[(2E-3-oxo-3,4-dihydroquinoxalin-2(1H-ylidene]urea and 1-[(2E-3-oxo-3,4-dihydroquinoxalin-2(1H-ylidene]thiourea have been investigated against mild steel in 1M H2SO4 solution using conventional weight loss, electrochemical impedance spectroscopy, potentiodynamic polarization and atomic absorption spectroscopy. The percentage inhibition efficiency was found to increase with increase in the inhibitor concentration due to the adsorption of the inhibitor molecules on the metal surface. In addition, it was established that the adsorption follows Langmuir adsorption isotherm. Moreover, some thermodynamic data were calculated and discussed. The density functional theory at the B3LYP/6-311G (d,p basis set level was performed for two inhibitors namely 1,4-dihydroquinoxaline-2,3-dione and (3E-3-hydrazinylidene-3,4-dihydroquinoxalin-2(1H-one. The quantum chemical parameters such as highest occupied molecular orbital energy (EHOMO, lowest unoccupied molecular orbital energy (ELUMO, energy gap (∆E, dipole moment (µ, softness (σ, hardness (η, electronegativity (χ, Mulliken atomic charges, the fraction of electrons transferred from the inhibitor to the metal surface (∆N and the total energy (TE have been calculated for these compounds. It was found that theoretical data support the experimental results.

  10. Quinolino[3,4-b]quinoxalines and pyridazino[4,3-c]quinoline derivatives: Synthesis, inhibition of topoisomerase IIα, G-quadruplex binding and cytotoxic properties.

    Science.gov (United States)

    Palluotto, Fausta; Sosic, Alice; Pinato, Odra; Zoidis, Grigoris; Catto, Marco; Sissi, Claudia; Gatto, Barbara; Carotti, Angelo

    2016-11-10

    The quinoline motif fused with other heterocyclic systems plays an important role in the field of anticancer drug development. An extensive series of tetracyclic quinolino[3,4-b]quinoxalines N-5 or C-6 substituted with basic side chain and a limited number of tricyclic pyridazino[4,3-c]quinolines N-6 substituted were designed, synthesized and evaluated for topoisomerase IIα (Topo IIα) inhibitory activity, ability to bind and stabilize G-quadruplex structures and cytotoxic properties against two human cancer cell lines (HeLa and MCF-7). Almost all of the tested agents showed a high activity as Topo IIα inhibitors and G-quadruplex stabilizers. Among all the derivatives studied, the quinolino[3,4-b]quinoxalines 11 and 23, N-5 and C-6 substituted respectively, stand out as the most promising compounds. Derivative 11 resulted a selective binder to selected G-quadruplex sequences, while derivative 23 displayed the most interesting Topo IIα inhibitory activity (IC50 = 5.14 μM); both showed high cytotoxic activity (IC50 HeLa = 2.04 μM and 2.32 μM, respectively).

  11. Synthesis of a new intercalating nucleic acid 6H-INDOLO[2,3-b] quinoxaline oligonucleotides to improve thermal stability of Hoogsteen-type triplexes.

    Science.gov (United States)

    Osman, Amany M A; Pedersen, Erik B; Bergman, Jan

    2013-01-01

    A new intercalating nucleic acid monomer X was obtained in high yield starting from alkylation of 4-iodophenol with (S)-(+)-2-(2,2-dimethyl-1,3-dioxolan-4-yl)ethanol under Mitsunobu conditions followed by hydrolysis with 80% aqueous acetic acid to give a diol which was coupled under Sonogashira conditions with trimethylsilylacetylene (TMSA) to achieve the TMS protected (S)-4-(4-((trimethylsilyl)ethynyl)phenoxy)butane-1,2-diol. Tetrabutylammonium flouride was used to remove the silyl protecting group to obtain (S)-4-(4-ethynylphenoxy)butane-1,2-diol which was coupled under Sonogashira conditions with 2-(9-bromo-6H-indolo[2,3-b]quinoxalin-6-yl)-N,N-dimethylethanamine to achieve (S)-4-(4-((6-(2-(dimethylamino)ethyl)-6H-indolo[2,3-b]quinoxalin-9-yl)ethynyl)phenoxy)butane-1,2-diol. This compound was tritylated with 4,4'-dimethoxytrityl chloride followed by treatment with 2-cyanoethyltetraisopropylphosphordiamidite in the presence of N,N'-diisopropyl ammonium tetrazolide to afford the corresponding phosphoramidite. This phosphoramidite was used to insert the monomer X into an oligonucleotide which was used for thermal denaturation studies of a corresponding parallel triplex.

  12. 6H-Indolo[2,3-b]quinoxaline-based organic dyes containing different electron-rich conjugated linkers for highly efficient dye-sensitized solar cells

    Science.gov (United States)

    Qian, Xing; Gao, Huan-Huan; Zhu, Yi-Zhou; Lu, Lin; Zheng, Jian-Yu

    2015-04-01

    A new class of organic dyes based on 6H-indolo[2,3-b]quinoxaline are synthesized and applied as photosensitizers for dye-sensitized solar cells. Different electron-rich π-conjugated bridges such as oligothiophene, thienyl carbazole, and furyl carbazole are introduced to cooperate with 6H-indolo[2,3-b]quinoxaline and cyanoacrylic acid anchoring group to give the dyes JY01, JY02, and JY03, respectively. Their photophysical, electrochemical, and photovoltaic properties are further investigated. All three dyes show good performances as photosensitizers. In particular, DSSC based on JY01 shows the best photovoltaic performance with a short-circuit photocurrent density of 16.0 mA cm-2, an open-circuit photovoltage of 708 mV and a fill factor of 0.67, corresponding to an overall power conversion efficiency of 7.62% under AM 1.5 irradiation (100 mW cm-2).

  13. Synthesis and evaluation of the antiproliferative activity of novel pyrrolo[1,2-a]quinoxaline derivatives, potential inhibitors of Akt kinase. Part II.

    Science.gov (United States)

    Desplat, Vanessa; Moreau, Stephane; Gay, Aurore; Fabre, Solene Belisle; Thiolat, Denis; Massip, Stephane; Macky, Gregory; Godde, Frederic; Mossalayi, Djavad; Jarry, Christian; Guillon, Jean

    2010-04-01

    Attenuation of protein kinases by selective inhibitors is an extremely active field of activity in anticancer drug development. Therefore, Akt, a serine/threonine protein kinase, also known as protein kinase B (PKB), represents an attractive potential target for therapeutic intervention. Recent efforts in the development and biological evaluation of small molecule inhibitors of Akt have led to the identification of novel inhibitors with various heterocycle scaffolds. Based on previous results obtained on the antiproliferative activities of new pyrrolo[1,2-a]quinoxalines, a novel series was designed and synthesized from various substituted phenyl-1H-pyrrole-2-carboxylic acid alkyl esters via a multistep heterocyclization process. These new compounds were tested for their in vitro ability to inhibit the proliferation of the human leukemic cell lines K562, U937, and HL60, and the breast cancer cell line MCF7. The first biological evaluation of our new substituted pyrrolo[1,2-a]quinoxalines showed antiproliferative activity against the tested cell lines. From a general SAR point of view, these preliminary biological results highlight the importance of substitution at the C-4 position of the pyrroloquinoxaline scaffold by a benzylpiperidinyl fluorobenzimidazole group, and also the need for a functionalization on the pyrrole ring.

  14. Synthesis and Biological Evaluation of 3-Aryl-quinoxaline-2-carbonitrile 1,4-Di-N-oxide Derivatives as Hypoxic Selective Anti-tumor Agents

    Directory of Open Access Journals (Sweden)

    Yongzhou Hu

    2012-08-01

    Full Text Available A series of 3-aryl-2-quinoxaline-carbonitrile 1,4-di-N-oxide derivatives were designed, synthesized and evaluated for hypoxic and normoxic cytotoxic activity against human SMMC-7721, K562, KB, A549 and PC-3 cell lines. Many of these new compounds displayed more potent hypoxic cytotoxic activity compared with TX-402 and TPZ in the tumor cells based evaluation, which confirmed our hypothesis that the replacement of the 3-amine with the substituted aryl ring of TX-402 increases the hypoxic anti-tumor activity. The preliminary SAR revealed that 3-chloro was a favorable substituent in the phenyl ring for hypoxic cytotoxicity and 7-methyl or 7-methoxy substituted derivatives exhibited better hypoxic selectivity against most of the tested cell lines. The most potent compound, 7-methyl-3-(3-chlorophenyl-quinoxaline-2-carbonitrile 1,4-dioxide (9h was selected for further anti-tumor evaluation and mechanistic study. It also exhibited significant cytotoxic activity against BEL-7402, HepG2, HL-60, NCI-H460, HCT-116 and CHP126 cell lines in hypoxia with IC50 values ranging from 0.31 to 3.16 μM, and preliminary mechanism study revealed that 9h induced apoptosis in a caspase-dependent pathway.

  15. Synthesis and biological evaluation of 3-aryl-quinoxaline-2-carbonitrile 1,4-di-N-oxide derivatives as hypoxic selective anti-tumor agents.

    Science.gov (United States)

    Hu, Yunzhen; Xia, Qing; Shangguan, Shihao; Liu, Xiaowen; Hu, Yongzhou; Sheng, Rong

    2012-08-13

    A series of 3-aryl-2-quinoxaline-carbonitrile 1,4-di-N-oxide derivatives were designed, synthesized and evaluated for hypoxic and normoxic cytotoxic activity against human SMMC-7721, K562, KB, A549 and PC-3 cell lines. Many of these new compounds displayed more potent hypoxic cytotoxic activity compared with TX-402 and TPZ in the tumor cells based evaluation, which confirmed our hypothesis that the replacement of the 3-amine with the substituted aryl ring of TX-402 increases the hypoxic anti-tumor activity. The preliminary SAR revealed that 3-chloro was a favorable substituent in the phenyl ring for hypoxic cytotoxicity and 7-methyl or 7-methoxy substituted derivatives exhibited better hypoxic selectivity against most of the tested cell lines. The most potent compound, 7-methyl-3-(3-chlorophenyl)-quinoxaline-2-carbonitrile 1,4-dioxide (9h) was selected for further anti-tumor evaluation and mechanistic study. It also exhibited significant cytotoxic activity against BEL-7402, HepG2, HL-60, NCI-H460, HCT-116 and CHP126 cell lines in hypoxia with IC₅₀ values ranging from 0.31 to 3.16 μM, and preliminary mechanism study revealed that 9h induced apoptosis in a caspase-dependent pathway.

  16. Design, synthesis and biological evaluation of (E)-2-(2-arylhydrazinyl)quinoxalines, a promising and potent new class of anticancer agents.

    Science.gov (United States)

    Rodrigues, Felipe A R; Bomfim, Igor da S; Cavalcanti, Bruno C; Pessoa, Claudia do Ó; Wardell, James L; Wardell, Solange M S V; Pinheiro, Alessandra C; Kaiser, Carlos Roland; Nogueira, Thais C M; Low, John N; Gomes, Ligia R; de Souza, Marcus V N

    2014-02-01

    A series of forty-seven quinoxaline derivatives, 2-(XYZC6H2CHN-NH)-quinoxalines, 1, have been synthesized and evaluated for their activity against four cancer cell lines: potent cytotoxicities were found (IC50 ranging from 0.316 to 15.749 μM). The structure-activity relationship (SAR) analysis indicated that the number, the positions and the type of substituents attached to the aromatic ring are critical for biological activity. The activities do not depend on the electronic effects of the substituents nor on the lypophilicities of the molecules. A common feature of active compounds is an ortho-hydroxy group in the phenyl ring. A potential role of these ortho-hydroxy derivatives is as N,N,O-tridentate ligands complexing with a vital metal, such as iron, and thereby preventing proliferation of cells. The most active compound was (1: X,Y=2,3-(OH)2, Z=H), which displayed a potent cytotoxicity comparable to that of the reference drug doxorubicin.

  17. Design, synthesis and in vitro antibacterial activities of methyl-4-((substituted phenyl) [6H-indolo (2,3-b)quinoxalin-6-yl]methyl-amino)benzoate derivatives

    Institute of Scientific and Technical Information of China (English)

    Yellajyosula Lakshmi Narasimha Murthy; Nagalakshmi Karthikeyan; Govindh Boddeti; Bhagavathula S. Diwakar; E. Rajendra Singh

    2011-01-01

    A series of new methyl-4-((substituted phenyl) [6H-indolo (2,3-b)quinoxalin-6yllmethylamino)benzoate derivatives have been synthesized and assayed for their antibacterial activity on 9 different bacterial strains. Among the screened compounds 2e-2g exhibited potent inhibitory activity compared to standard drug employed, worth further investigation.

  18. Iron-Catalyzed Intramolecular C(sp(2))-N Cyclization of 1-(N-Arylpyrrol-2-yl)ethanone O-Acetyl Oximes toward Pyrrolo[1,2-a]quinoxaline Derivatives.

    Science.gov (United States)

    Zhang, Zhiguo; Li, Junlong; Zhang, Guisheng; Ma, Nana; Liu, Qingfeng; Liu, Tongxin

    2015-07-01

    An efficient and convenient iron-catalyzed protocol has been developed for the synthesis of substituted pyrrolo[1,2-a]quinoxalines from 1-(N-arylpyrrol-2-yl)ethanone O-acetyl oximes through N-O bond cleavage and intramolecular directed C-H arylation reactions in acetic acid.

  19. Spectral and Kinetic Properties of Radicals Derived from Oxidation of Quinoxalin-2-One and Its Methyl Derivative

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    Konrad Skotnicki

    2014-11-01

    Full Text Available The kinetics and spectral characteristics of the transients formed in the reactions of •OH and •N3 with quinoxalin-2(1H-one (Q, its methyl derivative, 3-methylquinoxalin-2(1H-one (3-MeQ and pyrazin-2-one (Pyr were studied by pulse radiolysis in aqueous solutions at pH 7. The transient absorption spectra recorded in the reactions of •OH with Q and 3-MeQ consisted of an absorption band with λmax = 470 nm assigned to the OH-adducts on the benzene ring, and a second band with λmax = 390 nm (for Q and 370 nm (for 3-MeQ assigned, inter alia, to the N-centered radicals on a pyrazin-2-one ring. The rate constants of the reactions of •OH with Q and 3-MeQ were found to be in the interval (5.9–9.7 × 109 M–1·s–1 and were assigned to their addition to benzene and pyrazin-2-one rings and H-abstraction from the pyrazin-2-one nitrogen. In turn, the transient absorption spectrum observed in the reaction of •N3 exhibits an absorption band with λmax = 350 nm. This absorption was assigned to the N-centered radical on the Pyr ring formed after deprotonation of the respective radical cation resulting from one-electron oxidation of 3-MeQ. The rate constant of the reaction of •N3 with 3 MeQ was found to be (6.0 ± 0.5 × 109 M–1·s–1. Oxidation of 3-MeQ by •N3 and Pyr by •OH and •N3 confirms earlier spectral assignments. With the rate constant of the •OH radical with Pyr (k = 9.2 ± 0.2 × 109 M–1·s‒1, a primary distribution of the •OH attack was estimated nearly equal between benzene and pyrazin-2-one rings.

  20. A series of Keggin-based compounds constructed by conjugate ring-rich pyrazine and quinoxaline derivatives.

    Science.gov (United States)

    Tian, Aixiang; Tian, Yan; Ning, Yali; Hou, Xue; Ni, Huaiping; Ji, Xuebin; Liu, Guocheng; Ying, Jun

    2016-09-21

    Through the use of conjugate ring-rich pyrazine and quinoxaline derivatives, five new Keggin polymolybdate based compounds, [Ag(I)3L(1)2(H2O)2(PMo12O40)] (1), [Ag(I)4L(1)5(SiMo12O40)] (2), [Ag(I)6L(2)6(PMo12O40)2] (3), [Ag(I)2L(2)2(C16H36N)2](SiMo12O40)] (4), [Cu(I)3L(2)3(PMo12O40)] (5) (L(1) = 2,3-diphenylpyrazine, L(2) = 2,3-diphenylquinoxaline, C16H36N = tetrabutylammonium), were synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. In compound 1, three Ag(I) ions are fused by two L(1) molecules to form a [Ag3L(1)2](3+) subunit, and these subunits link the PMo12 anions to construct two kinds of 1D chains (I and II). Chains I and II connect to each other by sharing the same PMo12 anions and a 2D grid-like layer is built. The asymmetric unit of compound 2 is linked to form a dimer by sharing Ag ions, and a 1D double strand is formed. The SiMo12 anions connect adjacent 1D double strands through Ag3-O23 bonds and a 2D network is built. In compound 3, there exists a 1D ladder-like double chain with PMo12 anions as linking bars. A 2D layer is formed by linkage Ag2-O24 between adjacent chains. In compound 4, the PMo12 anions act as inorganic linkages to connect adjacent zigzag chains through Ag1-O3 bonds to construct a 2D grid-like layer. In compound 5 two Cu(I)-L(2) lines are fused by PMo12 anions to build a 1D ladder-like chain. Additionally, the electrochemical and photocatalytic properties of the title compounds have been studied.

  1. Microwave assisted synthesis of a series of charge-transfer photosensitizers having quinoxaline-2(1H)-one as anchoring group onto TiO2 surface

    Science.gov (United States)

    Caicedo, Mauricio; Echeverry, Carlos A.; Guimarães, Robson R.; Ortiz, Alejandro; Araki, Koiti; Insuasty, Braulio

    2017-04-01

    In this work, we present the synthesis of novel donor-acceptor compounds based on 3-methylquinoxaline-2(1H)one which follow an easy synthetic route, involving Knoevenagel reaction with electron-donor groups such as N,N-dimethylaminobenzene, ferrocene, triphenylamine (TPA) and ((E)-4,4'-(ethene-1,2-diyl) bis (N,N-diphenylaniline). Additionally, the optical properties were measured by means of the absorption and emission spectroscopy suggesting a push-pull behavior which was further confirmed by electrochemical experiments. Finally, the quinoxaline-2(1H)one fragment not only bestow wide absorption, but also can chelate to titanium ions on the TiO2 surface, allowing a strong electron coupling between the excited-state energy level of the dyes and the conduction band of TiO2.

  2. Organic Photosensitizers Incorporating Rigidified Dithieno[3,2-f:2',3'-h]quinoxaline Segment Tethered with Thiophene Substitutes for Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Ni, Jen-Shyang; Chiu, Tang-Yao; Kao, Wei-Siang; Chou, Hao-Ju; Su, Chao-Chin; Lin, Jiann T

    2016-09-01

    Metal-free D-π-RS-π-A type sensitizers, consisting of triphenylamine as the electron donor, 2,3-bis(3-(2-ethylhexyl)-5-methylthiophen-2-yl)dithieno[3,2-f:2',3'-h]quinoxaline (DTQT) as the rigidified conjugation spacer (RS), thiophene as the π-spacer, and 2-cyanoacrylic acid as the acceptor/anchor, have broad absorption spectra ranging from 350 to 550 nm and a high molar extinction coefficient up to >46 200 M(-1) cm(-1). Under simulated AM 1.5 G illumination, the dye-sensitized solar cells (DSSCs) fabricated from the dyes exhibited light-to-electricity conversions in the range of 6.78% to 8.27%. The best efficiency is slightly higher than that of N719-based standard DSSC (7.92%). The efficiency can be further boosted to 8.51% by optimizing the concentration of LiI electrolyte.

  3. Majority-Rules-Type Helical Poly(quinoxaline-2,3-diyl)s as Highly Efficient Chirality-Amplification Systems for Asymmetric Catalysis.

    Science.gov (United States)

    Ke, Yuan-Zhen; Nagata, Yuuya; Yamada, Tetsuya; Suginome, Michinori

    2015-08-01

    A highly efficient majority-rules effect of poly(quinoxaline-2,3-diyl)s (PQXs) bearing 2-butoxymethyl chiral side chains at the 6- and 7-positions was established and attributed to large ΔG(h) values (0.22-0.41 kJ mol(-1)), which are defined as the energy difference between P- and M-helical conformations per chiral unit. A PQX copolymer prepared from a monomer derived from (R)-2-octanol (23% ee) and a monomer bearing a PPh2 group adopted a single-handed helical structure (>99%) and could be used as a highly enantioselective chiral ligand in palladium-catalyzed asymmetric reactions (products formed with up to 94% ee), in which the enantioselectivity could be switched by solvent-dependent inversion of the helical PQX backbone.

  4. 6-Ferrocenoyl-7-phenylspiro[hexahydropyrrolo[1,2-c][1,3]thiazole-5,11′-indeno[1,2-b]quinoxaline

    Directory of Open Access Journals (Sweden)

    Sivasubramanian Suhitha

    2013-09-01

    Full Text Available In the title compound, [Fe(C5H5(C32H24N3OS], both the thiazolidine ring and the pyrrolidine ring adopt an envelope conformation, with the S atom and the phenyl-bearing C atom, respectively, as the flaps. The thiazolidine ring mean plane makes a dihedral angle of 59.08 (11° with the pyrrolidine ring mean plane, which in turn makes a dihedral angle of 83.40 (10° with the cyclopentane ring, indicating that the latter two rings are almost orthogonal to one another. In the crystal, a pair of C—H...O hydrogen bonds link the molecules forming inversion dimers. The dimers are linked via π–π interactions [centroid–centroid distance = 3.7764 (10 Å] involving the quinoxaline moieties forming chains propagating along [1-10].

  5. 1-Allyl-3-methyl-3′,5′-diphenylspiro[quinoxaline-2(1H,2′(3′H-[1,3,4]thiadiazole

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    Seik Weng Ng

    2010-12-01

    Full Text Available In the title spiro compound, C25H22N4S, the planar quinoxaline (r.m.s. deviation = 0.070 Å and planar thiadiazole (r.m.s. deviation = 0.060 Å ring systems share a common C atom; their mean planes are aligned at 89.7 (1°. The thiazole ring possesses two aromatic ring substituents and is nearly coplanar with these rings [the dihedral angles between the thiadiazole and phenyl rings are 5.7 (1 and 10.7 (1°]. The allyl unit is disordered over two positions in a 0.65 (1:0.35 (1 ratio.

  6. 2-(4-Bromobenzoyl-1-ferrocenylspiro[11H-pyrrolidizine-3,11′-indeno[1,2-b]quinoxaline

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    Sivasubramanian Suhitha

    2013-09-01

    Full Text Available In the title compound, [Fe(C5H5(C33H25BrN3O], the fused four-ring system, 11H-indeno[1,2-b]quinoxaline is essentially planar, with a maximum deviation of 0.087 (3 Å from the least-squares plane of the attached benzene ring. The pyrrolidine rings adopt envelope conformation and make a dihedral angle of 51.76 (19° with each other. The cyclopentadiene rings of the ferrocenyl moiety have an eclipsed conformation. The Br atom deviates by 0.0190 (9 Å from the attached benzene ring. The molecular structure features an intramolecular C—H...N interaction, which generates an S(8 ring motif. The crystal packing features C—H...O interactions, which generate R22(18 centrosymmetric dimers, as well as C—H...π interactions.

  7. Crystal structure of 1-ferrocenyl-2-(4-methylbenzoylspiro[11H-pyrrolidizine-3,11′-indeno[1,2-b]quinoxaline

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    Kuppan Chandralekha

    2014-09-01

    Full Text Available In the title compound, [Fe(C5H5(C34H28N3O], the four-fused-rings system of the 11H-indeno[1,2-b]quinoxaline unit is approximately planar [maximum deviation = 0.167 (4 Å] and forms a dihedral angle of 37.25 (6° with the plane of the benzene ring of the methylbenzoyl group. Both pyrrolidine rings adopt a twist conformation. An intramolecular C—H...O hydrogen bond is observed. In the crystal, molecules are linked by C—H...O hydrogen bonds and weak C—H...π interactions, forming double chains extending parallel to the c axis.

  8. Dipolar Dyes with a Pyrrolo[2,3-b]quinoxaline Skeleton Containing a Cyano Group and a Bridged Tertiary Amino Group: Synthesis, Solvatofluorochromism, and Bioimaging.

    Science.gov (United States)

    Łukasiewicz, Łukasz G; Deperasińska, Irena; Poronik, Yevgen M; Jun, Yong Woong; Banasiewicz, Marzena; Kozankiewicz, Bolesław; Ahn, Kyo Han; Gryko, Daniel T

    2016-06-01

    Two strongly polarized dipolar chromophores possessing a cyclic tertiary amino group at one terminus of the molecule and a CN group at the opposite terminus were designed and synthesized. Their rigid skeleton contains the rarely studied pyrrolo[2,3-b]quinoxaline ring system. The photophysical properties of these regioisomeric dyes were different owing to differing π conjugation between the CN group and the electron-donor moiety. These dipolar molecules showed very intense emission, strong solvatofluorochromism, and sufficient two-photon brightness for bioimaging. One of these regioisomeric dyes, namely, 11-carbonitrile-2,3,4,5,6,7-hexahydro-1H-3a,8,13,13b-tetraazabenzo[b]cyclohepta[1,2,3-jk]fluorene, was successfully utilized in two-photon imaging of mouse organ tissues and showed distinct tissue morphology with high resolution.

  9. Syntheses, structural, theoretical studies and thermal behaviors of two luminous copper(I) halide complexes of dipyrido[3,2-f:2,3-h]-quinoxaline

    Science.gov (United States)

    Chen, Aihua; Meng, Suci; Zhang, Jinfang; Zhang, Chi

    2013-10-01

    Two new copper(I) complexes containing PPh3 and Dpq, [Cu(Dpq)(PPh3)X] (X = I (1); Br (2)), {PPh3 = triphenylphosphine, Dpq = dipyrido[3,2-f:2,3-h]-quinoxaline} have been synthesized and characterized by elemental analysis, IR spectroscopy, X-ray single crystal analysis, fluorescent analysis, thermal gravimetric analysis and DFT calculations. Single crystal X-ray diffraction analysis reveals that complexes 1 and 2 are mononuclear with similar structures and display a favorable pairwise π-π stacking. Density functional theory and time-dependent density functional theory calculations at the B3LYP/LanL2DZf+6-31G∗ level were performed on both complexes to rationalize their experimental absorption spectra. In addition, 1 and 2 exhibit intense luminescence in ethanol solution at room temperature.

  10. Crystal structure of 1-ferrocenyl-2-(4-methyl-benzo-yl)spiro-[11H-pyrrolidizine-3,11'-indeno[1,2-b]quinoxaline].

    Science.gov (United States)

    Chandralekha, Kuppan; Gavaskar, Deivasigamani; Sureshbabu, Adukamparai Rajukrishnan; Lakshmi, Srinivasakannan

    2014-09-01

    In the title compound, [Fe(C5H5)(C34H28N3O)], the four-fused-rings system of the 11H-indeno-[1,2-b]quinoxaline unit is approximately planar [maximum deviation = 0.167 (4) Å] and forms a dihedral angle of 37.25 (6)° with the plane of the benzene ring of the methyl-benzoyl group. Both pyrrolidine rings adopt a twist conformation. An intra-molecular C-H⋯O hydrogen bond is observed. In the crystal, mol-ecules are linked by C-H⋯O hydrogen bonds and weak C-H⋯π inter-actions, forming double chains extending parallel to the c axis.

  11. 1-Benzyl-3-methyl-3′,5′-diphenylspiro[quinoxaline-2(1H,2′(3′H-1,3,4-thiadiazole

    Directory of Open Access Journals (Sweden)

    Caleb Ahoya Anothane

    2012-01-01

    Full Text Available In the title spiro compound, C29H24N4S, the quinoxaline and thiadiazole ring systems share a common C atom; their mean planes are aligned at 87.0 (1° in one molecule and at 84.1 (1° in the other independent molecule. The thiazole ring possesses two aromatic ring substituents and is roughly coplanar with these rings [the dihedral angles between the thiadiazole and phenyl rings are 10.7 (1 and 11.7 (1° in one molecule, and 16.8 (1 and 17.7 (1° in the other]. The aromatic ring of the benzyl unit of one molecule is disordered over two orientations in a 1:1 ratio.

  12. Regioselective differences in C(8)- and N-oxidation of 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline by human and rat liver microsomes and cytochromes P450 1A2.

    Science.gov (United States)

    Turesky, R J; Parisod, V; Huynh-Ba, T; Langouët, S; Guengerich, F P

    2001-07-01

    The metabolism of the mutagen 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) was investigated with human and rat liver microsomes, recombinant human cytochrome P450 1A2 (P450 1A2) expressed in Escherichia coli cells, and rat P450 1A2. Human liver microsomes and human P450 1A2 catalyzed the oxidation of the exocyclic amine group of MeIQx to form the genotoxic product 2-(hydroxyamino)-3,8-dimethylimidazo[4,5-f]quinoxaline (HONH-MeIQx). Human P450 1A2 also catalyzed the oxidation of C(8)-methyl group of MeIQx to form 2-amino-(8-hydroxymethyl)-3-methylimidazo[4,5-f]quinoxaline (8-CH(2)OH-IQx), 2-amino-3-methylimidazo[4,5-f]quinoxaline-8-carbaldehyde (IQx-8-CHO), and 2-amino-3-methylimidazo[4,5-f]quinoxaline-8-carboxylic acid (IQx-8-COOH). Thus, chemically stable C(8)-oxidation products of MeIQx may be useful biomarkers of P450 1A2 activity in humans. Rat liver microsomes were 10-15-fold less active than the human counterpart at both N-oxidation and C(8)-oxidation of MeIQx when expressed as nanomoles of product formed per minute per nanomoles of P450 1A2. Differences in regioselective oxidation of MeIQx were also observed with human and rat liver microsomes and the respective P450 1A2 orthologs. In contrast to human liver microsomes and P450 1A2, rat liver microsomes and purified rat P4501A2 were unable to catalyze the oxidation of MeIQx to the carboxylic derivative IQx-8-COOH, an important detoxication product formed in humans. However, rat liver microsomes and rat P4501A2, but not human liver microsomes or human P450 1A2, extensively catalyzed ring oxidation at the C-5 position of MeIQx to form the detoxication product 2-amino-3,8-dimethyl-5-hydroxyimidazo[4,5-f]quinoxaline (5-HO-MeIQx). There are important differences between human and rat P450 1A2, both in catalytic activities and oxidation pathways of MeIQx, that may affect the biological activity of this carcinogen and must be considered when assessing human health risk.

  13. Crystal structure of 1',1''-dimethyl-4'-(4-cholorophen-yl)di-spiro-[11H-indeno[1,2-b]quinoxaline-11,2'-pyrrolidine-3',3''-piperidin]-4''-one.

    Science.gov (United States)

    Nagalakshmi, R A; Suresh, J; Malathi, K; Kumar, R Ranjith; Lakshman, P L Nilantha

    2015-02-01

    In the title compound, C30H27ClN4O, the central pyrrolidine ring adopts an envelope conformation with the methyl-ene C atom being the flap. The quinoxaline and indane rings are each essentially planar, with r.m.s. deviations of 0.027 (1) and 0.0417 (1) Å, respectively. The pyrrolidine ring forms dihedral angles of 88.25 (1) and 83.76 (1)° with the quinoxaline and indane rings, respectively. A weak intra-molecular C-H⋯N inter-action is observed. In the crystal, C-H⋯π inter-actions lead to supra-molecular chains along [101] that assemble in the ac plane. Connections along the b axis are of the type Cl⋯Cl [3.6538 (16) Å].

  14. 1′,1′′-Dimethyl-4′-(4-methylphenyldispiro[11H-indeno[1,2-b]quinoxaline-11,2′-pyrrolidine-3′,3′′-piperidin]-4′′-one

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    R. A. Nagalakshmi

    2013-09-01

    Full Text Available In the title compound, C31H30N4O, the central pyrrolidine ring adopts an envelope conformation with the methylene C atom being the flap. The quinoxaline and indane rings are each planar, having r.m.s. deviations of 0.030 and 0.050 Å, respectively. The pyrrolidine ring mean plane forms dihedral angles of 88.25 (1 and 83.76 (1° with the quinoxaline and indane rings, respectively. Intramolecular C—H...O and C—H...N interactions are observed. In the crystal, C—H...π interactions lead to helical supramolecular chains along the b-axis direction.

  15. 1′,1′′-Dimethyl-4′-phenyldispiro[11H-indeno[1,2-b]quinoxaline-11,2′-pyrrolidine-3′,3′′-piperidin]-4′′-one

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    J. Suresh

    2013-09-01

    Full Text Available In the title compound, C30H28N4O, the central pyrrolidine ring adopts an envelope conformation with the CH2 C atom as the flap. The quinoxaline and indene ring systems are planar, with r.m.s. deviations of 0.0165 and 0.0181 Å, respectively. The pyrrolidine ring mean plane forms dihedral angles of 88.84 (1 and 86.14 (1° with the quinoxaline and indene ring systems, respectively. A weak intramolecular C—H...N interaction is observed. In the crystal, C—H...O interactions lead to helical supramolecular chains along the b axis having a C(9 motif.

  16. {1′-Phenyl-1′,2′,5′,6′,7′,7a'-hexahydrospiro[indeno[1,2-b]quinoxaline-11,3′-pyrrolizin]-2′-yl}(p-tolylmethanone

    Directory of Open Access Journals (Sweden)

    T. Srinivasan

    2012-08-01

    Full Text Available In the title compound, C35H29N3O, the quinoxaline and indene systems are essentially planar, with maximum deviations of 0.047 (2 and 0.032 (2 Å for C atoms, respectively. The quinoxaline system forms a dihedral angle of 4.75 (3° with the indene system. The pyrrolizine system is folded. The substituted five-membered ring adopts an envelope conformation. In the other five-membered ring, one C atom is disordered with a site-occupancy ratio of 0.676 (12:0.324 (12. In the crystal, molecules are linked via C—H...O hydrogen bonds involving the bifurcated carbonyl O atom.

  17. Quinoxaline 1,4-di-N-oxide Derivatives: Interest in the Treatment of Chagas Disease [ Derivados 1,4- i-N-óxido Quinoxalinas: O Interesse no Tratamento da Doença de Chagas

    OpenAIRE

    Elsa Moreno - Viguri; Silvia Pérez-Silanes

    2013-01-01

    More than 100 million people are at risk of contracting Chagas disease. It is estimated that in 2008, Chagas disease was responsible for the death of more than 10,000 people. Despite the fact that there are more than 100 years since the disease was discove red, safe and effective treatments still have to be found. Therefore, new drugs active against Chagas disease are urgently required. Quinoxaline derivatives show very interesting biological properties (anti-infective, cytotoxic, anticandida...

  18. Copper-catalyzed domino synthesis of 2-imino-1H-imidazol-5(2H)-ones and quinoxalines involving C-C bond cleavage with a 1,3-dicarbonyl unit as a leaving group.

    Science.gov (United States)

    Yang, Yan; Ni, Fan; Shu, Wen-Ming; Wu, An-Xin

    2014-09-08

    Although 2-imino-1H-imidazol-5(2H)-ones have important biological activities in metabolism, their synthesis has rarely been investigated. Quinoxalines as "privileged scaffolds" in medicinal chemistry have been extensively investigated, but the development of novel and efficient synthetic methods remains very attractive. Herein, we have developed two copper-catalyzed domino reactions for the synthesis of 2-imino-1H-imidazol-5(2H)-ones and quinoxalines involving CC bond-cleavage with a 1,3-dicarbonyl unit as a leaving group. The domino sequence for the synthesis of 2-imino-1H-imidazol-5(2H)-ones includes aza-Michael addition, intramolecular cyclization, CC bond-cleavage, 1,2-rearrangement, and aerobic dehydrogenation reaction, whereas the domino sequence for the synthesis of quinoxalines includes aza-Michael addition, intramolecular cyclization, elimination reaction, and CC bond-cleavage reaction. The two domino reactions have significant advantages including high efficiency, mild reaction conditions, and high tolerance of various functional groups. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Synthesis and evaluation of the cytotoxic activity of novel ethyl 4-[4-(4-substitutedpiperidin-1-yl)]benzyl-phenylpyrrolo[1,2-a]quinoxaline-carboxylate derivatives in myeloid and lymphoid leukemia cell lines.

    Science.gov (United States)

    Desplat, Vanessa; Vincenzi, Marian; Lucas, Romain; Moreau, Stéphane; Savrimoutou, Solène; Pinaud, Noël; Lesbordes, Jordi; Peyrilles, Elodie; Marchivie, Mathieu; Routier, Sylvain; Sonnet, Pascal; Rossi, Filomena; Ronga, Luisa; Guillon, Jean

    2016-05-01

    Leukemia is the most common blood cancer, and its development starts at diverse points, leading to distinct subtypes that respond differently to therapy. This heterogeneity is rarely taken into account in therapies, so it is still essential to look for new specific drugs for leukemia subtypes or even for therapy-resistant cases. Among heterocyclic compounds that attracted a lot of attention because of its wide spread biological activities, the pyrrolo[1,2-a]quinoxaline heterocyclic framework has been identified as interesting scaffolds for antiproliferative activity against various human cancer cell lines. In the present study, novel ethyl 4-[4-(4-substitutedpiperidin-1-yl)]benzyl-phenylpyrrolo[1,2-a]quinoxaline-carboxylate derivatives 1a-l have been designed and synthesized. Their cytotoxicities were evaluated against five different leukemia cell lines, including Jurkat and U266 (lymphoid cell lines), and K562, U937, HL60 (myeloid cell lines), as well as normal human peripheral blood mononuclear cells (PBMNCs). Then, apoptosis study was performed with the more interesting compounds. The new pyrrolo[1,2-a]quinoxaline series showed promising cytotoxic potential against all leukemia cell lines tested, and some compounds showed better results than the reference compound A6730. Some compounds, such as 1a, 1e, 1g and 1h are promising because of their high activity against leukemia and their low activity against normal hematopoietic cells. Structure-activity relationships of these new synthetic compounds 1a-l are here also discussed.

  20. Searching for the Multi-Target-Directed Ligands against Alzheimer's disease: discovery of quinoxaline-based hybrid compounds with AChE, H₃R and BACE 1 inhibitory activities.

    Science.gov (United States)

    Huang, Wenhai; Tang, Li; Shi, Ying; Huang, Shufang; Xu, Lei; Sheng, Rong; Wu, Peng; Li, Jia; Zhou, Naiming; Hu, Yongzhou

    2011-12-01

    A novel series of quinoxaline derivatives, as Multi-Target-Directed Ligands (MTDLs) for AD treatment, were designed by lending the core structural elements required for H(3)R antagonists and hybridizing BACE 1 inhibitor 1 with AChE inhibitor BYYT-25. A virtual database consisting of quinoxaline derivatives was first screened on a pharmacophore model of BACE 1 inhibitors, and then filtered by a molecular docking model of AChE. Seventeen quinoxaline derivatives with high score values were picked out, synthesized and evaluated for their biological activities. Compound 11a, the most effective MTDL, showed the potent activity to H(3)R/AChE/BACE 1 (H(3)R antagonism, IC(50)=280.0 ± 98.0 nM; H(3)R inverse agonism, IC(50)=189.3 ± 95.7 nM; AChE, IC(50)=483 ± 5 nM; BACE 1, 46.64±2.55% inhibitory rate at 20 μM) and high selectivity over H(1)R/H(2)R/H(4)R. Furthermore, the protein binding patterns between 11a and AChE/BACE 1 showed that it makes several essential interactions with the enzymes.

  1. Disposition of the Dietary Mutagen 2-Amino-3,8-dimethylimidazo[4,5-f]quinoxaline in Healthy and Pancreatic Cancer Compromised Humans.

    Science.gov (United States)

    Malfatti, Michael A; Kuhn, Edward A; Turteltaub, Kenneth W; Vickers, Selwyn M; Jensen, Eric H; Strayer, Lori; Anderson, Kristin E

    2016-03-21

    Pancreatic cancer is the fourth leading cause of cancer death in the U.S. Once diagnosed, prognosis is poor with a 5-year survival rate of less than 5%. Exposure to carcinogenic heterocyclic amines (HCAs) derived from cooked meat has been shown to be positively associated with pancreatic cancer risk. To evaluate the processes that determine the carcinogenic potential of HCAs for human pancreas, 14-carbon labeled 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx), a putative human carcinogenic HCA found in well-done cooked meat, was administered at a dietary relevant dose to human volunteers diagnosed with pancreatic cancer undergoing partial pancreatectomy and healthy control volunteers. After (14)C-MeIQx exposure, blood and urine were collected for pharmacokinetic and metabolite analysis. MeIQx-DNA adducts levels were quantified by accelerator mass spectrometry from pancreatic tissue excised during surgery from the cancer patient group. Pharmacokinetic analysis of plasma revealed a rapid distribution of MeIQx with a plasma elimination half-life of approximately 3.5 h in 50% of the cancer patients and all of the control volunteers. In 2 of the 4 cancer patients, very low levels of MeIQx were detected in plasma and urine suggesting low absorption from the gut into the plasma. Urinary metabolite analysis revealed five MeIQx metabolites with 2-amino-3-methylimidazo[4,5-f]quinoxaline-8-carboxylic acid being the most abundant accounting for 25%-50% of the recovered 14-carbon/mL urine. There was no discernible difference in metabolite levels between the cancer patient volunteers and the control group. MeIQx-DNA adduct analysis of pancreas and duodenum tissue revealed adduct levels indistinguishable from background levels. Although other meat-derived HCA mutagens have been shown to bind DNA in pancreatic tissue, indicating that exposure to HCAs from cooked meat cannot be discounted as a risk factor for pancreatic cancer, the results from this current study show that

  2. Synthetic routes to the food carcinogen 2 amino-3,8-dimethylimidazo[4,5-f]quinoxaline (8-MeIQx) and related compounds.

    Science.gov (United States)

    Grivas, S

    1995-01-01

    A review of five different routes to the synthesis of the grilled or fried food carcinogen 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (8-MeIQx) and of closely related compounds developed in different laboratories is presented. Interest in the synthesis of these amines began in the late 1970s when the research group led by Professor T. Sugimura (National Cancer Center, Tokyo) detected extremely high mutagenicity in the charred parts of fish and meat that could not be explained only by the presence of polyaromatic hydrocarbons. A number of new mutagenic heterocyclic amines have been detected, isolated and identified since then (de Meester, 1989; Overvik and Gustafsson, 1990; Felton and Knize, 1991; Jägerstad et al., 1991). It is still not entirely clear how these compounds are formed during cooking. For the "IQ-group" of the amines (2-amino-3-methylimidazo-quinoline and -quinoxaline congeners), a formation pathway from Maillard reaction products and creatinine was conceived by Professor K. Olsson (this laboratory) and presented at the 183rd meeting of the American Chemical Society, Las Vegas in 1982 (Jägerstad et al., 1983). However, the amounts of the amines formed during cooking or in model reaction systems are very small. Therefore, efficient and unambiguous synthetic methods yielding the compounds in isomerically pure form are required for reference purposes in analytical work and structure-biological activity studies. For instance, compare the mutagenicity of 4,8- and 5,8-DiMeIQx, and PhIP and its 3-methyl isomer shown on the following page. The pure compounds are also required in large quantities for long-term animal feeding studies. The length of this article does not allow a presentation of the published synthetic methods for all the heterocyclic amines. Therefore, the syntheses of only one of the food mutagens, 8-MeIQx, and some related compounds are presented. This will hopefully demonstrate the sort of problems the organic chemist encounters and some

  3. New osmium cluster compounds containing the heterocyclic ligand 2,3-bis-(diphenylphosphino)quinoxaline (dppq): Ligand isomerization and crystal structures of dppq, the isomeric clusters Os3(CO)10(dppq), and HOs3(CO)9[ -2,3-PhP(h1-C6H4)(Ph2P)quinoxaline

    Energy Technology Data Exchange (ETDEWEB)

    Hunt, Sean W [University of North Texas; Yang, Li [University of North Texas; Wang, Xiaoping [ORNL; Richmond, Michael G. [University of North Texas

    2011-01-01

    Treatment of the labile cluster 1,2-Os{sub 3}(CO){sub 10}(MeCN){sub 2} (1) with the diphosphine ligand 2,3-bis(diphenylphosphino)quinoxaline (dppq) at room temperature affords 1,2-Os{sub 3}(CO){sub 10}(dppq) (2b) as the kinetic product of ligand substitution in 84% yield. 2b isomerizes to the thermodynamically more stable dppq-chelated cluster 1,1-Os{sub 3}(CO){sub 10}(dppq) (2c) as the sole observable product under CO at temperatures below 358 K. The kinetics for the conversion of 2b {yields} 2c have been investigated by NMR spectroscopy in CDCl{sub 3} over the temperature range 323-353 K, and the reaction was found to exhibit a rate law that is first order in 2b. The calculated activation parameters [{Delta}H{sup {ne}} = 25.4(4) kcal/mol; {Delta}S{sup {ne}} = -3(1) eu] support an intramolecular isomerization scenario, one that involves the migration of phosphine and CO groups about the cluster polyhedron. The disposition of the dppq ligand in the isomeric Os{sub 3}(CO){sub 10}(dppq) clusters has been established by X-ray crystallography and {sup 31}P NMR spectroscopy. Photolysis of 2c at 366 nm leads to CO loss and ortho metalation of one of the aryl groups on the Ph{sub 2}P moiety to furnish the hydride cluster HOs{sub 3}(CO){sub 9}[{mu}-PhP({eta}{sup 1}-C{sub 6}H{sub 4})(Ph{sub 2}P)quinoxaline] (3). The isomerization behavior exhibited by 2b follows that of related diphosphine-substituted Os{sub 3} clusters prepared by us.

  4. Novel cyclophilin D inhibitors derived from quinoxaline exhibit highly inhibitory activity against rat mitochondrial swelling and Ca2+ uptake/release

    Institute of Scientific and Technical Information of China (English)

    Hong-xia GUO; Feng WANG; Kun-qian YU; Jing CHEN; Dong-lu BAI; Kai-xian CHEN; Xu SHEN; Hua-liang JIANG

    2005-01-01

    Aim: To investigate methods for identifying specific cyclophilin D (CypD) inhibitors derived from quinoxaline, thus developing possible lead compounds to inhibit mitochondrial permeability transition (MPT) pore opening. Methods: Kinetic analysis of the CypD/inhibitor interaction was quantitatively performed by using surface plasmon resonance (SPR) and fluorescence titration (FT) techniques.IC50 values of these inhibitors were determined by PPIase inhibition activity assays.Results: All the equilibrium dissociation constants (KD) of the seven compounds binding to CypD were below 10 μmol/L. The IC50 values were all consistent with the SPR and FT results. Compounds GW2, 5, 6, and 7 had high inhibition activities against Ca2+-dependent rat liver mitochondrial swelling and Ca2+ uptake/release.Compound GW5 had binding selectivity for CypD over CypA. Conclusion: The agreement between the measured IC50 values and the results of SPR and FT suggests that these methods are appropriate and powerful methods for identifying CypD inhibitors. The compounds we screened using these methods (GW1-7) are reasonable CypD inhibitors. Its potent ability to inhibit mitochondrial swelling and the binding selectivity of GW5 indicates that GW5 could potentially be used for inhibiting MPT pore opening.

  5. Synthesis, Spectral, Electrochemical and Theoretical Investigation of indolo[2,3-b]quinoxaline dyes derived from Anthraquinone for n–type materials

    Indian Academy of Sciences (India)

    BHARAT K SHARMA; AZAM M SHAIKH; SAJEEV CHACKO; RAJESH M KAMBLE

    2017-04-01

    Aseries of five novel dyes based on indolo[2,3-b]quinoxaline skeleton, derived from anthraquinone, have been synthesized through cyclo-condensation reaction in good yield. The photophysical, electrochemical and thermal properties along with computed HOMO-LUMO energy levels were studied for the synthesizedcompounds. Their absorption and photoluminescence properties were investigated in various solvents and in neat solid film and found to possess characteristic electronic absorption and emission spectra which stronglydepend on the nature of solvents used. Compounds show intramolecular charge transfer transitions (ICT) in the range of 501–561 nm with high molar absorption coefficient (ε). These indoloquinoxaline derivatives emit in the range of 580–648 nm in solutions and 672–700 nm (red region) in neat solid films. Electrochemical data indicate that the dyes possess relatively low–lying LUMO levels in the range −3.29 to −3.43 eV. The thermal stability observed for these compounds suggests their use under ambient conditions. The in–built donor– acceptor architecture and HOMO–LUMO energies were further rationalized using DFT calculations. This study suggests that these compounds have potential to be used as n–type materials for optoelectronic devices.

  6. Excited state intramolecular proton transfer (ESIPT) in six-coordinated zinc(ii)-quinoxaline complexes with ligand hydrogen bonds: their fluorescent properties sensitive to axial positions.

    Science.gov (United States)

    Sakai, Ken-Ichi; Takahashi, Sami; Kobayashi, Ataru; Akutagawa, Tomoyuki; Nakamura, Takayoshi; Dosen, Masaaki; Kato, Masako; Nagashima, Umpei

    2010-02-28

    Zinc(ii)-quinoxaline complexes, [Zn(hqxc)(2)(py)(2)] and [Zn(hqxc)(2)(DMSO)(2)] (hqxc = 3-hydroxy-2-quinoxalinecarboxylate, py = pyridine, DMSO = dimethyl sulfoxide), were prepared and characterized by X-ray crystallography and fluorescence spectroscopy. In both complexes, the zinc ion is six-coordinated by two equatorial bidentate hqxc ligands with an intramolecular hydrogen bond and two axial monodentate ligands such as pyridine or DMSO. In spite of similar coordination geometries, there is a remarkable difference between their solid-state fluorescent properties. The pyridine complex is strongly fluorescent (fluorescence quantum yield Phi = 0.22), giving rise to a significantly Stokes-shifted spectrum. From its thin film photopumped by a nitrogen gas laser, amplified spontaneous emission was observed. These results suggest that the fluorescence occurs by way of excited-state intramolecular proton-transfer (ESIPT) in the hydrogen bond of hqxc. On the other hand, the DMSO complex shows fluorescent intensity (Phi = 0.08) lower than that of the pyridine complex, and shows normal emission in addition to ESIPT emission. From IR measurements for these complexes, it is concluded that axial ligands influence the hydrogen bond strength of the equatorial hqxc ligand via zinc and thus the ESIPT efficiency.

  7. Synthesis and anticancer activity evaluation of new 2-alkylcarbonyl and 2-benzoyl-3-trifluoromethyl-quinoxaline 1,4-di-N-oxide derivatives.

    Science.gov (United States)

    Zarranz, Belén; Jaso, Andrés; Aldana, Ignacio; Monge, Antonio

    2004-07-01

    As a continuation of our research in quinoxaline 1,4-di-N-oxide and with the aim of obtaining new anticancer agents, which can improve the current chemotherapeutic treatments, new series of 2-alkylcarbonyl and 2-benzoyl-3-trifluoromethylquinoxaline 1,4-di-N-oxide derivatives have been synthesized and evaluated for in vitro antitumor activity against a 3-cell line panel, consisting of MCF7 (breast), NCI-H460 (lung), and SF-268 (CNS). These active compounds were then evaluated in the full panel of 60 human tumor cell lines derived from nine cancer cell types. The results have shown that, in general, anticancer activity depends on the substituents in the carbonyl group, improving in the order: ethyl

  8. Restrain recombination by spraying pyrolysis TiO2 on NiO film for quinoxaline-based p-type dye-sensitized solar cells.

    Science.gov (United States)

    Yu, Ying; Li, Xing; Shen, Zhongjin; Zhang, Xiaoyu; Liu, Peng; Gao, Yuting; Jiang, Tao; Hua, Jianli

    2017-03-15

    In this work, we reported two new quinoxaline-based sensitizers (BQI and BQII) for p-type dye-sensitized solar cells (p-DSSCs) featuring carboxylic acid and pyridine as anchoring groups, respectively, in combination with triphenylamine donor. The optical, electrochemical and photovoltaic properties of BQI and BQII were investigated. Results showed that BQI-based p-DSSC with carboxylic acid anchoring group obtained higher photoelectric conversion efficiency (PCE) of 0.140%. To further optimize the device performance, we added a layer of TiO2 on the surface of NiO film as a barrier layer, which contributed to the improvement of the photocurrent density from 3.00 to 3.84mAcm(-2). The p-DSSCs based on BQI reached the PCE of 0.20% at an irradiance of 100mWcm(-2) simulated AM1.5 sunlight. Electrochemical impedance spectroscopy (EIS) analysis indicated that the hole recombination resistance of p-DSSCs with TiO2 barrier layer was larger than that of the naked NiO film. Meanwhile, the surface profile of TiO2 on NiO film was verified by scanning electron microscope (SEM), X-ray diffraction (XRD) and the time of flight-secondary ion mass spectrometry (TOF-SIMS).

  9. Quinoxaline based bio-active mixed ligand transition metal complexes: Synthesis, characterization, electrochemical, antimicrobial, DNA binding, cleavage, antioxidant and molecular docking studies.

    Science.gov (United States)

    Dhanaraj, C Justin; Johnson, Jijo

    2015-10-01

    Co(II), Ni(II), Cu(II) and Zn(II) mixed ligand complexes have been synthesized from N(2), N(3)-bis(4-nitrophenyl)quinoxaline-2,3-diamine and 1,10-phenanthroline. The compounds were characterized by elemental analyses, molar conductance, magnetic susceptibility, IR, UV-Vis., (1)H NMR, mass and ESR spectra. Octahedral geometry has been assigned for Co(II), Ni(II) and Zn(II) complexes and distorted octahedral geometry for Cu(II) complex. Electrochemical behavior of the synthesized complexes was studied using cyclic voltammetry. Grain size and surface morphologies of the complexes were determined by powder XRD and SEM analyses. The mixed ligand metal complexes were screened for antimicrobial activity against bacterial species Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus; fungal species Aspergillus niger, and Candida albicans by disc diffusion method. The DNA binding and DNA cleavage activities of the compounds were determined using electronic absorption titration and agarose gel electrophoresis respectively. The superoxide radical scavenging and free radical scavenging activities of the Cu(II) complex was also evaluated. Molecular docking studies of the synthesized mixed ligand metal complexes were carried out against B-DNA dodecamer and the protein Plasmodium falciparum dihydrofolate reductase (pf DHFR).

  10. Detecting quinoxaline-2-carboxylic acid in animal tissues by using sensitive rapid enzyme-linked immunosorbent assay and time-resolved fluoroimmunoassay.

    Science.gov (United States)

    Le, Tao; Yu, Huan; Niu, Xiaodong

    2015-05-15

    An indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) and time-resolved fluoroimmunoassay (TR-FIA) based on an anti-N-butylquinoxaline-2-carboxamide (BQCA) monoclonal antibody were standardized and validated for quinoxaline-2-carboxylic acid (QCA) screening in animal tissues and its performance were compared to HPLC. The sensitivities obtained for edible tissue extracts were 1.62 and 1.12 ng ml(-1) for ic-ELISA and TR-FIA detection, respectively. Two samples were spiked with QCA and analyzed by both methods. The recovery values ranged from 92.6% to 112.2% and the coefficients of variation were less than 15% for QCA spiking into swine tissue samples at concentrations of 2.5-50.0 μg kg(-1). Excellent correlations (r(2)=0.987-0.996) of the ic-ELISA/HPLC and TR-FIA/HPLC data were observed for processed samples. The results demonstrated that the ic-ELISA and TR-FIA methods were rapid and accurate for the residue detection of QCA in animal tissues.

  11. Monoclonal antibody production and indirect competitive enzyme-linked immunosorbent assay development of 3-methyl-quinoxaline-2-carboxylic acid based on novel haptens.

    Science.gov (United States)

    Li, Guopeng; Zhao, Liang; Zhou, Feng; Li, Jiaying; Xing, Yuan; Wang, Tiangang; Zhou, Xilong; Ji, Baoping; Ren, Wanpeng

    2016-10-15

    Two novel immunizing haptens of 3-methyl-quinoxaline-2-carboxylic acid (MQCA) were synthesized and conjugated with cationized bovine serum albumin. Female BALB/c mice were immunized with above conjugates, splenocytes were fused with Sp2/0 cells to produce monoclonal antibody. Compared with previous studies, antibodies raised in this work showed higher sensitivity. Meantime, a novel heterologous coating hapten was also prepared. The indirect competitive enzyme-linked immunosorbent assay (icELISA) based on the optimum condition showed an IC50 of 3.1μg/kg (ppb), and the linear range of 0.46-10.5ppb for MQCA. The limit of detect (LOD) of MQCA in swine muscle, swine liver and chicken was 0.32, 0.54, and 0.28ppb, respectively. The LOD of this assay can satisfy the minimum required performance levels (4ppb) for MQCA. These results indicated that the proposed ELISA, with high sensitivity and specificity, as well as good reproducibility and accuracy, is suitable for determination of MQCA residues in food samples.

  12. Crosslinked sulfonated poly(arylene ether ketone) membranes bearing quinoxaline and acid-base complex cross-linkages for fuel cell applications

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xinbing; Chen, Pei; An, Zhongwei [Key Laboratory of Applied Surface and Colloid Chemistry, Ministry of Education, School of Chemistry and Materials Science, Shaanxi Normal University, Xi' an 710062 (China); Chen, Kangcheng; Okamoto, Kenichi [Graduate School of Science and Engineering, Yamaguchi University, Tokiwadai 2-16-1, Ube, Yamaguchi 755-8611 (Japan)

    2011-02-15

    A series of crosslinkable sulfonated poly(arylene ether ketone)s (SPAEKs) were synthesized by copolymerization of 4,4'-biphenol with 2,6-difluorobenzil and 5,5'-carbonyl-bis(2-fluorobenzene-sulfonate). A facile crosslinking method was successfully developed, based on the cyclocondensation reaction of benzil moieties in polymer chain with 3,3'-diaminobenzidine to form quinoxaline groups acting as covalent and acid-base ionic crosslinking. The uncrosslinked and crosslinked SPAEK membranes showed high mechanical properties and the isotropic membrane swelling, while the later became insoluble in tested polar aprotic solvents. The crosslinking significantly improved the membrane performance, i.e., the crosslinked membranes had the lower membrane dimensional change, lower methanol permeability and higher oxidative stability than the corresponding precursor membranes, with keeping the reasonably high proton conductivity. The crosslinked membrane (C-B4) with an ion exchange capacity of 2.02 mequiv. g{sup -1} showed a reasonably high proton conductivity of 111 mS cm{sup -1} with a low water uptake of 42 wt% at 80 C. C-B4 exhibited a low methanol permeability of 0.55 x 10{sup -6} cm{sup 2} s{sup -1} for 32 wt% methanol solution at 25 C. The crosslinked SPAEK membranes have potential for PEFC and DMFC applications. (author)

  13. Organic Dyes Incorporating the Dithieno[3,2-f:2',3'-h]quinoxaline Moiety for Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Ni, Jen-Shyang; Kao, Wei-Siang; Chou, Hao-Ju; Lin, Jiann T

    2015-09-01

    New donor-acceptor'-acceptor-type sensitizers (QBT dyes), comprising arylamine as the electron donor, dithieno[3,2-f:2',3'-h]quinoxaline as the internal acceptor, and 2-cyanoacrylic acid as both the acceptor and anchor, have been synthesized. The QBT dyes have broad absorption spectra covering the range of λ=368-487 nm with a highest molar extinction coefficient of up to approximately 40 000 M(-1)  cm(-1) . The light-to-electricity conversion efficiencies of the dye-sensitized solar cells (DSSCs) fabricated from the dyes range from 6.11 to 7.59 % under simulated AM 1.5 G illumination. Upon addition of a threefold concentration of chenodeoxycholic acid as the co-adsorbent, the best performance cell has a power-conversion efficiency of 8.41 %, which is higher than that of the N719-based standard DSSC (8.27 %).

  14. Study on solid phase extraction and spectrophotometric determination of vanadium with 2,3-dichloro-6-(2,7-dihydroxy-1-naphthylazo)quinoxaline

    Science.gov (United States)

    Amin, Alaa S.; Saber, Amr L.; Mohammed, T. Y.

    2009-07-01

    A sensitive, selective and rapid method has been developed for the determination micrograms per liter level of vanadium ion based on the rapid reaction of vanadium(V) with 2,3-dichloro-6-(2,7-dihydroxy-1-naphthylazo)quinoxaline (DCDHNAQ) and the solid phase extraction of the colored complex with C18 cartridge. The DCDHNAQ reacts with V(V) in the presence of citric acid-sodium hydroxide buffer solution (pH 3.3) and benzyldimethyl tetradecylammonium chloride (zephiramine) medium to form a violet complex of a molar ratio 1:2 [V(V) to DCDHNAQ]. This complex was enriched by solid phase extraction with C18 cartridge and the enrichment factor of 100 was obtained by elution of the complex from the cartridge with acetonitrile. The molar absorptivity and Sandell sensitivity of the complex are 2.45 × 10 5 L mol -1 cm -1 and 0.0208 ng cm -2 at 573 nm in the measured solution. Beer's law is obeyed in the range of 0.01-0.45 μg mL -1, whereas Ringbom optimum concentration ranges found to be 0.025-0.425 μg mL -1. The detection and quantification limits are 3.2 and 9.9 μg L -1, respectively in the original samples. This method was applied to the determination of vanadium(V) in steel, soil, water and biological samples with good results.

  15. Quinoxaline-2-carboxamide as a carrier ligand in two new platinum(II) compounds: Synthesis, crystal structure, cytotoxic activity and DNA interaction.

    Science.gov (United States)

    Marqués-Gallego, Patricia; Gamiz-Gonzalez, M Amparo; Fortea-Pérez, Francisco R; Lutz, Martin; Spek, Anthony L; Pevec, Andrej; Kozlevčar, Bojan; Reedijk, Jan

    2010-06-01

    The search for platinum compounds structurally different from cisplatin has led to two new platinum(II) compounds containing quinoxaline-2-carboxamide as a carrier ligand, i.e. cis-[Pt(qnxca)(MeCN)Cl2] (1) and the [Pt(qnxca-H)(dmso)Cl] (2). Both compounds have been synthesized and characterized using different spectroscopic methods. In addition, single-crystal structures have been determined by X-Ray diffraction for both compounds. In each case a square planar Pt(II) is present; in (1) the qnxca is monodentate and neutral, whereas in (2) the ligand has lost a hydrogen, to form the anionic chelating ligand abbreviated as qnxca-H. The biological activity of both compounds has been investigated in a panel of seven human tumour cells, displaying poor cytotoxic activity, compared to cisplatin. The interaction of the new compounds with 1 or 2 equiv. of 9-ethylguanine has been studied using (1)H NMR, (195)Pt NMR and ESI-MS spectroscopy, finding poor reactivity of 1 towards the model base, forming only the monosubstituted adduct. Surprisingly, compound 2, which is more sterically crowded, interacts more efficiently with the 9-EtG, forming a bifunctional adduct with two 9-EtG with substitution of the dmso and the chloride ligand. Unwinding studies of pUC19 plasmid DNA by compound 1 show similar unwinding properties to cisplatin.

  16. Saturable absorption and two-photon absorption of 1,2,5-thiadiazolo[3,4-g]quinoxaline based derivatives with near-infrared fluorescence

    Science.gov (United States)

    Du, Yabing; Lin, Xiaodong; Jia, Tingjian; Dong, Jun

    2015-03-01

    Organic molecules with near-infrared (NIR) fluorescence are extremely interesting for the applications in nonlinear optical devices and bioimaging. However, such kind of materials have been relatively rarely studied. In this work, the nonlinear optical properties of 1,2,5-thiadiazolo[3,4-g]quinoxaline based derivatives with NIR fluorescence emission have been investigated for the first time. Under the excitation of femtosecond pulses at 532 nm, the chromophore with dithienyl as donor (TQ2) presents saturable absorption (SA) behavior, while no SA has been observed in the derivative with biphenyl (TQ1) as donor. Moreover, TQ2 exhibits much larger two-photon absorption (TPA) cross-sections with strong NIR fluorescence in the second biological window. The larger nonlinear optical properties of TQ2 is due to the introduction of stronger electron-donating group (dithienyl) and the resultant enhanced intramolecular charge transfer properties. At the end, TPA based optical limiting behaviors of the molecules are demonstrated in THF solutions, thanks to their large solubility and strong TPA.

  17. Speciation of selenium in environmental samples by solid-phase spectrophotometry using 2,3-dichloro-6-(2,7-dihydroxy-naphthylazo)quinoxaline.

    Science.gov (United States)

    Amin, Alaa S

    2014-01-01

    Solid-phase spectrophotometry was applied to determination of trace amounts of selenium (Se) in water, soil, plant materials, human hair, and a cosmetic preparation (lipstick). Se(IV) was sorbed in a dextran type lipophilic gel as a complex with 2,3-dichloro-6-(2,7-dihydroxy-naphthylazo)quinoxaline (DCDHNAQ), whereas Se(VI) was determined after boiling in HCI for 10 min to convert Se(VI) to Se(IV). Resin phase absorbances at 588 and 800 nm were measured directly, which allowed the determination of Se in the range of 0.2-3.3 microg/L with an RSD of 1.22%. The influences of analytical parameters including pH of the aqueous solution, amounts of DCDHNAQ, and sample volume were investigated. The molar absorptivities were found to be 1.09 x 10(6), 4.60 x 10(6), and 1.23 x 10(7) L/mol cm for 100, 500, and 1000 mL, respectively. The LOD and LOQ of the 500 mL sample method were 110 and 360 ng/L, respectively, when using 50 mg dextran type lipophilic gel. For a 1000 mL sample, the LOD and LOQ were 60 and 200 ng/L, respectively, using 50 mg of the exchanger. Increasing the sample volume enhanced the sensitivity. No considerable interferences were observed from other investigated anions and cations on the Se determination.

  18. Side-chain engineering of benzodithiophene-fluorinated quinoxaline low-band-gap co-polymers for high-performance polymer solar cells.

    Science.gov (United States)

    Xu, Xiaopeng; Wu, Yulei; Fang, Junfeng; Li, Zuojia; Wang, Zhenguo; Li, Ying; Peng, Qiang

    2014-10-06

    A new series of donor-acceptor co-polymers based on benzodithiophene and quinoxaline with various side chains have been developed for polymer solar cells. The effect of the degree of branching and dimensionality of the side chains were systematically investigated on the thermal stability, optical absorption, energy levels, molecular packing, and photovoltaic performance of the resulting co-polymers. The results indicated that the linear and 2D conjugated side chains improved the thermal stabilities and optical absorptions. The introduction of alkylthienyl side chains could efficiently lower the energy levels compared with the alkoxyl-substituted analogues, and the branched alkoxyl side chains could deepen the HOMO levels relative to the linear alkoxyl chains. The branched alkoxyl groups induced better lamellar-like ordering, but poorer face-to-face packing behavior. The 2D conjugated side chains had a negative influence on the crystalline properties of the co-polymers. The performance of the devices indicated that the branched alkoxyl side chains improved the Voc, but decreased the Jsc and fill factor (FF). However, the 2D conjugated side chains would increase the Voc, Jsc, and FF simultaneously. For the first time, our work provides insight into molecular design strategies through side-chain engineering to achieve efficient polymer solar cells by considering both the degree of branching and dimensionality. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Synthesis and Molecular Structure of Acetic Acid-3,5-diacetoxy-2-acetoxymethyl-6-(4-quinoxalin-2-yl-phenoxy)-tetrahydro-pyran-4-yl-ester

    Institute of Scientific and Technical Information of China (English)

    WEI Hui-Qin; ZENG Run-Sheng; WU Gui-Ping; WANG Bao-An; ZOU Jian-Ping

    2006-01-01

    The title compound, acetic acid-3,5-diacetoxy-2-acetoxymethyl-6-(4-quinoxalin-2-yl-phenoxy)-tetrahydro-pyran-4-yl-ester 8 (C28H28N2O10, Mr = 552.54), has been synthesized and its crystal structure was determined by X-ray diffraction analysis. It crystallizes in monoclinic,space group P21, a = 10.060(8), b = 5.648(4), c=24.11(2)(A), β=91.078(10)O, Z = 2, V =1369.9(19)(A)3, Dc = 1.339 g/cm3,μ(MoKα) = 1.03 cm-1, F(000) = 580.00, T=193.1 K,θmax =25.03, (△/σ)max = 0.0000, Flack = -0.0(24), the final R = 0.0680 and wR= 0.140 (w =1/[0.0016Fo2+ 1.0000σ(Fo2)]/(4Fo2)) for 3126 observed reflections (I>2σ(I)). The pyranoid ring adopts chair conformation in the sugar moiety, and all of the acetyl groups are in the e bond of the pyranoid ring, so the sugar moiety is very stable.

  20. Design, synthesis, and biological evaluation of 1,2,3-trisubstituted-1,4-dihydrobenzo[g]quinoxaline-5,10-diones and related compounds as antifungal and antibacterial agents.

    Science.gov (United States)

    Tandon, Vishnu K; Yadav, Dharmendra B; Maurya, Hardesh K; Chaturvedi, Ashok K; Shukla, Praveen K

    2006-09-01

    A series of (S)-N-(3-chloro-1,4-naphthoquinon-2-yl)-alpha-amino acid ethyl esters 3 and 1,2,3-trisubstituted-1,4-dihydrobenzo[g]quinoxaline-5,10-diones 6-23 were synthesized and evaluated for antifungal and antibacterial activities. The structure-activity relationship of these compounds was studied and the results show that the compounds 3a and 3b exhibited in vitro antifungal activity against Candida albicans, Cryptococcus neoformans, and Sporothrix schenckii whereas compounds 12 and 22 showed in vitro antibacterial activity against Klebsiella pneumoniae and Escherichia coli.

  1. Antidepressant & anxiolytic activities of N-(pyridin-3-yl) quinoxalin-2-carboxamide: A novel serotonin type 3 receptor antagonist in behavioural animal models

    Science.gov (United States)

    Pandey, Dilip Kumar; Devadoss, Thangraj; Modak, Neha; Mahesh, Radhakrishnan

    2016-01-01

    Background & objectives: Alteration in the serotonin leads to the psychological illness, such as depression, anxiety, schizophrenia, eating disorders, obsessive-compulsive disorder, panic disorders and migraines. The objective of the current study was to investigate the antidepressant and anxiolytic activities of N-(pyridin-3-yl) quinoxalin-2-carboxamide (QCF-21), a novel 5-HT3 receptor antagonist in preclinical models of depression and anxiety. Methods: Antidepressant activity was evaluated in preliminary tests such as forced swim and tail suspension tests (FST & TST). Anti-anxiety effect of QCF-21 was investigated by employing elevated plus maze (EPM), light/dark and hole board tests. Olfactory bulbectomy (OBX) in rats was used as chronic model of depression. Mechanistic test of QCF-21 was evaluated by reserpine-induced hypothermia and 5-hydroxytryptophan (5-HTP)-induced head-twitch response. Results: The dose-response study revealed an initial antidepressant-like effect of QCF-21(0.25-1 mg/kg, i.p.) in the FST and TST and anxiolytic-like effect in EPM, light and dark and hole board tests. QCF-21 potentiated the 5-HTP-induced head-twitches response in mice and reversed reserpine-induced hypothermia in rats. QCF-21 significantly reversed the behavioural anomalies post-OBX in rats. Interpretation & conclusions: The present findings indicate the potential antidepressant-like and anxiolytic-like effects of QCF-21 at low doses in rodent behavioural models of depression and anxiety. Further studies need to be done to understand the underlying mechanism. PMID:28256473

  2. [Determination of 3-methyl-quinoxaline-2-carboxylic acid in animal and aquatic products by ultra performance liquid chromatography-tandem mass spectrometry].

    Science.gov (United States)

    Lü, Hailuan; Wu, Congming; Cheng, Linli; Zhang, Suxia; Shen, Jianzhong

    2012-01-01

    An ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/ MS) method was established for the determination of 3-methyl-quinoxaline-2-carboxylic acid (MQCA) in animal tissues and aquatic products. The analyte was extracted with 0.2 mol/L hydrochloric acid. The extract was cleaned up on a Bond Elut C18 cartridge. Then the eluate was collected and evaporated to dryness under nitrogen gas at 35 degrees C. The residue was redissolved in acetonitrile containing 0.1% (v/v) formic acid. The identification was performed by multiple reaction monitoring in positive electrospray ionization. The quantification was done by external standard method. The calibration curves showed good linearity within the range of 2-500 microg/L with the correlation coefficients (r2) greater than 0.990. The limits of detection (LODs) of MQCA in pork, swine liver, pig kidney, fish, prawn, and crab were 0.90, 1.51, 0.94, 1.04, 1.62 and 1.80 microg/kg, respectively; and the limits of quantification (LOQs) were 3.00, 5.02, 3.13, 3.46, 5.40 and 6.00 microg/kg, correspondingly. The recoveries of MQCA in animal tissues and aquatic products were 73.6%-89.0% at the spiked levels of 3-100 microg/kg. The intra-day relative standard deviations (RSDs, n = 5) were less than 15%, and inter-day RSDs (n = 3) were less than 20%. The results demonstrated that the sensitivity, accuracy, and precision were fit for the requirements of veterinary drug residue analysis.

  3. The critical role of oxidative stress in the toxicity and metabolism of quinoxaline 1,4-di-N-oxides in vitro and in vivo.

    Science.gov (United States)

    Wang, Xu; Martínez, María-Aránzazu; Cheng, Guyue; Liu, Zhaoying; Huang, Lingli; Dai, Menghong; Chen, Dongmei; Martínez-Larrañaga, María-Rosa; Anadón, Arturo; Yuan, Zonghui

    2016-05-01

    Quinoxaline 1,4-dioxide derivatives (QdNOs) have been widely used as growth promoters and antibacterial agents. Carbadox (CBX), olaquindox (OLA), quinocetone (QCT), cyadox (CYA) and mequindox (MEQ) are the classical members of QdNOs. Some members of QdNOs are known to cause a variety of toxic effects. To date, however, almost no review has addressed the toxicity and metabolism of QdNOs in relation to oxidative stress. This review focused on the research progress associated with oxidative stress as a plausible mechanism for QdNO-induced toxicity and metabolism. The present review documented that the studies were performed over the past 10 years to interpret the generation of reactive oxygen species (ROS) and oxidative stress as the results of QdNO treatment and have correlated them with various types of QdNO toxicity, suggesting that oxidative stress plays critical roles in their toxicities. The major metabolic pathways of QdNOs are N→O group reduction and hydroxylation. Xanthine oxidoreductase (XOR), aldehyde oxidase (SsAOX1), carbonyl reductase (CBR1) and cytochrome P450 (CYP) enzymes were involved in the QdNOs metabolism. Further understanding the role of oxidative stress in QdNOs-induced toxicity will throw new light onto the use of antioxidants and scavengers of ROS as well as onto the blind spots of metabolism and the metabolizing enzymes of QdNOs. The present review might contribute to revealing the QdNOs toxicity, protecting against oxidative damage and helping to improve the rational use of concurrent drugs, while developing novel QdNO compounds with more efficient potentials and less toxic effects.

  4. Antigens Synthesis and Antibodies Preparation of Quinoxaline-2-Carboxylic Acid%喹喔啉-2-羧酸人工抗原合成与抗体制备

    Institute of Scientific and Technical Information of China (English)

    张泽英; 袁宗辉

    2013-01-01

    试验以喹喔啉-2-羧酸(quinoxaline-2-carboxylic acid,QCA)及其与γ-氨基丁酸(ABA)的衍生物(QCA-ABA)为半抗原,将其与牛血清白蛋白(BSA)和鸡卵清蛋白(OVA)偶联,合成人工抗原.以QCA-BSA和QCA-ABA-BSA为免疫原,免疫大白兔制备多克隆抗体,利用紫外分光光度计分析结合物的结合情况,间接ELISA和间接竞争ELISA分析抗体特性.结果表明,以QCA-BSA、QCA-ABA-BSA为免疫原制备的抗体平均效价分别为12.8×10 4、6.4×104.2种抗体对QCA灵敏度低,IC50均大于10000 ng/mL,而对QCA-ABA的灵敏度高,IC50分别为14.2和7.75 ng/mL,特异性好,仅与3-甲基-喹喔啉-2-羧酸(12%)、卡巴氧(0.038%)和喹赛多(0.028%)有较低程度的交叉反应,与衍生试剂和结构类似物均无交叉反应(<0.01%).该抗体为建立动物可食性组织中QCA残留物的快速检测方法奠定了基础.

  5. Hantzsch reaction and quinoxaline synthesis using 1-methyl-3-(2-(sulfooxyethyl-1H-imidazol-3-ium chloride as a new, efficient and BrØnsted acidic ionic liquid catalyst

    Directory of Open Access Journals (Sweden)

    Sami Sajjadifar

    2013-10-01

    Full Text Available In this work, the efficiency, generality and applicability of new BrØnsted acidic ionic liquid (BAIL 1-methyl-3-(2-(sulfooxyethyl-1H-imidazol-3-ium chloride {[Msei]Cl} as heterogeneous and green catalyst for organic transformations are studied. Herein, the following one-pot multi-component reactions in the presence of [Msei]Cl are investigated: (i the synthesis of quinoxaline derivatives from the reaction of phenylenediamines and 1,2-diketones in EtOH under mild conditions (room temperature, (ii the preparation of 1,4-dihydropyridines from one-pot multi component condensation of 1,3-dicarbonyl compounds, NH4OAcand aldehydes under solvent-free conditions at moderate temperature (90 °C. High yields, relatively short reaction times, efficiency, generality, clean process, simple methodology, low cost, easy work-up, ease of preparation and regeneration of the catalyst and green conditions (in the synthesis of the quinoxaline derivatives are advantages of the application of [Mesi]Cl as catalyst in the above organic reactions.

  6. Synthesis and biological evaluation of 4-alkoxy-6,9-dichloro[1,2,4]triazolo[4,3-a]quinoxalines as inhibitors of TNF-α and IL-6.

    Science.gov (United States)

    Guirado, Antonio; López Sánchez, José I; Ruiz-Alcaraz, Antonio J; Bautista, Delia; Gálvez, Jesús

    2012-08-01

    An efficient synthetic method for previously unattainable 4-alkoxy-6,9-dichloro[1,2,4]triazolo[4,3-a]quinoxalines has been established. Reactions between 5,8-dichloro-2,3-dicyanoquinoxaline and alcohols in the presence of triethylamine led to 3-alkoxy-5,8-dichloro-2-cyanoquinoxalines in high to quantitative yields. These compounds were treated with hydrazine giving 3-alkoxy-5,8-dichloro-2-hydrazinoquinoxalines in near quantitative yields, that reacted with triethyl orthoformate to provide the title compounds in high yields. The molecular structure of a member of this family of compounds: 6,9-dichloro-4-ethoxy[1,2,4]triazolo[4,3-a]quinoxaline, was determined by X-ray crystallography. The series of compounds synthesized were evaluated for their potential anti-inflammatory activity as inhibitors of the pro-inflammatory cytokines TNF-α and IL-6. Compounds 8e, 8a, 8b and 8g presented simultaneously good levels of inhibition of both cytokines being compound 8e the most concomitantly potent one. Compounds 8d, 8f and 8h specifically inhibited IL-6 with no significant inhibition of TNF-α. Compound 8c was not significantly active upon TNF-α, and showed no activity upon IL-6.

  7. Effectiveness and security of the new type of quinoxalines in aquaculture%新型喹噁啉类药物在水产养殖中的有效性及安全性研究进展

    Institute of Scientific and Technical Information of China (English)

    张秀珍; 王忠全; 周全利; 任利华; 刘云; 徐英江; 宫向红; 宋向军; 刘慧慧; 田秀慧; 刘义豪; 秦华伟

    2013-01-01

    Quinoxalines are special man-made chemical drugs which are widely used as the antibacterial growth promoters in poultry and aquatic breeding. The early products such as olaquindox and carbadox were partly forbidden or re-stricted because of strong toxic and side effects. In recent years, the new developed types of quinoxalines were widely used in poultry and aquatic breeding because they could reduce the toxic effect, retain the antibacterial and promote the growth activities. This article mainly summarizes the effectiveness and security, metabolism and pharmacokinetics, residual elimi-nation, metabolic pathway and markers of the new types of quinoxalines in various kinds of aquatic breeding in order to ra-tionalize the medication use and to ensure the safety of aquatic products.%  噁喹啉类药物是一类人工合成的具有抗菌、促进生长作用的动物专用药,曾被广泛应用于畜禽和水产养殖业。本类早期品种喹乙醇与卡巴氧被证明有较强的毒副作用,已被不同程度地限制或禁止使用。近年来研制成功的新型喹啉类药物降低了毒性,保留了抗菌及促生长活性,已在畜禽养殖中广泛使用。本文对新型喹噁啉类药物的种类、有效性及安全性、代谢动力学及残留消除规律、代谢途径及标识残留物进行了综述,为该类药物在水产养殖生产中的安全合理应用提供参考。噁

  8. Double Sonogashira reactions on dihalogenated aminopyridines for the assembly of an array of 7-azaindoles bearing triazole and quinoxaline substituents at C-5: Inhibitory bioactivity against Giardia duodenalis trophozoites.

    Science.gov (United States)

    Leboho, Tlabo C; Giri, Somnath; Popova, Inessa; Cock, Ian; Michael, Joseph P; de Koning, Charles B

    2015-08-01

    The synthesis of 2,3,5-trisubstituted 7-azaindoles as well as 2,5-disubstituted 7-azaindoles from 3,5-dihalogenated 2-aminopyridines is outlined. Using a double Sonogashira coupling reaction on 2-amino-3,5-diiodopyridine followed by the Cacchi reaction the synthesis of 2,3,5-trisubstituted 7-azaindoles was accomplished. In addition, using two sequential Sonogashira coupling reactions on 2-amino-5-bromo-3-iodopyridine and a potassium t-butoxide mediated ring closure reaction resulted in the assembly of 2,5-disubstituted 7-azaindoles. The 5-alkynyl substituent of the azaindole was easily converted into both quinoxaline and triazole substituents, the latter utilizing an alkyne-azide cycloaddition reaction. Some of these azaindole derivatives showed very promising biological activity against the gastrointestinal protozoal parasite Giardia duodenalis.

  9. Study on synthesis and antitumour activities of 3-subsitituted quinoxaline derivatives%3-取代喹喔啉衍生物的合成及其抗肿瘤活性的研究

    Institute of Scientific and Technical Information of China (English)

    张春玲; 许秀枝; 王艰; 杨州; 李柱来

    2013-01-01

    Objective To synthetize 3-substituted quinoxaline derivatives and study their anti-tumor activities on cell K562 and PANC-1. Methods The compounds were synthesized with the reaction of 1,2-diaminobenzene and 1 ,2-dione compounds diethyl oxalate by cyclization, chloro and nucleophilic substitution. MTT method was used to evaluate antitumor activities of their compounds. Results Seven new compounds were synthesized and characterized by IR and 1H-NMR. The inhibition ratio of Compound 6 on K562 cell was the best with IC50 0.836 μmol · L-1. Conclusion Seven new 3-substituted quinoxaline derivatives were synthesized and had good antitumor activity in vitro.%目的 合成3-取代喹喔啉衍生物,并研究其对细胞株K562和PANC-1的抗肿瘤活性.方法 以邻苯二胺与1,2-二酮类化合物草酸二乙酯通过环合、氯代、亲核取代3步反应合成目标化合物;用MTT法测定目标化合物的抗肿瘤活性.结果 合成了7个新的喹喔啉衍生物,经IR、1 H-NMR表征确认结构,其中化合物6对K562细胞的抑制效果最佳,IC50值为0.836 μmol·L-1.结论 合成得到的7个新的3-取代喹喔啉衍生物,均有较好的体外抗肿瘤活性.

  10. Targeting π-conjugated multiple donor-acceptor motifs exemplified by tetrathiafulvalene-linked quinoxalines and tetrabenz[bc,ef,hi,uv]ovalenes: synthesis, spectroscopic, electrochemical, and theoretical characterization.

    Science.gov (United States)

    Jia, Hong-Peng; Ding, Jie; Ran, Ying-Fen; Liu, Shi-Xia; Blum, Carmen; Petkova, Irina; Hauser, Andreas; Decurtins, Silvio

    2011-12-02

    An efficient synthetic approach to a symmetrically functionalized tetrathiafulvalene (TTF) derivative with two diamine moieties, 2-[5,6-diamino-4,7-bis(4-pentylphenoxy)-1,3-benzodithiol-2-ylidene]-4,7-bis(4-pentylphenoxy)-1,3-benzodithiole-5,6-diamine (2), is reported. The subsequent Schiff-base reactions of 2 afford large π-conjugated multiple donor-acceptor (D-A) arrays, for example, the triad 2-[4,9-bis(4-pentylphenoxy)-1,3-dithiolo[4,5-g]quinoxalin-2-ylidene]-4,9-bis(4-pentylphenoxy)-1,3-dithiolo[4,5-g]quinoxaline (8) and the corresponding tetrabenz[bc,ef,hi,uv]ovalene-fused pentad 1, in good yields and high purity. The novel redox-active nanographene 1 is so far the largest known TTF-functionalized polycyclic aromatic hydrocarbon (PAH) with a well-resolved (1)H NMR spectrum. The electrochemically highly amphoteric pentad 1 and triad 8 exhibit various electronically excited charge-transfer states in different oxidation states, thus leading to intense optical intramolecular charge-transfer (ICT) absorbances over a wide spectral range. The chemical and electrochemical oxidations of 1 result in an unprecedented TTF(⋅+) radical cation dimerization, thereby leading to the formation of [1(⋅+)](2) at room temperature in solution due to the stabilizing effect, which arises from strong π-π interactions. Moreover, ICT fluorescence is observed with large solvent-dependent Stokes shifts and quantum efficiencies of 0.05 for 1 and 0.035 for 8 in dichloromethane. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Crystal structure of 1′,1′′-dimethyl-4′-(4-cholorophenyldispiro[11H-indeno[1,2-b]quinoxaline-11,2′-pyrrolidine-3′,3′′-piperidin]-4′′-one

    Directory of Open Access Journals (Sweden)

    R.A. Nagalakshmi

    2015-02-01

    Full Text Available In the title compound, C30H27ClN4O, the central pyrrolidine ring adopts an envelope conformation with the methylene C atom being the flap. The quinoxaline and indane rings are each essentially planar, with r.m.s. deviations of 0.027 (1 and 0.0417 (1 Å, respectively. The pyrrolidine ring forms dihedral angles of 88.25 (1 and 83.76 (1° with the quinoxaline and indane rings, respectively. A weak intramolecular C—H...N interaction is observed. In the crystal, C—H...π interactions lead to supramolecular chains along [101] that assemble in the ac plane. Connections along the b axis are of the type Cl...Cl [3.6538 (16 Å].

  12. Antidepressant-like activity of (4-phenylpiperazin-1-yl) (quinoxalin-2-yl) methanone (4a), a novel 5-HT(3) receptor antagonist: an investigation in behaviour-based rodent models of depression.

    Science.gov (United States)

    Mahesh, Radhakrishnan; Kumar, Baldev; Jindal, Ankur; Bhatt, Shvetank; Devadoss, Thangaraj; Pandey, Dilip Kumar

    2012-01-01

    The present study was designed to investigate the antidepressant potential of (4-phenylpiperazin-1-yl) (quinoxalin-3-yl) methanone (4a), a novel 5-HT(3) receptor antagonist, with an optimal log P (2.84) and pA(2) value (7.3) greater than ondansetron (6.9) using rodent behavioural models of depression. Swiss albino mice were used in actophotometer test, forced swim test (FST) and 5-hydroxytryptophan (5-HTP) induced head twitch response. Reserpine induced hypothermia (RIH) and olfactory bulbectomy were performed in male Wistar rats. Statistical analysis was carried out by using one-way analysis of variance followed by Tukey's test. Acute treatment of 4a (1-4 mg/kg, i.p.) in mice produced antidepressant-like effects in FST without affecting the baseline locomotion in actophotometer test. Further, 4a (2-4 mg/kg, i.p.) potentiated the 5-HTP induced head twitches response in mice and also antagonized RIH in rats. Furthermore, sub-chronic (14 days) treatment with 4a (2-4 mg/ kg, p.o.) significantly attenuated the behavioural anomalies induced by bilateral olfactory bulbectomy in rats in modified open field exploration. These preliminary investigations confirm that 4a exhibits antidepressant-like activity in behaviour based rodent models of depression.

  13. Study on the interaction of 6-(2-morpholin-4-yl-ethyl)-6H-indolo [2,3-b]quinoxaline hydrochloride with human serum albumin by fluorescence spectroscopy

    Science.gov (United States)

    Yegorova, A.; Leonenko, I.; Scrypynets, Yu; Maltsev, G.; Antonovich, V.

    2016-09-01

    Under physiological conditions, in vitro interaction between the bio-active substance 6-(2-morpholin-4-yl-ethyl)-6H-indolo[2,3-b]quinoxaline hydrochloride (MIQ) and human serum albumin (HSA) was investigated at an excitation wavelength 260 nm and at different temperatures (298 K, 308 K and 313 K) by fluorescence emission spectroscopy. From spectral analysis, MIQ showed a strong ability to quench the intrinsic fluorescence of HSA through a static quenching procedure. The binding constant is estimated asK A   =  2.55  ×  10-4 l · mol-1 at 298 K. Based on the thermodynamic parameters evaluated from the van ’t Hoff equation, the enthalpy change (ΔH°) and entropy change (ΔS°) were derived to be negative values. A value of 2.37 nm for the average distance r between MIQ (acceptor) and tryptophan residues of HSA (donor) was derived from the fluorescence resonance energy transfer. UV/vis absorption spectra were used to confirm the quenching mechanism.

  14. Quantum mechanical study of the structure and spectroscopic (FT-IR, FT-Raman, 13C, 1H and UV), NBO and HOMO-LUMO analysis of 2-quinoxaline carboxylic acid

    Science.gov (United States)

    Prabavathi, N.; Nilufer, A.; Krishnakumar, V.

    The FTIR and FT-Raman spectra of 2-quinoxaline carboxylic acid (2-QCA) has been recorded in the region 4000-450 and 4000-100 cm-1, respectively. The conformational analysis, optimized geometry, frequency and intensity of the vibrational bands of 2-QCA were obtained by the density functional theory (DFT) with complete relaxation in the potential energy surface using 6-31G(d) basis set. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FTIR and FT-Raman spectra. The observed and the calculated frequencies are found to be in good agreement. The 1H and13C NMR spectra have been recorded and 1H and 13C nuclear magnetic resonance chemical shifts of the molecule were also calculated using the gauge independent atomic orbital (GIAO) method and their respective linear correlations were obtained. The theoretical UV-visible spectrum of the compound using CIS method and the electronic properties, such as HOMO and LUMO energies, were performed by time-dependent DFT (TD-DFT) approach. The calculated HOMO and LUMO energies show that charge transfer occurs within molecule. The Mulliken charges, the values of electric dipole moment (μ) of the molecule were computed using DFT calculations. The change in electron density (ED) in the σ* antibonding orbitals and stabilization energies E(2) have been calculated by natural bond (NBO) analysis to give clear evidence of stabilization originating in the hyper conjugation of hydrogen-bonded interactions.

  15. Fragmentation Mechanism for A Group of 2(1H)-Quinoxalines%一类2(1H)-喹喔啉化合物的裂解机理

    Institute of Scientific and Technical Information of China (English)

    杨小兵; 丁松涛; 王安邦; 李小银; 杨裕生; 胡伟华

    2002-01-01

    用电子轰击质谱(EI-MS)研究了一类喹喔啉化合物:1-烷基-3-甲基-2(1H)-喹喔啉-2-酮(1-alkyl-3-methyl-2(1H)-quinoxalin-2-one,简称AMQ,其中alkyl=H,CH3,C2H5,n-C3H7,n-C5H11,n-C16H33);结果表明随着烷基链的增长,样品熔点通常会有所降低,结合在电子轰击下所产生的裂解碎片离子,并根据其结构特征以乙基化样品为代表,推导了该类化合物在电子轰击作用下可能发生的裂解机理.

  16. Indeno-1-one [2,3-b]quinoxaline as an effective inhibitor for the corrosion of mild steel in 0.5 M H{sub 2}SO{sub 4} solution

    Energy Technology Data Exchange (ETDEWEB)

    Obot, I.B., E-mail: proffoime@yahoo.com [Department of Chemistry, Faculty of Science, University of Uyo, P.M.B. 1017, Uyo, Akwa Ibom State (Nigeria); Obi-Egbedi, N.O. [Department of Chemistry, University of Ibadan, Ibadan (Nigeria)

    2010-08-01

    Indeno-1-one [2,3-b] quinoxaline (INQUI), synthesized in our laboratory, was tested as inhibitor for the corrosion of mild steel in 0.5 M H{sub 2}SO{sub 4} using gravimetric method at 30 {sup o}C. The inhibitor (INQUI) showed about 81% inhibition efficiency (E (%)) at an optimum concentration of 10 x 10{sup -6} M. The inhibition efficiency increases with increase in inhibitor concentration but decreases with increase in immersion time. The adsorption of the inhibitor on the mild steel in the acid solution was found to accord with Temkin's adsorption isotherm. The calculated value of the free energy for the adsorption process, {Delta}G{sub ads}, reveals a strong chemisorbed bond between the inhibitor and mild steel surface and a spontaneous adsorption of the inhibitor on the mild steel surface. Density functional theory (DFT) proves that INQUI molecule is adsorbed on the mild steel surface by the most negatively charged nitrogen and oxygen atoms.

  17. Synthesis of Novel Ferrocenyl Quinoxaline Piperazines and Their Relevant Antimalarial Activities%新型二茂铁基喹喔啉哌嗪的合成及其抗疟活性研究

    Institute of Scientific and Technical Information of China (English)

    谭平; 吴超; 向建南

    2013-01-01

    A series of novel ferrocenyl-substituted pyrrolo [1,2-α] quinoxaline piperazines 1a-h were synthe-sized from ferrocene-carboxaldehyde by six-step reactions .All of the compounds were screened for their antimalarial activities against plasmodium falciparum FcB1, K1, F32 strains.The results revealed that compounds 1 exhibited some inhibitory activities against the plasmodium falciparum strains.Among them, nitro substituted 1h was best. This work laid a foundation for further study of new antimalarial drugs .%以二茂铁甲醛为起始原料,经过6步反应合成得到新型的二茂铁吡咯并[1,2-α]喹喔啉哌嗪类衍生物1a-h.产物针对恶性疟原虫FcB1, K1, F32等菌株进行了体外抑制活性实验.实验结果表明,新合成的化合物具有一定的抗疟活性,其中芳环上4-位硝基取代的化合物1h体外抗疟活性最优.本工作为进一步研究具有更好活性的抗疟药物打下一定的基础.

  18. Crystal structure of ethyl (2S,2'R)-1'-benzyl-3-oxo-3H-di-spiro-[1-benzo-thio-phene-2,3'-pyrrolidine-2',11''-indeno[1,2-b]quinoxaline]-4'-carboxyl-ate.

    Science.gov (United States)

    Govindaraj, J; Raja, R; Suresh, M; Raghunathan, R; SubbiahPandi, A

    2015-03-01

    In the title compound, C35H27N3O3S, the spiro-linked five-membered rings both adopt twisted conformations. The pyrrolidine ring makes dihedral angles of 80.5 (1) and 77.4 (9)° with the benzo-thio-phene ring system and the quinoxaline ring system, respectively. The S atom and C=O unit of the benzo-thio-phene ring system are disordered over two opposite orientations in a 0.768 (4):0.232 (4) ratio. The atoms of the ethyl side chain are disordered over two sets of sites in a 0.680 (16):0.320 (16) ratio. In the crystal, mol-ecules are linked by C-H⋯O, C-H⋯N and π-π inter-actions [shortest centroid-centroid distance = 3.4145 (19) Å], resulting in a three-dimensional network.

  19. 2,3-Dipentyldithieno[3,2-f:2',3'-h]quinoxaline-Based Organic Dyes for Efficient Dye-Sensitized Solar Cells: Effect of π-Bridges and Electron Donors on Solar Cell Performance.

    Science.gov (United States)

    Huang, Zu-Sheng; Zang, Xu-Feng; Hua, Tao; Wang, Lingyun; Meier, Herbert; Cao, Derong

    2015-09-16

    Five novel metal-free organic dyes DQ1-5 containing a dipentyldithieno[3,2-f:2',3'-h]quinoxaline (DPQ) unit were synthesized and applied in dye-sensitized solar cells (DSSCs), where DPQ was employed as a π-spacer for the first time. Their photophysical, electrochemical, and theoretical calculations and photovoltaic properties were systematically investigated. All the five dyes show broad photoresponse. Especially the absorption edges of DQ3-5 extend to 800 nm on the TiO2 films. The inserted electron-rich unit 3,4-ethylenedioxythiophene or electron-withdrawing group benzothiadiazole (BTD) in DPQ-based dyes can greatly influence the optoelectronic properties of the dyes. In addition, the different electron donors also significantly affect the performance of the DSSCs. Under standard global AM 1.5 solar light conditions, the DQ5 sensitized solar cell obtained a power conversion efficiency of 7.12%. The result indicates that the rigid DPQ-based organic dye is a promising candidate for efficient DSSCs.

  20. Review on Detection of Quinoxalines Drug Residues in Animal-borne Food%动物源性食品中喹噁啉类药物残留检测方法研究进展

    Institute of Scientific and Technical Information of China (English)

    范立鹏; 段振娟; 方国臻; 汤轶伟; 韩海涛; 王硕

    2012-01-01

    Quinoxaline— 1,4—dioxides are a group of synthetic antimicrobial growth promotants which were widely used as feed additives for cow, goat, swine, chicken and fish, to improve feed efficiency, increase the rate of weight gain. Some members of the quinoxialin—1,4—dioxides family have severe toxicity and their residues in animal tissues are harmful to the health of human and animals. In this article, the source, harm and common analytical methods for quinoxaline residues in edible animal products were reviewed based on references, in order to promote more effective residual detection and supervision.%喹噁啉类药物是一类人工合成的抗菌促生长剂,曾被广泛用作牛、羊、猪、鸡和鱼的饲料添加剂,用以改善饲料利用率和提高动物体重增长率.有些品种毒性较大,在动物体内的残留对人和动物的健康具有极大危害.本文对动物源性食品中喹噁啉类药物的来源和危害以及国内外对动物源性食品中喹噁啉药物残留常用检测方法进行了评述及展望.

  1. Hydrothermal Synthesis, Crystal Structures and Photoluminescence of Two Novel Metal-organic Supramolecular Frameworks Based on Mixed Ligands of Dipyrazino[2,3f:2'3'-h]quinoxaline and Pyridine-2,5-dicarboxylic Acid

    Institute of Scientific and Technical Information of China (English)

    WANG Xiu-Li; LIU Guo-Cheng; LIN Hong-Yan; CHEN Bao-Kuan; FANG Jia-Ni; ZHAO Hai-Yan

    2008-01-01

    Two novel metal-organic frameworks [Zn2(DlXl)2(2,5-pda)2(H2O)2]·2H2O (1) (dipyrazino[2,3f2'3'-h]quinoxaline=Dpq) and [Cd2(Dpq)2(2,5-pda)2]·2H2O (2) (pyridine-2,5-dicarboxylic acid=2,5-H2pda) have been obtained from hydrothermal reactions of two different metal(II) nitrates with the same mixed ligands Dpq and 2,5-H2pda,and structurally characterized by elemental analyses,TG,IR spectroscopy,and single-crystal X-ray diffraction analyse.Single-crystal X-ray analyses show that the metal ions are bridged by different coordination modes of 2,5-pda to form a dimer in 1,2D rhombic grid in 2,respectively.In the compound 1,adjacent dimers are packed through hydrogen bonds and π-π aromatic stacking interactions to form a distorted a-Po supramolecular structure.In the compound 2,adjacent polymer layers are further linked by hydrogen bonds to form a distorted a-Po 3D supramolecular framework stabilized by π-π stacking interactions.The different structures of compounds 1 and 2 illustrate the influence of the metal ions and ligands on the self-assembly of polymeric coordination architectures.In addition,the title compounds exhibit blue emission in the solid state at room temperature.

  2. Synthesis and biological evaluation of analogues of 7-chloro-4,5-dihydro-4- oxo-8-(1,2,4-triazol-4-yl)-1,2,4-triazolo[1,5-a]quinoxaline-2-carboxylic acid (TQX-173) as novel selective AMPA receptor antagonists.

    Science.gov (United States)

    Catarzi, Daniela; Colotta, Vittoria; Varano, Flavia; Calabri, Francesca Romana; Filacchioni, Guido; Galli, Alessandro; Costagli, Chiara; Carlà, Vincenzo

    2004-01-01

    In recent papers (Catarzi, D.; et al. J. Med. Chem. 2000, 43, 3824-3826; 2001, 44, 3157-3165) we reported chemical and biological studies on 4,5-dihydro-4-oxo-1,2,4-triazolo[1,5-a]quinoxaline-2-carboxylates (TQXs) bearing different nitrogen-containing heterocycles at position-8. In particular, from these studies it emerged that both the 7-chloro-4,5-dihydro-4-oxo-8-(1,2,4-triazol-4-yl)-1,2,4-triazolo[1,5-a] quinoxaline-2-carboxylic acid TQX-173 (compound B) and its corresponding ethyl ester (compound A) were the most active and selective compounds of this series. In pursuing our investigation on the structure-activity relationships of these TQX derivatives, different electron-withdrawing groups (CF(3), NO(2)) were introduced at position 7 on the TQX ring system, replacing the 7-chloro substituent of B and of other selected 8-heteroaryltriazoloquinoxaline-2-carboxylates previously described. All the newly synthesized compounds were biologically evaluated for their binding at the Gly/NMDA, AMPA, and KA high-affinity receptors. Gly/NMDA binding assays were performed to assess the selectivity of the reported compounds toward the AMPA receptor. Compounds endowed with micromolar binding affinity for the KA high-affinity binding site were also evaluated for their binding at the KA low-affinity receptor. Some selected compounds were also tested for their functional antagonist activity at the AMPA and NMDA receptor-ion channel complex. The results obtained in this study have pointed out that 4,5-dihydro-7-nitro-4-oxo-8-(3-carboxypyrrol-1-yl)-1,2,4-triazolo[1,5-a]quinoxaline-2-carboxylic acid (9b) and its corresponding ethyl ester (9a) are the most potent and selective AMPA receptor antagonists reported to date among the TQX series.

  3. Electrochemical sensor based on molecularly imprinted polymer film via sol-gel technology and multi-walled carbon nanotubes-chitosan functional layer for sensitive determination of quinoxaline-2-carboxylic acid.

    Science.gov (United States)

    Yang, Yukun; Fang, Guozhen; Liu, Guiyang; Pan, Mingfei; Wang, Xiaomin; Kong, Lingjie; He, Xinlei; Wang, Shuo

    2013-09-15

    Quinoxaline-2-carboxylic acid (QCA) is difficult to measure since only trace levels are present in commercial meat products. In this study, a rapid, sensitive and selective molecularly imprinted electrochemical sensor for QCA determination was successfully constructed by combination of a novel modified glassy carbon electrode (GCE) and differential pulse voltammetry (DPV). The GCE was fabricated via stepwise modification of multi-walled carbon nanotubes (MWNTs)-chitosan (CS) functional composite and a sol-gel molecularly imprinted polymer (MIP) film on the surface. MWNTs-CS composite was used to enhance the electron transfer rate and expand electrode surface area, and consequently amplify QCA reduction electrochemical response. The imprinted mechanism and experimental parameters affecting the performance of MIP film were discussed in detail. The resulting MIP/sol-gel/MWNTs-CS/GCE was characterized using various electrochemical methods involving cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and DPV. The sensor using MIP/sol-gel/MWNTs-CS/GCE as working electrode showed a linear current response to the target QCA concentration in the wide range from 2.0×10(-6) to 1.0×10(-3)molL(-1) with a low detection limit of 4.4×10(-7)molL(-1) (S/N=3). The established sensor with excellent reproductivity and stability was applied to evaluate commercial pork products. At five concentration levels, the recoveries and standard deviations were calculated as 93.5-98.6% and 1.7-3.3%, respectively, suggesting the proposed sensor is promising for the accurate quantification of QCA at trace levels in meat samples.

  4. 一类2(1H)-喹喔啉衍生物的紫外光谱研究%Study on the Ultraviolet Spectrum in a Series of 2(1H)-Quinoxalin-2-one Derivatives

    Institute of Scientific and Technical Information of China (English)

    杨小兵; 丁松涛; 王安邦; 杨裕生

    2003-01-01

    研究了一类喹喔啉衍生物,1-烷基-3-甲基-2(1H)-喹喔啉-2-酮(1-alkyl-3-methyl-2(1H)-quinoxalin-2-one,简称AMQ, 其中alkyl =H, CH3, C2H5,n-C3H7,n-C5H11,n-C16H33)的紫外吸收光谱.这类化合物可应用于药物,如用作α-氨基羟甲基异恶唑丙酸(AMPA)受体拮抗剂、杀菌剂等;还可用作植物生长调节剂、荧光探针等领域.结果表明:化合物中氮原子上烷基链的增长对该类喹喔啉衍生物的紫外吸收光谱基本没有影响,谱图中峰形大体相同.紫外吸收谱图中,在327和340 nm左右有两个吸收强度相当的一对肩峰,280 nm处有一个吸收强度稍弱的峰;340 nm左右的吸收峰主要是n→Π*跃迁所致,其中也含有Π→Π*跃迁的成分;327和280 nm左右强吸收峰是Π→Π*跃迁所致.

  5. High risk of adrenal toxicity of N1-desoxy quinoxaline 1,4-dioxide derivatives and the protection of oligomeric proanthocyanidins (OPC) in the inhibition of the expression of aldosterone synthetase in H295R cells.

    Science.gov (United States)

    Wang, Xu; Yang, Chunhui; Ihsan, Awais; Luo, Xun; Guo, Pu; Cheng, Guyue; Dai, Menghong; Chen, Dongmei; Liu, Zhenli; Yuan, Zonghui

    2016-02-01

    Quinoxaline 1,4-dioxide derivatives (QdNOs) with a wide range of biological activities are used in animal husbandry worldwide. It was found that QdNOs significantly inhibited the gene expression of CYP11B1 and CYP11B2, the key aldosterone synthases, and thus reduced aldosterone levels. However, whether the metabolites of QdNOs have potential adrenal toxicity and the role of oxidative stress in the adrenal toxicity of QdNOs remains unclear. The relatively new QdNOs, cyadox (CYA), mequindox (MEQ), quinocetone (QCT) and their metabolites, were selected for elucidation of their toxic mechanisms in H295R cells. Interestingly, the results showed that the main toxic metabolites of QCT, MEQ, and CYA were their N1-desoxy metabolites, which were more harmful than other metabolites and evoked dose and time-dependent cell damage on adrenal cells and inhibited aldosterone production. Gene and protein expression of CYP11B1 and CYP11B2 and mRNA expression of transcription factors, such as NURR1, NGFIB, CREB, SF-1, and ATF-1, were down regulated by N1-desoxy QdNOs. The natural inhibitors of oxidant stress, oligomeric proanthocyanidins (OPC), could upregulate the expression of diverse transcription factors, including CYP11B1 and CYP11B2, and elevated aldosterone levels to reduce adrenal toxicity. This study demonstrated for the first time that N1-desoxy QdNOs have the potential to be the major toxic metabolites in adrenal toxicity, which may shed new light on the adrenal toxicity of these fascinating compounds and help to provide a basic foundation for the formulation of safety controls for animal products and the design of new QdNOs with less harmful effects.

  6. A novel copper(II) complex constructed with mixed ligands of biphenyl-4,4'-dicarboxylic acid (H 2bpdc) and dipyrido[3,2-d:2',3'-f]quinoxaline (Dpq): Synthesis, structure, electrochemistry and electrocatalysis

    Science.gov (United States)

    Lin, HongYan; Wang, XiuLi; Hu, HaiLiang; Chen, BaoKuan; Liu, GuoCheng

    2009-03-01

    A novel metal-organic framework [Cu 2(bpdc) 2(Dpq) 2(H 2O)]·H 2O ( 1) has been obtained from hydrothermal reaction of copper chloride with the mixed ligands [biphenyl-4,4'-dicarboxylic acid (H 2bpdc) and dipyrido[3,2-d:2',3'-f]quinoxaline (Dpq)], and structurally characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction analysis. The unique feature is that there simultaneously exist two kinds of one-dimensional (1-D) zigzag polymeric chains in complex 1. Moreover, the 1-D polymeric chains are ultimately packed into a three-dimensional (3-D) supramolecular framework through two different hydrogen bonding interactions. The adjacent different chains are linked by C-H⋯O hydrogen bonding interactions, and the same kind chains are further connected through C-H⋯π stacking interactions. Additionally, the complex 1 was used as solid bulk-modifier to fabricate renewable carbon paste electrode (Cu-CPE) by the direct mixing method. The electrochemical behavior and electrocatalysis of Cu-CPE have been studied in detail. The results indicate that Cu-CPE give one-electron quasi-reversible redox waves in potential range of 400 to -300 mV due to the metal copper ion Cu(II)/Cu(I). The Cu-CPE showed good electrocatalytic activity toward the reduction of the bromate, nitrite and hydrogen peroxide. The electrocatalytic reduction peak currents of KBrO 3, KNO 2 and H 2O 2 showed a linear dependence on their concentrations. All of the results revealed that the Cu-CPE had a good reproducibility, remarkable long-term stability and especially good surface renewability by simple mechanical polishing in the event of surface fouling, which is important for practical application.

  7. Sensitive and selective electrochemical determination of quinoxaline-2-carboxylic acid based on bilayer of novel poly(pyrrole) functional composite using one-step electro-polymerization and molecularly imprinted poly(o-phenylenediamine).

    Science.gov (United States)

    Yang, Yukun; Fang, Guozhen; Wang, Xiaomin; Pan, Mingfei; Qian, Hailong; Liu, Huilin; Wang, Shuo

    2014-01-01

    A facile and efficient molecularly imprinted polymer (MIP) recognition element of electrochemical sensor was fabricated by directly electro-polymerizing monomer o-phenylenediamine (oPD) in the presence of template quinoxaline-2-carboxylic acid (QCA), based on one-step controllable electrochemical modification of poly(pyrrole)-graphene oxide-binuclear phthalocyanine cobalt (II) sulphonate (PPY-GO-BiCoPc) functional composite on glassy carbon electrode (GCE). The MIP film coated on PPY-GO-BiCoPc functional composite decorated GCE (MIP/PPY-GO-BiCoPc/GCE) was presented for the first time. The synergistic effect and electro-catalytic activity toward QCA redox of PPY-GO-BiCoPc functional composite were discussed using various contrast tests. Also, the effect of experimental variables on the current response such as, electro-polymerization cycles, template/monomer ratio, elution condition for template removal, pH of the supporting electrolyte and accumulation time, were investigated in detail. Under the optimized conditions, the proposed MIP sensor possessed a fast rebinding dynamics and an excellent recognition capacity to QCA, while the anodic current response of square wave voltammetry (SWV) was well-proportional to the concentration of QCA in the range of 1.0×10(-8)-1.0×10(-4) and 1.0×10(-4)-5.0×10(-4) mol L(-1) with a low detection limit of 2.1 nmol L(-1). The established sensor was applied successfully to determine QCA in commercial pork and chicken muscle samples with acceptable recoveries (91.6-98.2%) and satisfactory precision (1.9-3.5% of SD), demonstrating a promising feature for applying the MIP sensor to the measurement of QCA in real samples.

  8. Theoretical Investigation on the Optoelectronic Properties of Fluorinated Quinoxaline Derivatives%F原子取代对喹喔啉(quinoxaline)衍生物光电性质影响的理论研究

    Institute of Scientific and Technical Information of China (English)

    胡波; 周凌云; 靳瑞发

    2012-01-01

    We investigate the variation in the electronic,optical,and charge transport properties upon the F substitutions based on the quinoxaline derivative by quantum-chemical calculations.The results show that,F substitutions decrease both the energies of the highest occupied molecular orbital and the lowest unoccupied orbital in comparison with those of the pristine molecule.Moreover,compared to those of the pristine molecule,the absorption and emission spectra of F substituted derivatives exhibit small shifts.F substituted derivatives can be used as hole transportation materials in organic light-emitting diodes(OLEDs).%采用量子化学方法研究了F原子取代对喹喔啉(quinoxaline)衍生物的电子性质、光谱性质以及电荷传输性质的影响.研究结果表明,与母体分子相比,F取代同时降低了最高占据轨道和最低空轨道的能量.相对于母体分子,由于F取代没有使能隙发生明显变化,所以F取代衍生物的吸收和发射光谱发生了少量变化.与母体分子相比,F取代有利于空穴传输性能的提高,F取代衍生物可以作为有机发光二极管的空穴传输材料.

  9. Antidepressant and anti-anxiety like effects of 4i (N-(3-chloro-2-methylphenyl) quinoxalin-2-carboxamide), a novel 5-HT3 receptor antagonist in acute and chronic neurobehavioral rodent models.

    Science.gov (United States)

    Gupta, Deepali; Radhakrishnan, Mahesh; Thangaraj, Devadoss; Kurhe, Yeshwant

    2014-07-15

    Depression and anxiety are the most debilitating mood disorders with poor therapeutic recovery rates. In the last decades, 5-HT3 receptor antagonists have been identified as potential agents for mood disorders. The current investigation focuses on evaluating the, antidepressant and anti-anxiety like effects of a novel 5-HT3 antagonist, 4i (N-(3-chloro-2-methylphenyl) quinoxalin-2-carboxamide). Preliminary, in vitro 5-HT3 receptor binding affinity was performed in isolated longitudinal muscle-myenteric plexus from the guinea pig ileum. Consequently, neurobehavioral effects of 4i in acute and chronic rodent models were evaluated. In addition, involvement of serotonergic system in the postulated effects of the compound was analyzed by in vivo assay. in vitro, 4i demonstrated high 5-HT3 receptor antagonistic activity (pA2, 7.6). in vivo acute study, 4i exhibited decreased duration of immobility in forced swim and tail suspension tests, and increased exploratory parameters as number and duration of nose-poking in hole board test and latency and time spent in aversive brightly illuminated light chamber in light-dark model. Moreover, in chronic model of depression, i.e., olfactory bulbectomy with behavioral deficits, 4i reversed depressive anhedonia in sucrose preference test and anxious hyperactive behavior in open field test in rats. Furthermore, synergistic effect of 4i with fluoxetine (a selective serotonin reuptake inhibitor) and inhibitory effect of 1-(m-chlorophenyl)-biguanide (a 5-HT3 receptor agonist) revealed serotonergic modulation by 4i mediated 5-HT3 receptor antagonism, which was further confirmed by potentiation of 5-hydroxytryptophan (a serotonin synthesis precursor) induced head twitch response. These findings suggest the potential antidepressant and anti-anxiety like effects of 4i, which may be related to the modulation of serotonergic system. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. 1,2,4-Triazolo[1,5-a]quinoxaline as a versatile tool for the design of selective human A3 adenosine receptor antagonists: synthesis, biological evaluation, and molecular modeling studies of 2-(hetero)aryl- and 2-carboxy-substituted derivatives.

    Science.gov (United States)

    Catarzi, Daniela; Colotta, Vittoria; Varano, Flavia; Lenzi, Ombretta; Filacchioni, Guido; Trincavelli, Letizia; Martini, Claudia; Montopoli, Christian; Moro, Stefano

    2005-12-15

    A number of 4-oxo-substituted 1,2,4-triazolo[1,5-a]quinoxaline derivatives bearing at position-2 the claimed (hetero)aryl moiety (compounds 1-15) but also a carboxylate group (16-28, 32-36) or a hydrogen atom (29-31) were designed as human A3 (hA3) adenosine receptor (AR) antagonists. This study produced some interesting compounds and among them the 2-(4-methoxyphenyl)-1,2,4-triazolo[1,5-a]quinoxalin-4-one (8), which can be considered one of the most potent and selective hA3 adenosine receptor antagonists reported till now. Moreover, as a new finding, replacement of the classical 2-(hetero)aryl moiety with a 2-carboxylate function (compounds 16-28 and 32-36) maintained good hA3 AR binding activity but, most importantly and interestingly, produced a large increase in hA3 versus hA1 selectivity. A receptor-based SAR analysis provided new interesting insights about the steric and electrostatic requirements that are important for the anchoring of these derivatives at the hA3 receptor recognition site, thus highlighting the versatility of the triazoloquinoxaline scaffold for obtaining potent and selective hA3 AR antagonists.

  11. A novel 5HT3 antagonist 4i (N-(3-chloro-2-methylphenyl)quinoxalin-2-carboxamide) prevents diabetes-induced depressive phenotypes in mice: Modulation of serotonergic system.

    Science.gov (United States)

    Gupta, Deepali; Thangaraj, Devadoss; Radhakrishnan, Mahesh

    2016-01-15

    Despite the presence of a multitudinous pharmacotherapy, diabetes-induced depressive disorder remains undertreated. Evidence suggests that brain serotonergic deficits are associated with depressive-like behavior in diabetes and that 5HT3 receptor (5HT3R) antagonists have serotonergic facilitatory effects. This study examined the effects of a novel 5HT3R antagonist, 4i (N-(3-chloro-2-methylphenyl)quinoxalin-2-carboxamide), in diabetes-induced depressive phenotypes. Experimentally, (1) to evaluate the effects of 4i, mice with 8-weeks of diabetes (induced by streptozotocin, 200mg/kg, i.p.) were treated with vehicle, 4i (0.5 and 1mg/kg/day, i.p.), fluoxetine (10mg/kg/day, i.p.) for 4-weeks and subjected to neurobehavioral assays, followed by biochemical estimation of serotonin levels in midbrain, prefrontal-cortex and cerebellum. (2) To evaluate the role of 5HT3R in the postulated effect of 4i, diabetic mice were given 4i (1mg/kg/day, i.p.) after 1h of 1-(m-chlorophenyl)-biguanide (mCPBG, a 5HT3R agonist, 10mg/kg/day, i.p.) treatment and subjected to the same protocol. The results showed that diabetic mice exhibited a significant behavioral deficit, including depression-like behavior in forced swim test, anxiety-like in open field test and sociability deficits in social interaction test, along with a significant decrease in serotonin level in these brain regions. 4i (1mg/kg), similar to fluoxetine, prevented these behavioral abnormalities and normalized brain serotonin levels. 4i (0.5mg/kg) ameliorated only diabetes-induced depressive-like behavior and serotonin deficits, but not anxiety-like effects. mCPBG blunted 4i-mediated behavioral response and increase in brain serotonin levels. Altogether, this study suggests that 4i prevents diabetes-induced depressive phenotypes in mice, which may involve antagonism of 5HT3Rs and increase in serotonin levels in discrete brain regions.

  12. Chelate Ring Size Effect as a Factor of Selective Fluorescent Recognition of Zn(2+) Ions by Pyrrolo[2,3-b]quinoxaline with a Substituted 2-Pyridyl Group Receptor.

    Science.gov (United States)

    Ostrowska, Katarzyna; Musielak, Bogdan; Szneler, Edward; Dudek, Łukasz; Gryl, Marlena; Stadnicka, Katarzyna

    2015-09-01

    Analysis of the spectral properties and structural differences of two turn-on ratiometric fluorescent receptors for Zn(2+) and Cd(2+) ions, derivatives of pyrrolo[2,3-b]quinoxaline (2), and earlier published 3 (Ostrowska et al. CrystEngComm 2015, 17, 498-502) was performed. Both ligands are E/Z push-pull olefins interconverting at room temperature, with barriers to rotation about enamine double bonds, from E to Z isomers of 19.3 ± 0.1 and 16.9 ± 0.3 kcal/mol and from Z to E of 16.9 ± 0.3 and 15.7 ± 0.2 kcal/mol, respectively. Diastereoisomers (E)-2 and (Z)-2 were isolated and characterized by X-ray structural analysis. The formation of complexes by (E/Z)-2 with acetates and acetylacetonates of Zn(2+) and Cd(2+) was monitored by UV-vis, fluorescence, and (1)H NMR titrations in acetonitrile, respectively. X-ray structural analysis for isolated [(E)-2]2Zn in relation to earlier published (E)-3-ZnOAc revealed the formation of a six-coordinated zinc ion with six- and four-membered bis-chelate rings by (E)-2. The chelate effect increases the ligand affinity for Zn(2+) (log β12 = 12.45) and causes the elongation of nitrogen-metal bonds. Extension of the coordination cavity size allows coordination of a cadmium ion. The introduction of a flexible ethylene linker between the fluorophore and ionophore pyridyl groups in 3 significantly affects the selectivity of zinc-ion recognition. The distorted tetrahedral geometry of (E)-3-ZnOAc with a four-coordinated zinc ion appears to be the most preferred because of the short donor-zinc distance with a 1:1 binding mode. The formation of the small coordination cavity size with six-membered bis-chelate rings provides an effective overlap of zinc and donor orbitals, precluding the coordination of a cadmium ion in the same manner as zinc.

  13. Progress of Study on the Special-toxicology of Quinoxaline-1,4- dioxide-type Antibacterial and Growth-promoting Agents%喹口恶啉-1,4-二氧化物类抗菌促生长剂特殊毒理学研究进展

    Institute of Scientific and Technical Information of China (English)

    曹随忠; 张力; 梁剑平; 刘宗平

    2001-01-01

    喹口恶啉-1,4-二氧化物取代衍生物卡巴氧、喹乙醇、西吖氧作为抗菌促生长饲料添加剂广泛应用于猪。为了评价它们的安全性,本文从致突变、致癌性和生殖毒性三方面对它们的特殊毒理学研究作了综述。%Quinoxaline-1,4-Dioxide-type derivatives such as carbadox,olaquindox and cyadox are added to pigs feed as antibacterial and growth-promoting feed additives.In order to evaluate theirs safety,the special-toxicology of the three compounds,including mutagenicity,carcinogenicity and genetic-toxicity were vreviewed the present article.

  14. Crystal structure of ethyl (2S,2′R-1′-benzyl-3-oxo-3H-dispiro[1-benzothiophene-2,3′-pyrrolidine-2′,11′′-indeno[1,2-b]quinoxaline]-4′-carboxylate

    Directory of Open Access Journals (Sweden)

    J. Govindaraj

    2015-03-01

    Full Text Available In the title compound, C35H27N3O3S, the spiro-linked five-membered rings both adopt twisted conformations. The pyrrolidine ring makes dihedral angles of 80.5 (1 and 77.4 (9° with the benzothiophene ring system and the quinoxaline ring system, respectively. The S atom and C=O unit of the benzothiophene ring system are disordered over two opposite orientations in a 0.768 (4:0.232 (4 ratio. The atoms of the ethyl side chain are disordered over two sets of sites in a 0.680 (16:0.320 (16 ratio. In the crystal, molecules are linked by C—H...O, C—H...N and π–π interactions [shortest centroid–centroid distance = 3.4145 (19 Å], resulting in a three-dimensional network.

  15. 猪食用组织中喹喔啉-2-羧酸的高效液相色谱检测方法%Liquid chromatographic determination of quinoxaline-2-carboxylic acid in edible swine tissues

    Institute of Scientific and Technical Information of China (English)

    邱银生; 袁宗辉; 殷居易

    2003-01-01

    为了监测猪食用组织中卡巴氧(carbadox)的残留,建立了检测猪肝脏、肾脏、肌肉等组织中卡巴氧的标示残留物喹喔啉2羧酸(Quinoxaline-2-carboxylic acid,QCA)的高效液相色谱法.组织样品经碱水解,液液分配提取,用离子交换色谱柱净化,洗脱液作浓缩后用甲醇溶解进行测定.色谱柱为ODS C18柱;流动相为甲醇-水(体积比40:60),每1L中加入8 mL冰乙酸,流速为1.0 mL/min;定量分析用紫外检测器,波长320 rm,确证性分析用二极管阵列检测器,波长250~500 nm.喹喔啉-2-羧酸工作液质量浓度在0.03~0.96 mg/L范围内,药物峰面积与浓度呈良好的线性关系,相关系数r=0.999 9.组织中添加药物的质量分数为0.015、0.03、0.06 μg/g时,肝脏样品回收率分别为(73.55士9.46)%、(80.33±14.95)%、(75.84±7.42)%;肾脏样品分别为(70.89±10.33)%、(74.89±7.19)%、(83.33±10.68)%;肌肉样品分别为(69.49±7.26)%、(66.44±5.09)%、(62.11±6.08)%.本方法条件下,3种组织中药物最低检出质量分数均为0.015 μg/g,回收率测定的日内及日间相对偏差(RSD)分别<18%和<20%.当组织中药物质量分数达0.06μg/g时,可检测到喹喔啉-2-羧酸的特征性紫外吸收光谱.

  16. Reactive Plasticizers for High Temperature Quinoxaline Thermoplastics

    Science.gov (United States)

    1976-06-01

    involves essentially two steps, consolidation of boardy prepreg into sheet stock and thermoforming the sheet stock into structural components. A...problem associated with the fabrication process is the high temperatures required in both the consolidation and thermoforming operations. High processing

  17. Determination of Four Kinds of Illegal Additives Quinoxalines in Quinolones Powder by UPLC%氟喹诺酮类药物粉剂中非法添加四种喹噁啉类药物的UP LC检测方法研究

    Institute of Scientific and Technical Information of China (English)

    罗成江; 陆春波; 林仙军; 周志强; 周芷锦; 蔡文金; 陈晓林; 应永飞

    2015-01-01

    A method for the determination of olaquindox, maquindox, carbadox, quinocetone in quinolones powder by UPLC was developed. Purospher RP-18 column ( 2. 1 mm × 100 mm, 2. 0 μm) was used with the mobile phase consisted of phosphoric acid solution and methanol-acetonitrile ( 7. 5 ∶ 7. 0 ) . The flow rate was 0.3 mL/min; the column temperature was 30℃;the wavelength range was 200~400 nm. The result showed that the standard curves for four quinoxalines were in good linearity within a concentration range of 0.2~100μg/mL( r=0.9999) , the recoveries for quinoxalines in quinolones powder ranged from 98.0%to 100.2%with the RSD from 0.27%to 0.89%. The limit of detection( LOD) was 200 mg/kg. The method was fast and accurate, and was suited for identification and determination of the quinoxalines in quinolones powder.%建立了超高效液相色谱法测定氟喹诺酮类药物粉剂中非法添加喹乙醇、乙酰甲喹、卡巴氧及喹烯酮的方法。采用purospher RP-18色谱柱(2.1 mm×100 mm,粒径2.0μm )分离四种喹噁啉类药物,以磷酸溶液和甲醇-乙腈(7.5∶7.0)为流动相进行梯度洗脱,流速0.3 mL/min,二极管阵列检测器检测,采集波长范围为200~400 nm,分辨率为1.2 nm,记录光谱图和365 nm波长处的色谱图。结果显示,四种喹噁啉类药物的浓度在0.2~100μg/mL范围内的线性良好,相关系数r均为0.9999,回收率在98.0%~100.2%范围内,RSD在0.27%~0.89%之间,检测限200 mg/kg。本方法快速、准确,可用于氟喹诺酮类粉剂中非法添加喹噁啉类药物的定性和定量检测。

  18. Thin Layer Chromatograph Method for Quantitative Determination of 3-methyl-2-acetyl-quinoxaline and 4-desoxymequindox%薄层扫描法测定N4-脱一氧乙酰甲喹及脱二氧乙酰甲喹含量

    Institute of Scientific and Technical Information of China (English)

    汤有志; 柳洪芳; 远立国

    2012-01-01

    采用薄层扫描法同时测定N4-脱一氧乙酰甲喹及3-甲基-2-乙酰基-喹喔啉(脱二氧乙酰甲喹)的含量。试验采用甲醇为溶剂对N4-脱一氧乙酰甲喹及脱二氧乙酰甲喹进行溶解,以石油醚-乙酸乙酯(6∶1)为展开剂上行展开;以瑞士卡玛IV型扫描仪,采用单波长吸收扫描法,λ=254 nm。结果表明:以扫描所得峰面积积分计算,N4-脱一氧乙酰甲喹及脱二氧乙酰甲喹的线性范围均为0.092~0.736μg(r≥0.985)。该方法适用于大规模样品中N4-脱一氧乙酰甲喹及脱二氧乙酰甲喹含量初筛。%The paper determined simultaneously 3-methyl-2-acetyl-quinoxaline and 4-desoxymequindox.Methanol was used as solvent.Linear ascending development was carried out with petroleum ether:ethyl acetate(6∶1)at room temperature.Camag TLC scanner IV was used for spectrodensitometric scanning and analysis in absorbance mode at 254 nm.The results showed that the data for calibration plots showed good linear relationship with r≥0.985 in the concentration range of 0.092 μg to 0.736 μg with respect to peak area.This method was suitable for screening large-scale sample containing 3-methyl-2-acetyl-quinoxaline and 4-desoxymequindox.

  19. Modeling the active site of [FeFe]-hydrogenase: Electro-catalytic hydrogen evolution from acetic acid catalysed by [Fe2(-L)(CO)6] and [Fe2(-L)(CO)5(PPh3)] (L=pyrazine-2, 3-dithiolate, quinoxaline-2, 3-dithiolate and pyrido[2,3-b] pyrazine-2, 3-dithiolate)

    Indian Academy of Sciences (India)

    Gummadi Durgaprasad; Samar K Das

    2015-02-01

    Compounds [Fe2{-pydt}(CO)6] (pydt = pyrazine-2,3-dithiolate) (1), [Fe2{-qdt}(CO)6] (qdt = quinoxaline-2,3-dithiolate) (2), [Fe2{-ppdt}CO)6] (ppdt = pyrido[2,3-b]pyrazine-2,3-dithiolate) (3), [Fe2{-pydt}(CO)5PPh3] (4), [Fe2{-qdt}(CO)5PPh3] (5) and [Fe2{-ppdt}(CO)5PPh3] (6) have been synthesized in order to model the active sites of `[FeFe]-hydrogenase’. Compounds 1–6 have been characterized by routine spectral studies and unambiguously by single crystal X-ray crystallography. Supramolecular chemistry of compounds 1–6 have been described in terms of intermolecular interactions, observed in their respective crystal structures. Electro-catalytic hydrogen evaluation studies (from acetic acid) have been performed using compounds 1–6 as electro-catalysts. The mechanistic aspects of relevant electro–catalytic proton reductions have been discussed in detail.

  20. Ethyl 1′′-benzyl-2′′-oxo-2′,3′,5′,6′,7′,7a'-hexahydro-1′H-dispiro[indeno[1,2-b]quinoxaline-11,2′-pyrrolizine-3′,3′′-indoline]-1′-carboxylate monohydrate

    Directory of Open Access Journals (Sweden)

    Piskala Subburaman Kannan

    2013-06-01

    Full Text Available In the title compound, C38H32N4O3·H2O, the quinoxaline–indene and pyrrolizine systems are essentially planar, with maximum deviations from their mean planes of 0.162 and 0.563 Å, respectively. The pyrrolizine ring forms dihedral angles of 88.53 (5 and 89.95 (8° with the quinoxaline–indene system and the indoline ring, respectively. The central pyrrolidine ring has an envelope conformation with the C atom bearing the quinoxaline-indene system as the flap. The pyrrolidine ring of the indole system adopts an envelope conformation with the C atom bonded to the pyrrolizine ring N atom as the flap. The five-membered ring attached to the central pyrolidine ring adopts a twisted conformation. In the crystal, O—H...N and O—H...O hydrogen bonds between water molecules and pyrrolizine N and carbonyl O atoms together with C—H...O interactions result in chains along [100].

  1. The Research for the synthesis of 6,7 - dimethyl - 2,3 - di - 2 - pyridinyl - quinoxaline and its coordination properties with copper%6,7-二甲基-2,3-二(2-吡啶基)-喹喔啉的合成及其与铜配位性能的研究

    Institute of Scientific and Technical Information of China (English)

    龚宁; 麻晖; 陈桂英

    2012-01-01

    Using the reaction of 1,2 - di - ( 2 - pyridyl) glyoxal and 4,5 - dimethyl - 1,2 - phenylenediamine, synthesized 6,7 - dimethyl - 2,3 - di - 2 - pyridinyl - quinoxaline ( MePyQ ) as a ligand, its structure was charac- terized by elemental analysis and 1H NMR, and preliminary study of UV absorption speetroseopy of complexes with copper ions. The results show that MePyQ and copper ions form 1:2 metal complex.%利用1,2-二(2-吡啶)-乙二酮与4,5-二甲基-邻苯二胺反应,合成了6,7-二甲基-2,3-二(2-吡啶基)-喹喔啉(MePyQ)作为配体,通过元素分析和1H NMR对其结构进行了表征,并初步研究了其与铜离子形成配合物的紫外吸收光谱。结果表明,MePyQ与铜离子形成1∶2的金属配合物。

  2. 6a-Nitro-6-(2,2,7,7-tetramethyltetrahydro-3aH-bis[1,3]dioxolo[4,5-b:4′,5′-d]pyran-5-yl-6a,6b,7,8,9,11a-hexahydro-6H-spiro[chromeno[3,4-a]pyrrolizine-11,11′-indeno[1,2-b]quinoxaline

    Directory of Open Access Journals (Sweden)

    T. Anuradha

    2014-01-01

    Full Text Available In the title compound, C39H38N4O8, the quinoxaline and indene subunits are essentially planar, with maximum deviations of 0.071 (2 and 0.009 (2 Å, respectively. The indenoquinoxaline system forms a dihedral angle of 72.81 (3° with the chromenopyrrolizine system. The two dioxolane rings, as well as the pyran ring of the chromeno group and the terminal pyrrolizine, each adopt an envelope conformation with O and C as flap atoms. The central pyrrolizine ring adopts a twisted conformation. Intramolecular C—H...O and C—H...N hydrogen bonds occur. The crystal structure exhibits C—H...O hydrogen bonds, and is further stablized by C—H...π interactions, forming a two-dimensional network along the bc plane.

  3. 高效液相色谱法测定猪肝组织中3-甲基喹喔啉-2-羧酸%Determination of 3-methyl-quinoxaline-2-carboxylic Acid in Porcine Liver by High Performance Liquid Chromatography

    Institute of Scientific and Technical Information of China (English)

    姚蕴珊; 沈建忠; 吴聪明; 程林丽

    2011-01-01

    To develop a high performance liquid chromatography method for determination of 3-methyl-quinoxaline-2-carboxylic acid (MQCA) in porcine liver. MQCA was extracted from porcine liver with 0.3 mol/L hydrochloric acid. The extract was cleaned up on MAX Sep-Pak Silica solid-phase extraction cartridge. Then the eluate was collected and dried under a gentle stream of nitrogen gas and the dissolved residue was analyzed by HPLC. The HPLC separation was performed on a Symmetry Shield reversed phase C18 boned silica column, with mobile phase of acetonitrile-methanol-0.5% formic acid (15 : 50: 35, V/V/V) and determination wave of 320 nm in an UV detector. The validation was carried out on spiked porcine liver(spiked at 20~250 μg/kg), and the average recoveries of target drug ranged from 72. 35% to 85.00%, with intra-day relative standard deviations(RSD)(n=5) of 5. 56% to 9. 49%, and inter-day RSD(n= 3) of 5. 96% to 9. 63%. The limits of quantification (LOQ) in porcine liver was 20 μg/kg and the limits of detection (LOD) was 6.65 μg/kg. The results demonstrated that the sensitivity , accuracy, and precision of this method meet the requirements of veterinary drug residue analysis. The method is applicable to detect MQCA in porcine liver.%本研究建立了猪肝组织中3-甲基喹喔啉-2羧酸(3-methyl-quinoxaline-2-carboxylic acid,MQCA)的高效液相色谱检测方法.采用0.3 mol/L盐酸提取猪肝组织中药物,经MAX柱净化,以乙腈:甲醇:0.5%甲酸水(15:50:35,V/V/V)为流动相,C18色谱柱进行药物分离,320 nm波长下紫外检测,结果当药物在猪肝组织中添加水平为20~250μg/kg时,平均回收率为72.35%~85.00%,日内测定的相对标准偏差(RSD)(n=5)为5.56%~9.49%,日间RSD(n=3)为5.96%~9.63%.猪肝组织中MQCA的定量限为20μg/kg,检出限为6.65 μg/kg,表明该方法灵敏度、准确度和精密度均符合兽药残留分析技术的要求,适用于猪肝组织中MQCA的检测.

  4. Ligand-controlled assembly of Cd(II) coordination polymers based on mixed ligands of naphthalene-dicarboxylate and dipyrido[3,2-d:2‧,3‧-f]quinoxaline: From 0D+1D cocrystal, 2D rectangular network (4,4), to 3D PtS-type architecture

    Science.gov (United States)

    Liu, Guocheng; Chen, Yongqiang; Wang, Xiuli; Chen, Baokuan; Lin, Hongyan

    2009-03-01

    Three novel Cd(II) coordination polymers, namely, [Cd(Dpq)(1,8-NDC)(H 2O) 2][Cd(Dpq)(1,8-NDC)]·2H 2O ( 1), [Cd(Dpq)(1,4-NDC)(H 2O)] ( 2), and [Cd(Dpq)(2,6-NDC)] ( 3) have been obtained from hydrothermal reactions of cadmium(II) nitrate with the mixed ligands dipyrido [3,2-d:2',3'-f]quinoxaline (Dpq) and three structurally related naphthalene-dicarboxylate ligands [1,8-naphthalene-dicarboxylic acid (1,8-H 2NDC), 1,4-naphthalene-dicarboxylic acid (1,4-H 2NDC), and 2,6-naphthalene-dicarboxylic acid (2,6-H 2NDC)]. Single-crystal X-ray diffraction analysis reveals that the three polymers exhibit novel structures due to different naphthalene-dicarboxylic acid. Compound 1 is a novel cocrystal of left- and right-handed helical chains and binuclear complexes and ultimately packed into a 3D supramolecular structure through hydrogen bonds and π- π stacking interactions. Compound 2 shows a 2D rectangular network (4,4) bridged by 1,4-NDC with two kinds of coordination modes and ultimately packed into a 3D supramolecular structure through inter-layer π- π stacking interactions. Compound 3 is a new 3D coordination polymer with distorted PtS-type network. In addition, the title compounds exhibit blue/green emission in solid state at room temperature.

  5. Hydrothermal Synthesis and Crystal Structure of a One-Dimensional Cadmium(Ⅱ)Complex with Isophthalic Acid and 2-Methyldipyrido[3,2-f:2′,3′-h]quinoxaline Ligands%由间苯二甲酸和喹喔啉类配体构筑的一维隔(Ⅱ)的配合物的水热合成及晶体结构

    Institute of Scientific and Technical Information of China (English)

    王蕾; 倪良; 朱(羽中); 黄艳菊

    2011-01-01

    A metal-organic coordination polymer [Cd(ipt)(Medpq)]n (H2ipt=isophthalic acid,Medpq=2-methyldipyrido[3,2-f:2′,3′-h]quinoxaline) has been hydrothermally synthesized and structurally characterized by elemental analysis,IR spectrum,UV-Vis spectrum,TG and single-crystal X-ray diffraction.Title compound crystallizes in the monoclinic system,space group C2/c,with a=2.0136(4) nm,b=1.6089(3) nm,c=1.6093(3) nm,β=125.12(3)°,V=4.3028(15) nm3,C23H18N4O6Cd,Mr=558.81,Dc=1.725 g.cm-3,Z=8,the final R=0.0531 and wR=O.1403.In the crystal structure,the cadmium is six-coordinated with four carboxylate oxygen atoms from three different carboxylate groups,and two nitrogen atoms from Medpq ligand,showing a slightly distorted octahedral geometry.Furthermore,it exhibits a one-dimensional zigzag structure with ipt-Cd-medpq as building units.CCDC:800998.%采用水热法合成了一种金属-有机配合物[Cd (ipt)(Medpq)]n(H2ipt =isophthalic acid,Medpq =2-methyldipyrido[3,2-f:2′,3′-h]quinoxaline),并对其进行了元素分析、红外光谱、紫外-可见光谱、热重表征、和X-射线单晶衍射测定.该配合物属于单斜晶系,C2/c空间群.在晶体结构中,Cd(Ⅱ)原子为六配位与来自于间苯二甲酸配体上的4个羧基氧原子,及Medpq配体上的2个氮原子配位,呈现畸变的八面体构型.整个晶体由ipt-Cd-medpq单元组成一维结构.

  6. 一类2(1H)-喹喔啉衍生物的电子轰击质谱分析%Electron Impact Mass Spectrometric Analysis of a Class of 2(1H)-Quinoxalin-2-one Derivatives

    Institute of Scientific and Technical Information of China (English)

    杨小兵; 丁松涛; 王安邦; 杨裕生; 胡伟华

    2002-01-01

    以邻苯二胺为原料合成并表征了一类喹喔啉衍生物:1-烷基-3-甲基-2(1H)-喹喔啉-2-酮(1-alkyl-3-methyl-2(1H)-quinoxalin-2-one,简称AMQ,其中alkyl=H、CH3、Et、n-C3H5、n-C5H11、n-C16H33).用电子轰击电离质谱(EI-MS)和核磁共振谱图(1H-NMR)鉴定了AMQ,研究了不同取代基对这类化合物EI-MS谱图的影响,分析得到一些裂解规律.结果表明:所有样品谱图中均有芳香化合物的特征CnH+n系列峰m/z 78,65,52,39和(或)m/z 77、76、64、63、51、50、38、37.对于未取代的样品及低级烷烃取代的样品,谱图中的基峰为分子离子峰.对于取代基中碳数大于等于3的样品,谱图中的基峰不是分子离子峰,分子离子峰强度随着碳数的增加而降低.这些样品一般容易发生骨架重排,丢失一分子CO,生成1-烷基-2-甲基苯并哒唑正离子.此外,还讨论了谱图中其它的一些碎片离子峰.这对于研究和指导喹喔啉衍生物的合成,探讨它们在药效及结构特征与生理活性的关系等方面具有重要的应用价值和理论意义.

  7. Synthesis and Characterization of VO(Ⅱ), Fe(Ⅱ), Co(Ⅱ), Ni(Ⅱ) and Cu(Ⅱ) Complexes of 2, 3-Bis(3, 5-dimethyl-1H-pyrazol-1-yl) Quinoxaline%VO(Ⅱ),Fe(Ⅱ),Co(Ⅱ),Ni(Ⅱ)和Cu(Ⅱ)的2,3-二(3,5-二甲基-1H-吡唑基)喹啉配合物的合成与表征

    Institute of Scientific and Technical Information of China (English)

    SandhyaRani D; AnanthaLakshmi P V; KamalaPrasad V; JayatyagaRaju V

    2012-01-01

    VO(Ⅱ),Fe(Ⅱ),Co(Ⅱ),Ni(Ⅱ)and Cu(Ⅱ)complexes of 2,3-bis (dimethyl -1H-pyrazol-1-yl)quinoxaline (BDMPQ) have been synthesized and characterized by elemental analysis,conductance,thermal,spectral and ESR techniques.Octahedral geometries have been proposed for all the complexes.BDMPQ acts as a neutral bisbidentate NN donor and forms polynuclear complexes.%合成了VO(Ⅱ),Fe(Ⅱ),Co(Ⅱ),Ni(Ⅱ)和Cu(Ⅱ)的2,3-二(3,5-二甲基-1H-吡唑基)喹啉配合物(BDMPQ)并用元素分析、电导、热分析、光谱和顺磁共振等技术对其表征.结果表明所有配合物均为八面体构型.BDMPQ起中性双二齿NN供体的作用并形成多核配合物.

  8. Nitrile crosslinked polyphenyl-quinoxaline/graphite fiber composites

    Science.gov (United States)

    Alston, W. B.

    1976-01-01

    Studies were performed to reduce the 600 F thermoplasticity of polyphenylquinoxaline (PPQ) matrix resins by introducing crosslinking by the reaction of terminal nitrile groups. Seven solvents and solvent mixtures were studied as the crosslinking catalysts and used to fabricate crosslinked PPQ/HMS graphite fiber composites. The room temperature and 600 F composite mechanical properties after short time and prolonged 600 F air exposure and the 600 F composite weight loss were determined and compared to those properties of high molecular weight, linear PPQ/HMS graphite fiber composites.

  9. Synthesis of a Phenothiazine-Quinoxaline Polymer for Photovoltaic Applications

    Energy Technology Data Exchange (ETDEWEB)

    Jang, Wooree; Yang, Yu Qi; Kim, Jeongseok; Lee, Soohyoung; Lee, Younsik [Chonbuk National Univ., Jeonju (Korea, Republic of)

    2013-06-15

    A new polymer, PPTQX, was successfully synthesized in this work. The polymer has a low band-gap of 1.76 eV with a HOMO level of .5.20 eV. The PPTQX-based photovoltaic devices exhibited PCEs of 0.21-0.83% under AM 1.5G illumination conditions. The unexpectedly low PCE values of the PPTQX-based devices were attributed primarily to the low absorption coefficient of the polymer and the good miscibility of the polymer and PCBM without the formation of a nanostructured morphology. Polymer solar cells (PSCs) have attracted considerable attention because of their unique advantages of low cost, light weight, and potential use in flexible devices. Based on the concept of a bulk heterojunction (BHJ) structure, PSCs made by blending poly(3-hexylthiophene) (P3HT) as a p-type material and [6,6]-phenyl-C61-butyric acid methyl ester (PC{sub 61}BM) as an n-type material have been most intensively investigated and have shown power conversion efficiencies (PCEs) up to 5-6%.

  10. Synthesis, Structure and Superoxide Dismutase-Like Activity of A New (Glycyl-β-alanine)(dipyrido[3,2-d:2′,3′-f]quinoxaline)Copper(Ⅱ) Complex%(甘氨酰-β-丙氨酸)(二吡啶[3,2-d:2′,3′-f]喹喔啉)铜( Ⅱ)配合物合成、结构及其超氧化物歧化酶活性

    Institute of Scientific and Technical Information of China (English)

    丁杨; 邓剑生; 乐学义

    2011-01-01

    A new complex, [Cu(Gly-^-Ala)(dpq)]?2H2O [Gly-/?-Ala=Glycyl-/?-alanine, dpq=dipyrido [3,2-J:2',3'-^]quinoxaline], has been synthesized and characterized by X-ray single crystal diffraction, elemental analysis, molar conductivity, IR and UV-Vis spectra. The complex crystallizes in triclinic space group P\\ , with a=0.70787(3) nm, 6=0.96727(4) nm, c=0.52436(6) nm, a=97.016(2)°, yS= 100.859(2)°, 7=108.046(2)°, F=0.95624(7) nm3. The SOD-like activity of the complex in water solution has been measured by improved nitroblue tetrazolium (NBT)-illumination method, and the electrochemical property of the complex has been studied by cyclic voltammetry method. The results indicated that the complex possesses an excellent SOD-like activity, and the rate constant (Kq) of the complex for catalyzing the dismuta-tionof Of isl^X^moP'-L's"1.%合成了新的(甘氨酰-β-丙氨酸)(二吡啶[3,2-d:2′,3′-f]喹喔啉)铜(Ⅱ)配合物:[Cu(Gly-β-Ala)(dpq)]·2H2O [Gly-β-Ala=甘氨酰-β-丙氨酸,dpq=二吡啶[3,2-d:2′,3′-f]喹喔啉].通过元素分析、红外光谱、紫外-可见光谱、摩尔电导率以及X射线单晶衍射对该配合物组成及结构进行了表征.配合物晶体属三斜晶系,空间群P-1,晶胞参数为:a=0.70787(3) nm,b=0.96727(4) nm,c=0.52436(6) nm,α=97.016(2)°,β= 100.859(2)°,γ=108.046(2)°,V=0.95624(7) nm3.应用改进的氯化硝基四氮唑蓝(NBT)光照还原法研究了配合物在水溶液中催化超氧阴离子自由基(O(.)-2)歧化分解超氧化物歧化酶(SOD)的活性,用循环伏安法研究了配合物的电化学性质.结果表明:该配合物具有良好的超氧化物歧化酶活性,表观催化速率常数为1.53×107L·mol- 1·s-1).

  11. Simultaneous screening analysis of 3-methyl-quinoxaline-2-carboxylic acid and quinoxaline-2-carboxylic acid residues in edible animal tissues by a competitive indirect immunoassay

    Science.gov (United States)

    Immunoassays contribute greatly to veterinary drug residue analysis and food safety, but there are no reported immunoassays on simultaneously detecting MQCA and QCA, the marker residues for carbadox and olaquindox. It is extremely difficult to produce broad-specificity antibodies that bind both res...

  12. Fused thiophene/quinoxaline low band gap polymers for photovoltaic's with increased photochemical stability

    DEFF Research Database (Denmark)

    Carlé, Jon Eggert; Jørgensen, Mikkel; Manceau, Matthieu

    2011-01-01

    and inverted geometry were prepared and tested in air. The normal geometry devices showed the highest efficiencies compared to the inverted, in particular owing to a higher Voc, with TQ1 being the most efficient with a power conversion efficiency (PCE) of 1.5% (1000 W m−2, AM1.5 G). For the inverted devices TQ...... of the three polymers was examined and compared to P3HT. They were found to be substantially more robust than P3HT with a ranking of DTTQ>BDTQ>TQ1P3HT, indicating that the fused ring systems of DTT and BDT impart a large degree of photochemical stability than thiophene. Furthermore devices with normal...

  13. The Discovery of Quinoxaline-Based Metathesis Catalysts from Synthesis of Grazoprevir (MK-5172).

    Science.gov (United States)

    Williams, Michael J; Kong, Jongrock; Chung, Cheol K; Brunskill, Andrew; Campeau, Louis-Charles; McLaughlin, Mark

    2016-05-01

    Olefin metathesis (OM) is a reliable and practical synthetic methodology for challenging carbon-carbon bond formations. While existing catalysts can effect many of these transformations, the synthesis and development of new catalysts is essential to increase the application breadth of OM and to achieve improved catalyst activity. The unexpected initial discovery of a novel olefin metathesis catalyst derived from synthetic efforts toward the HCV therapeutic agent grazoprevir (MK-5172) is described. This initial finding has evolved into a class of tunable, shelf-stable ruthenium OM catalysts that are easily prepared and exhibit unique catalytic activity.

  14. The position effect of electron-deficient quinoxaline moiety in porphyrin based sensitizers

    Science.gov (United States)

    Fan, Suhua; Lv, Kai; Sun, Hong; Zhou, Gang; Wang, Zhong-Sheng

    2015-04-01

    An electron-deficient group, 2,3-diphenylquinoxaline (DPQ), is incorporated as an auxiliary acceptor into the different positions of the porphyrin (Por) based donor-π bridge-acceptor (D-π-A) dye (FNE57) to construct D-A‧-Por-π-A (FNE58) and D-Por-A‧-π-A (FNE59) configurations. The incorporation of DPQ unit between the donor and porphyrin unit has negligible influence on the absorption property, whereas the DPQ unit located between the porphyrin unit and acceptor significantly increases the absorbance for the Soret band and the valley between the Soret and Q bands. Theoretical calculation reveals that incorporating the DPQ unit adjacent to the acceptor is more advantageous to delocalize the lowest unoccupied molecular orbital and enhance the electronic asymmetry, which facilitates the intramolecular charge transfer. The effect of DPQ unit and its linkage position on the performance of related quasi-solid-state dye-sensitized solar cells (DSSCs) is systematically investigated. The quasi-solid-state DSSC with sensitizer FNE59 displays a power conversion efficiency of 6.02%, which is 23% and 51% higher than those for FNE57 and FNE58 based DSSCs. Our studies facilitate the understanding of the crucial importance of molecular engineering and pave a new path to design novel porphyrin based sensitizers for highly efficient DSSCs.

  15. Preparation of 6-Substituted Quinoxaline JSP-1 Inhibitors by Microwave Accelerated Nucleophilic Substitution

    Directory of Open Access Journals (Sweden)

    Jingkang Shen

    2006-12-01

    Full Text Available A small library of 6-aminoquinoxalines has been prepared by nucleophilic substitution of 6-fluoroquinoxaline with amines and nitrogen-containing heterocycles under computer-controlled microwave irradiation. Some compounds were found to be potent inhibitors of JNK Stimulatory Phosphatase-1 (JSP-1 in an in vitro biological assay.

  16. 2-[(E-2-(3,4-Dichlorobenzylidenehydrazin-1-yl]quinoxaline

    Directory of Open Access Journals (Sweden)

    Thais C. M. Noguiera

    2014-02-01

    Full Text Available The 21 non-H atoms of the title compound, C15H10Cl2N4, are almost planar (r.m.s. deviation = 0.032 Å; the conformation about the N=C bond [1.277 (6 Å] is E. In the crystal, zigzag supramolecular chains along the c axis (glide symmetry are formed via N—H...N hydrogen bonds. These associate along the b axis by π–π interactions between the fused and terminal benzene rings [intercentroid distance = 3.602 (3 Å] so that layers form in the bc plane.

  17. Efficient white light generation from 2,3-diphenyl-1,2-dihydro-quinoxaline complex

    Science.gov (United States)

    Dwivedi, Y.; Kant, S.; Rai, R. N.; Rai, S. B.

    2010-11-01

    In this article, we report two organic materials dispersed in transparent poly (methyl methacrylate) matrix for efficient white light simulation under different optical excitations. A newly synthesized complex of benzoin and o-phenyldiamine is observed to be white on illumination with a blue LED. A new concept of white light emitting tube is also demonstrated. A mixture of 2,2″-([1,1'-biphenyl]-4,4'-diyldi-2,1-ethenediyl)-bis-benzenesulfonic acid disodium salt and complex is optimized to emit white light extended in the violet region on 355 nm laser excitation. The optical quality of the emitted white light is adjudged by the CIE coordinate, correlated color temperature and color rendition index in both the cases.

  18. C-H-Activated Direct Arylation of Strong Benzothiadiazole and Quinoxaline-Based Electron Acceptors.

    Science.gov (United States)

    Zhang, Junxiang; Parker, Timothy C; Chen, Wayne; Williams, LaRita; Khrustalev, Victor N; Jucov, Evgheni V; Barlow, Stephen; Timofeeva, Tatiana V; Marder, Seth R

    2016-01-15

    Electron acceptors are important components of π-conjugated materials, but the strong electron-withdrawing properties of the required synthetic intermediates often make them poor substrates in synthetic schemes designed around conventional organometallic cross-coupling. Here, strong benzodiimine-based acceptors, including 5,6-difluoro[2,1,3]benzothiadiazole, 5,6-dicyano[2,1,3]benzothiadiazole, 5,6-dicyanobenzo[d][1,2,3]triazole, 6,7-dicyanoquinoxaline, and 6,7-dinitroquinoxaline, are shown to undergo facile palladium-catalyzed C-H direct arylation with a variety of bromoarenes in moderate to high yields. The electrochemical characteristics of di-2-thienyl derivatives synthesized using this methodology are compared and suggest that, in an electron-transfer sense, 5,6-dicyano[2,1,3]benzothiadiazole is a comparably strong acceptor to benzo[1,2-c:4,5-c']bis[1,2,5]thiadiazole. The synthetic results suggest that high electron-withdrawing ability, which has traditionally limited reaction yields and structural variety in organic electronic materials, may be advantageous when employing C-H activated direct arylation in certain circumstances.

  19. Synthesis and biological evaluation of some novel quinoxaline derivatives as anticonvulsant agents.

    Science.gov (United States)

    Elhelby, Abdelghany Aly; Ayyad, Rezk Rezk; Zayed, Mohamed Fathalla

    2011-01-01

    In view of their expected anticonvulsant activity, some new derivatives of quinonxaline (V1-7) were designed and synthesized by condensation of different aromatic aldehydes with 2-(2-oxo-3-phenylquinoxalin-1(2H)-yl)acetohydrazide (IV). All synthesized compounds were isolated and confirmed by IR, 1H-NMR, MS, elemental analysis and then tested as anticonvulsant agents. Compound V3 and V1 showed the highest anticonvulsant effect with anticonvulsant potency relative to phenobarbital sodium of 0.8 and 0.75 whereas compound V5 exhibited the lowest relative potency of 0.09. The other compounds showed variable activity between these values as follows: V2 = 0.19, V4 = 0.41, V6 = 0.1 and V7 = 0.15. All compounds showed less activity than the reference compound phenobarbital. But the compounds provided a basis for further optimization.

  20. Synthesis and Photoluminescence of a New Red Phosphorescent Iridium(III) Quinoxaline Complex

    Institute of Scientific and Technical Information of China (English)

    Guo Lin ZHANG; Ze Hua LIU; Hai Qing GUO

    2004-01-01

    A new cyclometalated iridium(III) complex with the formula [Ir(DPQ)2(acac)] (DPQ= 2,3-diphenylquinoxaline; acac=acetylacetone) was prepared. The structure of the complex was confirmed by Elemental Analysis (EA), 1H NMR, and mass spectroscopy (MS). The UV-vis absorption and photoluminescent properties of the complex were investigated.

  1. Functionalization of quinoxalines by using TMP bases: preparation of tetracyclic heterocycles with high photoluminescene quantum yields.

    Science.gov (United States)

    Nafe, Julia; Herbert, Simon; Auras, Florian; Karaghiosoff, Konstantin; Bein, Thomas; Knochel, Paul

    2015-01-12

    Tetracyclic heterocycles that exhibit high photoluminescence quantum yields were synthesized by anellation reactions of mono-, di-, and trifunctionalized 2,3-dichloroquinoxalines. Thus, treatment of 2,3-dichloroquinoxaline with TMPLi (TMP = 2,2,6,6-tetramethylpiperidyl) allows a regioselective lithiation in position 5. Quenching with various electrophiles (iodine, (BrCl2 C)2 , allylic bromide, acid chloride, aryl iodide) leads to 5-functionalized 2,3-dichloroquinoxalines. Further functionalization in positions 6 and 8 can be achieved by using TMPLi or TMPMgCl⋅LiCl furnishing a range of new di- and tri-functionalized 2,3-dichloroquinoxalines. The chlorine atoms are readily substituted by anellation with 1,2-diphenols or 1,2-dithiophenols leading to a series of new tetracyclic compounds. These materials exhibit strong, tunable optical absorption and emission in the blue and green spectral region. The substituted O-heterocyclic compounds exhibit particularly high photoluminescence quantum yields of up to 90%, which renders them interesting candidates for fluorescence imaging applications.

  2. Low Cost Aromatic Acetylene and Oligomeric Benzils and Their Conversion to Acetylene Terminated Quinoxalines

    Science.gov (United States)

    1982-07-01

    toluene with azeotropic removal of water . The product was isolated by precipitation in methanol. Only moderate yields, 50-80%, were attained because...oligomer (n=2.2, 712-60B), 15.0 g o-phenylenediamine and 400 mX toluene . The mixture was brought to reflux. Water was no longer formed after about 1.5...occurring. The mixture was cooled, filtered to remove amine salts, and stripped of solvent. The residue was taken up in 400 ml toluene and water

  3. Liquid-Liquid Extraction Of Zinc By 3-Methyl-Quinoxaline-2-Thione From Nitrate Medium

    Directory of Open Access Journals (Sweden)

    Sanae Baki Senhaji

    2015-09-01

    Full Text Available The extraction of zinc with 3-methyl-2 (1H-quinoxalinethione LH, is investigated in nitrate solution as a function of pHrange 2-6, and analytical concentrations of NO-3 anions (CNO3 and extractant (CLH. The extraction mechanism with LH,is determined on the basis of the variation of the distribution coefficient D with pH, CNO3 and CLH. As a result, the partition equilibrium involves complexing phenomenon, ion-pair formation, and 1H+ exchange reaction. The overall extraction constants are logK01.5 = 5.1, and logK11.5 = -0.6. The extraction complexes are found to be Zn(LH2∫(NO3∫+2 and Zn(L (LH∫-1 (NO3 with l = 1 or 2. The hydrolysis reaction of Zn(II is evaluated and it is found that it results in the formation of Zn(OH+and Zn(OH2aq species, at pH >5.6. Zinc shows maximum percent extraction (75% with the pH 4.7 at low organic ligand concentration (0.01M.

  4. Synthesis, Characterization and Antimicrobial Activity of Oxovanadium(IV) Complexes of Schiff Base Hydrazones Containing Quinoxaline Moiety

    Institute of Scientific and Technical Information of China (English)

    Lakshmi, P. V. Anantha; Satyanarayana, T.; Reddy, P. Saritha

    2012-01-01

    The oxovanadium(IV) complexes of the Schiff base hydrazones, synthesized from 3-hydrazinoquinoxaline-2- one (HQO) with salicylaldehyde (HSHQO), o-hydroxyacetophenone (HHAHQO), dehydroacetic acid (HDHAHQO) and o-nitrobenzaldehyde (NBHQO) were synthesized and characterized on the basis of analytical, conductance, magnetic moment, infrared, NMR, ESR and electronic spectral data. The ligands HSHQO, HDHAHQO behaved as monobasic tridentate ONN donors through phenolic oxygen, azomethine nitrogens. The ligand HAHQO acted as a monobasic bidentate ON donor through the phenolic oxygen, azomethine (free) nitrogen and the ligand NBHQO acted as neutral bidentate ON donor through oxygen of the nitro group and azomethine (free) nitrogen.

  5. 4-Ferrocenyl-1-methyl-3-benzoylspiro[pyrrolidine-2,11′-indeno[1,2-b]quinoxaline

    Directory of Open Access Journals (Sweden)

    B. Vijayakumar

    2012-12-01

    Full Text Available In the title compound, [Fe(C5H5(C31H24N3O], the pyrrolidine ring adopts a twist conformation. The pyrrolidine ring is almost perpendicular to the indenoquinoxaline ring system, making a dihedral angle of 84.44 (5°. The cyclopentadienyl rings of the ferrocene moiety adopt an eclipsed conformation. The crystal packing features weak C—H...N and C—H...π interactions.

  6. Conformationally blocked quinoxaline cavitand as solid-phase microextraction coating for the selective detection of BTEX in air.

    Science.gov (United States)

    Riboni, N; Trzcinski, J W; Bianchi, F; Massera, C; Pinalli, R; Sidisky, L; Dalcanale, E; Careri, M

    2016-01-28

    A tetraquinoxaline cavitand functionalized with methylenoxy bridges at the upper rim is proposed as selective solid-phase microextraction (SPME) coating for the determination of BTEX at trace levels in air. The SPME fibers were characterized in terms of film thickness, morphology, thermal stability and extraction capabilities. An average coating thickness of 35 (±4) μm, a thermal stability up to 350 °C and a good fiber-to-fiber and batch-to-batch repeatability with RSD lower than 15% were obtained. Excellent enrichment factors ranging from 360-700 × 10(3) were obtained for the investigated compounds. Finally, method validation proved the capabilities of the developed coating for the selective sampling of BTEX, achieving LOD values in the 0.4-1.2 ng m(-3) range.

  7. Cell death by the quinoxaline dioxide DCQ in human colon cancer cells is enhanced under hypoxia and is independent of p53 and p21

    Directory of Open Access Journals (Sweden)

    Haddadin Makhluf J

    2010-11-01

    Full Text Available Abstract Introduction We have shown that the radio sensitizer DCQ enhances sensitivity of HCT116 human colon cancer cells to hypoxia. However, it is not known whether the p53 or p21 genes influence cellular response to DCQ. In this study, we used HCT116 that are either wildtype for p53 and p21, null for p53 or null for p21 to understand the role of these genes in DCQ toxicity. Methods HCT116 cells were exposed to DCQ and incubated under normoxia or hypoxia and the viability, colony forming ability, DNA damage and apoptotic responses of these cells was determined, in addition to the modulation of HIF-1α and of p53, p21, caspase-2, and of the ataxia telangiectasia mutated (ATM target PIDD-C. Results DCQ decreased colony forming ability and viability of all HCT116 cells to a greater extent under hypoxia than normoxia and the p21-/-cell line was most sensitive. Cells had different HIF-1α responses to hypoxia and/or drug treatment. In p53+/+, DCQ significantly inhibited the hypoxia-induced increases in HIF-1α protein, in contrast to the absence of a significant HIF-1α increase or modulation by DCQ in p21-/- cells. In p53-/- cells, 10 μM DCQ significantly reduced HIF-1α expression, especially under hypoxia, despite the constitutive expression of this protein in control cells. Higher DCQ doses induced PreG1-phase increase and apoptosis, however, lower doses caused mitotic catastrophe. In p53+/+ cells, apoptosis correlated with the increased expression of the pro-apoptotic caspase-2 and inhibition of the pro-survival protein PIDD-C. Exposure of p53+/+ cells to DCQ induced single strand breaks and triggered the activation of the nuclear kinase ATM by phosphorylation at Ser-1981 in all cell cycle phases. On the other hand, no drug toxicity to normal FHs74 Int human intestinal cell line was observed. Conclusions Collectively, our findings indicate that DCQ reduces the colony survival of HCT116 and induces apoptosis even in cells that are null for p53 or p21, which makes it a molecule of clinical significance, since many resistant colon tumors harbor mutations in p53.

  8. Antidepressant & anxiolytic activities of N-(pyridin-3-yl quinoxalin-2-carboxamide: A novel serotonin type 3 receptor antagonist in behavioural animal models

    Directory of Open Access Journals (Sweden)

    Dilip Kumar Pandey

    2016-01-01

    Interpretation & conclusions: The present findings indicate the potential antidepressant-like and anxiolytic-like effects of QCF-21 at low doses in rodent behavioural models of depression and anxiety. Further studies need to be done to understand the underlying mechanism.

  9. Water-soluble isoindolo[2,1-a]quinoxalin-6-imines: in vitro antiproliferative activity and molecular mechanism(s) of action.

    Science.gov (United States)

    Parrino, Barbara; Carbone, Anna; Ciancimino, Cristina; Spanò, Virginia; Montalbano, Alessandra; Barraja, Paola; Cirrincione, Girolamo; Diana, Patrizia; Sissi, Claudia; Palumbo, Manlio; Pinato, Odra; Pennati, Marzia; Beretta, Giovanni; Folini, Marco; Matyus, Peter; Balogh, Balázs; Zaffaroni, Nadia

    2015-04-13

    Water-soluble isoindoloquinoxalin (IIQ) imines and the corresponding acetates were conveniently prepared from the key intermediates 2-(2'-aminophenyl)-2H-isoindole-1-carbonitriles obtained by a Strecker reaction between substituted 1,2-dicarbaldehydes and 1,2-phenylenediamines. Both series were screened by the National Cancer Institute (Bethesda, MD) and showed potent antiproliferative activity against a panel of 60 human tumor cell lines. Several of the novel compounds showed GI50 values at a nanomolar level on the majority of the tested cell lines. Among IIQ derivatives, methoxy substituents at positions 3 and 8 or/and 9 were especially effective in impairing cell cycle progression and inducing apoptosis in cancer cells. These effects were associated to IIQ-mediated impairment of tubulin polymerization at pharmacologically significant concentrations of tested compounds. In addition, impaired DNA topoisomerase I functions and perturbation in telomere architecture were observed in cells exposed to micromolar concentrations of IIQ derivatives. The above results suggest that IIQ derivatives exhibit multi-target cytotoxic activities.

  10. Quinoxaline polymers and copolymers derived from 1,4-bis(1'-naphthalenyloxalyl)benzene and their graphite composites. [polymer chemistry and polymer physics

    Science.gov (United States)

    Port, W. S.

    1976-01-01

    Experimental studies were performed with new polyquinoxalines and their graphite composites. Four polymers were synthesized, and then were characterized with respect to their inherent viscosity, elemental chemical analysis, mechanical, and thermodynamic properties. Structural formulas of the polymers and their precursors are given; methods of synthesis are described; and specifically examined was the preparation of polymers from 3,3' diamino-benzidine from 1,4- and 1,3- bis ((1'-napthalenyl) oxalyl) benzene respectively. Also considered was the preparation of polyquinoxalines from poly (p-benzil), and 1,2- aryldiamines.

  11. Synthesis of a new intercalating nucleic acid 6H-INDOLO[2,3-b] quinoxaline oligonucleotides to improve thermal stability of Hoogsteen-type triplexes

    DEFF Research Database (Denmark)

    Osman, Amany M A; Pedersen, Erik Bjerregaard; Bergman, Jan

    2013-01-01

    A new intercalating nucleic acid monomer X was obtained in high yield starting from alkylation of 4-iodophenol with (S)-(+)-2-(2,2-dimethyl-1,3-dioxolan-4-yl)ethanol under Mitsunobu conditions followed by hydrolysis with 80% aqueous acetic acid to give a diol which was coupled under Sonogashira...

  12. New IKK inhibitors: Synthesis of new imidazo[1,2-a]quinoxaline derivatives using microwave assistance and biological evaluation as IKK inhibitors.

    Science.gov (United States)

    Moarbess, Georges; Guichou, Jean-François; Paniagua-Gayraud, Stéphanie; Chouchou, Adrien; Marcadet, Olivier; Leroy, Fiona; Ruédas, Rémi; Cuq, Pierre; Deleuze-Masquéfa, Carine; Bonnet, Pierre-Antoine

    2016-06-10

    The inhibition of the NF-κB-dependent pathways by IKK inhibitors plays an important role in immunity, inflammation, and cancer. New imidazoquinoxalines tricyclic derivatives are prepared using microwave assistance and their biological activities as IKK inhibitors are described. Compounds 6a present a potent inhibition activity and selectivity for IKK2. Docking studies in the IKK2 binding site allowed identification of residues most likely to interact with theses inhibitors and explain their potent IKK2 inhibition activity and selectivity.

  13. Detection of 6-chloro-2-hydroxyl-quinoxaline content%2-羟基-6-氯喹喔啉含量的测定

    Institute of Scientific and Technical Information of China (English)

    宋丽华; 苗革新

    2009-01-01

    采用高效液相色谱法,以Kromasil C-18(200 mm x4.6 mm,5μm)为固定相,以甲醇+水混合液(V(甲醇):V(水)=700:300)为流动相,流速为0.6 mL/min,柱温为35℃,检测波长为254 nm,测得2-羟基-6-氯喹喔啉的变异系数为0.23%,平均回收率为99.69%.

  14. 6-Ferrocenoyl-7-(4-fluorophenylspiro[hexahydropyrrolo[1,2-c][1,3]thiazole-5,11′-indeno[1,2-b]quinoxaline

    Directory of Open Access Journals (Sweden)

    Sivasubramanian Suhitha

    2013-09-01

    Full Text Available In the title compound, [Fe(C5H5(C32H23FN3OS], both the thiazolidine ring and the pyrrolidine ring adopt a twist conformation on the N—C(H bridging bond. Their mean planes are inclined to one another by 10.05 (10°, and they make dihedral angles of 82.09 (10 and 89.67 (11°, respectively, with the cyclopentane ring. The F atom deviates by −0.0238 (2 Å from the benzene ring to which it is attached. In the crystal, molecules are linked by a pair of C—H...O hydrogen bonds, forming inversion dimers.

  15. Potent quinoxaline-spaced phosphono alpha-amino acids of the AP-6 type as competitive NMDA antagonists: synthesis and biological evaluation.

    Science.gov (United States)

    Baudy, R B; Greenblatt, L P; Jirkovsky, I L; Conklin, M; Russo, R J; Bramlett, D R; Emrey, T A; Simmonds, J T; Kowal, D M; Stein, R P

    1993-02-01

    A series of alpha-amino-3-(phosphonoalkyl)-2-quinoxalinepropanoic acids was synthesized and evaluated for NMDA receptor affinity using a [3H] CPP binding assay. Functional antagonism of the NMDA receptor complex was evaluated in vitro using a stimulated [3H]TCP binding assay and in vivo by employing an NMDA-induced seizure model. Some analogues also were evaluated in the [3H]-glycine binding assay. Several compounds of the AP-6 type show potent and selective NMDA antagonistic activity both in vitro and in vivo. In particular alpha-amino-7-chloro-3-(phosphonomethyl)-2-quinoxalinepropanoic acid (1) displayed an ED50 of 1.1 mg/kg ip in the NMDA lethality model. Noteworthy is alpha-amino-6,7-dichloro-3-(phosphonomethyl)-2-quinoxalinepropanoic++ + acid (3) with a unique dual activity, displaying in the NMDA receptor binding assay an IC50 of 3.4 nM and in the glycine binding assay an IC50 of 0.61 microM.

  16. Potent quinoxaline-based inhibitors of PDGF receptor tyrosine kinase activity. Part 2: the synthesis and biological activities of RPR127963 an orally bioavailable inhibitor.

    Science.gov (United States)

    He, Wei; Myers, Michael R; Hanney, Barbara; Spada, Alfred P; Bilder, Glenda; Galzcinski, Helen; Amin, Dilip; Needle, Saul; Page, Ken; Jayyosi, Zaid; Perrone, Mark H

    2003-09-15

    RPR127963 demonstrates an excellent pharmacokinetic profile in several species and was found to be efficacious in the prevention of restenosis in a Yucatan mini-pig model upon oral administration of 1-5 mg/kg. The in vitro selectivity profile and SAR of the highly optimized PDGF-R tyrosine kinase inhibitor are highlighted.

  17. A green and efficient protocol for the synthesis of quinoxaline, benzoxazole and benzimidazole derivatives using heteropolyanion-based ionic liquids: as a recyclable solid catalyst.

    Science.gov (United States)

    Vahdat, Seyed Mohammad; Baghery, Saeed

    2013-09-01

    In this paper, we introduce two nonconventional ionic liquid compounds which are composed of propane sulfonate functionalized organic cations and heteropolyanions as green solid acid catalysts for the highly efficient and green synthesis of 2,3-disubstitutedquinoxaline derivatives. These ionic liquids are in the solid state at room temperature and the synthesis is carried out via the one-pot condensation reaction of various o-phenylenediamine with 1,2-diketone derivatives. Benzoxazole and benzimidazole derivatives were also synthesized by these novel catalysts via the one-pot condensation from reaction orthoester with o-aminophenol (synthesis of benzoxazole derivatives) and ophenylenediamine (synthesis of benzimidazole derivatives). All experiments successfully resulted in the desired products. The described novel synthesis method has several advantages of safety, mild condition, high yields, short reaction times, simplicity and easy workup compared to the traditional method of synthesis.

  18. 3-Methyl-1-(prop-2-en-1-ylquinoxalin-2(1H-one

    Directory of Open Access Journals (Sweden)

    Youssef Ramli

    2010-07-01

    Full Text Available In the molecule of the title compound, C12H12N2O, the quinoxaline ring is planar with an r.m.s. deviation of 0.007 (15 Å. The dihedral angle between the quinoxaline and propenyl planes is 82.1 (2°. The crystal packing is stabilized by offset π–π stacking between the quinoxaline rings [centroid–centroid distance = 3.8832 (9 Å].

  19. 2-溴甲基-3-(二溴甲基)喹喔啉的合成研究%The Synthesis of 2-(Bromomethyl)-3-(dibromomethyl)quinoxaline

    Institute of Scientific and Technical Information of China (English)

    黄丽莎; 曾志; 曾和平

    2002-01-01

    以2,3-二(溴甲基)喹喔啉为原料,以N-溴琥珀酰亚胺为溴化试剂合成了2-溴甲基-3-(二溴甲基)喹喔啉(1),1是Diels-Alder环加成反应中形成含杂原子环的C60衍生物的一种重要中间体.通过IR,1H NMR,13C NMR,DEPT谱和MS对其进行了结构表征.

  20. Crystal structure of methyl 3′-benzamido-4′-(4-methoxyphenyl-1′-methylspiro[indeno[1,2-b]quinoxaline-11,2′-pyrrolidine]-3′-carboxylate

    Directory of Open Access Journals (Sweden)

    Kuppan Chandralekha

    2016-09-01

    Full Text Available In the title compound, C35H30N4O3, the spiro C atom connects the five-membered pyrrolidine ring and the indenoquinoxaline ring system. The pyrrolidine ring adopts a twist conformation. An intramolecular N—H...N interaction between the amino group and the pyrazine ring is observed. In the crystal, molecules are linked by a pairs of C—H...O hydrogen bonds, forming inversion dimers.

  1. A Green Synthesis Method of 6-Chloro-2-Hydroxyl-Quinoxaline%一种2-羟基-6-氯喹噁啉绿色合成方法

    Institute of Scientific and Technical Information of China (English)

    朱冬梅

    2016-01-01

    目前国内生产精喹禾灵关键中间体2-羟基-6-氯喹噁啉主要用硫化钠还原,其产生的污水多且难处理;而文章采用双氧水作为还原剂,大大缓解了生产过程中污水的处理难题,为以后精喹绿色生产提供较好路线.

  2. 6′-Amino-3′-methyl-11H,2′H-spiro[indeno[1,2-b]quinoxaline-11,4′-pyrano[2,3-c]pyrazole]-5′-carbonitrile ethanol monosolvate

    Directory of Open Access Journals (Sweden)

    Jia Zheng

    2012-07-01

    Full Text Available In the title spiroindenoquinoxaline compound, C22H14N6O·C2H6O, the five-membered ring of the indene unit and the pyran ring are perpendicular [89.11 (3°]. In the crystal, N—H...N hydrogen bonds connect the spiroindenoquinoxaline molecules, and the ethanol solvent molecules complete the hydrogen-bond network via O—H...N and N—H...O interactions.

  3. 2(1H)-喹喔啉系列衍生物的质谱研究%Mass Spectrometry Research on a Series of 2(1H)-Quinoxalin-2-one Derivatives

    Institute of Scientific and Technical Information of China (English)

    杨小兵; 丁松涛; 王安邦; 杨裕生; 胡伟华

    2001-01-01

    2(1H)-喹喔啉衍生物是一类重要的杂环化合物,可应用于药物,如用作受体及受体拮抗剂、杀菌剂等;还可用作植物生长调节剂、荧光探针等诸多领域.本文研究了一系列喹喔啉衍生物的电子轰击质谱,得到了一些裂解规律.……

  4. Synthesis of 1, 3, 4-oxadiazole derivatives containing quinoxaline moiety%含喹喔啉环1,3,4- 二唑衍生物的合成及结构鉴定

    Institute of Scientific and Technical Information of China (English)

    刘方明; 张正方; 张春霞; 刘育亭

    2000-01-01

    报道了果糖与邻苯二胺反应制得喹喔啉-2-甲醛后,与芳酞肼作用得到相应的芳酰腙,芳酰腙在不同的条件下环化分别得到1,3,4- 二唑衍生物,产物经元素分析、IR、1 HNMR和MS确证了其结构.

  5. Synthesis of 2,3-dihydroxyl quinoxaline and its application in the determination of trace lead%2,3-二羟喹喔啉的合成及其在微量铅分析中的应用

    Institute of Scientific and Technical Information of China (English)

    杨昌昕; 肖向旭; 杨志斌

    2003-01-01

    合成了新荧光试剂2,3-二羟喹喔啉(DHQX),并研究了Pb(Ⅱ)对它的荧光熄灭作用,建立了荧光熄灭法测定食醋中的微量Pb(Ⅱ),检出线性范围为0~75μg/25mL,结果满意.

  6. Microwave-assisted Synthesis and Photoluminescence of a Novel Iridium (Ⅲ)Quinoxaline Complex%新型喹喔啉铱(Ⅲ)配合物的微波合成及其光致发光

    Institute of Scientific and Technical Information of China (English)

    潘彤; 宁静恒; 蔡红革

    2009-01-01

    采用微波辐射方法,由2-苯基喹喔啉(PQ)与水合三氯化铱(IrCl3·H2O)反应,合成了一种新型三环喹喔啉铱配合物[Ir(PQ)3](PQ=2-苯基喹喔啉),通过1H NMR、元素分析和质谱方法对配合物进行了表征,并研究了配合物的紫外吸收光谱和光致发光光谱.结果表明,配合物Ir(PQ)3在476 nm和607am处存在单线态1MLCT(金属到配体的电荷跃迁)和三线态3MLCT的吸收;在625 nm处有较强的金属配合物三线态的磷光发射.是一种新型红色三线态磷光材料.

  7. Microwave-Assisted Synthesis and Photoluminescence of Iridium(Ⅲ) Quinoxaline Complex%微波辐射法合成喹喔啉铱(Ⅲ)配合物及其发光性质

    Institute of Scientific and Technical Information of China (English)

    吴秋华; 王传红; 宋溪明; 吴抒遥; 姜玉春; 张国林

    2009-01-01

    采用微波辐射加热方法,将2,3-二苯基喹喔啉(DPQ)与水合三氯化铱(IrCl3·H2O)反应,合成了一种新型三环喹喔啉铱配合物[Ir(DPQ)3],通过元素分析、1H NMR和质谱方法对配合物结构进行了表征,并初步研究了配合物的吸收光谱和荧光光谱. 结果表明,配合物Ir(DPQ)3在387和458 nm处存在单线态1MLCT和三线态3MLCT(金属到配体的电荷跃迁)的吸收;在634 nm处有较强的金属配合物三线态的磷光发射.

  8. Microwave-assisted synthesis and photoluminescence of anew triplet iridium (Ⅲ) quinoxaline complex%新型三线态喹喔啉铱(Ⅲ)配合物的微波合成及其光致发光

    Institute of Scientific and Technical Information of China (English)

    吴秋华; 王传红; 宋溪明; 吴抒遥; 张国林

    2011-01-01

    在微波辅助加热下,4,4'-二氟-2,3-二苯基喹喔啉(DPQF)与水合三氯化铱(IrCl3·H2O)反应,合成了一种新型三环喹喔啉铱配合物[Ir(DPQF)3],通过1HNMR、元素分析和质谱方法对配合物结构进行了表征,并研究了配合物的吸收光谱和光致发光光谱.结果表明,配合物Ir(DPQF),在391和453 nm处存在单线态1MLCT(金属到配体的电荷跃迁)和三线态3MLCT的吸收;在618 nm处有较强的金属配合物三线态的磷光发射,是一种新型红色磷光材料.

  9. Synthesis and antimalarial activity of new 3-arylquinoxaline-2-carbonitrile derivatives.

    Science.gov (United States)

    Zarranz, Belén; Jaso, Andrés; Aldana, Ignacio; Monge, Antonio; Maurel, Séverine; Deharo, Eric; Jullian, Valérie; Sauvain, Michel

    2005-01-01

    New series of 3-arylquinoxaline-carbonitrile derivatives have been synthesized from various 5-substituted or 5,6-disubstituted benzofuroxanes and tested for their in vitro and in vivo activity against the erythrocytic development of Plasmodium falciparum strain with different chloroquine-resistance status. Quinoxaline 1,4-dioxide derivatives showed superior antimalarial activity in respect to reduced quinoxaline analogues. The best activity was observed with nonsubstituted quinoxaline 1,4-dioxides in positions 6 and 7 of the aromatic ring and with a hydrogen or chloro substituent in para position of the phenyl group.

  10. Heterocyclic-2-carboxylic Acid (3-Cyano-1,4-di-N-oxidequinoxalin-2-ylamide Derivatives as Hits for the Development of Neglected Disease Drugs

    Directory of Open Access Journals (Sweden)

    Antonio Monge

    2009-06-01

    Full Text Available Neglected diseases represent a major health problem. It is estimated that one third of the world population is infected with tuberculosis (TB. Besides TB, Chagas disease, affects approximately 20 million people. Quinoxalines display great activities against TB and Chagas. Forty new quinoxaline 1,4-di-N-oxide derivatives have been prepared and tested against M. tuberculosis and T. cruzi. Carboxylic acid quinoxaline 1,4-di-N-oxides (CAQDOs 5 and 17 showed MIC values on the same order as the reference antituberculosis drug, rifampicin. Meanwhile, CAQDOs 12 and 22 presented IC50 values in the same order as the anti-chagasic drug, nifurtimox.

  11. Synthesis of novel pyrazolylquinoxalines

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ho Sik [Catholoic University of Taegu-Hyosung, Gyongsan (Korea, Republic of); Kwag, Sam Tag [Pukyong National Univ., Pusan (Korea, Republic of)

    2000-06-01

    The reaction of 6-chloro-2-hydrazinoquinoxaline 4-oxide (10) with acetylacetone or dibenzoylmethane gave 6-chloro-2-(3,5-disubstituted pyrazol-1-yl)quinoxaline 4-oxide (11) through the intramolecular cyclization. The chlorination of compound 11 with phosphoryl chloride afforded 3,6-dichloro-2-(3,5-disubstituted pyrazol-l-yl)quinoxalines (12), whose reaction with hydrazine hydrate provided 6-chloro-3-hydrazino-2-(3,4-disubstituted pyrazol-l-yl)quinoxalines (13). The reaction of compound 13 with substituted benzaldehydes, benzenesulfonyl chloride, substituted benzoyl chlorides or acyl chlorides gave novel pyrazolylquinoxalines.

  12. Nonracemic 2-diazo-1-oxiranyl-ethanone, a versatile chiral epoxide educt in diazocarbonyl reactions

    Science.gov (United States)

    Groarke; McKervey; Miel; Nieuwenhuyzen

    2000-08-10

    (S)-(-)-2-Diazo-1-oxiranyl-ethanone, prepared in two steps from (R)-(+)-glycidol, has been employed as an intermediate in several characteristic diazocarbonyl reactions to yield novel, nonracemic products including an epoxy quinoxaline and epoxy thiazoles and oxazoles.

  13. Drug: D08292 [KEGG MEDICUS

    Lifescience Database Archive (English)

    Full Text Available D08292 Drug Olaquindox (INN); Olaquindox [veterinary] (TN) C12H13N3O4 263.0906 263....2493 D08292.gif Antiinfective, antibacterial, veterinary Quinoxalin DNA synthesis inhibitor Antiinfectives [

  14. Synthesis and biological activity of some new 1-benzyl and 1-benzoyl-3-heterocyclic indole derivatives.

    Science.gov (United States)

    El-Sawy, Eslam Reda; Bassyouni, Fatma A; Abu-Bakr, Sherifa H; Rady, Hanaa M; Abdlla, Mohamed M

    2010-03-01

    Starting from 1-benzyl- (2a) and 1-benzoyl-3-bromoacetyl indoles (2b) new heterocyclic, 2-thioxoimidazolidine (4a, b), imidazolidine-2,4-dione (5a, b), pyrano(2,3-d)imida-zole (8a, b and 9a, b), 2-substituted quinoxaline (11a, b-17a, b) and triazolo(4,3-a)quinoxaline derivatives (18a, b and 19a, b) were synthesized and evaluated for their antimicrobial and anticancer activities. Antimicrobial activity screening performed with concentrations of 0.88, 0.44 and 0.22 microg mm(-2) showed that 3-(1-substituted indol-3-yl)quinoxalin-2(1H)ones (11a, b) and 2-(4-methyl piperazin-1-yl)-3-(1-substituted indol-3-yl) quinoxalines (15a, b) were the most active of all the tested compounds towards P. aeruginosa, B. cereus and S. aureus compared to the reference drugs cefotaxime and piperacillin, while 2-chloro-3-(1-substituted indol-3-yl)quinoxalines (12a, b) were the most active against C. albicans compared to the reference drug nystatin. On the other hand, 2-chloro-3-(1-benzyl indol-3-yl) quinoxaline 12a display potent efficacy against ovarian cancer xenografts in nude mice with tumor growth suppression of 100.0 +/- 0.3 %.

  15. GC/MS Analysis of Quinoxaline-2-Carboxylic Acid Residues in Animal Muscle, Liver and Kidney Products%气质联用法分析动物肌肉、肝脏和肾脏中喹喔啉-2羧酸的含量

    Institute of Scientific and Technical Information of China (English)

    彭艳; 刘煜

    2006-01-01

    The developed GC-MS method provided a high sensitivity and specificity for the analysis of QCA (Quinoxatine-2-Carboxylic Acid) in animal muscle, liver and kidney products. Less interferences and reproducible recoveries were obtained.The minimum detection limit for QCA was 1.0μ g/kg, which was defmed on the basis of the current international maximum limit for carbadox and its metabolites residues in animal muscle, liver and kidney products. The recoveries for these samples ranged from 60%~125%. The correlation coefficient was 0.998.%本文研究了用气质联用仪检测动物肌肉、肝脏及肾脏中喹喔啉-2-羧酸的含量,该方法灵敏度较高,检测低限为1.0μg/kg,干扰较少,并具有较好的重现性,可达到60%~125%,相关线性系数为0.998.

  16. Crystal structure of 6-(4-chlorophenyl-6a-nitro-6,6a,6b,7,9,11a-hexahydrospiro[chromeno[3′,4′:3,4]pyrrolo[1,2-c]thiazole-11,11′-indeno[1,2-b]quinoxaline] chloroform monosolvate

    Directory of Open Access Journals (Sweden)

    Nithya Sivakumar

    2014-10-01

    Full Text Available In the title compound, C33H23ClN4O3S·CHCl3, the thiazole ring adopts an envelope conformation with the N atom as the flap, and the pyrrolidine ring adopts a half-chair conformation. The thiazole ring mean plane makes a dihedral angle of 59.31 (1° with the pyrrolidine ring mean plane, 71.67 (1° with the chromene ring and 82.59 (1° with the chlorobenzene ring. An intramolecular C—H...N hydrogen bond occurs. In the crystal, a second C—H...N hydrogen bond links the main and solvent molecules. The solvent chloroform molecule is disordered about two positions with an occupancy ratio of 0.508 (14:0.492 (14.

  17. Determination of residual olaquindox and methyl-3-quinoxaline-2-carboxylic acid in penaeus vannamei by HPLC-MS/MS%南美白对虾中喹乙醇及其代谢物3-甲基-喹恶啉-2-羧酸残留的高效液相色谱-串联质谱检测

    Institute of Scientific and Technical Information of China (English)

    郭霞; 孙振中; 戚隽渊; 孙建华; 黄雪玲; 刘琴; 丁义

    2014-01-01

    以南美白对虾为试验材料,建立了喹乙醇(OLA)及3-甲基-喹恶啉-2-羧酸(MQCA)多残留的高效液相色谱-串联质谱(HPLC-MS/MS)确证检测法.组织样品经2 mol/L盐酸提取,Oasis HLB固相萃取柱净化,采用HPLC-MS/MS仪进行测定.质谱检测采用正离子选择反应监测模式,外标法定量.样品中OLA和MQCA质量分数分别为2~200和4~200 μg/kg时,线性关系良好;当质量分数分别为2~50和4~50 μg/kg时,平均回收率为93.9%~103.2%,变异系数为6.3%~11.5%.OLA及MQCA的检测限分别为0.5和1.0 μg/kg,定量限分别为2.0和4.0 g/kg.该方法灵敏、准确、简便、快速,适于南美白对虾中OLA及MQCA残留的同时定量分析和确证检测.

  18. Aza-isoindolo and isoindolo-azaquinoxaline derivatives with antiproliferative activity.

    Science.gov (United States)

    Parrino, Barbara; Carbone, Anna; Spanò, Virginia; Montalbano, Alessandra; Giallombardo, Daniele; Barraja, Paola; Attanzio, Alessandro; Tesoriere, Luisa; Sissi, Claudia; Palumbo, Manlio; Cirrincione, Girolamo; Diana, Patrizia

    2015-04-13

    Three new ring systems, pyrido[2',3':3,4]pyrrolo[1,2-a]quinoxalines, pyrido[3',2':3,4]pyrrolo[1,2-a]quinoxalines and pyrido[2',3':5,6]pyrazino[2,1-a]isoindoles, were synthesized through an aza-substitution on the already active isoindolo-quinoxaline system and in particular in the position 7 or 4 of the isoindole moiety and in position 5 of the quinoxaline portion. All new compounds were screened by the National Cancer Institute (Bethesda, MD) against a panel of 60 human tumor cell lines. Biological results of the most active derivatives, with pGI50 values between 7.09 and 7.27, confirmed the importance of the presence of methoxy substituents for biological activity. The anti-proliferative effect of selected quinoxalines was associated with apoptosis of the cells and arrest in G2/M phase of the cell cycle. DNA binding properties of the compounds was also assessed to investigate the possible mechanism of action.

  19. rac-(2R,3S-2-Phenyl-3-(3-phenyl-1,2,3,4-tetrahydroquinoxalin-2-ylquinoxaline

    Directory of Open Access Journals (Sweden)

    Sven Ammermann

    2008-07-01

    Full Text Available The title compound, C28H22N4, is the unexpected by-product of the reaction of 2-hydroxyacetophenone and 1,2-diaminobenzene under iodine catalysis, during which a carbon–carbon σ-bond between two quinoxaline units was formed. Although a fully oxidized title compound should sterically be possible, only one quinoxaline ring is fully oxidized while the second ring remains in the reduced form. As expected, the tetrahydroquinoxaline unit is not planar; it adopts a sofa conformation, whereby the atom joining the two heterocyclic systems lies out of the plane of the other atoms. The quinoxaline ring system makes a dihedral angle of 53.61 (4° with its phenyl ring substituent. The crystal packing is determined by pairs of N—H...N, N—H...π and weak C—H...N hydrogen bonds, forming a chain parallel to the a axis.

  20. Re-engineering nalidixic acid's chemical scaffold: A step towards the development of novel anti-tubercular and anti-bacterial leads for resistant pathogens.

    Science.gov (United States)

    Peraman, Ramalingam; Varma, Raghu Veer; Reddy, Y Padmanabha

    2015-10-01

    Occurrence of antibacterial and antimycobacterial resistance stimulated a thrust to discover new drugs for infectious diseases. Herein we report the work on re-engineering nalidixic acid's chemical scaffold for newer leads. Stepwise clubbing of quinoxaline, 1,2,4-triazole/1,3,4-oxadiazole with nalidixic acid yielded better compounds. Compounds were screened against ciprofloxacin resistant bacteria and Mycobacterium tuberculosis H37Rv species. Results were obtained as minimum inhibitory concentration, it was evident that molecule with quinoxaline linked azide as side chain served as antitubercular lead (<6.25 μg/ml) whilst molecule with oxadiazole or triazole linked quinoxaline side chain served as anti-bacterial lead. Few compounds were significantly active against Escherichia coli and Proteus vulgaris with MIC less than 0.06 μg/ml and relatively potent than ciprofloxacin. No true compound was potentially active against Salmonella species as compared to amoxicillin.

  1. An Efficient and Regioselective Synthesis of 2,3-Disubstituted 6-Aminoquinoxaline Derivatives Using Alkoxylation and Microwave-assisted Sonogashira Coupling

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Doohyun; Seo, Young Ho; Bae, Jongsup; Lee, Sangkyu; Lee, Taeho [Kyungpook National Univ., Daegu (Korea, Republic of); Lee, Tae Im [Osteogenic Core Technologies, Seongnam (Korea, Republic of); Gong, Youngdae [Dongguk Univ., Seoul (Korea, Republic of)

    2013-08-15

    The yields for 2,3-disubstituted 6-amino-quinoxaline derivatives produced through regioselective subsequent synthetic reactions (alkoxylation and microwave-assisted Sonogashira coupling) ranged from 49 to 85% from known 2,3-dichloro-6-aminoqunoxaline. In addition, the desired 6-aminoqunoxalines with two-diversity points were obtained in high purities (> 95%) as judged from LC-MS and {sup 1}H NMR analyses. This strategy allows for a ready access to a large library and is potentially applicable to the preparation of other 6-aminoquinoxaline derivatives. Further studies in this area are underway, and the results of these studies will be reported in due course. The quinoxalines are a common skeleton of nitrogencontaining heterocycles with biological properties. Because of their good biological activities quinoxalines, which contain 2,3-di-substituents, are of particular interest in medicinal chemistry and drug discovery programs.

  2. 1-Allyl-3-phenylquinoxalin-2(1H-one

    Directory of Open Access Journals (Sweden)

    Hanane Benzeid

    2011-11-01

    Full Text Available The title compound, C17H14N2O, crystallizes with two molecules in the asymmetric unit. The dihedral angles between the mean planes of the quinoxaline ring system and the phenyl ring in the two molecules are 38.27 (10 and 37.14 (8°. In the crystal, π-stacking along the b axis contributes to the crystal cohesion with an average distance between quinoxaline units of 3.397 (3 Å. Weak C—H...O interactions also occur.

  3. Tetra-μ-benzoato-bis[(quinoxalinecopper(II

    Directory of Open Access Journals (Sweden)

    Youngmee Kim

    2008-02-01

    Full Text Available The paddlewheel-type centrosymmetric dinuclear title complex, [Cu2(C7H5O24(C8H6N22], contains four bridging benzoate groups and two terminal quinoxaline ligands. The octahedral coordination around each Cu atom, with four O atoms in the equatorial plane, is completed by an N atom of a quinoxaline molecule [Cu—N = 2.2465 (18 Å] and by the second Cu atom [Cu...Cu = 2.668 (5 Å]. The Cu atom is 0.216 Å out of the plane of the four O atoms.

  4. 1-Ethyl-3-methylquinoxalin-2(1H-one

    Directory of Open Access Journals (Sweden)

    Hanane Benzeid

    2008-11-01

    Full Text Available The asymmetric unit of the title compound, C11H12N2O, contains two independent molecules. In the crystal structure, intermolecular C—H...O hydrogen bonds link the molecules. There are π–π contacts between the quinoxaline rings [centroid–centroid distances = 3.446 (2, 3.665 (2, 3.645 (3 and 3.815 (3 Å]. There also exist C—H...π contacts between the methyl groups and the quinoxaline rings.

  5. Unexpected Reduction of Ethyl 3-Phenylquinoxaline-2- carboxylate 1,4-Di-N-oxide Derivatives by Amines

    Directory of Open Access Journals (Sweden)

    Antonio Monge

    2008-01-01

    Full Text Available The unexpected tendency of amines and functionalized hydrazines to reduceethyl 3-phenylquinoxaline-2-carboxylate 1,4-di-N-oxide (1 to afford a quinoxaline 1c andmono-oxide quinoxalines 1a and 1b is described. The experimental conditions werestandardized to the use of two equivalents of amine in ethanol under reflux for two hours,with the aim of studying the distinct reductive profiles of the amines and thechemoselectivity of the process. With the exception of hydrazine hydrate, which reducedcompound 1 to a 3-phenyl-2-quinoxalinecarbohydrazide derivative, the amines only actedas reducing agents.

  6. Synthesis,Structure,Fluorescent Property and Natural Bond Orbital(NBO) Analysis of a One-dimensional Cobalt(III) Complex Containing 1,3-Benzenedicarboxylate and 2-Methyldipyrido[3,2-f:2',3'-h]quinoxaline Ligand%Synthesis,Structure,Fluorescent Property and Natural Bond Orbital(NBO) Analysis of a One-dimensional Cobalt(III) Complex Containing 1,3-Benzenedicarboxylate and 2-Methyldipyrido[3,2-f:2',3'-h]quinoxaline LigandSynthesis,Structure,Fluorescent Property and Natural Bond Orbital(NBO) Analysis of a One-dimensional Cobalt(III) Complex Containing 1,3-Benzenedicarboxylate and 2-Methyldipyrido[3,2-f:2',3'-

    Institute of Scientific and Technical Information of China (English)

    王蕾; 倪良; 黄艳菊; 姚加

    2012-01-01

    A novel metal-organic coordination polymer [Co(m-BDC)(Medpq)·2H2O]n(m-H2BDC = benzene-1,3-dicarboxyalic acid,Medpq = 2-methyldipyrido[3,2-f:2',3'-h]quinoxaline) has been hydrothermally synthesized and structurally characterized by elemental analysis,IR spectrum and single-crystal X-ray diffraction.The title compound crystallizes in monoclinic,space group C2/c with a = 19.986(4),b = 15.789(3),c = 16.292(3)(A°),β = 126.54(3)°,V = 4130.3(14)(A°)^3,C23H18N4O6Co,Mr = 505.34,Dc = 1.625 g·cm^-3,Z = 8,μ = 0.883 mm^-1,F(000) = 2072,the final R = 0.0772 and wR = 0.1428.The crystal structure of complex 1 is an infinite zigzag-like chain of hexacoordinate Co^3+ ions,in which the Co^3+ ions are bridged in two coordination modes by m-BDC^2+ ligands and decorated by Medpq ligands,showing a slightly distorted octahedral geometry.Additionally,the compound shows strong fluorescence in the solid state at room temperature.Natural bond orbital(NBO) analysis is performed by using the NBO method built in Gaussian 03 Program.The calculation results show a covalent interaction between the coordinated atoms and Co^3+ ions.

  7. Large-Scale Solvent-Free Chlorination of Hydroxy-Pyrimidines, -Pyridines, -Pyrazines and -Amides Using Equimolar POCl3

    Directory of Open Access Journals (Sweden)

    Zhihua Sun

    2012-04-01

    Full Text Available Chlorination with equimolar POCl3 can be efficiently achieved not only for hydroxypyrimidines, but also for many other substrates such as 2-hydroxy-pyridines, -quinoxalines, or even -amides. The procedure is solvent-free and involves heating in a sealed reactor at high temperatures using one equivalent of pyridine as base. It is suitable for large scale (multigram batch preparations.

  8. Effects of met-enkephalin on GABAergic spontaneous miniature IPSPs in organotypic slice cultures of the rat hippocampus

    DEFF Research Database (Denmark)

    Rekling, J C

    1993-01-01

    The action of met-enkephalin on GABAergic spontaneous miniature IPSPs (smIPSPs) was investigated in CA1 neurons from hippocampal slice cultures. In the presence of excitatory amino acid blockers (2,3-dihydroxy-6-nitro-7-sulphamoyl-benzo(F)quinoxaline, DL-2-amino-5-phosphonovaleric acid) and TTX, ...

  9. 1-Methyl-3-phenylquinoxalin-2(1H-one

    Directory of Open Access Journals (Sweden)

    Hanane Benzeid

    2009-10-01

    Full Text Available The phenyl substituents in both independent molecules of the title compound, C15H12N2O, are twisted with respect to the quinoxaline system [dihedral angles = 19.3 (1 and 30.4 (1°].

  10. The role of cGMP hydrolysing phosphodiesterases 1 and 5 in cerebral artery dilatation

    DEFF Research Database (Denmark)

    Kruuse, Christina; Rybalkin, S D; Khurana, T S;

    2001-01-01

    -IBMX) and the phosphodiesterase 5 inhibitors zaprinast and dipyridamole induced dilatation of cerebral arteries. The dilatory response to 8-MM-IBMX was reduced by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) (10 microM) and endothelial removal and restored by sodium nitroprusside (0.1 microM) pretreatment, indicating...

  11. Transient absorption probe of intermolecular triplet excimer of naphthalene in fluid solutions: Identification of the species based on comparison to the intramolecular triplet excimers of covalently-linked dimers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.; Kofron, W.G.; Kong, S.; Rajesh, C.S.; Modarelli, D.A.; Lim, E.C.

    2000-02-24

    The authors report here the observation of the laser-induced transient absorption spectrum of intermolecular triplet excimers of naphthalene in fluid solution. This assignment is confirmed by comparison to the transient absorption spectra of the intramolecular triplet excimers of covalently linked dimers of naphthalene and quinoxaline.

  12. 2-Isopropyl-3-methylquinoxaline 1,4-dioxide

    Directory of Open Access Journals (Sweden)

    Jian-Ye Li

    2010-08-01

    Full Text Available In the title compound, C12H14N2O2, the quinoxaline ring system and the C atoms of the methylene and methyl substituents lie on a mirror plane. The crystal packing is stabilized by weak π–π interactions [centroid–centroid distance = 3.680 (7 Å].

  13. The in-feed antibiotic carbadox induces phage gene transcription in the swine gut microbiome

    Science.gov (United States)

    Carbadox is a quinoxaline-di-N-oxide antibiotic fed to over 40 percent of young pigs in the U.S. and has been shown to induce phage DNA transduction in vitro; however, the effects of carbadox on swine microbiome functions are poorly understood. We investigated the in vivo effects of carbadox on swin...

  14. Rational design of a triple helix-specific intercalating ligand.

    Science.gov (United States)

    Escudé, C; Nguyen, C H; Kukreti, S; Janin, Y; Sun, J S; Bisagni, E; Garestier, T; Hélène, C

    1998-03-31

    DNA triple helices offer new perspectives toward oligonucleotide-directed gene regulation. However, the poor stability of some of these structures might limit their use under physiological conditions. Specific ligands can intercalate into DNA triple helices and stabilize them. Molecular modeling and thermal denaturation experiments suggest that benzo[f]pyrido[3, 4-b]quinoxaline derivatives intercalate into triple helices by stacking preferentially with the Hoogsteen-paired bases. Based on this model, it was predicted that a benzo[f]quino[3,4-b]quinoxaline derivative, which possesses an additional aromatic ring, could engage additional stacking interactions with the pyrimidine strand of the Watson-Crick double helix upon binding of this pentacyclic ligand to a triplex structure. This compound was synthesized. Thermal denaturation experiments and inhibition of restriction enzyme cleavage show that this new compound can indeed stabilize triple helices with great efficiency and specificity and/or induce triple helix formation under physiological conditions.

  15. ANALISIS QSAR-2D DE LOS DERIVADOS DE 1,4-DI-N-OXIDOS DE QUINOXALINA CON ACTIVIDAD CONTRA LA ENFERMEDAD DE CHAGAS

    Directory of Open Access Journals (Sweden)

    Cristian J. Guerra

    2016-07-01

    Full Text Available In the present work was performed a quantitative structure-activity relationship (QSAR for a set of derivatives of 1,4-quinoxaline N-oxides with antichagasic activity based on reactivity descriptors from the frame conceptual DFT. QSAR models showed a good statistical quality and capacity internal prediction with R2 > 0.6 and Q2> 0.5 respectively. QSAR model suggest that antichagasic activity of the studied compounds depends largely from the reactive behavior of N-oxide group (N-O. Also, reactivity descriptors showed that the N-oxide group is a reactive site in theses derivatives with nucleophilic characteristics. The results QSAR shed light on the understanding of the mechanism of action and design of new drugs based on derivatives of 1,4-di-N-oxides quinoxaline.

  16. Direct and selective small-molecule inhibition of photosynthetic PEP carboxylase: New approach to combat C4 weeds in arable crops.

    Science.gov (United States)

    Paulus, Judith Katharina; Förster, Kerstin; Groth, Georg

    2014-06-05

    Phosphoenolpyruvate carboxylase (PEPC) is a key enzyme of C4 photosynthesis. Besides, non-photosynthetic isoforms of PEPC are found in bacteria and all types of plants, although not in animals or fungi. A single residue in the allosteric feedback inhibitor site of PEPC was shown to adjust the affinity of the photosynthetic and non-photosynthetic isoforms for feedback inhibition by metabolites of the C4 pathway. Here, we applied computational screening and biochemical analyses to identify molecules that selectively inhibit C4 PEPC, but have no effect on the activity of non-photosynthetic PEPCs. We found two types of selective inhibitors, catechins and quinoxalines. Binding constants in the lower μM range and a strong preference for C4 PEPC qualify the quinoxaline compounds as potential selective herbicides to combat C4 weeds. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  17. Influence of D/A ratio on photovoltaic performance of a highly efficient polymer solar cell system.

    Science.gov (United States)

    Guo, Xia; Zhang, Maojie; Tan, Jiahui; Zhang, Shaoqing; Huo, Lijun; Hu, Wenping; Li, Yongfang; Hou, Jianhui

    2012-12-18

    A new copolymer PIDTDTQx based on indacenodithiophene and quinoxaline is synthesized and characterized. The correlation between the D/A ratio, mobility, and photovoltaic properties, as well as morphology of the D/A blend based on a PIDTDTQx:PC(70) BM system is investigated. The power conversion efficiency of the polymer solar cells based on PIDTDTQx/PC(70) BM (1:4, w/w) reaches 7.51%.

  18. Trimerization of aromatic nitriles

    Science.gov (United States)

    Hsu, L. C. (Inventor)

    1977-01-01

    Triazine compounds and cross-linked polymer compositions were made by heating aromatic nitriles to a temperature in the range of about 100 C to about 700 C, in the presence of a catalyst or mixture of catalysts. Aromatic nitrile-modified (terminated and/or appended) imide, benzimidazole, imidazopyrrolone, quinoxaline, and other condensation type prepolymers or their precopolymers were made which were trimerized with or without a filler by the aforementioned catalytic trimerization process.

  19. A nanoporous Ag(I)-MOF showing unique selective adsorption of benzene among its organic analogues.

    Science.gov (United States)

    Cheng, Jun-Yan; Wang, Peng; Ma, Jian-Ping; Liu, Qi-Kui; Dong, Yu-Bin

    2014-11-18

    A stable porous Ag(I)-MOF with new topology is constructed from AgSbF6 and 3,6-bis[2-(4-oxide-quinoxaline)-yl]-4,5-diaza-3,5-octadiene (L). This compound can be a highly selective porous MOF material to effectively separate benzene from its six-membered cyclic organic analogues such as cyclohexane, cyclohexene and o-, m-, p-xylene under ambient conditions in both vapor and liquid phases.

  20. Crystal structure and pharmacological characterization of a novel N-methyl-D-aspartate (NMDA) receptor antagonist at the GluN1 glycine binding site

    DEFF Research Database (Denmark)

    Kvist, Trine; Steffensen, Thomas Bielefeldt; Greenwood, Jeremy R;

    2013-01-01

    glycine site antagonist, 1-thioxo-1,2-dihydro-[1,2,4]triazolo[4,3-a]quinoxalin-4(5H)-one (TK40). Here, we show by Schild analysis that TK40 is a potent competitive antagonist with Kb values of 21-63 nm at the GluN1 glycine-binding site of the four recombinant GluN1/N2A-D receptors. In addition, TK40...

  1. Nitrogen heterocycles as potential monoamine oxidase inhibitors: Synthetic aspects

    Directory of Open Access Journals (Sweden)

    Pravin O. Patil

    2014-12-01

    Full Text Available The present review highlights the synthetic methods of monoamine oxidase inhibitors (MAO belonging to a group of nitrogen heterocycles such as pyrazoline, indole, xanthine, oxadiazole, benzimidazole, pyrrole, quinoxaline, thiazole and other related compounds (1990–2012. Moreover, it emphasizes salient findings related to chemical structures and the bioactivities of these heterocycles as MAO inhibitors. The aim of this review is to find out different methods for the synthesis of nitrogen containing heterocycles and their bioactivity related aspects as MAO inhibitors.

  2. Syntheses, Crystal Structures and Fluorescent Properties of Two New Imidazolidino Schiff Base Compounds

    Institute of Scientific and Technical Information of China (English)

    FENG Yue; LIU Gang; TIAN Xiu-Mei; WANG Ji-De; WANG Wei

    2008-01-01

    Two new imidazolidino Schiff base compounds, (E)-N-((quinoxalin-2-yl)methylene)-2-(2-(quinoxalin-3-yl)imidazolidin-1-yl)ethanamine 1 and 2-(1-(2-(2-(quinoxalin-3-yl)imidazolidin-1-yl)ethyl)imidazolidin-2-yl)quinoxaline 2, have been synthesized and characterized by elemental analysis,1H NMR, IR, MS and single-crystal X-ray diffraction. Crystallographic data for 1: C22H21N7,Mr = 383.46, monoclinic, space group P21, a = 7.0036(14), b=6.9151(14), c=19.701(4)(A),β=96.57(3)°, Z = 2, V=947.9(3)(A)3, Dc = 1.344 g/cm3, F(000)=404, μ = 0.085 mm-1, Flack parameter =0(2), R = 0.0464 and wR = 0.1055; and those for 2: C24H26N8, Mr = 426.53, triclinic, space group P(1),a = 9.6680(19), b = 10.334(2), c = 11.389(2)(A),α= 104.12(3),β= 102.95(3),γ= 100.48(3)°, Z=2,V=1041.2(4)(A)3, Dc=1.361 g/cm3, F(000) = 452,μ = 0.086 mm-1, R = 0.0373 and wR = 0.1155. For the two compounds, the five-membered imidazolidine rings all adopt envelope conformation.Moreover, the title compounds show one-dimensional layered and three-dimensional supramolecular chainlike structures, respectively. Fluorescent properties of the two compounds have been investigated in the solid state at room temperature. Compound 1 exhibits strong fluorescence and thus may serve as excellent candidates of green fluorescent materials.

  3. USAF Summer Faculty Research Program. 1981 Research Reports. Volume II.

    Science.gov (United States)

    1981-10-01

    triazines are widely employed as dyestuffs, and the much used melamine - formaldehyde resins are formed from 2,4,6-triamino-s- 2 triazines. The high...Acetylene Terminated Systems: Quinoxalines and Dr. William A. Feld Isomeric Sulfones 24 A Simulation Framework for the Evaluation ot D~r. John A. Fleming...reaction of hydrazine and its derivatives with salicylaldehyde, indanedione, p-dimethylaminobenzaldehyde, 1,2-naphthoquinone-4 sulfonate , 2,3-dichloro-l,4

  4. Synthesis and Pharmacological Evaluation of Some Phenylpyrazolo Indoquinoxaline Derivatives

    Directory of Open Access Journals (Sweden)

    CH. Sridevi

    2011-01-01

    Full Text Available Indoloquinoxalin was fused with 2,3 diphenyl quinoxaline by a methylene bridge which was then allowed for acetylation. The acetylated product was made to react with different aromatic aldehydes to give chalcones. Chalcones refluxed with substituted acid hydrazides to afford different indoloquinoxaline pyrazolines. The structure of chalcones and indoloquinoxaline pyrazolines were confirmed by M.P, TLC and spectral data. All the synthesized compounds were screened for their antioxidant, anti-inflammatory and antihistamic activities.

  5. Stabilization of acyclic water tetramer in a copper(II) malonate framework structure.

    Science.gov (United States)

    Deshpande, Megha S; Kumbhar, Avinash S; Näther, Christian

    2010-10-14

    Copper(II) complex [Cu(dpq)(mal)(H(2)O)]·3H(2)O (1) (dpq = dipyrido-[3,2-d:2',3'-f]-quinoxaline, mal = malonato) was synthesized and characterized by elemental analysis, infrared spectroscopy, thermogravimetric analysis and single-crystal X-ray crystallography. The single-crystal X-ray structure of 1 reveals a square pyramidal structure, with the dipyrido-[3,2-d:2',3'-f]-quinoxaline and malonato at the equatorial positions and a water molecule at the axial position. The molecule acts as a building block generating a supramolecular three-dimensional metal-organic framework (MOF) encapsulating metal linked acyclic water tetramer. The H-bonding capacity of malonato and the π-π stacking interactions of dipyrido-[3,2-d:2',3'-f]-quinoxaline further reinforce the framework. The copper(II) bound hydroxyl group is demonstrated to mediate hydrolytic cleavage of plasmid pBR322 DNA under dark conditions.

  6. 2-Carboxyquinoxalines kill mycobacterium tuberculosis through noncovalent inhibition of DprE1.

    Science.gov (United States)

    Neres, João; Hartkoorn, Ruben C; Chiarelli, Laurent R; Gadupudi, Ramakrishna; Pasca, Maria Rosalia; Mori, Giorgia; Venturelli, Alberto; Savina, Svetlana; Makarov, Vadim; Kolly, Gaelle S; Molteni, Elisabetta; Binda, Claudia; Dhar, Neeraj; Ferrari, Stefania; Brodin, Priscille; Delorme, Vincent; Landry, Valérie; de Jesus Lopes Ribeiro, Ana Luisa; Farina, Davide; Saxena, Puneet; Pojer, Florence; Carta, Antonio; Luciani, Rosaria; Porta, Alessio; Zanoni, Giuseppe; De Rossi, Edda; Costi, Maria Paola; Riccardi, Giovanna; Cole, Stewart T

    2015-03-20

    Phenotypic screening of a quinoxaline library against replicating Mycobacterium tuberculosis led to the identification of lead compound Ty38c (3-((4-methoxybenzyl)amino)-6-(trifluoromethyl)quinoxaline-2-carboxylic acid). With an MIC99 and MBC of 3.1 μM, Ty38c is bactericidal and active against intracellular bacteria. To investigate its mechanism of action, we isolated mutants resistant to Ty38c and sequenced their genomes. Mutations were found in rv3405c, coding for the transcriptional repressor of the divergently expressed rv3406 gene. Biochemical studies clearly showed that Rv3406 decarboxylates Ty38c into its inactive keto metabolite. The actual target was then identified by isolating Ty38c-resistant mutants of an M. tuberculosis strain lacking rv3406. Here, mutations were found in dprE1, encoding the decaprenylphosphoryl-d-ribose oxidase DprE1, essential for biogenesis of the mycobacterial cell wall. Genetics, biochemical validation, and X-ray crystallography revealed Ty38c to be a noncovalent, noncompetitive DprE1 inhibitor. Structure-activity relationship studies generated a family of DprE1 inhibitors with a range of IC50's and bactericidal activity. Co-crystal structures of DprE1 in complex with eight different quinoxaline analogs provided a high-resolution interaction map of the active site of this extremely vulnerable target in M. tuberculosis.

  7. Photoexcited triplet state provides a quantitative measure of intercalating drug-DNA binding energies

    Science.gov (United States)

    Maki, August H.; Alfredson, T. V.; Waring, M. J.

    1992-04-01

    A linear correlation between spectroscopic and thermodynamic properties of systems is rarely encountered. In triplet state ODMR studies of various DNA complexes of echinomycin, a quinoxaline-containing cyclic depsipeptide bis-intercalating antibiotic, and its biosynthesized quinoline analogs, such correlations are observed. The zero field splitting D-parameter of the intercalated quinoxaline or quinoline residue varies linearly with the free energy of drug-DNA complexing. From previous work, the DNA sequence specificity of echinomycin analogs is known to be influenced by the identity of the intercalating residue (e.g., quinoxaline vs. quinoline). The present results strongly suggest that the DNA sequence-specificity of these drugs is controlled largely by the intercalated residue, and that the energetics of the peptide- DNA interaction, although considerable, are relatively sequence independent. These conclusions run counter to the generally accepted idea that DNA recognition by sequence- seeking proteins is controlled by specific hydrogen bonding interactions. The high degree of N-methylation of the echinomycin peptide portion severely restricts these interactions, however. A simple theoretical model is presented to support the experimentally observed linear correlation between (Delta) D and (Delta) G.

  8. Quinazolinones-Phenylquinoxaline hybrids with unsaturation/saturation linkers as novel anti-proliferative agents.

    Science.gov (United States)

    Palem, Jyothsna Devi; Alugubelli, Gopi Reddy; Bantu, Rajashaker; Nagarapu, Lingaiah; Polepalli, Sowjanya; Jain, S Nishanth; Bathini, Raju; Manga, Vijjulatha

    2016-07-01

    A new series of novel quinazolinones with allylphenyl quinoxaline hybrids 9a-n were efficiently synthesized in good yields by the reaction of 3-allyl-2-methylquinazolin-4(3H)-one (5a-n) with bromophenyl)quinoxaline (8) utilizing Pd catalyzed Heck-cross coupling and evaluated for anti-proliferative activity against four cancer cell lines such as HeLa (cervical), MIAPACA (pancreatic), MDA-MB-231 (breast) and IMR32 (neuroblastoma). Compounds 9a, 9e, 9g and 9h exhibited promising anti-proliferative activity with GI50 values ranging from 0.06 to 0.2μM against four cell lines, while compounds 9e and 9k showed significant activity against HeLa and MIAPACA cell lines and compounds 9b, 9d, 9h and 9j showed selective potency against IMR32 and MDA-MB-231 cell lines. This is the first report on the synthesis and in vitro anti-proliferative evaluation of E-2-(4-substituted)-3-(3-(4-(quinoxalin-2-yl)phenyl)allyl)quinazolin-4(3H)-ones (9a-n). Docking results indicate a sign of good correlation between experimental activity and calculated binding affinity (dock score), suggesting that these compounds could act as promising DNA intercalates.

  9. 2,3-Dimethyl-6-nitroquinoxaline

    Directory of Open Access Journals (Sweden)

    Raza Murad Ghalib

    2010-07-01

    Full Text Available The asymmetric unit of the title quinoxaline compound, C10H9N3O2, contains two crystallographically independent molecules (A and B. The quinoxaline ring systems are essentially planar, with maximum deviations of 0.006 (1 and 0.017 (1 Å, respectively, for molecules A and B. In molecule A, the dihedral angle formed between the quinoxaline ring system and nitro group is 10.94 (3° [6.31 (13° for molecule B]. In the crystal, molecules are linked into chains propagating along [001]: one forms zigzag chains linked by C—H...O hydrogen bonds, whilst the other forms ladder-like chains by way of C—H...N and C—H...O hydrogen bonds. The packing is further consolidated by weak π–π interactions [range of centroid–centroid distances = 3.5895 (7–3.6324 (7 Å].

  10. Synthesis of Pyridine– and Pyrazine–BF 3 Complexes and Their Characterization in Solution and Solid State

    Energy Technology Data Exchange (ETDEWEB)

    Chénard, Etienne; Sutrisno, Andre; Zhu, Lingyang; Assary, Rajeev S.; Kowalski, Jeffrey A.; Barton, John L.; Bertke, Jeffery A.; Gray, Danielle L.; Brushett, Fikile R.; Curtiss, Larry A.; Moore, Jeffrey S.

    2016-03-31

    Following the discovery of the redox-active 1,4- bis-BF3-quinoxaline complex, we undertook a structure- activity study with the objective to understand the active nature of the quinoxaline complex. Through systematic synthesis and characterization, we have compared complexes prepared from pyridine and pyrazine derivatives, as heterocyclic core analogues. This paper reports the structural requirements that give rise to the electrochemical features of the 1,4-bis-BF3-quinoxaline adduct. Using solution and solidstate NMR spectroscopy, the role of aromatic ring fusion and nitrogen incorporation in bonding and electronics was elucidated. We establish the boron atom location and its interaction with its environment from 1D and 2D solution NMR, X-ray diffraction analysis, and 11B solid-state NMR experiments. Crystallographic analysis of single crystals helped to correlate the boron geometry with 11B quadrupolar coupling constant (CQ) and asymmetry parameter (ηQ), extracted from 11B solid-state NMR spectra. Additionally, computations based on density functional theory were performed to predict electrochemical behavior of the BF3-heteroaromatic complexes. We then experimentally measured electrochemical potential using cyclic voltammetry and found that the redox potentials and CQ values are similarly affected by electronic changes in the complexes.

  11. Change in the site of electron-transfer reduction of a zinc-quinoxalinoporphyrin/gold-quinoxalinoporphyrin dyad by binding of scandium ions and the resulting remarkable elongation of the charge-shifted-state lifetime.

    Science.gov (United States)

    Ohkubo, Kei; Garcia, Rachel; Sintic, Paul J; Khoury, Tony; Crossley, Maxwell J; Kadish, Karl M; Fukuzumi, Shunichi

    2009-10-12

    The site of electron-transfer reduction of AuPQ(+) (PQ = 5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)quino-xalino[2, 3-b']porphyrin) and AuQPQ(+) (QPQ = 5,10,15,20-tetrakis(3,5-di-tert-butylphenyl)bisquinoxalino[2,3-b':12,13-b'']porphyrin) is changed from the Au(III) center to the quinoxaline part of the PQ macrocycle in the presence of Sc(3+) in benzonitrile because of strong binding of Sc(3+) to the two nitrogen atoms of the quinoxaline moiety. Strong binding of Sc(3+) to the corresponding nitrogen atoms on the quinoxaline unit of ZnPQ also occurs for the neutral form. The effects of Sc(3+) on the photodynamics of an electron donor-acceptor compound containing a linked Zn(II) and Au(III) porphyrin ([ZnPQ-AuPQ]PF(6)) have been examined by femto- and nanosecond laser flash photolysis measurements. The observed transient absorption bands at 630 and 670 nm after laser pulse irradiation in the absence of Sc(3+) in benzonitrile are assigned to the charge-shifted (CS) state (ZnPQ(*)(+)-AuPQ). The CS state decays through back electron transfer (BET) to the ground state rather than to the triplet excited state. The BET rate was determined from the disappearance of the absorption band due to the CS state. The decay of the CS state obeys first-order kinetics. The CS lifetime was determined to be 250 ps in benzonitrile. Addition of Sc(3+) to a solution of ZnPQ-AuPQ(+) in benzonitrile caused a drastic lengthening of the CS lifetime that was determined to be 430 ns, a value 1700 times longer than the 250 ps lifetime measured in the absence of Sc(3+). Such remarkable prolongation of the CS lifetime in the presence of Sc(3+) results from a change in the site of electron transfer from the Au(III) center to the quinoxaline part of the PQ macrocycle when Sc(3+) binds to the quinoxaline moiety, which decelerate BET due to a large reorganization energy of electron transfer. The change in the site of electron transfer was confirmed by ESR measurements, redox potentials, and UV

  12. Synthetic Control of the Excited-State Dynamics and Circularly Polarized Luminescence of Fluorescent "Push-Pull" Tetrathia[9]helicenes.

    Science.gov (United States)

    Yamamoto, Yuki; Sakai, Hayato; Yuasa, Junpei; Araki, Yasuyuki; Wada, Takehiko; Sakanoue, Tomo; Takenobu, Taishi; Kawai, Tsuyoshi; Hasobe, Taku

    2016-03-14

    A series of fluorescent "push-pull" tetrathia[9]helicenes based on quinoxaline (acceptor) fused with tetrathia[9]helicene (donor) derivatives was synthesized for control of the excited-state dynamics and circularly polarized luminescence (CPL) properties. In this work, introduction of a quinoxaline onto the tetrathia[9]helicene skeleton induced the "push-pull" character, which was enhanced by further introduction of an electron-releasing Me2 N group or an electron-withdrawing NC group onto the quinoxaline unit (denoted as Me2 N-QTTH and NC-QTTH, respectively). These trends were successfully discussed in terms of by electrochemical measurements and density functional theory (DFT) calculations. As a consequence, significant enhancements in the fluorescence quantum yields (ΦFL ) were achieved. In particular, the maximum ΦFL of Me2 N-QTTH was 0.43 in benzene (NC-QTTH: ΦFL =0.30), which is more than 20 times larger than that of a pristine tetrathia[9]helicene (denoted as TTH; ΦFL =0.02). These enhancements were also explained by kinetic discussion of the excited-state dynamics such as fluorescence and intersystem crossing (ISC) pathways. Such significant enhancements of the ΦFL values thus enabled us to show the excellent CPL properties. The value of anisotropy factor gCPL (normalized difference in emission of right-handed and left-handed circularly polarized light) was estimated to be 3.0 × 10(-3) for NC-QTTH. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. The preparation of a 10-membered ring macrolactone by selective ozonolysis and the role of the dihydropyran-substituent on the MCPBA-oxidation reaction profile of {beta}-lapachone phenazines

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Raphael S.F.; Guimaraes, Tiago T.; Teixeira, Daniel V.; Lobato, Ana Paula G.; Pinto, Maria do Carmo F.R.; Pinto, Antonio V. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Nucleo de Pesquisas de Produtos Naturais; Simone, Carlos Alberto de; Soares, Janaina G.; Cioletti, Alessandra G.; Goulart, Marilia O.F. [Universidade Federal de Alagoas, Maceio, AL (Brazil). Dept. de Quimica]. E-mail: mofg@qui.ufal.br; ventura@nppn.ufrj.br

    2005-09-15

    The benzophenazine from {beta}-lapachone was submitted to ozonolysis under conditions that selectively furnished the corresponding rigid macrocyclic lactone 7,7-dimethyl-7,8,9,10-tetrahydro-5H-benzo[3,4]oxecino[5,6-b]quinoxaline-5, 10-dione in an yield of 52%. The effect of substituents located at the dihydropyrane moiety of the phenazines, namely C2'-OH, C2'-Br and C2'-I, in the oxidation with MCPBA, was also investigated. (author)

  14. Polymer/Solvent and Polymer/Polymer Interaction Studies

    Science.gov (United States)

    1979-08-01

    m-Cresol 14 p-Cresol El Benzene 15 Resorcinol .E2 Toluene 16 m-Methoxy phenol E3 m-Xylene 17 Propylene glycol E4 Ethyl bezene 18 Resorcinolmonoacetate...F9 Quinoxaline 79 TABLE 2 (Continued) Code: Solvent: Code: Solvent: Ji Dichioromethane MI Diethyl ether J2 1,2-Dichioroethane M2 Phenyl ether J3 1...or phenylated PBO’s or PBT’s). Saturation concentration measurements for "good" solvents for Radel polysulfone indicate that chloroform is a viable

  15. DNA damage in isolated rat hepatocytes exposed to C.I. pigment orange 5 and C.I. pigment yellow 12 by the alkaline comet assay

    DEFF Research Database (Denmark)

    Møller, P; Wallin, Håkan; Grunnet, N

    1998-01-01

    The induction of DNA damage by commonly used printing ink pigments, C.I. pigment orange 5 (C.I. 12075) and C.I. pigment yellow 12 (C.I. 21090), was investigated in freshly isolated rat hepatocytes with the comet assay. C.I. pigment yellow 12 is a 3,3'-dichlorobenzidine-based diarylide pigment, an......]quinoxaline. Our data indicate that both C.I. pigment orange 5 and C.I. pigment yellow 12 are genotoxic in hepatocytes with metabolizing capacities. However, further investigation of the metabolism and disposition are required for the evaluation of the safety of these pigments....

  16. 3-Carbamoylquinoxalin-1-ium chloride

    Directory of Open Access Journals (Sweden)

    James K. Harper

    2012-01-01

    Full Text Available The title compound, C9H8N3O+·Cl−, was isolated from a liquid culture of streptomyces sp. In the cation, the ring system makes a dihedral angle of 0.2 (2° with the amide group. The protonation creating the cation occurs at ome of the N atoms in the quinoxaline ring system. In the crystal, the ions are linked through N—H...O and N—H...Cl hydrogen bonds, forming a two-dimensional network parallel to (10overline{3}.

  17. Recent advances in the synthesis of nitrogen heterocycles via radical cascade reactions using isonitriles as radical acceptors.

    Science.gov (United States)

    Zhang, Bo; Studer, Armido

    2015-06-07

    Nitrogen heterocycles belong to a highly important class of compounds which are found in various natural products, biologically active structures, and medicinally relevant compounds. Therefore, there is continuing interest in the development of novel synthetic methods for the construction of nitrogen containing heterocycles. Recently, radical insertion reactions into isonitriles have emerged as an efficient and powerful strategy for the construction of nitrogen heterocycles, such as phenanthridines, indoles, quinolines, quinoxalines, and isoquinolines. This review highlights recent advances in this fast growing research area and also includes important pioneering studies in this area.

  18. Largely enhanced efficiency with a PFN/Al bilayer cathode in high efficiency bulk heterojunction photovoltaic cells with a low bandgap polycarbazole donor

    Energy Technology Data Exchange (ETDEWEB)

    He, Zhicai; Zhang, Chen; Xu, Xiaofeng; Zhang, Lianjie; Huang, Liang; Chen, Junwu; Wu, Hongbin; Cao, Yong [Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Physics and Chemistry of Luminescence, South China University of Technology, Guangzhou 510640 (China)

    2011-07-19

    Quinoxaline-containing poly(4,5-ethylene-2,7-carbazole) (PECz-DTQx) shows a high efficiency of 6.07% in solar cells with a PFN/Al bilayer cathode. This is higher than the efficiency achieved with sole Al (3.99%) or with Ca/Al (4.52%) cathodes. A bilayer cathode could be valuable in device configurations to achieve high efficiency in combination with a high-performance polymer donor. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. 6,7-Dichloro-3-(2,4-dichlorobenzylquinoxalin-2(1H-one

    Directory of Open Access Journals (Sweden)

    Jinpeng Zhang

    2012-08-01

    Full Text Available In the title compound, C15H8Cl4N2O, the quinoxaline ring system is almost planar, with a dihedral angle between the benzene and pyrazine rings of 3.1 (2°. The 2,4-dichlorophenyl ring is approximately perpendicular to the pyrazine ring, with a dihedral angle of 86.47 (13° between them. The crystal packing features intermolecular N—H...O hydrogen bonds and π–π stacking interactions, with centroid–centroid distances in the range 3.699 (3–4.054 (3 Å.

  20. Photophysical characterization of 2,3-difunctionalized thieno[3,4-b]pyrazines

    Energy Technology Data Exchange (ETDEWEB)

    Rasmussen, S.C. E-mail: seth.rasmussen@ndsu.nodak.edu; Sattler, D.J.; Mitchell, K.A.; Maxwell, John

    2004-08-01

    In order to better understand the optical properties of polythieno[3,4-b]pyrazine materials, the photophysical characteristics of a series of monomeric 2,3-difunctionalized thieno[3,4-b]pyrazines (where R=H, CH{sub 3}, C{sub 6}H{sub 13}, C{sub 8}H{sub 17}, C{sub 10}H{sub 21}, C{sub 12}H{sub 25}, and Ph) have been studied. Characterization of the room temperature UV-vis and fluorescence spectra, including solvent and pH dependence, are presented and compared to the related species isothianaphthene and quinoxaline.

  1. 2-(3-Nitrophenoxyquinoxaline

    Directory of Open Access Journals (Sweden)

    Noor Doha Hassan

    2010-09-01

    Full Text Available In the title molecule, C14H9N3O3, the dihedral angle between the quinoxaline and benzene rings is 77.13 (9°. The molecule is twisted about the ether–benzene O—C bond, with a C—O—C—C torsion angle of −102.8 (2°. In the crystal, molecules are linked by C—H...O hydrogen bonds, forming layers in the ab plane, with one nitro O atom accepting two such interactions. The layers stack along the c-axis direction via weak C—H...π interactions.

  2. (Z-1,2-Dichloro-1,2-bis(3-chloroquinoxalin-2-ylethene

    Directory of Open Access Journals (Sweden)

    Hoong-Kun Fun

    2011-02-01

    Full Text Available The title compound, C18H8Cl4N4, exists in a cis configuration with respect to the bridging C=C bond. The two essentially planar quinoxaline ring systems [maximum deviations = 0.012 (1 and 0.022 (1 Å] are inclined at an angle of 59.84 (3. In the crystal, adjacent molecules are linked into chains propagating along [001] via intermolecular C—H...N hydrogen bonds. Weak intermolecular π–π [centroid–centroid distance = 3.6029 (7°] and C—H...π interactions are also observed.

  3. 1,2,3,4-Tetrahydrophenazine 5,10-dioxide

    Directory of Open Access Journals (Sweden)

    Tao Sun

    2010-09-01

    Full Text Available The complete molecule of the title compound, C12H12N2O2, lies on two crystallographic symmetry elements: a twofold axis and a mirror plane. In the molecular structure, the quinoxaline ring and two methylene substituents lie on the mirror plane while the other two methylene groups are disordered about the plane. The crystal packing is stabilized by weak intermolecular π–π stacking interactions with centroid–centroid distances of 3.6803 (7 Å.

  4. Photo- and Electro-luminescence of the New Ternary Europium(Ⅲ) Complex

    Institute of Scientific and Technical Information of China (English)

    Chen Xia DU; Zhi Qiang WANG; Qi XIN; Yang Jie WU; Wen Lian LI

    2005-01-01

    A new luminescent europium complex [Eu(DBM)3dpq] (DBM = 1, 3-diphenyl-1, 3-propanedionate and dpq=dipyrido[2,3-f][2',3'-h]quinoxaline) has been synthesized and shows intense red emission under UV excitation. With the device structure ITO/TPD/Eu(DBM)3dpq:TPD (1:2)/Gd(DBM)3bath/Mg:Ag, sharp-band red emissions with low turn-on voltage of 3V and high brightness of 304cd m-2 were achieved.

  5. Influence of D/A ratio on photovoltaic performance of a highly efficient polymer solar cell system

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Xia [State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); Zhang, Maojie; Zhang, Shaoqing; Huo, Lijun; Hou, Jianhui [State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China); Tan, Jiahui; Hu, Wenping; Li, Yongfang [Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2012-12-18

    A new copolymer PIDTDTQx based on indacenodithiophene and quinoxaline is synthesized and characterized. The correlation between the D/A ratio, mobility, and photovoltaic properties, as well as morphology of the D/A blend based on a PIDTDTQx:PC{sub 70}BM system is investigated. The power conversion efficiency of the polymer solar cells based on PIDTDTQx/PC{sub 70}BM (1:4, w/w) reaches 7.51%. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. A novel Cu(I) complex based organic ultraviolet optical sensor

    Institute of Scientific and Technical Information of China (English)

    车广波; 刘春波; 徐占林; 李文连; 孔治国; 王庆伟

    2009-01-01

    A novel Cu(I) complex with the formula of [Cu(DPEphos)(Dicnq)]BF4(CuDD) was synthesized and characterized by X-ray single crystal diffraction method,in which DPEphos and Dicnq denote bis[2-(diphenylphosphino)phenyl]ether and 6,7-Dicyanodipyrido[2,2-d:2',3'-f] quinoxaline,respectively.Organic ultraviolet optical sensor based on photovoltaic diode is fabricated by using CuDD as an electron acceptor and 4,4′,4″-tris-(2-methylphenyl phenylamino) triphenylamine(m-MTDATA) as an electron donor.The sensor is sensit...

  7. Synthesis of novel tricyclic oxazolidinones by a tandem SN2 and SNAr reaction: SAR studies on conformationally constrained analogues of Linezolid.

    Science.gov (United States)

    Selvakumar, N; Yadi Reddy, B; Sunil Kumar, G; Khera, Manoj Kumar; Srinivas, D; Sitaram Kumar, M; Das, Jagattaran; Iqbal, Javed; Trehan, Sanjay

    2006-08-15

    A series of conformationally constrained analogues of Linezolid were synthesised by employing a tandem SN(2) and SNAr reaction as the key step and tested for antibacterial activity. While the hexahydroazolo-quinoxaline compounds were inactive, the tetrahydroazolo-benzothiazine compounds exhibited interesting antibacterial activity. The introduction of fluorine in the aromatic ring further made the compounds more potent in acetamide compounds resulting in an interesting analogue 32. However, the introduction of fluorine (analogue 34) on the already potent non-fluorine thiocarbamate 21 did not have any influence on the activity.

  8. Design and synthesis of new biprivileged molecular scaffolds: indolo-fused benzodiazepinyl/quinoxalinyl benzimidazoles.

    Science.gov (United States)

    Barve, Indrajeet J; Chen, Chan-Yu; Salunke, Deepak B; Chung, Wen-Sheng; Sun, Chung-Ming

    2012-06-01

    The present article describes the design and synthesis of new biprivileged molecular scaffolds with diverse structural features. Commercially available, simple heterocyclic building blocks such as 4-fluoro-3-nitrobenzoic acid, 2-chloro-3-nitrobenzoic acid, and indoline were utilized for the synthesis of the novel heterocycles. Pictet-Spengler-type condensation was used as a key step to construct tetracyclic indolo-benzodiazepines and indolo-quinoxalines linked with substituted benzimidazoles. Analysis of single crystals of representative compounds showed that these molecular skeletons have the potential to present various substituents with distinct three-dimensional orientations.

  9. Well-done meat intake and meat-derived mutagen exposures in relation to breast cancer risk: the Nashville Breast Health Study.

    Science.gov (United States)

    Fu, Zhenming; Deming, Sandra L; Fair, Alecia M; Shrubsole, Martha J; Wujcik, Debra M; Shu, Xiao-Ou; Kelley, Mark; Zheng, Wei

    2011-10-01

    Previous studies of the association of meat intake and meat-derived mutagen exposure with breast cancer risk have produced inconsistent results. We evaluated this association in a population-based case-control study of incident breast cancer conducted in Nashville, Tennessee, United States, including 2,386 breast cancer cases and 1,703 healthy women controls. Telephone interviews were conducted to obtain information related to meat intake including amount, cooking methods, and doneness levels, as well as other known or hypothesized risk factors for breast cancer. Unconditional logistic regression was used to derive odds ratios (ORs) after adjusting for potential confounders. High intake of red meat was associated with a significantly elevated risk of breast cancer (P-trend mutagens such as 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline and 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline, were significantly associated with increased breast cancer risk among postmenopausal women only (P-trend = 0.002 and 0.003, respectively). The results from this study provide strong support for the hypotheses that high red meat intake and meat-derived mutagen exposure may be associated with an increase in breast cancer risk.

  10. Syntheses, Structure, Magnetic Properties and 57Fe Mossbauer Spectroscopies of Two Iron(Ⅱ) Complexes: Room-temperature Spin Crossover Behavior Observed in [Fe(dpq)(MePy)2(NCS)2

    Institute of Scientific and Technical Information of China (English)

    TAO, Jianqing; GU, Yunlan; ZHOU, Xinhui; GU, Zhiguo; ZUO, Jinglin; YOU, Xiaozeng

    2009-01-01

    Two new complexes [Fe(dpq)(MePy)2(NCS)2] (1) and [Fe(Medpq)(MePy)2(NCS)2] (2) (dpq=2-dipyrido[3,2-f: 2',3'-h]quinoxaline, Medpq=2-methyidipyrido[3,2-f.2',3'-h]quinoxaline, MePy=4-methylpyridine) have been syn- thesized. The crystal structure of 2 was characterized by X-ray diffraction at room temperature. It crystallizes in or- thorhombic space group I212121, with a =15.057(3)A, b =14.569(3)A, c=13.180(3) A,α=90.00°,β= 90.00°,γ= 90.00°, and V=2891.2(11)A3. The distorted [FEN6] octahedron in 2 is formed by six nitrogen atoms from Medpq, two trans-MePy molecules and two cis-NCS- anions. Variable-temperature magnetic susceptibilities and Moss- bauer spectroscopies of 1 and 2 reveal the occurrence of a gradual spin transition. The transition for I spans the 200 -450 K temperature range with a T1/2 of 340 K, while for 2, the transition in low temperature is incomplete.

  11. Synthesis and in vitro and in vivo biological evaluation of substituted nitroquinoxalin-2-ones and 2,3-diones as novel trichomonacidal agents.

    Science.gov (United States)

    Ibáñez-Escribano, Alexandra; Reviriego, Felipe; Nogal-Ruiz, Juan José; Meneses-Marcel, Alfredo; Gómez-Barrio, Alicia; Escario, José Antonio; Arán, Vicente J

    2015-04-13

    Two series of ten novel 7-nitroquinoxalin-2-ones and ten 6-nitroquinoxaline-2,3-diones with diverse substituents at positions 1 and 4 were synthesized and evaluated against the sexually transmitted parasite Trichomonas vaginalis. Furthermore, diverse molecular and drug-likeness properties were analyzed to predict the oral bioavailability following the Lipinski's "rule of five". 7-Nitroquinoxalin-2-one derivatives displayed moderate to high in vitro activity while the efficiency of most nitroquinoxaline-2,3-diones was rather low; both kinds of compounds did not show cytotoxic effects in mammalian cells. 7-Nitro-4-(3-piperidinopropyl)quinoxalin-2-one 9 achieved the highest trichomonacidal activity (IC50 = 18.26 μM) and was subsequently assayed in vivo in a murine model of trichomonosis. A 46.13% and a 50.70% reduction of pathogenic injuries were observed in the experimental groups treated orally during 7 days with 50 mg/kg and 100 mg/kg doses. The results obtained in the biological assays against T. vaginalis indicate that compounds with ω-(dialkylamino)alkyl substituents and a keto group at positions 4 and 2 of quinoxaline ring, respectively, provide interesting structural cores to develop novel prototypes to enhance the nitroquinoxalinones activity as trichomonacidal agents with interesting ADME properties according to virtual screening analysis.

  12. Development and evaluation of elastomeric materials for geothermal applications. Annual report, October 1977-December 1978

    Energy Technology Data Exchange (ETDEWEB)

    Mueller, W.A.; Kalfayan, S.H.; Reilly, W.W.; Yavrouian, A.H.; Mosesman, I.D.; Ingham, J.D.

    1979-05-15

    The research involved formulation of commercially available materials and synthesis of new elastomers. Formulation studies at JPL and elsewhere produced a material having about 250-350 psi tensile strength and 30 to 80% elongation at 260/sup 0/C for at least 24 hours in simulated brine. The relationship between these laboratory test results and sealing performance in actual or simulated test conditions is not entirely clear; however, it is believed that no conventional formation or casing packer design is likely to perform well using these materials. The synthetic effort focused on high temperature block copolymers and development of curable polystyrene. Procedures were worked out for synthesizing these new materials. Initial results with heat-cured unfilled polystyrene gum at 260/sup 0/C indicated a tensile strength of about 50 psi. Cast films of the first sample of polyphenyl quinoxaline-polystyrene block copolymer, which has a graft-block structure consisting of a polystyrene chain with pendant polyphenyl quinoxaline groups, showed elastomeric behavior in the required temperature range. Its tensile strength and elongation at 260/sup 0/C were 220 to 350 psi and 18 to 36%, respectively. All of these materials also showed satisfactory hydrolytic stability. A procedure for the synthesis of a linear block copolymer of this type has been devised, and the required new intermediates have been synthesized and characterized. A description of the previous year's work is included in an appendix.

  13. Electron-deficient N-heteroaromatic linkers for the elaboration of large, soluble polycyclic aromatic hydrocarbons and their use in the synthesis of some very large transition metal complexes.

    Science.gov (United States)

    Fogel, Yulia; Kastler, Marcel; Wang, Zhaohui; Andrienko, Denis; Bodwell, Graham J; Müllen, Klaus

    2007-09-26

    The selective oxidation of the perimeter of an extended polycyclic aromatic hydrocarbon (PAH), namely a six-fold tert-butylated tetrabenzo[bc,ef,hi,uv]ovalene, led to the formation of an alpha-diketone. The newly installed carbonyl centers allowed this building block to be converted into the largest known heteroatom-containing PAHs (up to 224 atoms in the aromatic core) by way of the quinoxaline ring condensation reaction. The tert-butyl substituents caused a distortion of the usually planar aromatic frameworks, which hampered the aggregation tendency of the extended aromatic pi-systems and led to extraordinarily high solubilities. All of the systems described here, even the giant phthalocyanine, could thus be purified using standard chromatographic techniques and characterized using typical spectroscopic methods. For the first time, fully resolved 1H NMR spectra of soluble, diamagnetic, 98- and 104-atom-containing aromatic systems are presented. The computed and experimental UV/vis spectra emphasize the dependence of the characteristic alpha-, p-, and beta-bands upon the size of the PAHs. It was also possible to obtain the largest known ligand to yet be complexed around a ruthenium center. A quadrupolar solvatochromic effect was observed when two donating PAH moieties were fused to an accepting quinoxaline center, in which case the photoluminescence spanned a range of about 80 nm. Electrochemical properties of the new nanographenes were investigated using cyclic voltammetry, and this showed quasi-reversible reductions.

  14. New 6-Aminoquinoxaline Derivatives with Neuroprotective Effect on Dopaminergic Neurons in Cellular and Animal Parkinson Disease Models.

    Science.gov (United States)

    Le Douaron, Gael; Ferrié, Laurent; Sepulveda-Diaz, Julia E; Amar, Majid; Harfouche, Abha; Séon-Méniel, Blandine; Raisman-Vozari, Rita; Michel, Patrick P; Figadère, Bruno

    2016-07-14

    Parkinson's disease (PD) is a neurodegenerative disorder of aging characterized by motor symptoms that result from the loss of midbrain dopamine neurons and the disruption of dopamine-mediated neurotransmission. There is currently no curative treatment for this disorder. To discover druggable neuroprotective compounds for dopamine neurons, we have designed and synthesized a second-generation of quinoxaline-derived molecules based on structure-activity relationship studies, which led previously to the discovery of our first neuroprotective brain penetrant hit compound MPAQ (5c). Neuroprotection assessment in PD cellular models of our newly synthesized quinoxaline-derived compounds has led to the selection of a better hit compound, PAQ (4c). Extensive in vitro characterization of 4c showed that its neuroprotective action is partially attributable to the activation of reticulum endoplasmic ryanodine receptor channels. Most interestingly, 4c was able to attenuate neurodegeneration in a mouse model of PD, making this compound an interesting drug candidate for the treatment of this disorder.

  15. Heterocyclic Aromatic Amines in Domestically Prepared Chicken and Fish from Singapore Chinese Households

    Energy Technology Data Exchange (ETDEWEB)

    Salmon, C P; Knize, M G; Felton, J S; Zhao, B; Seow, A

    2005-05-16

    Chicken and fish samples prepared by 42 Singapore Chinese in their homes were obtained. Researchers were present to collect data on raw meat weight, cooking time, maximum cooking surface temperature, and cooked meat weight. Each participant prepared one pan-fried fish sample and two pan-fried chicken samples, one marinated, one not marinated. The cooked samples were analyzed for five heterocyclic aromatic amine (HAA) mutagens, including MeIQx (2-amino 3,8-dimethylimidazo[4,5-f]quinoxaline); 4,8-DiMeIQx (2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline); 7,8-DiMeIQx (2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline); PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine), and IFP (2-amino-(1,6-dimethylfuro[3,2-e]imidazo [4,5-b])pyridine). A paired Student's t-test showed that marinated chicken had lower concentrations of PhIP (p<0.05), but higher concentrations of MeIQx (p<0.05) and 4,8-DiMeIQx (p<0.001) than non-marinated chicken, and also that weight loss due to cooking was less in marinated chicken than in non-marinated chicken (p<0.001). Interestingly, the maximum cooking surface temperature was higher for fish than for either marinated or non-marinated chicken (P<0.001), yet fish was lower in 4,8-DiMeIQx per gram than marinated or non-marinated chicken (p<0.001), lower in PhIP than non-marinated chicken (P<0.05), and lost less weight due to cooking than either marinated or non-marinated chicken (P<0.001). Fish was also lower in MeIQx and 7,8-DiMeIQx than marinated chicken (P<0.05). This study provides new information on HAA content in the Singapore Chinese diet.

  16. Pharmacokinetics and metabolism of cyadox and its main metabolites in beagle dogs following oral, intramuscular and intravenous administration

    Directory of Open Access Journals (Sweden)

    Adeel Sattar

    2016-08-01

    Full Text Available Cyadox (Cyx is an antibacterial drug of the quinoxaline group that exerts markedly lower toxicity in animals, compared to its congeners. Here, the pharmacokinetics and metabolism of Cyx after oral (PO, intramuscular (IM and intravenous (IV routes of administration were studied to establish safety criteria for the clinical use of Cyx in animals. Six beagle dogs (3 males, 3 females were administered Cyx through PO (40 mg kg-1 b.w., IM (10 mg kg-1 b.w. and IV (10 mg kg-1 b.w. routes with a washout period of 2 weeks in a crossover design. Highly sensitive high-performance liquid chromatography with ultraviolet detection (HPLC-UV was employed for determination of Cyx and its main metabolites, 1, 4-bisdesoxycyadox (Cy1, cyadox-1-monoxide (Cy2, N-(quinoxaline-2-methyl-cyanide acetyl hydrazine (Cy4 and quinoxaline-2-carboxylic acid (Cy6 in plasma, urine and feces of dogs. The oral bioavailability of Cyx was 4.75%, suggesting first-pass effect in dogs. The concentration vs. time profile in plasma after PO administration indicates that Cyx is rapidly dissociated into its metabolites and eliminated from plasma earlier, compared to its metabolites. The areas under the curve (AUC of Cyx after PO, IM and IV administration were 1.22 h×µg mL-1, 6.3 h×µg mL-1, and 6.66 h×µg mL-1, while mean resident times (MRT were 7.32, 3.58 and 0.556 h, respectively. Total recovery of Cyx and its metabolites was >60% with each administration route. In feces, 48.83% drug was recovered after PO administration, while 18.15% and 17.11% after IM and IV injections, respectively, suggesting renal clearance as the major route of excretion with IM and IV administration and feces as the major route with PO delivery. Our comprehensive evaluation of Cyx has uncovered detailed information that should facilitate its judicious use in animals by improving understanding of its pharmacology.

  17. 荧光分光光度计法测定腊肉中维生素C%Determination of Vitamin C in bacon by fluorescence spectrophotometry

    Institute of Scientific and Technical Information of China (English)

    张金艳; 袁林峰; 聂根新; 魏益华; 罗林广

    2011-01-01

    Samples of Vitamin C was extracted by sodium metaphosphate ,2,6- dichloro indophend oxidized dehydro-genation into phenol indigo type ascorbic acid, reacted with o - phenylendiamine in order to generate the flourescent material - quinoxaline. That the fluorescent intensity and dehydrogenation ascorbic acid is proportional to the concentration determine the content of VC in bacon. The fluorescence intensity of quinoxaline was detected by fluorescence spec-trophotometry with 360nm excitation wavelength and 430nm emission wavelength. The detection limit in bacon of this method was 0. 95 mg kg -1, RSD was 2.4%. The recovery rate of VC was between 87. 2% and 94. 3%. By using fluorescence spectrophotometer method and 2,4- dinitrophenylhydrazine colorimetric method determined the VC in the bacon simultaneously, there were no significant difference, but the fluorescence spectrophotometer method had higher precision. It is proved that determination of VC in bacon by fluorescence spectrophotometry is high sensitivity, speedi-ness and accurate.%样品中的VC用偏磷酸钠提取,经2,6-二氯靛酚氧化成脱氢型抗坏血酸后与邻苯二胺(OPDA)反应,生成具有荧光的喹喔啉(quinoxaline),其荧光强度与脱氢抗坏血酸的浓度在一定条件下成正比,以此测定腊肉中VC含量.荧光分光光度计在激发波长360nm,发射波长430nm测定喹喔啉荧光强度.该方法VC的检出限为0.95mg.kg-1,相对标准偏差(RSD) 2.4%,回收率在87.2%~94.3%之间.用荧光分光光度计法和2,4-二硝基苯肼比色法同时测定腊肉中VC,发现二者结果无显著差异,但荧光分光光度计法精密度高于2,4-二硝基苯肼比色法.实验证明,荧光分光光度计法测量腊肉中VC具有灵敏度高、快速、准确等优点.

  18. Study on Residue Depletion of Quinocetone and Its Major Metabolites in Swine%喹烯酮及其主要代谢物在猪体内的残留规律研究

    Institute of Scientific and Technical Information of China (English)

    钟家林; 王林; 赵宁; 于慧敏; 贾慧琴; 鲁晓雄; 吴子莹; 丁焕中

    2012-01-01

    研究了喹烯酮及其3种主要代谢物在猪肌肉、肝脏、肾脏、脂肪中的残留消除规律.猪按体质量20 mg/kg多剂量灌服给药,按既定时间点采集组织样品.组织样品用乙酸乙酯提取后经固相萃取小柱净化,液相色谱-串联质谱法测定样品中喹烯酮及其代谢物含量.结果表明:给药后猪几种组织中以肌肉中喹烯酮及其代谢物消除相对缓慢,药物含量以猪肝脏中3-甲基-苯乙烯酮-喹恶啉含量较高.3-甲基-苯乙烯酮-喹恶啉-N4-一氧化物在肌肉中的消除半衰期可达39.50 h.3-甲基-2-羧酸-喹恶啉仅能在肾脏中检测到.%Residue depletion of quinocetone and three of its major metabolites in muscle, liver, kidney and fat of swine were determined in this study. Quinocetone was administered to 40 healthy cross-bread swine orally at dosage of 20 mg · Kg-1 body mass twice a day for 5 consecutive days. Animals were slaughtered in groups and samples were taken at different time intervals after administration. The tissues were extracted with ethyl acetate, and cleaned up with HLB SPE column. A sensitive high-performance liquid chromatography-tandem mass spectrometry ( LC-MS/MS) method was developed to determine quinocetone and its metabolites. Quinocentone and its metabolites were eliminated more slowly in swine muscle than those in other tissues. The highest drug levels occurred in liver for 3 -methyl-styryl ketone-quinoxaline. The residue lasted the longest half-life of elimination for 39. 50 h with 3-methyl-styryl ke-tone-quinoxaline -N4-monoxide in pig muscle. The 3-methyl-2-carboxylic acid-quinoxaline was detected only in kidney at very low concentration.

  19. Pharmacokinetics and Metabolism of Cyadox and Its Main Metabolites in Beagle Dogs Following Oral, Intramuscular, and Intravenous Administration.

    Science.gov (United States)

    Sattar, Adeel; Xie, Shuyu; Huang, Lingli; Iqbal, Zahid; Qu, Wei; Shabbir, Muhammad A; Pan, Yuanhu; Hussain, Hafiz I; Chen, Dongmei; Tao, Yanfei; Liu, Zhenli; Iqbal, Mujahid; Yuan, Zonghui

    2016-01-01

    Cyadox (Cyx) is an antibacterial drug of the quinoxaline group that exerts markedly lower toxicity in animals, compared to its congeners. Here, the pharmacokinetics and metabolism of Cyx after oral (PO), intramuscular (IM), and intravenous (IV) routes of administration were studied to establish safety criteria for the clinical use of Cyx in animals. Six beagle dogs (3 males, 3 females) were administered Cyx through PO (40 mg kg(-1) b.w.), IM (10 mg kg(-1) b.w.), and IV (10 mg kg(-1) b.w.) routes with a washout period of 2 weeks in a crossover design. Highly sensitive high-performance liquid chromatography with ultraviolet detection (HPLC-UV) was employed for determination of Cyx and its main metabolites, 1, 4-bisdesoxycyadox (Cy1), cyadox-1-monoxide (Cy2), N-(quinoxaline-2-methyl)-cyanide acetyl hydrazine (Cy4), and quinoxaline-2-carboxylic acid (Cy6) in plasma, urine and feces of dogs. The oral bioavailability of Cyx was 4.75%, suggesting first-pass effect in dogs. The concentration vs. time profile in plasma after PO administration indicates that Cyx is rapidly dissociated into its metabolites and eliminated from plasma earlier, compared to its metabolites. The areas under the curve (AUC) of Cyx after PO, IM and IV administration were 1.22 h × μg mL(-1), 6.3 h × μg mL(-1), and 6.66 h × μg mL(-1), while mean resident times (MRT) were 7.32, 3.58 and 0.556 h, respectively. Total recovery of Cyx and its metabolites was >60% with each administration route. In feces, 48.83% drug was recovered after PO administration, while 18.15% and 17.11% after IM and IV injections, respectively, suggesting renal clearance as the major route of excretion with IM and IV administration and feces as the major route with PO delivery. Our comprehensive evaluation of Cyx has uncovered detailed information that should facilitate its judicious use in animals by improving understanding of its pharmacology.

  20. Synthesis of 2,3-dimorpholino-6-aminoquinoxaline derivatives and application to a new intramolecular fluorescent probe

    Energy Technology Data Exchange (ETDEWEB)

    Matsumura, Yuriko [Department of Materials and Life Science, Faculty of Science and Technology, Seikei University, 3-3-1 Kitamachi, Kichijoji, Musashino-shi, Tokyo 180-8633 (Japan)], E-mail: matsumura@st.seikei.ac.jp; Katoh, Akira [Department of Materials and Life Science, Faculty of Science and Technology, Seikei University, 3-3-1 Kitamachi, Kichijoji, Musashino-shi, Tokyo 180-8633 (Japan)], E-mail: katoh@st.seikei.ac.jp

    2008-04-15

    Two fluorescent monomers having a quinoxaline skeleton, N-(2,3-dimorpholinoquinoxalin-6-yl)acrylamide (QxA) and N-(1-(2,3-dimorpholinoquinoxalin-6-ylamino)prop-2-yl)methacrylamide (QxAlaMA), were synthesized. Thermo-responsive copolymers of N-isopropylacrylamide (NIPAM) and a small amount of a fluorescent monomer were synthesized and their fluorescence properties investigated. The fluorescent monomers showed intense solvatochromism in their fluorescence. The wavelength at the maximum fluorescence intensity of the QxAlaMA-labeled PNIPAM dramatically blue-shifted and the fluorescence intensity of the QxA-labeled PNIPAM significantly increased around the transition temperature. It was found that these fluorescent dyes can sense and report the thermo-responsive behavior of the PNIPAM in water. Both QxAlaMA and QxA were demonstrated to be applicable to new intramolecular fluorescent probes.

  1. A low-temperature processed environment-friendly full-organic carrier collection layer for polymer solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Ai-Li; Li, Yan-Qing, E-mail: yqli@suda.edu.cn, E-mail: zhangdd@suda.edu.cn, E-mail: jxtang@suda.edu.cn; Jiang, Xiao-Chen; Ma, Zhong-Sheng; Wang, Qian-Kun; Guo, Zhen-Yu; Zhang, Dan-Dan, E-mail: yqli@suda.edu.cn, E-mail: zhangdd@suda.edu.cn, E-mail: jxtang@suda.edu.cn; Lee, Shuit-Tong; Tang, Jian-Xin, E-mail: yqli@suda.edu.cn, E-mail: zhangdd@suda.edu.cn, E-mail: jxtang@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou, Jiangsu 215123 (China)

    2014-08-04

    We constructed a concept of the full-organic carrier collection layer (CCL) used for polymer solar cells. The CCL is composed of dipyrazino[2,3-f:2′,3′-h]quinoxaline-2,3,6,7,10,11-hexacarbonitrile as hole collection layer (HCL) and chlorine-free solvents (formic acid (FA)) processed 4,7-Diphenyl-1,10-phenanthroline (Bphen) as electron collection layer, exhibiting good solubility, and environmental protection. The FA based device shows ideal power conversion efficiency (3.75%), which is higher than that of control device (3.6%). Besides, the HCL shows a different mechanism in hole extraction by functioning as a charge recombination zone for electrons injected from anode and holes extracted from the donor materials.

  2. Binding of /sup 14/C-labeled food mutagens (IQ, MeIQ, MeIQx) by dietary fiber in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Sjoedin, P.B.; Nyman, M.E.; Nilsson, L.; Asp, N.L.; Jaegerstad, M.

    Binding of three mutagens, known to occur in fried or broiled foods, by thirteen different types of dietary fiber was investigated in vitro. Nonspecific binding by other food polymers was minimized by using protease and amylase treatment. Water-insoluble fiber components were responsible for most of the binding capacity. Generally, a slightly larger proportion of 2-amino-3,4-dimethylimidazo (4,5-f)quinoline (MeIQ) than of 2-amino-3-methylimidazo (4,5-f)quinoline (IQ) and 2-amino-3,8-dimethylimidazo) -4,5-f)quinoxaline (MeIQx) was bound. There was a significant correlation between Klason lignin content and binding of mutagens. Optimum pH for binding was between 4 and 6. Dietary fiber from sorghum had the highest binding capacity, which could be due to the presence of a large Klason lignin fraction.

  3. From byproducts to efficient fluorophores: a route to the synthesis of fluorubines.

    Science.gov (United States)

    Fleischhauer, Jan; Beckert, Rainer; Jüttke, Yvonne; Hornig, David; Günther, Wolfgang; Birckner, Eckhard; Grummt, Ulrich-W; Görls, Helmar

    2009-11-23

    The reaction of bis(imidoyl) chlorides of oxalic acid with monoalkyl hydrazines leads to substituted Delta(2)-1,2-diazetines, which are versatile building blocks for ring-transformation reactions. One remarkable product originating from side reactions featured by a strong orange/red fluorescence was confirmed as a novel fluorubine derivative. In continuing our studies to substituted oligoazaacenes, we developed several synthetic entries to build up novel fluorubine derivatives, in which particularly aminobridged bis(quinoxaline)s are the key products for cationic hexaazapentacenes. We would like to discuss the possible formation pathways of these fluorubine derivatives, which exhibit interesting photophysical and chemical properties. The structures of all new derivatives were confirmed by common analytical methods (NMR spectroscopy, CV, UV/Vis, mass spectrometry, elemental analysis, and X-ray structural analysis) and will be discussed on selected examples in more detail.

  4. Mapping fullerene crystallization in a photovoltaic blend: an electron tomography study

    Science.gov (United States)

    Bäcke, Olof; Lindqvist, Camilla; Diaz de Zerio Mendaza, Amaia; Gustafsson, Stefan; Wang, Ergang; Andersson, Mats R.; Müller, Christian; Olsson, Eva

    2015-04-01

    The formation of fullerene crystals represents a major degradation pathway of polymer/fullerene bulk-heterojunction thin films that inexorably deteriorates their photovoltaic performance. Currently no tools exist that reveal the origin of fullerene crystal formation vertically through the film. Here, we show that electron tomography can be used to study nucleation and growth of fullerene crystals. A model bulk-heterojunction blend based on a thiophene-quinoxaline copolymer and a fullerene derivative is examined after controlled annealing above the glass transition temperature. We image a number of fullerene nanocrystals, ranging in size from 70 to 400 nanometers, and observe that their center is located close to the free-surface of spin-coated films. The results show that the nucleation of fullerene crystals predominately occurs in the upper part of the films. Moreover, electron tomography reveals that the nucleation is preceded by more pronounced phase separation of the blend components.

  5. Synthesis of 2-(3-methyl-2-oxoquinoxalin-1(2)-yl)acetamide-based azetidinone derivatives as potent antibacterial and antifungal agents

    Indian Academy of Sciences (India)

    Shiv Kumar; Nitin Kumar; Sushma Drabu; Md Akram Minhaj

    2013-01-01

    Twelve compounds belonging to series N-[3-chloro-2-oxo-4-(substituted)phenylazetidin-1-yl]-2-(3-methyl-2-oxoquinoxalin-1(2)-yl)acetamide (5a-l) were synthesized. These compounds were evaluated for their in vitro antibacterial against E. coli, S. aureus, K. pneumoniae, P. aeruginosa and antifungal activity against C. albicans, A. niger and A. flavus by cup-plate method. Structures of all the newly synthesized compounds were confirmed by their spectral data interpretation. Compound 5g having -dimethylaminophenyl group on 4-position of azetidinone ring attached to N-atom of acetamido group on 1-position of 3-methyl-1-quinoxaline-2-one, was found to be active against all the bacterial and fungal strains under investigation.

  6. Characterization of glutamate-induced formation of N- acylphosphatidylethanolamine and N-acylethanolamine in cultured neocortical neurons

    DEFF Research Database (Denmark)

    Hansen, Harald S.; Lauritzen, L.; Strand, A.M.;

    1997-01-01

    Glutamate-induced formation of N-acylethanolamine (NAE) and N- acylphosphatidylethanolamine (NAPE) was studied in primary cultures of mouse neocortical neurons prelabeled with [C]ethanolamine. The formation of these two lipids was dependent on the maturity of the cell culture; i.e., no glutamate......-stimulated mouse astrocytes, rat Leydig cells and cardiomyocytes, and several other cells. These results suggest that the glutamate-induced formation of NAPE and NAE was mediated by the NMDA receptor and the formation of these lipids may be associated with neuronal death.......-quinoxaline-2,3-dione (CNQX). In 6-day-old cultures, exposure to NMDA (100 µM for 24 h) induced a linear increase in the formation of NAPE and NAE as well as a 40-50% neuronal death, as measured by a decrease in cellular formazan formation [3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide (MTT...

  7. Toxic effects of nine polycyclic aromatic compounds on Enchytraeus crypticus in artificial soil in relation to their properties.

    Science.gov (United States)

    Kobetičová, Klára; Simek, Zdeněk; Brezovský, Jan; Hofman, Jakub

    2011-09-01

    The aim of this study was to compare the toxic effects of selected two- and three-ringed PAHs (naphthalene, phenanthrene, and anthracene) and their N-heterocyclic analogs with one (quinoline, acridine, and phenanthridine) or two (quinoxaline, phenazine, and 1,10-phenanthroline) nitrogen atoms on the survival and reproduction of Enchytraeus crypticus in artificial soil. Toxicity of compounds was recalculated to soil pore-water concentrations using the data of chemical analyses of 0.01 M CaCl(2) extracts of spiked soils. When toxicity was based on molar concentrations in pore water (μmol/L), it significantly increased with increasing K(ow) value. This relationship indicates nonpolar narcosis as the general toxicity mechanism of the tested compounds. In addition, significant correlation between the toxicity of PACs and their ionization potential has been identified by multidimensional QSAR models.

  8. EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF); Scientific Opinion on Flavouring Group Evaluation 17, Revision 3 (FGE.17Rev3): Pyrazine derivatives from chemical group 24

    DEFF Research Database (Denmark)

    Larsen, John Christian; Nørby, Karin Kristiane; Beltoft, Vibe Meister

    The Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids of the European Food Safety Authority was requested to evaluate 28 flavouring substances in the Flavouring Group Evaluation 17, including seven additional substances considered in this Revision 3, using the Procedure...... in Commission Regulation (EC) No 1565/2000. From the in vitro data available, genotoxic potential is indicated for the flavouring substances quinoxaline [FL-no: 14.147] and 2- methylquinoxaline [FL-no: 14.139]. Therefore, the Panel decided that the Procedure could not be applied to these two substances, until.......126, 14.127, 14.128, 14.129, 14.148, 14.161 and 14.170] do not give rise to safety concerns at their levels of dietary intake, estimated on the basis of the MSDI approach. For the remaining substance [FL-no: 14.052], additional toxicity data are required. Besides the safety assessment of these flavouring...

  9. Novel Alternating Current Electroluminescent Devices with an Asymmetric Structure Based on a Polymer Heterojunction

    Institute of Scientific and Technical Information of China (English)

    谭海曙; 姚建铨; 王昕; 王鹏; 谢洪泉

    2002-01-01

    Novel alternating current electroluminescent devices with an asymmetric structure are successfully fabricated by using a hole-type polymer, poly(2,5-bis (dodecyloxy)-phenylenevinylene) (PDDOPV), and an electron-type polymer, poly(phenyl quinoxaline) (PPQ). The performance of the polymer devices with heteto junctions under ac operation is insensitive to the thickness of the two polymer layers, compared to that under dc operation. This new advantage means easy and cheap production facility on a large scale in the near future. Different emission spectra are obtained when our ac devices are operated in an ac mode, forward or reverse bias. The emission spectrum at reverse bias includes two parts: one from PDDOPV and the other from PPQ.

  10. Alternating current organic light emitting diodes based on polymer heterojunction

    Institute of Scientific and Technical Information of China (English)

    Yewen Jiang(蒋业文); Haishu Tan(谭海曙); Jianquan Yao(姚建铨)

    2003-01-01

    Most alternating current (ac) polymer EL (electroluminescent) devices to date are based on symmetricalstructure. Here novel alternating current EL devices with asymmetric structure are successfully fabricatedby using a hole type polymer PDDOPV [poly (2,5-bis (dodecyloxy)-phenylenevinylene)] and an electrontype polymer PPQ [poly (phenyl quinoxaline)]. We report that performance of polymer devices withheterojunction in ac operation is not so sensitive to thickness of the two polymer layers as in direct current(dc) operation. This new advantage of ac operation mode over dc means easy production and cheapfacilities in large-scale production in the near future. Different emission spectra are obtained when ourac devices operate in ac mode, forward and reverse bias. Emission spectrum at reverse bias includes twoparts: one is from PDDOPV, the other is from PPQ.

  11. Biophysical insights into the intercalative interaction of surfactant cobalt(III) complexes of certain diimine ligands bound to yeast tRNA: Effects of hydrophobicity

    Science.gov (United States)

    Nagaraj, Karuppiah; Sakthinathan, Subramanian; Arunachalam, Sankaralingam

    2015-08-01

    The interaction of two surfactant cobalt(III) complexes, cis-[Co(ip)2(DA)2](ClO4)3 1 and cis-[Co(dpq)2(DA)2](ClO4)3 2 where ip = imidazo[4,5-f][1,10]phenanthroline and dpq = dipyrido[3,2-d:2‧-3‧-f]quinoxaline with yeast tRNA have been explored by using electronic absorption, competitive binding, electrochemical studies and viscosity measurements. The results suggest that these complexes can bind to tRNA by intercalation. The presence of hydrophobic diimine ligand and the long aliphatic double chains of these complexes facilitate its intercalative interaction with the hydrophobic interior of the tRNA. The extent of tRNA binding of complex 2 has greater affinity than that of complex containing imidazo[4,5-f][1,10]phenanthroline ligands.

  12. 3-[2-(3-Methyl-2-oxo-1,2-dihydroquinoxalin-1-ylethyl]oxazolidin-2-one

    Directory of Open Access Journals (Sweden)

    Ahoya Anothane Caleb

    2009-08-01

    Full Text Available The title heterocyclic compound, C14H15N3O3, is a new synthetic molecule containing oxazolidine and quinoxaline rings. It is built up from two fused six-membered rings linked to a five-membered oxazolidin-2-one ring by a C2 chain. Both ring systems are essentially planar [maximum deviation = 0.894 (3 Å, r.m.s. deviation = 0.0043 Å]. The structure is held together by van der Waals forces [electrostatic interactions between dipoles, O...C = 3.002 (2 Å] between molecules and by weak π–π stacking between symmetry-related molecules, with an interplanar distance of 3.579 Å and a centroid–centroid distance of 3.800 (1 Å. Intermolecular C—H...O hydrogen bonds are also observed in the crystal structure.

  13. Peroxiredoxin-1 from the human hookworm Ancylostoma ceylanicum forms a stable oxidized decamer and is covalently inhibited by conoidin A.

    Science.gov (United States)

    Nguyen, Jennifer B; Pool, Christopher D; Wong, Christina Y B; Treger, Rebecca S; Williams, David L; Cappello, Michael; Lea, Wendy A; Simeonov, Anton; Vermeire, Jon J; Modis, Yorgo

    2013-08-22

    Hookworms are parasitic nematodes that have a devastating impact on global health, particularly in developing countries. We report a biochemical and structural analysis of a peroxiredoxin from the hookworm Ancylostoma ceylanicum, AcePrx-1. Peroxiredoxins provide antioxidant protection and act as signaling molecules and chaperones. AcePrx-1 is expressed in adult hookworms and can be inactivated by 2,3-bis(bromomethyl)quinoxaline-1,4-dioxide (conoidin A). Conoidin A inactivates AcePrx-1 by alkylating or crosslinking the catalytic cysteines, while maintaining the enzyme in the "locally unfolded" conformation. Irreversible oxidation of the resolving cysteine may contribute additional inhibitory activity. A crystal structure of oxidized AcePrx-1 reveals a disulfide-linked decamer. A helix macrodipole near the active site increases the reactivity of the catalytic cysteines to conoidin A. This work demonstrates the promise of conoidin compounds as probes to evaluate peroxiredoxins as drug targets in human parasites.

  14. Synthesis, Characterization, and Electropolymerization of Extended Fused-Ring Thieno[3,4-b]pyrazine-Based Terthienyls

    Directory of Open Access Journals (Sweden)

    Kristine L. Konkol

    2016-05-01

    Full Text Available The synthesis, characterization, and electropolymerization of a series of extended fused-ring thieno[3,4-b]pyrazine-based terthienyls are reported. The target terthienyls contain a central extended thieno[3,4-b]pyrazine analogue containing 2-thienyl units at the reactive α-positions of the central thiophene. The extended fused-ring thieno[3,4-b]pyrazine analogues studied include acenaphtho[1,2-b]thieno[3,4-e]pyrazine, dibenzo[f,h]thieno[3,4-b]quinoxaline, and thieno[3′,4′:5,6]-pyrazino[2,3-f][1,10]phenanthroline. Comparison of the electrochemical and photophysical properties to simple thieno[3,4-b]pyrazine-based terthienyls and their polymeric analogues are reported in order to provide structure-function relationships within this series of compounds and materials.

  15. Two-dimensional, phenanthroline-based, extended {pi}-conjugated molecules for single-molecule conduction

    Energy Technology Data Exchange (ETDEWEB)

    Wohlthat, Soeren; Reimers, Jeffrey R [School of Chemistry, The University of Sydney, Sydney, NSW 2006 (Australia); Pauly, Fabian [Institut fuer Theoretische Festkoerperphysik and DFG-Center for Functional Nanostructures, Universitaet Karlsruhe, 76128 Karlsruhe (Germany)], E-mail: reimers@chem.usyd.edu.au

    2008-07-23

    The conduction properties of phenanthroline-terminated, polycyclic extended {pi}-conjugated molecular wires are investigated using density functional theory (DFT) in combination with Green's function techniques and group theory. While these molecules could possibly be thought of as accessible graphene-like fragments, they are calculated to conduct poorly. The decay constant for their exponential decrease of conductance with length is in excess of 0.6 A{sup -1} for the addition of internal fused quinoxaline groups and in excess of 0.9 A{sup -1} for the addition of internal pyrazine-fused pyrene groups. Furthermore, while the bidentate phenanthroline connectors adhere strongly to gold, they are sometimes predicted to be less conductive than related monodentate connectors. Careful design is thus required for any graphene-like extended {pi}-system intended for single-molecule conduction applications.

  16. N-(3-Methylphenylquinoxalin-2-amine monohydrate

    Directory of Open Access Journals (Sweden)

    Azila Idris

    2010-09-01

    Full Text Available The quinoxaline system in the title hydrate, C15H13N3·H2O, is roughly planar, the r.m.s. deviation for the 18 non-H atoms being 0.188 Å; this conformation features a short intramolecular C—H...N(pyrazine interaction. In the crystal, the amine H atom forms an N—H...O hydrogen bond to the water molecule, which in turn forms two O—H...N hydrogen bonds to the pyrazine N atoms of different organic molecules. These interactions lead to supramolecular arrays in the bc plane that are two molecules thick; additional π–π interactions stabilize the layers [ring centroid–centroid distance = 3.5923 (7 Å]. The layers stack along the a-axis direction via C—H...π contacts.

  17. Crystal structure of propaquizafop

    Directory of Open Access Journals (Sweden)

    Youngeun Jeon

    2014-12-01

    Full Text Available The title compound, C22H22ClN3O5 {systematic name: 2-(propan-2-ylideneaminooxyethyl (R-2-[4-(6-chloroquinoxalin-2-yloxyphenoxy]propionate}, is a herbicide. The asymmetric unit comprises two independent molecules in which the dihedral angles between the phenyl ring and the quinoxaline ring plane are 75.93 (7 and 82.77 (8°. The crystal structure features C—H...O, C—H...N, and C—H...Cl hydrogen bonds, as well as weak π–π interactions [ring-centroid separation = 3.782 (2 and 3.5952 (19 Å], resulting in a three-dimensional architecture.

  18. 3-(4-Fluorophenyl-6-methoxy-2-(4-pyridylquinoxaline

    Directory of Open Access Journals (Sweden)

    Hartmut Jahns

    2009-07-01

    Full Text Available In the title compound, C20H14FN3O, the quinoxaline system makes dihedral angles of 32.38 (7 and 48.04 (7° with the 4-fluorophenyl and pyridine rings, respectively. The 4-fluorophenyl ring makes a dihedral angle of 57.77 (9° with the pyridine ring. In the crystal, the molecules form dimeric C—H...N hydrogen-bonded R22(20 ring motifs lying about crystallographic inversion centers. The dimeric units stack via π–π interactions between methoxyphenyl rings and pyridine–fluorophenyl rings with centroid–centroid distances of 3.720 (1 and 3.823 (1 Å, respectively. The respective average perpendicular distances are 3.421 and 3.378 Å, with dihedral angles between the rings of 1.31 (9 and 11.64 (9°.

  19. 由羧酸配体和铁(Ⅱ)构筑的两个过渡金属配位聚合物的结构、表征和性质%Two Coordination Polymers Based on Carboxylate Ligands and Fe(Ⅱ): Preparation,Structural Characterization and Properties

    Institute of Scientific and Technical Information of China (English)

    黄艳菊; 杜刚; 郝向荣; 张铁赢

    2016-01-01

    采用水热法合成了2个铁的过渡金属配位聚合物[Fe(Medpq)(BDC)H2O]n(1)和{[Fe(Medpq)(QUI)H2O]·2H2O}n(2)(Medpq=2-methyldipyrido[3,2-f:2',3'-h]quinoxaline;H2BDC=terephthalic acid;H2QUI=2,3-pyridinedicarboxylic acid),并对其进行了元素分析、红外光谱和热重表征,并用X射线单晶衍射测定结构.2个配位聚合物中的中心铁(Ⅱ)离子,都呈现一个稍微扭曲的八面体几何构型.

  20. Synthesis and Photoluminescence of Three Europium (Ⅲ) Ternary Complexes with New Secondary Ligands of Different Structure

    Institute of Scientific and Technical Information of China (English)

    袁继兵; 李嘉航; 梁万里; 苏树江; 石建新; 龚孟濂

    2004-01-01

    Three new 1,10-phenanthroline derivatives, dipyrido (3,2-f: 2,3-h) quinoxaline (DPQN), imidazo (5,6-f)-(1,10)-phenanthroline (IP) and 3-phenyl-imidazo (5,6-f)-(1,10)-phenanthroline (PIP) were designed and synthesized as a secondary ligand to coordinate with europium (Ⅲ) ion while dibenzoylmethane (DBM) was used as the first ligand. The compositions of the ligands and the europium (Ⅲ) ternary complexes were confirmed by elementary analysis, IR and 1H-NMR spectroscopy. The UV-visible absorption spectra, thermal stability, photoluminescence spectra, quantum yield and fluorescence life time of the Eu(Ⅲ) complexes were investigated. The effect of the structure of the secondary ligand on the photoluminescence of the complexes was discussed. The results show that the synthesized Eu(Ⅲ) complexes are good red-emitiing materials for potential application in fabrication of organic electroluminescence devices.

  1. New imidazoquinoxaline derivatives: Synthesis, biological evaluation on melanoma, effect on tubulin polymerization and structure-activity relationships.

    Science.gov (United States)

    Zghaib, Zahraa; Guichou, Jean-François; Vappiani, Johanna; Bec, Nicole; Hadj-Kaddour, Kamel; Vincent, Laure-Anaïs; Paniagua-Gayraud, Stéphanie; Larroque, Christian; Moarbess, Georges; Cuq, Pierre; Kassab, Issam; Deleuze-Masquéfa, Carine; Diab-Assaf, Mona; Bonnet, Pierre-Antoine

    2016-06-01

    Microtubules are considered as important targets of anticancer therapy. EAPB0503 and its structural imidazo[1,2-a]quinoxaline derivatives are major microtubule-interfering agents with potent anticancer activity. In this study, the synthesis of several new derivatives of EAPB0503 is described, and the anticancer efficacy of 13 novel derivatives on A375 human melanoma cell line is reported. All new compounds show significant antiproliferative activity with IC50 in the range of 0.077-122μM against human melanoma cell line (A375). Direct inhibition of tubulin polymerization assay in vitro is also assessed. Results show that compounds 6b, 6e, 6g, and EAPB0503 highly inhibit tubulin polymerization with percentages of inhibition of 99%, 98%, 90%, and 84% respectively. Structure-activity relationship studies within the series are also discussed in line with molecular docking studies into the colchicine-binding site of tubulin.

  2. Excitotoxic effects of non-NMDA receptor agonists in organotypic corticostriatal slice cultures

    DEFF Research Database (Denmark)

    Kristensen, B W; Noraberg, J; Jakobsen, B

    1999-01-01

    of the cytosolic enzyme lactate dehydrogenase (LDH) into the culture medium and loss of glutamic acid decarboxylase (GAD) activity in the tissue. Histological sections were also stained by the fluorescent dye Fluoro-Jade (FJ), for degenerating neurons and by immunocytochemical staining for gamma-aminobutyric acid......The excitotoxic effects of the glutamate receptor agonists kainic acid (KA) and 2-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) and the corresponding neuroprotective effects of the AMPA/KA receptor antagonist 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F)quinoxaline (NBQX) were examined...... rats and grown on semiporous membranes in serum-free medium for 3-4 weeks before exposure to KA or AMPA for 48 h. The uptake by injured cells of the fluorescent dye propidium iodide (PI) added to the culture medium was used as a quantifiable measure for neuronal degeneration and compared with efflux...

  3. Hydroamination reactions of alkynes with ortho-substituted anilines in ball mills: synthesis of benzannulated N-heterocycles by a cascade reaction.

    Science.gov (United States)

    Weiße, Maik; Zille, Markus; Jacob, Katharina; Schmidt, Robert; Stolle, Achim

    2015-04-20

    It was demonstrated that ortho-substituted anilines are prone to undergo hydroamination reactions with diethyl acetylenedicarboxylate in a planetary ball mill. A sequential coupling of the intermolecular hydroamination reaction with intramolecular ring closure was utilized for the syntheses of benzooxazines, quinoxalines, and benzothiazines from readily available building blocks, that is, electrophilic alkynes and anilines with OH, NH, or SH groups in the ortho position. For the heterocycle formation, it was shown that several stress conditions were able to initiate the reaction in the solid state. Processing in a ball mill seemed to be advantageous over comminution with mortar and pestle with respect to process control. In the latter case, significant postreaction modification occurred during solid-state analysis. Cryogenic milling proved to have an adverse effect on the molecular transformation of the reagents. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Near-infrared response photovoltaic device based on novel narrow band gap small molecule and PCBM fabricated by solution processing

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Mingliang; Wang, Li; Zhu, Xuhui; Du, Bin; Liu, Ransheng; Yang, Wei; Cao, Yong [Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, Key Lab of Specially Functional Materials, Ministry of Education, Wushan Road, Guangzhou 510640 (China)

    2007-11-06

    In this paper, we report on synthesis of a novel diphenylaminofluorenyl-capped thiadiazoloquinoxaline (6,7-dimethyl-4,9-di{l_brace}5-[9,9-bis(octyl)-7-diphenylaminofluorene-2-yl]-4-hexylthien-2-yl{r_brace}[1,2,5]-thiadiazolo[3,4-g]quinoxaline (DPAFL-TDOX-DPAFL which is further abbreviated to TDOX), Scheme 1) and its use as donor material for the realization of efficient bulk-heterojunction organic solar cell by spin coating from blend with PCBM as acceptor. TDOX showed very good solution processibility and film uniformity up to weight ratio TDOX:PCBM=1:4. Spectral response was extended to near-infrared region (at around 1000 nm) with energy conversion efficiency (ECE) 0.75% and short-curcuit current density 1.95 mA/cm{sup 2}. (author)

  5. Nitric oxide promotes survival of cerebellar granule neurons cultured in vitro through the Akt pathway

    Institute of Scientific and Technical Information of China (English)

    Lin Wang; Mei Li; Lihua Zhou

    2011-01-01

    In this study, cerebellar granule neurons were used to examine the role of nitric oxide on cell survival. The N-methyl-D-aspartic acid receptor antagonist, MK-801, and the soluble guanylate cyclase antagonist, 1H-[1, 2, 4]oxadiazolo-[4, 3-a] quinoxalin-1-one, decreased cell viability, induced caspase-3, and decreased phosphorylated-Akt levels, suggesting that blockade of nitric oxide production promotes apoptosis of differentiating cerebellar granule neurons. After administration of sodium nitroprusside, an endogenous nitric oxide donor, cell viability recovered,caspase-3 expression was decreased, and phosphorylated-Akt levels increased. This study provides direct evidence that nitric oxide can sustain the survival of developing cerebellar granule neurons in vitro through the nitric oxide-Akt pathway. Moreover, endogenous nitric oxide exerts these effects in a cyclic guanosine monophosphate-dependent manner while exogenous nitric oxide does so in a cyclic guanosine monophosphate-independent manner.

  6. Photoinduced energy transfer processes within dyads of metallophthalocyanines compactly fused to a ruthenium(II) polypyridine chromophore.

    Science.gov (United States)

    Haas, Marco; Liu, Shi-Xia; Kahnt, Axel; Leiggener, Claudia; Guldi, Dirk M; Hauser, Andreas; Decurtins, Silvio

    2007-09-28

    An unsymmetric, peripherally octasubstituted phthalocyanine (Pc) 1, which contains a combination of dipyrido[3,2-f:2',3'-h] quinoxaline and 3,5-di-tert-butylphenoxy substituents, has been obtained via a statistical condensation reaction of two corresponding phthalonitriles. Synthetic procedures for the selective metalation of the macrocyclic cavity and the periphery of 1 were developed, leading to the preparation of the key precursor metallophthalocyanines 3-5 in good yields. Two different strategies were applied to the synthesis of compact dyads MPc-Ru(II) 6-8 (M = Mg(II), Co(II), Zn(II)). Intramolecular electronic interactions in these dyads were studied by absorption, emission, and transient absorption spectroscopy. Upon photoexcitation, these dyads exhibit efficient intramolecular energy transfer from the Ru(II) chromophore to the MPc moiety.

  7. Recent advances in QSAR-based identification and design of anti-tubercular agents.

    Science.gov (United States)

    Nidhi; Siddiqi, Mohammad Imran

    2014-01-01

    Increasing worldwide incidence and the advent of multi drug resistant and extensively drug resistant tuberculosis raise the need of new drugs for the treatment of tuberculosis soon. To meet the required pace QSAR-based rational approaches may prove fruitful as they render rapid and cost-efficient design and optimization of new drug candidates. This review presents a comprehensive overview of QSAR studies reported for newer anti-tubercular agents including nitroimidazoles, fluoroquinolones, quinoxalines, carboxamides and other classes of molecules. The article includes review of 2D and 3D-QSAR approaches and the recent trend of integration of these methods with virtual screening using 3D pharmacophore and molecular docking approaches for the identification and design of novel anti-tubercular agents.

  8. Biophysical insights into the intercalative interaction of surfactant cobalt(III) complexes of certain diimine ligands bound to yeast tRNA: Effects of hydrophobicity.

    Science.gov (United States)

    Nagaraj, Karuppiah; Sakthinathan, Subramanian; Arunachalam, Sankaralingam

    2015-08-01

    The interaction of two surfactant cobalt(III) complexes, cis-[Co(ip)₂(DA)₂](ClO₄)₃ 1 and cis-[Co(dpq)₂(DA)₂](ClO₄)₃ 2 where ip=imidazo[4,5-f][1,10]phenanthroline and dpq=dipyrido[3,2-d:2'-3'-f]quinoxaline with yeast tRNA have been explored by using electronic absorption, competitive binding, electrochemical studies and viscosity measurements. The results suggest that these complexes can bind to tRNA by intercalation. The presence of hydrophobic diimine ligand and the long aliphatic double chains of these complexes facilitate its intercalative interaction with the hydrophobic interior of the tRNA. The extent of tRNA binding of complex 2 has greater affinity than that of complex containing imidazo[4,5-f][1,10]phenanthroline ligands.

  9. Mass spectrometric studies of cis- and trans-1a,3-disubstituted-1,1-dichloro-4-formyl-1a, 2,3,4-tetrahydro-1H-azirino [ 1,2-a ][ 1,5 ] benzodiazepines

    Institute of Scientific and Technical Information of China (English)

    XU, Jia-Xi(许家喜); ZHANG, Xin-Yu(张新宇); JIN, Sheng(金声)

    2000-01-01

    The mass spectrometric behaviour of four cis- and trans-1a,3- disubstituted -1,1 - dichloro-4-formyl-1a,2,3,4-tetrahydro1H-azirino[1,2-a] [1,5] benzodiazepines has been studied with the aid of mass-analysed ion kinetic energy spectrometry and exact mass measurements under electron impact ionization. All compounds show a tendency to eliminate a chlorine atom from the aziridine ring, and then eliminate a neutral propene or styrene from the diazepine ring to yield azirino[1,2-b][1,3]benzimidazole ions. These azirino[1,2-a] [1,5]-benzodiazepines can also eliminate HCl, or Cl plus HCl simultaneously to undergo a ring enlargement rearrangement to yield 1,6-benzodiazocine ions, which further lose small molecular fragments, propyne or phenylacetylene, with rearrangement to give quinoxaline ions.

  10. Optimised extraction of heterocyclic aromatic amines from blood using hollow fibre membrane liquid-phase microextraction and triple quadrupole mass spectrometry.

    Science.gov (United States)

    Cooper, Kevin M; Jankhaikhot, Natcha; Cuskelly, Geraldine

    2014-09-05

    Heterocyclic aromatic amines (HCA) are carcinogenic mutagens formed during cooking of proteinaceous foods, particularly meat. To assist in the ongoing search for biomarkers of HCA exposure in blood, a method is described for the extraction from human plasma of the most abundant HCAs: 2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx) (and its isomer 7,8-DiMeIQx), using hollow fibre membrane liquid-phase microextraction. This technique employs 2.5cm lengths of porous polypropylene fibres impregnated with organic solvent to facilitate simultaneous extraction from an alkaline aqueous sample into a low volume acidic acceptor phase. This low cost protocol is extensively optimised for fibre length, extraction time, sample pH and volume. Detection is by UPLC-MS/MS using positive mode electrospray ionisation with a 3.4min runtime, with optimum peak shape, sensitivity and baseline separation being achieved at pH 9.5. To our knowledge this is the first description of HCA chromatography under alkaline conditions. Application of fixed ion ratio tolerances for confirmation of analyte identity is discussed. Assay precision is between 4.5 and 8.8% while lower limits of detection between 2 and 5pg/mL are below the concentrations postulated for acid-labile HCA-protein adducts in blood.

  11. Metabolism of olaquindox in rat liver microsomes: structural elucidation of metabolites by high-performance liquid chromatography combined with ion trap/time-of-flight mass spectrometry.

    Science.gov (United States)

    Liu, Zhaoying; Huang, Lingli; Dai, Menghong; Chen, Dongmei; Wang, Yulian; Tao, Yanfei; Yuan, Zonghui

    2008-04-01

    Olaquindox (N-(2-hydroxyethyl)-3-methyl-2-quinoxalincarboxamide-1,4-dioxide) is a growth-promoting feed additive for food-producing animals. Its toxicity is closely related to the metabolism. The complete metabolic pathways of olaquindox are not revealed. To improve studies of the metabolism and toxicity of olaquindox, its biotransformation in rat liver microsomes and the structure of its metabolites using high-performance liquid chromatography combined with ion trap/time-of-flight mass spectrometry (LC/MS-ITTOF) were investigated. When olaquindox was incubated with an NADPH-generating system and rat liver microsomes, ten metabolites (M1-M10) were detected. The structures of these metabolites were identified from mass spectra and comparison of their changes in their accurate molecular masses and fragment ions with those of the parent drug. With the high resolution and good mass accuracy achieved by this technique, the elemental compositions of the metabolites and their fragment ions were exactly determined. The results indicate that the N --> O group reduction is the main metabolic pathway of olaquindox metabolism in rat liver microsomes, because abundant 1-desolaquindox (M2), 4-desolaquindox (M1) and bisdesoxyolaquindox (M9) were produced during the incubation step. Seven other minor metabolites were revealed which were considered to be hydroxylation metabolites, based on the position of the quinoxaline ring or 3-methyl group and a carboxylic acid derivative on the side chain at position 2 of the quinoxaline ring. Among the identified metabolites, five new hydroxylated metabolites (M3-M7) were found for the first time in rat liver microsomes. This work will conduce to complete clarification of olaquindox metabolism, and improve the in vivo metabolism of olaquindox in food animals.

  12. Generation, characterization, and reactivity of the transition metal-o-benzne analog of pyrazine (Fe{sup +}-2,3-didehydropyrazine) in the gas phase: An experimental and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Chen, H.; Jacobson, D.B.; Freiser, B.S. [Purdue Univ., West Lafayette, IN (United States). H.C. Brown Lab. of Chemistry

    1999-04-26

    Fe{sup +}-2,3-didehydropyrazine (2) has been generated and its reactivity with simple olefins and alkynes studied by using Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. 2, which is prepared by dehalogenation of chloropyrazine by Fe{sup +}, undergoes a simple adduct formation (no ligand coupling) with ethene and ethene-d{sub 4}. Ethyne also yields adduct formation; however, ligand coupling has clearly occurred in this reaction. Interestingly, reactions with propene and isobutene yield the same products with similar product distributions. Again, ligand coupling is involved and a metal-centered mechanism featuring activation of the allylic carbon-hydrogen bonds is proposed. Propyne, allene, 1-butene, and cis-2-butene yield a variety of products with 2. However, 2 yields exclusive dehydrogenation with 1,3-butadiene to generate FeC{sub 8}H{sub 6}N{sub 2}{sup +}. CID results suggest that this FeC{sub 8}H{sub 6}N{sub 2}{sup +} ion consists of quinoxaline bound to Fe{sup +}. Ligand displacement reactions yield a bond dissociation energy of 47 {+-} 5 kcal/mol for D{degree}(Fe{sup +}-quinoxaline). FeC{sub 4}H{sub 2}N{sub 2}{sup +} ion (2) has also been investigated theoretically. Density functional calculations predicted that the ground state of 2,3-didehydropyrazine is the triplet state, with the singlet state being 9.9 kcal/mol higher than the triplet state. 2 has C{sub 2{nu}} symmetry with the metal center coplanar with the 2,3-didehydropyrazine ring. 2 has a sextet ground state with doublet and quartet states 4.9 and 6.8 kcal/mol higher, respectively. The bond dissociation energy D{degree}(Fe{sup +}-C{sub 4}H{sub 2}N{sub 2}) for the sextet ground state is computed to be 87 {+-} 10 kcal/mol.

  13. Radical and Non-Radical Mechanisms for Alkane Oxidations by Hydrogen Peroxide-Trifluoroacetic Acid

    Energy Technology Data Exchange (ETDEWEB)

    Camaioni, Donald M.; Bays, J. Timothy; Shaw, Wendy J.; Linehan, John C.; Birnbaum, Jerome C.

    2001-02-01

    The oxidation of cyclohexane by the H2O2-trifluoroacetic acid system is revisited. Consistent with a previous report (Deno, N.; Messer, L. A. Chem. Comm. 1976, 1051), cyclohexanol forms initially but then esterifies to cyclohexyl trifluoroacetate. Small amounts of trans-1,2-cyclohexadiyl bis(trifluoroacetate) also form. Although these products form irrespective of the presence or absence of O2, dual mechanisms are shown to operate. In the absence of O2, the dominant mechanism is a radical chain reaction that is propagated by CF3• abstracting H from C6H12 and SH2 displacement of C6H11• on CF3CO2OH. The intermediacy of C6H11• and CF3• is inferred from production of CHF3 and CO2 along with cyclohexyl trifluoroacetate, or CDF3 when cyclohexane-d12 is used. In the presence of O2, fluoroform and CO2 are suppressed, the reaction rate slows, and the rate law approaches second order (first order in peracid and in C6H12). Trapping of cyclohexyl radicals by quinoxaline is inefficient except at elevated (75 °C) temperatures. Fluoroform and CO2, telltale evidence for the chain pathway, were not produced when quinoxaline was present in room temperature reactions. These observations suggest that a parallel, nonfree radical, oxenoid insertion mechanism dominates when O2 is present. A pathway is discussed in which a biradicaloid-zwiterionic transition state is attained by hydrogen transfer from alkane to peroxide oxygen with synchronous O-O bond scission.

  14. Tailoring the optoelectronic properties of donor-acceptor-donor type {pi}-conjugated polymers via incorporating different electron-acceptor moieties

    Energy Technology Data Exchange (ETDEWEB)

    Tarkuc, Simge [Department of Chemistry, Middle East Technical University, 06531, Ankara (Turkey); Opto-Electronic Materials, DelftChemTech, Delft University of Technology, Julianalaan 136, 2628 BL Delft (Netherlands); Udum, Yasemin Arslan [Institute of Science and Technology, Department of Advanced Technologies, Gazi University, 06570 Ankara (Turkey); Toppare, Levent, E-mail: toppare@metu.edu.tr [Department of Chemistry, Middle East Technical University, 06531, Ankara (Turkey); Department of Biotechnology, Middle East Technical University, 06531 Ankara (Turkey); Department of Polymer Science and Technology, Middle East Technical University, 06531 Ankara (Turkey)

    2012-01-31

    Syntheses of donor-acceptor-donor type of {pi}-conjugated monomers were performed to examine the effect of the acceptor units' strength on the electrochemical and optoelectrochemical properties of the resulting monomer and polymer. Palladium catalyzed Stille cross-coupling reaction of an organotin reagent with an organic electrophile was used for the synthesis of target monomers, 5,8-bis(4-hexylthiophen-2-yl)-2-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl) -3-(2,3-dihydrobenzo[b][1,4]dioxin-7-yl)quinoxaline (DBQHT) and 10,13-bis(4-hexylthiophen-2-yl)dibenzo[a,c]phenazine (PHEHT). The presence of the strong electron-donating ethylenedioxy groups on pendant phenyl rings increased electron density on DBQHT, thus the oxidation potential of DBQHT shifts to a lower value than that of PHEHT. The {pi}-{pi}* absorption maximum of PPHEHT was about 40 nm red-shifted compare to that of PDBQHT, which can be attributed to the increase of the effective conjugation and coplanarity of PPHEHT relative to PDBQHT via using phenanthrene fused quinoxaline unit as the acceptor. The electronic band gap of polymer, defined as the onset of the {pi}-{pi}* transition, is found to be 1.65 eV for PPHEHT and 1.82 eV for PDBQHT. Both polymer films showed multi-color electrochromism. PDBQHT can be switched between a red neutral state and a green oxidized state with two intermediate states; purple and brown. PPHEHT also shows multicolored electrochromic behavior with three distinct states: a blue neutral state, a gray intermediate state, and a green oxidized state.

  15. Contrasting solvent polarity effect on the photophysical properties of two newly synthesized aminostyryl dyes in the lower and in the higher solvent polarity regions.

    Science.gov (United States)

    Shaikh, M; Mohanty, J; Singh, P K; Bhasikuttan, A C; Rajule, R N; Satam, V S; Bendre, S R; Kanetkar, V R; Pal, H

    2010-04-08

    Solvent polarity effect on the photophysical properties of two newly synthesized aminostyryl-thiazoloquinoxaline dyes, one with a flexible diphenylamino group, namely, N,N-diphenyl-4-[2-(thiazolo[4,5-b]quinoxalin-2-yl)vinyl]aniline (TQ1), and the other with a rigid julolidinylamino group, namely, (9-[2-(thiazolo[4,5-b]quinoxalin-2-yl)vinyl]julolidine) (TQ2), have been investigated in different aprotic solvents and solvent mixtures. From the polarity dependent changes in the absorption and fluorescence spectral properties, it is indicated that the fluorescent states of the dyes are of intramolecular charge transfer (ICT) character. For both the dyes, the photophysical properties like fluorescence quantum yields (Phi(f)), fluorescence lifetimes (tau(f)), radiative rate constants (k(f) = Phi(f)/tau(f)), and nonradiative rate constants (k(nr) = 1/tau(f) - Phi(f)/tau(f)) show clearly contrasting solvent polarity effects in the lower and in the higher solvent polarity region, causing an interesting reversal in the properties below and above an intermediate solvent polarity. It is inferred that the domination of the cis-trans isomerization in the lower solvent polarity region and that of the twisted intramolecular charge transfer (TICT) state formation in the higher solvent polarity region are responsible for the observed contrasting solvent polarity effects on the photophysical properties of the two dyes. As both isomerization and TICT state formation causes an enhancement in the nonradiative decay rate of the excited dyes and both the processes become less significant at the intermediate solvent polarity region, the two dyes show their largest Phi(f) and tau(f) values at intermediate solvent polarities. Suitable mechanistic schemes have been proposed and qualitative potential energy diagrams have been presented to explain the observed results with the changes in the polarity of the solvents used.

  16. Effect of phenolic compounds from spices consumed in China on heterocyclic amine profiles in roast beef patties by UPLC-MS/MS and multivariate analysis.

    Science.gov (United States)

    Zeng, Maomao; Li, Yang; He, Zhiyong; Qin, Fang; Chen, Jie

    2016-06-01

    Ultra performance liquid chromatography-tandem mass spectrometry and multivariate analysis were used to exploit the effect and further synergistic or antagonistic interactions of main phenolic compounds with the same ratios as in spices consumed in China, on the profiles of HAs in roast beef patties. Quantitative levels of harman (1-methyl-9H-pyrido[3,4-b]indole), norharman (9H-pyrido[3,4-b]indole), PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine), DMIP (2-amino-1,6-dimethylimidazo[4,5-b]pyridine), 1,5,6-TMIP (2-amino-1,5,6-trimethylimidazo[4,5-b]pyridine), MeIQx (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline) and 4,8-DiMeIQx (2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline) were detected in all of the beef patties. The formation of most of these seven HAs was significantly (Pphenolic compounds. Mixed and corresponding single phenolic compounds had different effects on HA profiles. DMIP, 1,5,6-TMIP and 4,8-DiMeIQx were investigated as differentiating factors for single compounds, while harman and MeIQx for mixed ones. Moreover, certain combination of phenolic compounds have synergistic on harman, norharman and MeIQx, but antagonistic effects on the formation of DMIP and 4,8-DiMeIQx. The results may shed light on the mechanism for the effects of spices on the formation of HAs.

  17. Synthesis and characterization of thermoplastic polyphenoxyquinoxalines

    Science.gov (United States)

    Erdem, Haci Bayram

    This research was divided into two main parts. In the first part, a new facile route to relatively inexpensive thermoplastic polyphenoxyquinoxalines was developed. The synthetic route involves the aromatic nucleophilic substitution reaction of bisphenols with 2,3-dichloroquinoxaline. The dichloro monomer was prepared in two steps. In the first step, oxalic acid was condensed with o-phenylenediamine to give 2,3-dihydroxyquinoxaline. In the second step, 2,3-dihydroxyquinoxaline was treated with thionyl chloride to give 2,3-dichloroquinoxaline. This monomer was successfully polymerized with bisphenol-A, bisphenol-S, hexafluorobisphenol-A and 9,9-bis(4-hydroxyphenyl)fluorenone. Hydroquinone and biphenol, however, can not be polymerized to high molecular weight polymers because of the premature precipitation of crystalline oligomers. The glass transition temperatures of the high molecular weight polymers prepared from a series of bisphenols range from 191 °C to 279 °C, and their thermal decomposition temperatures are around 500 °C. The polymers are soluble in a wide range of solvents and can be solution-cast into thin films that are colorless and transparent. The polymers have tensile strengths ranging from 61 to 107 MPa, and tensile moduli ranging from 3.5 to 2.3 GPa. The synthesis of polymer obtained from 2,3-dichloroquinoxaline and bisphenol-A was scaled up to afford 500 g of material. This polymer is a thermoplastic with a melt-viscosity less than 1000 Pa.s. at 300 °C. The notched Izod impact strength of injection-molded samples of this polymer is 40.7 J/m. In the second part of this research, the synthetic method has been modified to allow the preparation of quinoxaline containing polyimides. Thus, 2,3-dichloroquinoxaline was treated either with p-nitrophenol followed by reduction of nitro groups, or with p-aminophenols to directly obtain the desired 2,3-(4-aminophenoxy)quinoxaline. This diamine was polymerized with 3,3',4,4'-biphenyldianhydride, 4

  18. Constructing high-efficiency D-A-π-A-featured solar cell sensitizers: a promising building block of 2,3-diphenylquinoxaline for antiaggregation and photostability.

    Science.gov (United States)

    Pei, Kai; Wu, Yongzhen; Islam, Ashraful; Zhang, Qiong; Han, Liyuan; Tian, He; Zhu, Weihong

    2013-06-12

    Controlling the sensitizer morphology on a nanocrystalline TiO2 surface is beneficial to facilitating electron injection and suppressing charge recombination. Given that the grafted alkyl chain on a π-bridge thiophene segment for preventing π aggregation can deteriorate its intrinsic photostability, we incorporate a promising building block of 2,3-diphenylquinoxaline as the additional acceptor to construct a novel D-A-π-A-featured dye IQ4, which exhibits several characteristics: (i) efficiently decreasing the molecular HOMO-LUMO energy gap by extending its absorption bands; (ii) showing a moderate electron-withdrawing capability for an ideal balance in both promising photocurrent and photovoltage; (iii) endowing an ideal morphology control with strong capability of restraining the intermolecular aggregation and facilitating the formation of a compact sensitizer layer via two twisted phenyl groups grafted onto the quinoxaline unit. The coadsorbent-free dye-sensitized solar cell (DSSC) based on dye IQ4 exhibits very promising conversion efficiency as high as 9.24 ± 0.05%, with a short-circuit current density (Jsc) of 17.55 mA cm(-2), an open-circuit voltage (Voc) of 0.74 V, and a fill factor (FF) of 0.71 under AM 1.5 illumination (100 mW cm(-2)). IQ4-based DSSC devices with an ionic liquid electrolyte can keep constant performance during a 1000 h aging test under 1 sun at 60 °C. Because of spatial restriction, the two phenyl groups grafted onto the additional electron-withdrawing quinoxaline are demonstrated as efficient building blocks, not only improving its photostability and thermal stability but also allowing it to be a successful antiaggregation functional unit. As a consequence, the incorporated 2,3-diphenylquinoxaline unit can realize a facile structural modification for constructing organic coadsorbent-free D-A-π-A-featured sensitizers, thus paving a way to replace the common, stability-deleterious grafted alkyl chain on the thienyl bridge.

  19. Prevention of heterocyclic amine-induced DNA damage in colon and liver of rats by different lactobacillus strains.

    Science.gov (United States)

    Zsivkovits, Markus; Fekadu, Kassie; Sontag, Gerhard; Nabinger, Ursula; Huber, Wolfgang W; Kundi, Michael; Chakraborty, Asima; Foissy, Helmuth; Knasmüller, Siegfried

    2003-12-01

    The aim of the present study was to investigate the impact of four different lactobacillus (LB) strains, namely Lactobacillus bulgaricus 291, Streptococcus thermophilus F4, S.thermophilus V3 and Bifidobacterium longum BB536, which are used for the production of yogurt, on the DNA-damaging effects of heterocyclic aromatic amines (HCAs). Male F344 rats were treated orally with HCA mixtures containing 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline, 2-amino-3,4,8-trimethyl-3H-imidazo[4,5-f]quinoxaline, 2-amino-9H-pyrido[2,3-b]indole and 2-amino-3-methyl-3H- imidazo[4,5-f]quinoline, which were representative of the HCA contents found in fried beef ('beef mix') and chicken ('chicken mix'). Suspensions of LB were given by gavage to the animals simultaneously with and at different time periods before administration of the HCAs. Subsequently, the extent of DNA migration was measured in colon and liver cells in single cell gel electrophoresis (SCGE) assays. All four strains caused complete inhibition of DNA damage induced with beef mix after administration of 1 x 1010 LB cells/animal, whereas with chicken mix only marginal (non-significant) effects were seen. The inhibition of beef-induced DNA damage was dose dependent and was still significant when 1 x 107 cells/animal were administered. Kinetics studies showed that the protective effects were still significant when LB was given 12 h before the beef mix. A comparison of the present results with chemical analytical data from in vitro experiments suggests that the strong reduction in DNA migration seen in the animals can be only partly explained by direct binding effects. The results of the present study show that LB are highly protective against the genotoxic effects of HCAs under conditions which are relevant for humans and provide a possible explanation for the reduced colon cancer rates observed in some studies in individuals with either high LB counts in their feces or with

  20. Hydrothermal Synthesis, Characterization and Natural Bond Orbital(NBO) Analysis of a Binuclear Lead(Ⅱ) Complex with Cinnamic Acid and Medpq Ligands%由肉桂酸和甲基联吡啶喹喔啉配体构筑的双核铅(Ⅱ)的配合物的水热合成、表征及自然键轨道(NBO)分析

    Institute of Scientific and Technical Information of China (English)

    方燕; 王蕾; 倪良; 姚加

    2013-01-01

    采用水热法合成了一种新型双核铅(Ⅱ)配合物[Pb2(CA)4(Medpq)2](HCA=cinnamic acid,Medpq=2-methyldipyrido[3,2-f:2,3'-h]quinoxaline),并对其进行了元素分析、红外光谱、紫外可见光光谱、热重表征、荧光光谱、X射线单晶衍射测定和理论计算.标题配合物属于三斜晶系,空间群为P(1).在晶体中,铅与来自Medpq配体的2个氮原子和3个肉桂酸配体的5个氧原子形成七配位.应用Gaussian 03程序,对标题配合物进行了自然键轨道(NBO)分析,结果表明Pb(Ⅱ)与配位原子间的价键类型都属于共价键范畴.%A binuclear Pb(Ⅱ) complex [Pb2(CA)4(Medpq)2] (HCA=cinnamic acid,Medpq=2-methyldipyrido[3,2-f:2,3'-h]quinoxaline) has been hydrothermally synthesized and structurally characterized by elemental analysis,IR spectrum,UV-Vis spectrum,TG,fluorescent emission,single-crystal X-ray diffraction and theoretical calculations.Title compound crystallizes in triclinic,space group P(1) with a=0.854 35(17) nm,b=1.250 9(3) nm,c=1.436 6 (3) nm,α=107.45 (3)°,β=105.63 (3)°,y=97.04 (3)°.In the crystal structure,the lead atom is sevencoordinated with two nitrogen atoms from Medpq ligand and five oxygen atoms from three cinnamic acid ligands.Natural bond orbital (NBO) analysis was performed by using the NBO method built in Gaussian 03 Program.The calculation results shown an covalent interaction between the coordinated atoms and Pb(Ⅱ) ion.CCDC:859036.

  1. Synthesis, Crystal Structure and Magnetic Susceptibility Measurements of a Manganese Coordination Polymer with Phthalate and Phenanthroline Derivatives%以邻苯二甲酸根及邻菲咯啉衍生物构筑的锰配位聚合物的合成、晶体结构及磁性

    Institute of Scientific and Technical Information of China (English)

    黄艳菊; 倪良; 王强

    2012-01-01

    A coordination polymer {[Mn(Pht)(Medpq)(H2O)]·0.25nH2O}n (Pht=phthalate,Medpq=2-methyldipyrido [3,2-f∶2',3'-h]quinoxaline) 1 has been hydrothennally synthesized and structurally characterized by elemental analysis,IR spectrum,TG,magnetic susceptibility measurements and single-crystal X-ray diffraction.Polymer 1 crystallizes in the monoclinic system,space group P21/c,with a=1.598 0(3),b=2.092 5(4),c=0.659 67(13) nm,β=93.06(3)°,V=2.202 7(8) nm3.In the crystal structure,the manganese atom is six-coordinated with four oxygen atoms and two nitrogen atoms,showing a slightly distorted octahedral geometry.Furthermore,it exhibits a onedimensional dual chains structure with Pht-Mn-Medpq as building units.CCDC∶ 867320.%采用水热法合成了一个配位聚合物([Mn(Pht)(Medpq)(H2O)]·0.25nH2O]n(Pht=phthalate,Medpq=2-methyldipyrido[3,2-f∶2',3'-h]quinoxaline)1,并对其进行了元素分析、红外光谱、热重表征、磁性表征和X射线单晶衍射测定.配位聚合物1属于单斜晶系,空间群为P21/c.晶胞参数为:a=1.598 0(3) nm,b=2.092 5(4) nm,c=0.659 67(13) nm,β=93.06(3)°,V=2.202 7(8) nm3.在晶体中,锰原子与4个氧原子和2个氮原子形成六配位的畸变的八面体构型.整个晶体由Pht-Mn-Medpq单元组成一维双链结构.

  2. 配合[Ni(Pht)(Medpq)(H2O)3]n的水热合成、表征及自然键轨道(NBO)分析%Hydrothermal Synthesis,Characterization and Natural Bond Orbital(NBO)Analysis of[Ni(Pht)(Medpq)(H2O)3]n Complex

    Institute of Scientific and Technical Information of China (English)

    黄艳菊; 倪良; 王蕾; 朱翀

    2011-01-01

    A metal-organic complex [Ni(Pht)(Medpq)(H2O)3]n (1) (Pht=phthalic acid, Medpq=2-methyldipyrido[3,2-f:2',3'-h]quinoxaline) has been hydrothermally synthesized and structurally characterized by elemental analysis, IR spectrum, TG, single-crystal X-ray diffraction and theoretical calculations. In the crystal structure, the nickel atom is hexa-coordinated with two nitrogen atoms from Medpq ligand, one oxygen atom from Pht ligand and three oxygen atoms from three different coordination water molecules, assuming a slightly distorted octahedral geometry. Furthermore, it exhibits a zero-dimensional structure with Pht-Ni-Medpq as building units. Natural bond orbital (NBO) analysis was performed by using the NBO method built in Gaussian03 Program. The calculation results show there is the obvious covalent interaction between the coordinated atoms and Ni(Ⅱ) ion.%采用水热法合成了一种新型金属配合物[Ni(Pht)(Medpq)(H2O)3]n(1)(Pht=phthalic acid,Medpq=2-methyldipyrido[3,2-f:2',3'-h]quinoxaline),并对其进行了元素分析、红外光谱、热重表征、X射线单晶衍射测定和理论计算.在晶体中,Ni(Ⅱ)与来自于Medpq分子上的2个氮原子,邻苯二甲酸上的1个氧原子及来自于3个不同的配位水分子上的3个氧原子配位,形成畸变的八面体构型.整个晶体由Pht-Ni-Medpq单元组成零维结构.应用Guassian03W程序,在HF/LANL2DZ水平上对标题化合物的自然键轨道(NBO)进行了分析,结果表明Ni(Ⅱ)与配位原子间的价键类型都属于共价键范畴.

  3. Synthesis, Antibacterial and Antifungal Activity of Some New Pyrazoline and Pyrazole Derivatives

    Directory of Open Access Journals (Sweden)

    Seham Y. Hassan

    2013-02-01

    Full Text Available A series of 2-pyrazolines 5–9 have been synthesized from α,β-unsaturated ketones 2–4. New 2-pyrazoline derivatives 13–15 bearing benzenesulfonamide moieties were then synthesized by condensing the appropriate chalcones 2–4 with 4-hydrazinyl benzenesulfonamide hydrochloride. Ethyl [1,2,4] triazolo[3,4-c][1,2,4]triazino[5,6-b]-5H-indole-5-ethanoate (26 and 1-(5H-[1,2,4]triazino[5,6-b] indol-3-yl-3-methyl-1H-pyrazol-5(4H-one (32 were synthesized from 3-hydrazinyl-5H-[1,2,4]triazino[5,6-b]indole (24. On the other hand ethyl[1,2,4]triazolo[3,4-c][1,2,4]triazino[5,6-b]-5,10-dihydroquinoxaline- 5-ethanoate (27 and 1-(5,10-dihydro-[1,2,4]triazino[5,6-b]quinoxalin-3-yl-3-methyl-1H-pyrazol-5(4H-one (33 were synthesized from 3-hydrazinyl-5,10-dihydro-[1,2,4]triazino[5,6-b]quinoxaline (25 by reaction with diethyl malonate or ethyl acetoacetate, respectively. Condensation of 6,6-dimethyl-4-oxo-4,5,6,7-tetrahydro-1H-indole-2-carbaldehyde (1' with compound 24 or 25 afforded the corresponding Schiff's bases 36 and 37, respectively. Reaction of the Schiff's base 37 with benzoyl hydrazine or acetic anhydride afforded benzohydrazide derivative 39 and the cyclized compound 40, respectively. Furthermore, the pyrazole derivatives 42–44 were synthesized by cyclization of hydrazine derivative 25 with the prepared chalcones 2–4. All the newly synthesized compounds have been characterized on the basis of IR and 1H-NMR spectral data as well as physical data. Antimicrobial activity against the organisms E. coli ATCC8739 and P. aeruginosa ATCC 9027 as examples of Gram-negative bacteria, S. aureus ATCC 6583P as an example of Gram-positive bacteria and C. albicans ATCC 2091 as an example of a yeast-like fungus have been studied using the Nutrient Agar (NA and Sabouraud Dextrose Agar (SDA diffusion methods. The best performance was found for the compounds 16, 17, 19 and 20.

  4. Can creatine supplementation form carcinogenic heterocyclic amines in humans?

    Science.gov (United States)

    Pereira, Renato Tavares dos Santos; Dörr, Felipe Augusto; Pinto, Ernani; Solis, Marina Yazigi; Artioli, Guilherme Giannini; Fernandes, Alan Lins; Murai, Igor Hisashi; Dantas, Wagner Silva; Seguro, Antônio Carlos; Santinho, Mirela Aparecida Rodrigues; Roschel, Hamilton; Carpentier, Alain; Poortmans, Jacques Remi; Gualano, Bruno

    2015-09-01

    There is a long-standing concern that creatine supplementation could be associated with cancer, possibly by facilitating the formation of carcinogenic heterocyclic amines (HCAs). This study provides compelling evidence that both low and high doses of creatine supplementation, given either acutely or chronically, does not cause a significant increase in HCA formation. HCAs detection was unrelated to creatine supplementation. Diet was likely to be the main factor responsible for HCAs formation after either placebo (n = 6) or creatine supplementation (n = 3). These results directly challenge the recently suggested biological plausibility for the association between creatine use and risk of testicular germ cell cancer. Creatine supplementation has been associated with increased cancer risk. In fact, there is evidence indicating that creatine and/or creatinine are important precursors of carcinogenic heterocyclic amines (HCAs). The present study aimed to investigate the acute and chronic effects of low- and high-dose creatine supplementation on the production of HCAs in healthy humans (i.e. 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (8-MeIQx), 2-amino-(1,6-dimethylfuro[3,2-e]imidazo[4,5-b])pyridine (IFP) and 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx)). This was a non-counterbalanced single-blind crossover study divided into two phases, in which low- and high-dose creatine protocols were tested. After acute (1 day) and chronic supplementation (30 days), the HCAs PhIP, 8-MeIQx, IFP and 4,8-DiMeIQx were assessed through a newly developed HPLC-MS/MS method. Dietary HCA intake and blood and urinary creatinine were also evaluated. Out of 576 assessments performed (from 149 urine samples), only nine (3 from creatine and 6 from placebo) showed quantifiable levels of HCAs (8-MeIQx: n = 3; 4,8-DiMeIQx: n = 2; PhIP: n = 4). Individual analyses revealed that diet rather than creatine supplementation was

  5. Inhibitory Effect of Rosa rugosa Tea Extract on the Formation of Heterocyclic Amines in Meat Patties at Different Temperatures

    Directory of Open Access Journals (Sweden)

    Muneer Ahmed Jamali

    2016-01-01

    Full Text Available In previous studies, heterocyclic amines (HCAs have been identified as carcinogenic and a risk factor for human cancer. Therefore, the present study was designed to identify bioactive natural products capable of controlling the formation of HCAs during cooking. For this purpose we have evaluated the effect of Rosa rugosa tea extract (RTE on the formation of HCAs in ground beef patties fried at 160 °C or 220 °C. RTE is rich in phenolic compounds and capable of inhibiting the formation of free radicals. The pyrido[3,4-b]indole (norharman and 1-methyl-9H-pyrido[3,4-b]indole (harman contents were significantly (p < 0.05 decreased in RTE-treated patties at 220 °C. 9H-3-Amino-1-methyl-5H-pyrido[4,3-b]indole acetate (Trp-P-2 and 3-amino-1,4-dimethyl-5H-pyrido-[4,3-b]indole acetate (Trp-P-1 were not detected at 160 °C and were statistically (p < 0.01 reduced at 220 °C compared to the control. RTE remarkably inhibited the formation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP at 220 °C (p < 0.001 and at 160 °C (p < 0.05. 2-Amino-9H-pyrido[2,3-b]indole (AαC and 2-amino-3-methyl-9H-pyrido[2,3-b]-indole (MeAαC were only detected in the control group at 160 °C but were comparatively (p > 0.05 similar in the control and treated groups at 220 °C. 2-Amino-3-methylimidazo[4,5-f]quinoline (IQ, 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ, 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx, and 2-amino-3,4,8-trimethylimidazo[4,5-f]-quinoxaline (4,8-DiMeIQx were not detected in any sample. Total HCAs were positively correlated with cooking loss. In the RTE-treated groups, 75% of the total HCAs were decreased at 160 °C and 46% at 220 °C, suggesting that RTE is effective at both temperatures and can be used during cooking at high temperatures to lessen the amount of HCAs formed.

  6. Metal complexes with 2,3-bis(diphenylphosphino)-1,4-diazadiene ligands: synthesis, structures, and an intramolecular metal-mediated [4 + 2] cycloaddition employing a benzene ring as a dienophile.

    Science.gov (United States)

    Walther, Dirk; Liesicke, Stefan; Böttcher, Lars; Fischer, Reinald; Görls, Helmar; Vaughan, Gavin

    2003-01-27

    2,3-Bis(diphenylphosphino)-1,4-diazadienes RN=C(PPh2)-C(PPh2)=NR (1a, R = 4-tolyl; 1b, R = 4-tert-butylphenyl; 1c, R = mesityl) were used as novel ligands for transition metals. The metal complexes [(1c)Mo(CO)4] (2a), [(1c)[Mo(CO)4]2] (2b), [(1a)Cu(Cl)(PPh3)] (3), and [(1b)[(NiBr2(THF))]2] (4) were characterized by elemental analysis, MS, and 31P[1H], 1H, and 13C NMR spectra (except the paramagnetic complex 4). Additionally, the molecular structure of the complexes in the solid state was determined by single-crystal X-ray diffraction. In 2a and 2b the chelating ligand coordinates via the N,P donor set, whereas in 3 the chelating ligand coordinates via the two P atoms. 4 contains a square-planar (P,P)NiBr2 moiety on the one side of the bridging ligand 1b. On the opposite side the 1,2-dimine unit bonds to another Ni center having octahedral geometry. The bulkier ligand 1c reacts to form the mononuclear compound 5. X-ray diffraction analysis of single crystals shows that 5 contains a quinoxaline derivative with a cyclohexa-1,3-diene ring in the peripheral position. Furthermore, it contains a bis(diphenylphosphino)-ethylene unit coordinating the NiBr2. This arrangement is the result of an intramolecular [4 + 2] cycloaddition between the 1,2-diimine unit (as diheterodiene) and the benzene ring of the 4-tolyl-N substituent (as dieneophile). The same type of ring-closing reaction followed by a tautomerization reaction to form the mononuclear compound 6 occurred by dissolution of the binuclear complex 4 in methanol. This reaction can be used as a simple method for the synthesis of novel 1,2-bis(diarylphosphanyl)ethylenes containing a quinoxaline backbone.

  7. Formation of heterocyclic amines in salami and ham pizza toppings during baking of frozen pizza.

    Science.gov (United States)

    Gibis, Monika; Weiss, Jochen

    2013-06-01

    Heterocyclic amines (HAs) are formed as Maillard reaction products in the crust of meat products during heating processes. Two typical pizza toppings--salami and cooked ham--were analyzed for the presence of HAs after baking frozen pizzas at top and bottom temperatures of 250 and 230 °C, respectively. After baking pizza slices for 12 min, MeIQx (2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline; 0.2 ng/g), 4,8-DiMeIQx (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline; 0.5 ng/g), PhIP (2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine; 0.2 ng/g), norharman (4.5 ng/g), and harman (2.5 ng/g) were found in the ham toppings, whereas only the comutagenic norharman (107.4 ng/g) and harman (11.4 ng/g) were found in the salami toppings. The content of MeIQx and 4,8-DiMeIQx in ham increased from 0.3 to 1.8 ng/g and 0.8 to 1.6 ng/g, respectively, when the recommended baking time was increased from 15 min (manufacturer's specification) to 18 min at 230 °C. MeIQx was formed in salami when the heating time was extended to 18 min. Moreover, higher concentrations of PhIP in salami or ham slices were found when baking temperatures were 250 °C rather than 230 °C (baking time of 12 min). However, sensory tests showed that panelists preferred longer-baked pizzas due to an increased crispiness. Thus, results show that a substantial formation of HAs may occur in pizza toppings such as ham and salami, with ham being particularly susceptible when compared to salami. Formation of HAs increases with increasing baking time and temperature. The occurrence of the cupping of ham or salami slices during baking may also increase the formation of HAs.

  8. Heme oxygenase-1 deficiency leads to alteration of soluble guanylate cyclase redox regulation.

    Science.gov (United States)

    Jones, Allan W; Durante, William; Korthuis, Ronald J

    2010-10-01

    Heme oxygenase-1 knockout, H(mox)1(-/-), mice exhibit exacerbated vascular lesions after ischemia-reperfusion and mechanical injury. Surprisingly, we found no studies that reported contractile responses and sensitivity to vasorelaxants in H(mox)1(-/-) mice. The contractile responses [superior mesenteric arteries (SMA), from female H(mox)1(-/-) mice] exhibited increased sensitivity to phenylephrine (p mox)1(-/-) mice (p mox)1(-/-) than H(mox)1(+/+) mice (p mox)1(-/-) mesenteric and renal arteries also showed reduced relaxation (p mox)1(-/-) arteries were 15 times more sensitive to BAY 60-2770 (p mox)1(+/+) arteries. Pretreatment with 1H-[1,2,4]oxadiazolo[3,4-a]quinoxalin-1-one (ODQ), an oxidizer of sGC, predictably shifted the BAY 60-2770 response of H(mox)1(+/+) to the left (p mox)1(-/-) arteries, indicating that much of sGC was oxidized/heme-free. Western analyses of sGC in SMA indicated that both α1 and β1 subunit levels were reduced to mox)1(+/+) level (p mox)1 plays a significant role in the maintenance of sGC in a reduced state, which is resistant to degradation and is sensitive to NO. This function may be especially important in reducing vascular damage during ischemia-reperfusion injury.

  9. Acute stress-induced antinociception is cGMP-dependent but heme oxygenase-independent

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho-Costa, P.G. [Programa de Graduação em Psicobiologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Branco, L.G.S. [Departamento de Morfologia, Fisiologia e Patologia Básica, Faculdade de Odontologia de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Leite-Panissi, C.R.A. [Programa de Graduação em Psicobiologia, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil); Departamento de Morfologia, Fisiologia e Patologia Básica, Faculdade de Odontologia de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP (Brazil)

    2014-09-19

    Endogenous carbon monoxide (CO), which is produced by the enzyme heme oxygenase (HO), participates as a neuromodulator in physiological processes such as thermoregulation and nociception by stimulating the formation of 3′,5′-cyclic guanosine monophosphate (cGMP). In particular, the acute physical restraint-induced fever of rats can be blocked by inhibiting the enzyme HO. A previous study reported that the HO-CO-cGMP pathway plays a key phasic antinociceptive role in modulating noninflammatory acute pain. Thus, this study evaluated the involvement of the HO-CO-cGMP pathway in antinociception induced by acute stress in male Wistar rats (250-300 g; n=8/group) using the analgesia index (AI) in the tail flick test. The results showed that antinociception induced by acute stress was not dependent on the HO-CO-cGMP pathway, as neither treatment with the HO inhibitor ZnDBPG nor heme-lysinate altered the AI. However, antinociception was dependent on cGMP activity because pretreatment with the guanylate cyclase inhibitor 1H-[1,2,4] oxadiazolo [4,3-a] quinoxaline-1-one (ODQ) blocked the increase in the AI induced by acute stress.

  10. The Nitric oxide/CGMP/KATP pathway mediates systemic and central antinociception induced by resistance exercise in rats.

    Science.gov (United States)

    Galdino, Giovane S; Xavier, Carlos H; Almeida, Renato; Silva, Grazielle; Fontes, Marcos A; Menezes, Gustavo; Duarte, Igor D; Perez, Andrea C

    2015-01-01

    Resistance exercise (RE) is characterized to increase strength, tone, mass, and/or muscular endurance and also for produces many beneficial effects, such as blood pressure and osteoporosis reduction, diabetes mellitus control, and analgesia. However, few studies have investigated endogenous mechanisms involved in the RE-induced analgesia. Thus, the aim of this study was evaluate the role of the NO/CGMP/KATP pathway in the antinociception induced by RE. Wistar rats were submitted to acute RE in a weight-lifting model. The nociceptive threshold was measured by mechanical nociceptive test (paw-withdrawal). To investigate the involvement of the NO/CGMP/KATP pathway the following nitric oxide synthase (NOS) non-specific and specific inhibitors were used: N-nitro-l-arginine (NOArg), Aminoguanidine, N5-(1-Iminoethyl)-l-ornithine dihydrocloride (l-NIO), Nω-Propyl-l-arginine (l-NPA); guanylyl cyclase inhibitor, 1H-[1,2,4]oxidiazolo[4,3-a]quinoxalin-1-one (ODQ); and KATP channel blocker, Glybenclamide; all administered subcutaneously, intrathecally and intracerebroventricularly. Plasma and cerebrospinal fluid (CSF) nitrite levels were determined by spectrophotometry. The RE protocol produced antinociception, which was significantly reversed by NOS specific and unspecific inhibitors, guanylyl cyclase inhibitor (ODQ) and KATP channel blocker (Glybenclamide). RE was also responsible for increasing nitrite levels in both plasma and CSF. These finding suggest that the NO/CGMP/KATP pathway participates in antinociception induced by RE.

  11. Involvement of nitric oxide in the signal transduction of salicylic acid regulating stomatal movement

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The effects and the relationship between salicylic acid (SA) and nitric oxide (NO) on Vicia faba L. stomatal movement were studied. The results here showed that exogenous SA and NO induced stomatal closure, 100 μmol/L SA induced a rapid and striking NO increase in the cytosol of guard cells. This phenomenon was largely pre-vented by 200 μmol/L 2-phenyl-4,4,5,5-tetramethylimida-zoline-1-oxyl-3-oxide (PTIO), a specific NO scavenger, and 25 μmol/L NG-nitro-L-Arg-methyl eater (L-NAME), an in-hibitor of NO synthase (NOS) in mammalian cells that also inhibits plant NOS. In addition, SA-induced stomatal closure was largely prevented by PTIO and L-NAME. These results provide evidence that guard cells generate NO in response to SA via NOS-like activity, and that such NO production is required for full stomatal closure in response to SA. H-(1,2,4)-oxadiazole-[4,3-α]quinoxalin-1-one (ODQ), an inhibitor of guanylate cyclase, and nicotinamide, an antago-nist of cADPR production, inhibited the effects of SA- and NO-induced stomatal closure. It suggests that both cGMP and cADPR might mediate the signal transduction of SA and NO-induced stomatal closure.

  12. Meat-related mutagen exposure, xenobiotic metabolizing gene polymorphisms and the risk of advanced colorectal adenoma and cancer.

    Science.gov (United States)

    Gilsing, Anne M J; Berndt, Sonja I; Ruder, Elizabeth H; Graubard, Barry I; Ferrucci, Leah M; Burdett, Laura; Weissfeld, Joel L; Cross, Amanda J; Sinha, Rashmi

    2012-07-01

    Meat mutagens, including heterocyclic amines (HCAs), polycyclic aromatic hydrocarbons (PAHs) and N-nitroso compounds (NOCs), may be involved in colorectal carcinogenesis depending on their activation or detoxification by phase I and II xenobiotic metabolizing enzymes (XME). Using unconditional logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI), we examined the intake of five meat mutagens and >300 single nucleotide polymorphisms (SNPs) in 18 XME genes in relation to advanced colorectal adenoma (1205 cases and 1387 controls) and colorectal cancer (370 cases and 401 controls) within the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Dietary intake of meat mutagens was assessed using a food frequency questionnaire with a detailed meat-cooking module. An interaction was observed between 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) intake and the NAT1 polymorphism rs6586714 in the adenoma study (P(interaction) = 0.001). Among individuals carrying a GG genotype, high MeIQx intake was associated with a 43% increased risk of adenoma (95% CI 1.11-1.85, P(trend) = 0.07), whereas the reverse was observed among carriers of the A variant (OR = 0.50, 95% CI 0.30-0.84, P(trend) = 0.01). In addition, we observed some suggestive (P mutagens and the risk of colorectal tumours found that a NAT1 polymorphism modified the association between MeIQx intake and colorectal adenoma risk.

  13. Determination of dideoxyosone precursors of AGEs in human lens proteins.

    Science.gov (United States)

    Linetsky, Mikhail; Kaid Johar, S R; Meltretter, Jasmin; Padmanabha, Smitha; Parmar, Trilok; Vasavada, Abhay R; Pischetsrieder, Monika; Nagaraj, Ram H

    2011-10-01

    Dideoxyosones (DDOs) are intermediates in the synthesis of advanced glycation endproducts (AGEs), such as pentosidine and glucosepane. Although the formation of pentosidine and glucosepane in the human lens has been firmly established, the formation of DDOs has not been demonstrated. The aim of this study was to develop a reliable method to detect DDOs in lens proteins. A specific DDO trapping agent, biotinyl-diaminobenzene (3,4-diamino-N-(3-[5-(2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl)pentanoyl]aminopropyl)benzamide) (BDAB) was added during in vitro protein glycation or during protein extraction from human lenses. In vitro glycated human lens protein showed strong reaction in monomeric and polymeric crosslinked proteins by Western blot and ELISA. Glycation of BSA in the presence of BDAB resulted in covalent binding of BDAB to the protein and inhibited pentosidine formation. Mass spectrometric analysis of lysozyme glycated in the presence of BDAB showed the presence of quinoxalines at lysine residues at positions K1, K33, K96, and K116. The ELISA results indicated that cataractous lens proteins contain significantly higher levels of DDO than non-cataractous lenses (101.9±67.8 vs. 31.7±19.5AU/mg protein, p<0.0001). This study provides first direct evidence of DDO presence in human tissue proteins and establishes that AGE crosslink synthesis in the human lens occurs via DDO intermediates. Copyright © 2011 Elsevier Inc. All rights reserved.

  14. Use of cloud-point preconcentration for spectrophotometric determination of trace amounts of antimony in biological and environmental samples.

    Science.gov (United States)

    El-Sharjawy, Abdel-Azeem M; Amin, Alaa S

    2016-01-01

    This work presents a cloud-point extraction process using the micelle-mediated extraction method for simultaneous preconcentration and determination of Sb(III) and Sb(V) species in biological and environmental samples as a prior preconcentration step to their spectrophotometric determination. The analytical system is based on the selective reaction between Sb(III) and 3-dichloro-6-(3-carboxy-2-hydroxy-1-naphthylazo)quinoxaline (DCHNAQ) in the presence of cetyltrimethylammonium bromide (CTAB) and potassium iodide at pH 4.5. Total Sb concentration was determined after reduction of Sb(V) to Sb(III) in the presence of potassium iodide and ascorbic acid. The optimal reaction conditions and extraction were studied, and the analytical characteristics of the method (e.g., limits of detection and quantification, linear range, preconcentration, improvement factors) were obtained. Linearity for Sb(III) was obeyed in the range of 0.2-20 ng ml(-1). The detection and quantification limits for the determination of Sb(III) were 0.055 and 0.185 ng ml(-1), respectively. The method has a lower detection limit and wider linear range, inexpensive instrument, and low cost, and is more sensitive compared with most other methods. The interference effect of some anions and cations was also studied. The method was applied to the determination of Sb(III) in the presence of Sb(V) and total antimony in blood plasma, urine, biological, and water samples.

  15. No effects of chlorophyllin on IQ (2-amino-3-methylimidazo[4,5-f]-quinoline)-genotoxicity and -DNA adduct formation in Drosophila.

    Science.gov (United States)

    Negishi, Tomoe; Shinoda, Aki; Ishizaki, Nao; Hayatsu, Hikoya; Sugiyama, Chitose

    2004-02-01

    Previously we demonstrated that chlorophyllin suppressed the genotoxicities of many carcinogens. However, the genotoxicity of IQ (2-amino-3-methylimidazo[4,5-f]quinoline), a carcinogenic heterocyclic amine, was not suppressed in Drosophila. On the contrary, it has been reported that chrolophyllin suppressed the genotoxicity of IQ in rodents, rainbow trout and Salmonella. We demonstrated that the chlorophyllin-induced suppression of MeIQx (2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline)-genotoxicity was associated with a decrease in MeIQx-DNA adduct formation in Drosophila larval DNA. MeIQx represents another type of heterocyclic amine and is similar to IQ in structure. In this study we utilized (32)P-postlabeling to examine whether chlorophyllin reduced IQ-DNA adduct formation in Drosophila DNA in the same way as MeIQx. The results revealed that the formation of IQ-DNA adducts was unaffected by treatment with chlorophyllin. This was consistent with the absence of any inhibitory effect on genotoxicity as observed in the Drosophila repair test. These results suggest that IQ-behavior in Drosophila is not affected by chlorophyllin, indicating that the process of IQ-DNA adduct formation followed by expression of genotoxicity in Drosophila may be different from that in other organisms.

  16. Strong emissive nanofibers of organogels for the detection of volatile acid vapors.

    Science.gov (United States)

    Xue, Pengchong; Sun, Jiabao; Yao, Boqi; Gong, Peng; Zhang, Zhenqi; Qian, Chong; Zhang, Yuan; Lu, Ran

    2015-03-16

    Two L-phenylalanine derivatives with 5,8-bis(2-(carbazol-3-yl)vinyl)quinoxaline (PCQ) and 5,8-bis[2-(carbazol-3-yl)]-2,3-dimethylquinoxaline (DCQ) as fluorophores were synthesized, and their photophysical properties were measured and compared. The two compounds were found to gelate some organic solvents and self-assemble into 1D nanofibers in gels. The wet gel of PCQ emitted a weak orange fluorescence, but the DCQ gel had a strong green one. This result can be due to the presence of two methyl groups and the nonplanar conformation of fluorophore in DCQ. The gel film of DCQ also showed significantly stronger fluorescence than that of PCQ. Thus, the wet gel and xerogel film of DCQ were selected to study their sensing properties to acids. The yellow wet gel of DCQ transformed into a brown sol upon the addition of 0.2 equiv trifluoroacetic acid (TFA), accompanied by emission quenching. The xerogel film of DCQ rapidly responded to volatile acids, such as TFA, HCl, and HOAc. The fluorescence of the xerogel film was gradually quenched with increased concentration of volatile acid vapors. The fibrous film exhibited low detection limits for volatile acid. The detection limits of the thin films for TFA, HCl, and HOAc reached 43, 122, and 950 ppb, respectively.

  17. Nicorandil prevents sirolimus-induced production of reactive oxygen species, endothelial dysfunction, and thrombus formation

    Directory of Open Access Journals (Sweden)

    Ken Aizawa

    2015-03-01

    Full Text Available Sirolimus (SRL is widely used to prevent restenosis after percutaneous coronary intervention. However, its beneficial effect is hampered by complications of thrombosis. Several studies imply that reactive oxygen species (ROS play a critical role in endothelial dysfunction and thrombus formation. The present study investigated the protective effect of nicorandil (NIC, an anti-angina agent, on SRL-associated thrombosis. In human coronary artery endothelial cells (HCAECs, SRL stimulated ROS production, which was prevented by co-treatment with NIC. The preventive effect of NIC on ROS was abolished by 5-hydroxydecanoate but not by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one. NIC also inhibited SRL-induced up-regulation of NADPH oxidase subunit p22phox mRNA. Co-treatment with NIC and SRL significantly up-regulated superoxide dismutase 2. NIC treatment significantly improved SRL-induced decrease in viability of HCAECs. The functional relevance of the preventive effects of NIC on SRL-induced ROS production and impairment of endothelial viability was investigated in a mouse model of thrombosis. Pretreatment with NIC inhibited the SRL-induced acceleration of FeCl3-initiated thrombus formation and ROS production in the testicular arteries of mice. In conclusion, NIC prevented SRL-induced thrombus formation, presumably due to the reduction of ROS and to endothelial protection. The therapeutic efficacy of NIC could represent an additional option in the prevention of SRL-related thrombosis.

  18. Affinin (Spilanthol, Isolated from Heliopsis longipes, Induces Vasodilation via Activation of Gasotransmitters and Prostacyclin Signaling Pathways

    Directory of Open Access Journals (Sweden)

    Jesús Eduardo Castro-Ruiz

    2017-01-01

    Full Text Available Heliopsis longipes roots have been widely used in Mexican traditional medicine to relieve pain, mainly, toothaches. Previous studies have shown that affinin, the major alkamide of these roots, induces potent antinociceptive and anti-inflammatory activities. However, the effect of H. longipes root extracts and affinin on the cardiovascular system have not been investigated so far. In the present study, we demonstrated that the dichloromethane and ethanolic extracts of H. longipes roots, and affinin, isolated from these roots, produce a concentration-dependent vasodilation of rat aorta. Affinin-induced vasorelaxation was partly dependent on the presence of endothelium and was significantly blocked in the presence of inhibitors of NO, H2S, and CO synthesis (NG-nitro-l-arginine methyl ester (l-NAME, dl-propargylglycine (PAG, and chromium mesoporphyrin (CrMP, respectively; K+ channel blockers (glibenclamide (Gli and tetraethyl ammonium (TEA, and guanylate cyclase and cyclooxygenase inhibitors (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ and indomethacin (INDO, respectively. Our results demonstrate, for the first time, that affinin induces vasodilation by mechanisms that involve gasotransmitters, and prostacyclin signaling pathways. These findings indicate that this natural alkamide has therapeutic potential in the treatment of cardiovascular diseases.

  19. Selecting danger signals: dissociable roles of nucleus accumbens shell and core glutamate in predictive fear learning.

    Science.gov (United States)

    Li, Susan S Y; McNally, Gavan P

    2015-06-01

    Conditioned stimuli (CSs) vary in their reliability as predictors of danger. Animals must therefore select among CSs those that are appropriate to enter into an association with the aversive unconditioned stimulus (US). The actions of prediction error instruct this stimulus selection so that when prediction error is large, attention to the CS is maintained and learning occurs but when prediction is small attention to the CS is withdrawn and learning is prevented. Here we studied the role of glutamate acting at rat nucleus accumbens shell (AcbSh) and core (AcbC) α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors in this selection of danger signals. Using associative blocking and unblocking designs in rats, we show that antagonizing AcbSh AMPA receptors via infusions of 2,3-dihydroxy-6-nitro-7-sulphamoyl-benzo[f]quinoxaline-2,3-dione (NBQX; 0.5 μg) prevents the unblocking of fear learning, whereas antagonizing AcbC AMPA receptors via infusions of NBQX (0.5 μg) prevents both the blocking and unblocking of fear learning. These results identify dissociable but complementary roles for AcbSh and AcbC glutamate acting at AMPA receptors in selecting danger signals: AcbSh AMPA receptors upregulate attention and learning to CSs that signal surprising USs, whereas AcbC AMPA receptors encode the predicted outcome of each trial.

  20. Involvement of TRPV4-NO-cGMP-PKG pathways in the development of thermal hyperalgesia following chronic compression of the dorsal root ganglion in rats.

    Science.gov (United States)

    Ding, Xin-Li; Wang, Yong-Hui; Ning, Li-Ping; Zhang, Yang; Ge, Hong-You; Jiang, Hong; Wang, Rong; Yue, Shou-Wei

    2010-03-17

    The aim of the present study was to test the hypothesis that the TRPV4-NO-cGMP-PKG cascade is involved in the maintenance of thermal hyperalgesia following chronic compression of the dorsal root ganglion (DRG) (the procedure hereafter termed CCD) in rats. CCD rats showed thermal hyperalgesia and increased nitrite production. Intrathecal administration of ruthenium red (TRPV4 antagonist, 0.1-1 nmol), TRPV4 antisense ODN (TRPV4 AS, 40 microg, daily for 7 days), N(G)-L-nitro-arginine methyl ester (l-NAME, inhibitor of NO synthase, 30-300 nmol), 1H-[1,2,4]-oxadiazolo [4,3-a] quinoxalin-1-one (ODQ, a soluble guanylate cyclase inhibitor, 50-100 nmol) or 8-(4-Chlorophenylthio) guanosine 3',5'-cyclic Monophosphothioate, Rp-Isomer sodium salt (Rp-8-pCPT-cGMPS, a PKG inhibitor, 25-50 nmol) induced a significant (Pthermal hyperalgesia and nitrite production. Our data suggested that the TRPV4-NO-cGMP-PKG pathway could be involved in CCD-induced thermal hyperalgesia.