The Experts below are selected from a list of 888 Experts worldwide ranked by ideXlab platform
Pengfei Wang - One of the best experts on this subject based on the ideXlab platform.
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synthesis and properties of fluorescence dyes tetracyclic pyrazolo 3 4 b pyridine based coumarin chromophores with intramolecular charge transfer character
Journal of Organic Chemistry, 2012Co-Authors: Jianhong Chen, Weimin Liu, Xianglin Tang, Zhiyuan Fan, Pengfei WangAbstract:Two series of new tetracyclic pyrazolo[3,4-b]pyridine-based coumarin chromophores were synthesized through a facile reaction between 3-aldehyde-7-diethylaminocoumarin (5) or 3-acetyl-7-diethylaminocoumarin (6) and 5-aminopyrazole derivatives (7) in a one-pot procedure. Different condensed products were obtained from compounds 5 and 6, and the potential reaction mechanism was studied using the reaction of 5 with 5-amino-1-Phenylpyrazole (7a). The molecular structures were characterized by NMR and HRMS and confirmed by X-ray diffraction. The photophysical, electrochemical, and thermal properties of these compounds were investigated by absorption spectroscopy, fluorescence spectroscopy, single photon counting technique, cyclic voltammetry, thermogravimetric analysis, etc. Results show that the compounds exhibited high fluorescence quantum yields and good electrochemical, thermal, and photochemical stabilities. In addition, the application of these highly fluorescent compounds in living cell imaging was also ...
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Synthesis and Properties of Fluorescence Dyes: Tetracyclic Pyrazolo[3,4-b]Pyridine-Based Coumarin Chromophores with Intramolecular Charge Transfer Character
2012Co-Authors: Jianhong Chen, Weimin Liu, Xianglin Tang, Zhiyuan Fan, Pengfei WangAbstract:Two series of new tetracyclic pyrazolo[3,4-b]pyridine-based coumarin chromophores were synthesized through a facile reaction between 3-aldehyde-7-diethylaminocoumarin (5) or 3-acetyl-7-diethylaminocoumarin (6) and 5-aminopyrazole derivatives (7) in a one-pot procedure. Different condensed products were obtained from compounds 5 and 6, and the potential reaction mechanism was studied using the reaction of 5 with 5-amino-1-Phenylpyrazole (7a). The molecular structures were characterized by NMR and HRMS and confirmed by X-ray diffraction. The photophysical, electrochemical, and thermal properties of these compounds were investigated by absorption spectroscopy, fluorescence spectroscopy, single photon counting technique, cyclic voltammetry, thermogravimetric analysis, etc. Results show that the compounds exhibited high fluorescence quantum yields and good electrochemical, thermal, and photochemical stabilities. In addition, the application of these highly fluorescent compounds in living cell imaging was also explored by laser scanning confocal microscopy
Karci F - One of the best experts on this subject based on the ideXlab platform.
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tautomeric structures
'Elsevier BV', 2015Co-Authors: Karci F, Bakan E.Abstract:5-amino-4-arylazo-3-methyl-1-Phenylpyrazoles (2a-k) were diazotised and coupled with 5-hydroxy-3-methyl-1H-pyrazole and 5-hydroxy-3-methyl-1-Phenylpyrazole to generate two series disazo pyrazole disperse dyes (3a-k and 4a-k). These novel synthesized disazo pyrazole disperse dyes were characterized by elemental analysis and spectral methods. Absorption ability and tautomeric structure of synthesized disazo pyrazole disperse dyes substituted with electron-withdrawing and electron-donating groups at their o, m- and p-positions were also examined in detail. (C) 2015 Elsevier B.V. All rights reserved
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Synthesis, absorption properties and biological evaluation of some novel disazo dyes derived from pyrazole derivatives
'Asian Journal of Chemistry', 2015Co-Authors: Şener Nesrin., Yavuz S., Karci FAbstract:In this study, 20 novel disazo dyes containing pyrazole derivatives were synthesized by a convenient method. Diazotized aniline and some aniline derivatives were reacted with malononitrile to give 2-arylazomalononitrile derivatives 1(a-e). The synthesized 2-arylazomalononitrile derivatives were reacted with hydrazine and phenyl hydrazine to afford the corresponding 3,5-diamino-4-arylazo-1 H-pyrazole 2(a-e) and 3,5-diamino-4-arylazo-1-Phenylpyrazole 3(a-e). Diazotized compounds of 2(a-e)and 3(a-e) reacted with ethylacetoacetate to give 4-arylazo-3-amino-1 H-pyrazole-5-ylazo-ethylacetoacetate 4(a-e) and 4-arylazo-3-amino-1-Phenylpyrazole-5-ylazo-ethylacetoacetate 7(ae). The obtained 4(a-e) and 7(a-e) were reacted with hydrazine and phenyl hydrazine to give disazo dyes 5(a-e), 6(a-e), 8(a-e) and 9(a-e), respectively. The synthesized disazo dyes were characterized by spectroscopic techniques as well as elemental analysis. The solvatochromic behaviours of these dyes in various solvents were examined. Acid-base effects on the absorption maxima of the dyes were also reported. Antimicrobial activities of the synthesized novel disazo dyes were investigated
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Synthesis and tautomeric structures of some novel thiophene-based bis-heterocyclic monoazo dyes
'Elsevier BV', 2012Co-Authors: Karci FAbstract:In this study, ethyl 2-amino-5-methyl-4-(phenylcarbamoyl)thiophene-3- carboxylate (1) was prepared using Gewald's methodology. This 2-aminothiophene derivative was diazotised and coupled with, 3-methyl-1H-pyrazolin-5-one, 3-methyl-1-phenylpyrazolin-5-one, 3-amino-5-hydroxy-1H-pyrazole, 3-amino-5-hydroxy-1-Phenylpyrazole, 3-cyano-6-hydroxy-4-methyl-2-pyridone, barbituric acid and 4-hydroxycoumarin, respectively (2-8). The newly synthesized bis-heterocyclic monoazo dyes based on thiophene ring were characterised by elemental analysis and spectral methods. The solvatochromic behaviour and tautomeric structures of these bis-heterocyclic monoazo dyes in various solvents was evaluated. Acid and base effects on the visible absorption maxima of the dyes are also reported. © 2012 Elsevier B.V. All rights reserved
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bis-heterocyclic monoazo dyes
'Elsevier BV', 2012Co-Authors: Karci FAbstract:In this study, ethyl 2-amino-5-methyl-4-(phenylcarbamoyl)thiophene-3-carboxylate (1) was prepared using Gewald's methodology. This 2-aminothiophene derivative was diazotised and coupled with, 3-methyl-1H-pyrazolin-5-one, 3-methyl-1-phenylpyrazolin-5-one, 3-amino-5-hydroxy-1H-pyrazole, 3-amino-5-hydroxy-1-Phenylpyrazole, 3-cyano-6-hydroxy-4-methyl-2-pyridone, barbituric acid and 4-hydroxycoumarin, respectively (2-8). The newly synthesized bis-heterocyclic monoazo dyes based on thiophene ring were characterised by elemental analysis and spectral methods. The solvatochromic behaviour and tautomeric structures of these bis-heterocyclic monoazo dyes in various solvents was evaluated. Acid and base effects on the visible absorption maxima of the dyes are also reported. (C) 2012 Elsevier B.V. All rights reserved
Jianji Wang - One of the best experts on this subject based on the ideXlab platform.
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ionic liquid promoted multi component reaction novel and efficient preparation of pyrazolo 3 4 b pyridinone pyrazolo 3 4 b quinolinone and their hybrids with pyrimidine nucleoside
Molecular Diversity, 2010Co-Authors: Xinying Zhang, Xuesen Fan, Xia Wang, Jianji WangAbstract:The utilization of an ionic liquid, [bmim][BF4] as both reaction medium and promoter for a multi-component reaction of aldehyde (1) and 5-amino-3-methyl-1-Phenylpyrazole (2) with Meldrum acid (3) or dimedone (5) is studied. From this reaction, pyrazolo[3,4-b]pyridinone (4) and pyrazolo[3,4-b]quinolinone (6) derivatives were prepared in high yields. This novel procedure showed such advantages as environmentally benign nature, enhanced efficiency, simple operation process, and mild reaction conditions. As an application, the procedure was successfully used in the preparation of a set of pyrimidine nucleoside–pyrazolo[3,4-b]pyridine and pyrazolo[3,4-b]quinolinone hybrids with potential biological activities.
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an alternative preparation of pyrazolo pyridine derivatives in ionic liquid and comparison study on the reactivity of thioamide and amide group
Heterocycles, 2008Co-Authors: Xuesen Fan, Xinying Zhang, Xia Wang, Jianji WangAbstract:A novel and efficient preparation of pyrazolo[3,4-b]pyridine (5) and pyrazolo[3,4-b]pyridin-6-one (8) derivatives from the condensation of arylidenecyanothioacetamide (1) or arylidenecyanoacetamide (7) with 5-amino-3-methyl-1-Phenylpyrazole (4) in [bmim]BF 4 is reported for the first time. The mechanism for the formation of 5 from 1 and 4, or 8 from 7 and 4, and the comparison between the reactivity of thioamide group versus amide group are briefly discussed.
Masahiro Miura - One of the best experts on this subject based on the ideXlab platform.
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ruthenium catalyzed oxidative alkenylation of arenes via regioselective c h bond cleavage directed by a nitrogen containing group
Chemistry Letters, 2011Co-Authors: Yuto Hashimoto, Koji Hirano, Tetsuya Satoh, Takumi Ueyama, Tatsuya Fukutani, Masahiro MiuraAbstract:Direct alkenylation of 1-Phenylpyrazoles with alkenes such as acrylates accompanied by regioselective C–H bond cleavage proceeds efficiently under ruthenium catalysis in the presence of a copper ox...
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rhodium catalyzed oxidative 1 1 1 2 and 1 4 coupling reactions of phenylazoles with internal alkynes through the regioselective cleavages of multiple c h bonds
ChemInform, 2011Co-Authors: Nobuyoshi Umeda, Koji Hirano, Tetsuya Satoh, Naoto Shibata, Hirofumi Sato, Masahiro MiuraAbstract:The direct oxidative coupling of phenylazoles with internal alkynes proceeds efficiently in the presence of a rhodium catalyst and a copper oxidant accompanied by double or quadruple C−H bond cleavages. Thus, as a representative example, 4,5-diphenylpyrazolo[1,5-a]quinoline, 1-(1,2,3,4-tetraphenylnaphthalen-5-yl)pyrazole, and 1-(1,2,3,4,5,6,7,8-octaphenylanthracen-9-yl)pyrazole can be obtained selectively through the coupling of 1-Phenylpyrazole and diphenylacetylene in 1:1, 1:2, and 1:4 manners, respectively. The reactions preferentially take place at the electron-deficient sites on the aromatic substrates. A comparison of reactivities of variously substituted and deuterated substrates sheds light on the mechanism of C−H bond cleavage steps. The reaction pathway is highly dependent on reaction conditions employed, especially on the nature of solvent. The influence of solvation of a key rhodacycle intermediate has been investigated computationally. In addition, some of the condensed aromatic products have...
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rhodium catalyzed mono and divinylation of 1 phenylpyrazoles and related compounds via regioselective c h bond cleavage
Journal of Organic Chemistry, 2009Co-Authors: Nobuyoshi Umeda, Koji Hirano, Tetsuya Satoh, Masahiro MiuraAbstract:The selective 2-mono- and 2,6-divinylations of (N-containing heteroaryl)benzenes can be achieved effectively through rhodium-catalyzed oxidative coupling reactions with alkenes. The installation of two different vinyl groups is also possible by a simple one-pot manner. Thus, a series of 1,3-divinylbenzene derivatives, some of which exhibit solid-state fluorescence, is readily prepared.
Jianhong Chen - One of the best experts on this subject based on the ideXlab platform.
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synthesis and properties of fluorescence dyes tetracyclic pyrazolo 3 4 b pyridine based coumarin chromophores with intramolecular charge transfer character
Journal of Organic Chemistry, 2012Co-Authors: Jianhong Chen, Weimin Liu, Xianglin Tang, Zhiyuan Fan, Pengfei WangAbstract:Two series of new tetracyclic pyrazolo[3,4-b]pyridine-based coumarin chromophores were synthesized through a facile reaction between 3-aldehyde-7-diethylaminocoumarin (5) or 3-acetyl-7-diethylaminocoumarin (6) and 5-aminopyrazole derivatives (7) in a one-pot procedure. Different condensed products were obtained from compounds 5 and 6, and the potential reaction mechanism was studied using the reaction of 5 with 5-amino-1-Phenylpyrazole (7a). The molecular structures were characterized by NMR and HRMS and confirmed by X-ray diffraction. The photophysical, electrochemical, and thermal properties of these compounds were investigated by absorption spectroscopy, fluorescence spectroscopy, single photon counting technique, cyclic voltammetry, thermogravimetric analysis, etc. Results show that the compounds exhibited high fluorescence quantum yields and good electrochemical, thermal, and photochemical stabilities. In addition, the application of these highly fluorescent compounds in living cell imaging was also ...
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Synthesis and Properties of Fluorescence Dyes: Tetracyclic Pyrazolo[3,4-b]Pyridine-Based Coumarin Chromophores with Intramolecular Charge Transfer Character
2012Co-Authors: Jianhong Chen, Weimin Liu, Xianglin Tang, Zhiyuan Fan, Pengfei WangAbstract:Two series of new tetracyclic pyrazolo[3,4-b]pyridine-based coumarin chromophores were synthesized through a facile reaction between 3-aldehyde-7-diethylaminocoumarin (5) or 3-acetyl-7-diethylaminocoumarin (6) and 5-aminopyrazole derivatives (7) in a one-pot procedure. Different condensed products were obtained from compounds 5 and 6, and the potential reaction mechanism was studied using the reaction of 5 with 5-amino-1-Phenylpyrazole (7a). The molecular structures were characterized by NMR and HRMS and confirmed by X-ray diffraction. The photophysical, electrochemical, and thermal properties of these compounds were investigated by absorption spectroscopy, fluorescence spectroscopy, single photon counting technique, cyclic voltammetry, thermogravimetric analysis, etc. Results show that the compounds exhibited high fluorescence quantum yields and good electrochemical, thermal, and photochemical stabilities. In addition, the application of these highly fluorescent compounds in living cell imaging was also explored by laser scanning confocal microscopy
