- Push-pull fluorophores with viscosity dependent and aggregation induced emissions insensitive to polarity
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Abstract A series of push-pull chromophoric extended styryls from 5,5′-(9-ethyl-9H-carbazole-3,6-diyl)bis(2-morpholinothiazole-4-carbaldehyde) were synthesized by Knoevenagal condensation reaction with active methylene compounds. The intermediate carbaldehyde was synthesized from carbazole through multistep reactions. The intramolecular charge transfer of synthesized highly conjugated symmetrical D-π-A (D-donor, A-acceptor) extended styryls with rigid structure have been investigated by means of photophysical properties. The photophysical properties like absorption, emission and quantum yield of styryl derivatives were evaluated in various solvents of different polarities. All these synthesized extended styryls have exhibited aggregation induced emission with enhanced fluorescence intensity. This series of compounds can also be used as fluorescence molecular rotors for viscosity sensing. The sensitivity of viscosity towards UV absorption as well as fluorescence emission has also been investigated.
- Telore, Rahul D.,Satam, Manjaree A.,Sekar, Nagaiyan
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- Initiation and propagation rate constants for the cationic polymerization of N-vinylcarbazole
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Initiation and propagation rate constants for the cationic polymerization of N-vinylcarbazole were discussed. Benzhydryl cations were used as reference electrophiles to determine the reactivity parameters. All reactions were undertaken under dry, oxygenfr
- Schimmel, Holger,Ofial, Armin R.,Mayr, Herbert
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- Fluorescence Quenching Mechanism of Aromatic Hydrocarbons by Closed-Shell Heavy Metal Ions in Aqueous and Organic Solutions
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Fluorescence quenching rate constants of some aromatic hydrocarbons by Zn2+, Ag+, Cd2+, In3+, Sn2+, Cs+, Hg2+, Tl+, and Pb2+ were determined in aqueous and N,N-dimethylformamide solutions.Paramagnetic interactions, the heavy atom effect, and electron transfer were excluded as a possible quenching mechanism.N2 gas laser photolysis studies revealed that a cation radical of the fluorescer was detected only N-ethylcarbazole quenched by Ag+, Pb2+, and Hg2+ in N,N-dimethylformamide and for 1-pyrenesulfonic acid by Hg2+ in water.All other systems yielded the triplet state of the fluorescer quantitatively.The intermediates observed in the microsecond time region are the transient species with the lowest free energy.Picosecond laser photolysis of the Ag+ and Pb2+ quencher systems in N,N-dimethylformamide confirmed directly that the triplet state is induced by fluorescence quenching.On the basis of these results, it has been concluded that fluorescence quenching is due to nonfluorescent complex formation followed by rapid intersystem crossing.The electronic and geometrical structures of this complex were considered and compared to the excited aromatic hydrocarbon-halogen anion systems.
- Masuhara, Hiroshi,Shioyama, Hiroshi,Saito, Tokashi,Hamada, Kei,Yasoshima, Seikichi,Mataga, Noboru
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- Dehydrogenation of dodecahydro-N-ethylcarbazole on Pt(111)
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Sloshing hydrogen: Liquid organic hydrogen carriers are high-boiling organic molecules, which can be reversibly hydrogenated and dehydrogenated in catalytic processes and are, therefore, a promising chemical hydrogen storage material. One of the promising candidates is the pair N-ethylcarbazole/perhydro- N-ethylcarbazole (NEC/H12-NEC). The dehydrogenation and possible side reactions on a Pt(111) surface are evaluated in unprecedented detail. Copyright
- Gleichweit, Christoph,Amende, Max,Schernich, Stefan,Zhao, Wei,Lorenz, Michael P. A.,Hoefert, Oliver,Brueckner, Nicole,Wasserscheid, Peter,Libuda, Joerg,Steinrueck, Hans-Peter,Papp, Christian
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- Fabrication of Eu(III) complex doped nanofibrous membranes and their oxygen-sensing properties
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In this paper, we report the synthesis, characterization, and photophysical properties of Eu(TTA)3ECIP, where TTA = 2-thenoyltrifluoroacetonate, and ECIP = 1-ethyl-2-(N-ethyl-carbazole-yl-4-)imidazo[4,5-f]1,10- phenanthroline. Its elementary application for oxygen-sensing application is also investigated by doping it into a polymer matrix of polystyrene (PS). Experimental data suggest that the 2.5 wt% doped Eu(TTA)3ECIP/PS nanofibrous membrane exhibits a high sensitivity of 3.4 towards oxygen with a good linear relationship of R2 = 0.9962. In addition, the 2.5 wt% doped Eu(TTA)3ECIP/PS nanofibrous membrane owns a quick response of 8 s towards oxygen, along with its excellent atmosphere insensitivity and photobleaching resistance. All these results suggest that both Eu(TTA) 3ECIP and Eu(TTA)3ECIP/PS system are promising candidates for oxygen-sensing optical sensors.
- Songzhu, Lin,Xiangting, Dong,Jinxian, Wang,Guixia, Liu,Wenshen, Yu,Ruokun, Jia
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- 5-(N-Ethylcarbazol-3-yl)thiophene-2-carbaldehyde (ECTC): A novel fluorescent sensor for ferric ion
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5-(N-Ethylcarbazol-3-yl)thiophene-2-carbaldehyde (ECTC), was synthesized by Suzuki coupling reaction and characterized by 1H NMR, 13C NMR and elemental analysis. This compound strongly quenches fluorescence of Fe3+ ion, whereas almost no quenching is observed in the presence of other metal ions including Na+, K+, Mg2+, Ca2+, Cu2+, Mn2+ and Co2+. Under optimized conditions, the fluorescence intensity of ECTC is quenched in a linear fashion by Fe3+ ion in a wide range of 0.1 μm-10 μm with the limit of detection below 0.1 μm.
- Zhang, Qiang,Wei, Huaixin,Zhai, Rongjia,Ji, Zhongling,Qi, Yu,Zhao, Xin
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- NLOphoric 3,6-di(substituted quinoxalin) Carbazoles – Synthesis, Photophysical Properties and DFT Studies
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Synthesis of novel 3,6-di(substituted quinoxalin) carbazole fluorophores by the condensation of 1,1′-(9-ethyl-9H-carbazole-3,6-diyl)bis(2-bromoethanone) with methyl, chloro and unsubstituted o-phenylenediamine is presented. Synthesized derivatives are well characterized by 1H NMR, 13C NMR, FTIR and Mass spectroscopy. Photophysical studies are carried out using solvents of varying polarities revealed positive solvatochromism and intramolecular charge transfer from carbazole (Donor) to quinoxalin (Acceptor). Intramolecular charge transfer properties are correlated by dipole moment changes and different polarity functions like Lippert–Mataga, Bilot-Kawski, Bakhshiev and Liptay plots with very good regression factors. Mulliken hush-analysis further support charge transfer characteristic. Linear and Nonlinear optical properties are explained by solvatochromic data using two-level quantum mechanical model and are correlated with computational calculations using density functional theory at B3LYP/6-31G(d) level. First hyperpolarizability value of all the synthesized compounds is found to be greater than urea by >333 times. Moreover, increase of hyperpolarizability values from non-polar to polar solvents are in good correlation with the significant charge transfer characteristic in polar solvents.
- Telore, Rahul D.,Jadhav, Amol G.,Sekar, Nagaiyan
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- The synthesis of a series of fluorescent emitters and their application for dye lasing and cation sensing
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The following paper reported four carbazole-modified fluorescent emitters. Their molecular structure and electronic transition were analyzed via their single crystal and theoretical calculation. Their photophysical parameters, including absorption, emission and quantum yield, were determined and discussed. It was found that the emission performance of benzo-thiazole-based dyes was better than that of benzo-imidazole-based dyes, owing to the electron-donating effect from the S atom. Upon the presence of metal cations, these photophysical parameters were re-measured. Benzo-thiazole-based dyes were found insensitive towards most metal cations, while benzo-imidazole-based dyes showed obvious photophysical variation upon these metal cations, including absorption red shift and emission quenching. Detailed sensing performance of a representative dye was discussed. A linear working curve with good selectivity was finally observed. Its sensing mechanism was confirmed as the coordination between metal cation and deprotonated benzo-imidazole group. Benzo-thiazole-based dyes showed amplified spontaneous emission (ASE) behavior, with threshold energy of ~220 μJ. Given the optimal condition, a highest ASE efficiency of ~2% was observed, with FWHM value of 6 nm and emission peak of 435 nm. The major novelty and advancement of these fluorescent dyes shall be the stable ASE output (dye 4) under UV excitation and the linear sensing curve with good selectivity (dye 3), which was a hard task for emission turn off sensing probes. We attributed its causation to the valent-recognizing sensing mechanism.
- Cang, Sheng,Liu, Liang,Tian, Yaqiang,Yang, Zixuan,Zhang, Leiyu
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- Carbazole-based semicarbazones and hydrazones as multifunctional anti-Alzheimer agents
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With the aim to combat a multi-faceted neurodegenerative Alzheimer’s disease (AD), a series of carbazole-based semicarbazide and hydrazide derivatives were designed, synthesized and assessed for their cholinesterase (ChE) inhibitory, antioxidant and biometal chelating activity. Among them, (E)-2-((9-ethyl-9H-carbazol-3-yl)methylene)-N-(pyridin-2-yl)hydrazinecarbothioamide (62) and (E)-2-((9-ethyl-9H-carbazol-3-yl)methylene)-N-(5-chloropyridin-2-yl)hydrazinecarbothioamide (63) emerged as the premier candidates with good ChE inhibitory activities (IC50 values of 1.37 μM and 1.18 μM for hAChE, IC50 values of 2.69 μM and 3.31 μM for EqBuChE, respectively). All the test compounds displayed excellent antioxidant activity (reduction percentage of DPPH values for compounds (62) and (63) were 85.67% and 84.49%, respectively at 100 μM concentration). Compounds (62) and (63) conferred specific copper ion chelating property in metal chelation study. Molecular docking studies of compounds (62) and (63) indicate strong interactions within the active sites of both the ChE enzymes. Besides that, these compounds also exhibited significant in silico drug-like pharmacokinetic properties. Thus, taken together, they can serve as a starting point in the designing of multifunctional ligands in pursuit of potential anti-AD agents that might further prevent the progression of ADs. Communicated by Ramaswamy H. Sarma.
- Chaudhary, Bharat N.,Gandhi, Bhumi,Kanhed, Ashish M.,Patel, Dushyant V.,Patel, Kirti V.,Patel, Kishan B.,Patel, Nirav R.,Prajapati, Navnit K.,Shah, Bhavik S.,Teli, Divya M.,Yadav, Mange Ram
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- A general strategy to increase emission shift of two-photon ratiometric pH probes using a reversible intramolecular reaction of spiro-oxazolidine
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Fluorescent pH probes have been served as powerful tools in biological and pathological studies in recent years due to the important roles of pH values in various physiological processes. Although plenty of pH probes have been delivered, development of two-photon ratiometric pH probes with large emission shift for detecting the variation of intracellular pH values is still a greatly challenging task. To address this concern, in this work, we have discovered a general strategy designing pH probes by means of a pH-dependent reversible intramolecular reaction of spiro-oxazolidine which can efficiently change their conjugation length and the electronic effect concurrently. To display the generality of the strategy, we have synthesized six pH probes, and all these probes exhibit short emission in basic conditions and dramatically red-shifted emission in acid environments. The emission shift of the six probes is more than 150 nm and even up to 210 nm, much larger than shift of all commercial and reported pH probes. The chemical sensing mechanism of intramolecular ring opening/closing reaction of spiro-oxazolidine has been confirmed with 1H NMR spectra and density functional theory (DFT) calculations. Finally, we have used one of six with one- and two-photon properties to successfully image lysosomal pH changes under confocal and two-photon microscopes in a ratiometric manner. We believed that this spiro-oxazolidine strategy can serve as a general and powerful platform for the design of ideal pH probes.
- He, Xiuquan,Tian, Minggang,Yang, Rui,Yu, Xiaoqiang,Zhang, Huamiao
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supporting information
(2020/10/18)
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- Multi-Step Synthesis, Physicochemical investigation and optical properties of pyrazoline derivative: A Donor-π-Acceptor chromophore
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The new extended π-bond pyrazoline derivative (ENTD) was prepared from heterocyclic chalcone with 2-hydrazinylbenzo[d] thiazole. The spectroscopic methods established the structure of the ENTD, and the elemental analysis established the purity of the ENTD. In ten different solvents, physicochemical ENTD parameters such as the molar absorption coefficient, transition dipole moments, Stokes shift, oscillator intensity and fluorescence quantum yield were determined to see the effect of the solvent with pyrazoline derivative (ENTD) on the basis of different polarity. In addition, the interaction of ENTD chromophore with the cationic and anionic surfactants have been studied. The intensity of fluorescence spectrum of the ENTD was found to increase with an increase in the surfactant concentration. This indicates that there is a strong interaction between ENTD and surfactants. The ENTD chromophore can therefore be used as a probe to define the surfactants' CMC.
- Alfaifi, S. Y.,Alimuddin,Almalki, Abdulraheem S. A.,Alsharif, Meshari A.,Khan, Salman A.,Kumar, Sanjay,Obaid, Rami J.,Syed, Salauddin,Ullah, Qasim
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- Microwave assisted one-pot synthesis, photophysical and physicochemical studies of novel biologically active heterocyclic Donor (D)-π-Acceptor (A) chromophore
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A donor-π-acceptor (D-π-A) chromophore, 2-amino-4-(9-ethyl-9H-carbazol-3-yl)-8-methoxy-5,6-dihydrobenzo[h]quinoline-3-carbonitrile (AEDQ) was synthesized from the condensation of 6-methoxy-3,4-dihydronaphthalen-1(2H)-one, 9-ethyl-9H-carbazole-3-carbaldehyde, malononitrile and NH4OAc in ethanol. Spectroscopic techniques and elemental analysis were employed to establish the structure of AEDQ. Photophysical parameters and fluorescence quantum yield were calculated in the different polarity solvents to evaluate the interactions of the solvent with AEDQ chromophore. Further, the interaction of the AEDQ with cationic and anionic surfactants (CTAB, SDS) were also evaluated by using fluorescence spectroscopy techniques. The intensity of the fluorescence spectrum increased as the concentration of surfactants increased, suggesting that strong interaction occurs between AEDQ with surfactants, and this interaction arises from electrostatic forces. As a result, the AEDQ chromophore could be used to determine the CMC of surfactants. The disc diffusion and minimal inhibitory concentration (MIC) technique were used to test in-vitro antibacterial activity against Gram +ve and Gram ?ve bacteria, and the results are compared with the standard drug, tetracycline. AEDQ also showed good ADMET, pharmacokinetics and drug-likeness properties, which are desirable for a good drug candidate. The molecule also fits well in the DNA gyrase A active pocket site with the binding free energy of ?17.92 kcal/mol, which testifies its good antibacterial activity.
- Khan, Salman A.,Ullah, Qasim,Syed, Salahuddin,Alimuddin,Almalki, Abdulraheem S.A.,Kumar, Sanjay,Obaid, Rami J.,Alsharif, Meshari A.,Alfaifi,Parveen, Humaira
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- Multi-step Synthesis, Characterization and Photophysical Investigation of Novel Biologically Active Heterocyclic Chalcone (AECO)
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Novel alkylated heterocyclic chalcone (E)-1-(2-(allyloxy)phenyl)-3-(9-ethyl-9H-carbazol-3-yl)prop-2-en-1-one (AECO) with extended π-bond was prepared by the multi-steps synthesis. The structure of the AECO was established by the spectroscopic technics and purity of the compound was confirmed by the elemental analysis. Physicochemical parameters of the AECO such as molar absorption coefficient, transition dipole moments, stokes shift, oscillator strength and fluorescence quantum yield were calculated in ten various solvents on the basis of polarity of the solvents to see the effect of the solvent with AECO. Interaction of the AECO chromophore with cationic CTAB and anionic SDS surfactants were determined by using the fluorescence spectroscopy techniques. The intensity of the florescence spectrum increase with increasing the concentrations of surfactants. This suggests that strong interaction occurs between AECO with surfactants and this interaction arise from electrostatic forces. So, AECO chromophore could be used as analysis to define the Critical Micelle Concentration (CMC) of the surfactants. In addition the in-vitro antibacterial active of novel heterocyclic chalcone agents four bacteria’s strain were evaluated and result showed AECO is beater antibacterial agent against Gram-Negative Bacteria (E. coli and S. flexneri) as compare to the Gram Negative Bacteria with respected to the standard drug Tetracycline.
- Zayed, Mohie E. M.,Alzahrani, Khalid Ahmed,Khan, Salman A.
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p. 1823 - 1831
(2021/09/18)
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- Coumarin-carbazole based functionalized pyrazolines: Synthesis, characterization, anticancer investigation and molecular docking
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A series of novel pyrazoline scaffolds from coumarin-carbazole chalcones were synthesized. We explored various acetyl, amide, and phenyl substituents at the N-1 position of the pyrazoline core. The synthesized compounds were characterized by FTIR, 1H-NMR, 13C-NMR, DEPT, and mass spectroscopic techniques. The in vitro cytotoxicity study of all the synthesized compounds was evaluated against HeLa, NCI-H520 and NRK-52E cell lines. Compounds 4a and 7b became the most active compounds and exhibited their potential to arrest the cell cycle progression and induce apoptosis in both the cell lines. In addition, molecular docking studies revealed a higher binding affinity of both the molecules with CDK2 protein. Based on the obtained results, a comprehensive analysis is warranted to establish the role of compounds 4a and 7b as promising cancer therapeutic agents.
- Chauhan, Alex,Jain, Neeraj,Pandey, Nilesh,Parikh, Paranjay,Patel, Kaushal,Patel, Mrugesh,Timaniya, Jignesh
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p. 27627 - 27644
(2021/08/25)
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- Carbazole-based π-conjugated 2,2′-Bipyridines, a new class of organic chromophores: Photophysical, ultrafast nonlinear optical and computational studies
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The developmen of donor-acceptor (D-A) architecture based organic chromophores with large two-photon absorption (2 PA) cross-sections are essential for myriad of applications, ranging from nonlinear microscopy to biomedical imaging. Here, we present the results from a comprehensive study of 2 PA cross-sections of a new series of carbazole mono substituted-π-conjugated-2,2′-bipyridine derivatives with D-π-A architecture, possessing carbazole as the donor moiety and bipyridine core as an acceptor. Further, we have extended the π-conjugation by introducing the phenyl and butoxy substituted phenyl linkers. The fluorescence properties of these D-A chromophores are highly sensitive to solvent polarity and alteration of electron donor functionalities. The relevant computation studies support our experimental results, e.g., a shift in emission maxima and band gaps of the molecules. The third-order nonlinear optical (NLO) properties of the title donor-acceptor (D-A) chromophores demonstrated that 2 PA cross-section values are in the range of 6–39 GM, obtained using ~50 fs (fs) laser pulses at a wavelength of 800 nm. Further, the nonlinear refractive indices (n2) of these chromophores were found to be ~10?14 cm2/W, rendering them potential optical switching candidates since the coefficients were obtained with kHz, fs pulses extracting pure electronic nonlinearities. Based on our experimental findings and theoretical calculations presented in this study, we believe that carbazole-based π-conjugated 2,2′-bipyridines, demonstrated in this work, would be potential ligands to obtain a series of transition metal coordination complexes of interesting physical properties (for example, superior NLO behaviour).
- Bodapati, Ramakrishna,Das, Samar K.,Dey, Gaurav Ranjan,Jose, K. V. Jovan,Krishnakanth, Katturi Naga,Ramteke, Gunjan R.,Rao, S. Venugopal
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- Design, synthesis and evaluation of carbazole derivatives as potential antimicrobial agents
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Five series of novel carbazole derivatives containing an aminoguanidine, dihydrotriazine, thiosemicarbazide, semicarbazide or isonicotinic moiety were designed, synthesised and evaluated for their antimicrobial activities. Most of the compounds exhibited potent inhibitory activities towards different bacterial strains (including one multidrug-resistant clinical isolate) and one fungal strain with minimum inhibitory concentrations (MICs) between 0.5 and 16 μg/ml. Compounds 8f and 9d showed the most potent inhibitory activities (MICs of 0.5–2 μg/ml). Furthermore, compounds 8b, 8d, 8f, 8k, 9b and 9e with antimicrobial activities were not cytotoxic to human gastric cancer cell lines (SGC-7901 and AGS) or a normal human liver cell line (L-02). Structure–activity relationship analyses and docking studies implicated the dihydrotriazine group in increasing the antimicrobial potency and reducing the toxicity of the carbazole compounds. In vitro enzyme activity assays suggested that compound 8f binding to dihydrofolate reductase might account for the antimicrobial effect.
- Xue, Yi-Jie,Li, Ming-Yue,Jin, Xue-Jun,Zheng, Chang-Ji,Piao, Hu-Ri
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p. 295 - 306
(2021/01/13)
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- Comparing Separation vs. Fresh Start to Assess Reusability of Pd/C Catalyst in Liquid-Phase Hydrogenation
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The reusability of metal catalysts is a key issue for the potential application of new catalysts in research and industrial practice. The most common procedure for testing catalyst reusability in liquid-phase heterogeneous reactions is based on separating a catalyst from a reaction mixture followed by the next run. An alternative procedure called “fresh start” consists of the addition of a new portion of reagents to the reaction mixture without any isolation operation. In this work, we compare both procedures in a model Pd/C-catalyzed hydrogenation with different heteroatoms, e. g., O-, S-, and N-vinyl derivatives. It was shown that regardless of whether the catalyst is stable or potentially poisoned during the reaction, both procedures lead to comparable results. It appears that a much easier implementation of a fresh start procedure may be an option of choice. The possibilities of using both procedures to rationalize the experimental protocol for assessing Pd/C catalyst reusability in liquid-phase hydrogenations are discussed.
- Mironenko, Roman M.,Saybulina, Elina R.,Trenikhin, Mikhail V.,Izmailov, Rinat R.,Lotsman, Kristina A.,Rodygin, Konstantin S.,Ananikov, Valentine P.
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p. 3656 - 3661
(2021/07/02)
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- Photoredox-Catalyzed Simultaneous Olefin Hydrogenation and Alcohol Oxidation over Crystalline Porous Polymeric Carbon Nitride
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Booming of photocatalytic water splitting technology (PWST) opens a new avenue for the sustainable synthesis of high-value-added hydrogenated and oxidized fine chemicals, in which the design of efficient semiconductors for the in-situ and synergistic utilization of photogenerated redox centers are key roles. Herein, a porous polymeric carbon nitride (PPCN) with a crystalline backbone was constructed for visible light-induced photocatalytic hydrogen generation by photoexcited electrons, followed by in-situ utilization for olefin hydrogenation. Simultaneously, various alcohols were selectively transformed to valuable aldehydes or ketones by photoexcited holes. The porosity of PPCN provided it with a large surface area and a short transfer path for photogenerated carriers from the bulk to the surface, and the crystalline structure facilitated photogenerated charge transfer and separation, thus enhancing the overall photocatalytic performance. High reactivity and selectivity, good functionality tolerance, and broad reaction scope were achieved by this concerted photocatalysis system. The results contribute to the development of highly efficient semiconductor photocatalysts and synergistic redox reaction systems based on PWST for high-value-added fine chemical production.
- Qiu, Chuntian,Sun, Yangyang,Xu, Yangsen,Zhang, Bing,Zhang, Xu,Yu, Lei,Su, Chenliang
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p. 3344 - 3350
(2021/07/26)
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- Synthesis method of N-ethyl carbazole
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The invention discloses a synthesis method of N-ethyl carbazole, and belongs to the technical field of organic synthesis. The method comprises the following steps: (1) adding anhydrous acetonitrile, sodium and carbazole into a high-pressure reactor, introducing ethylene to replace air, continuously introducing ethylene until the pressure is 45 MPa, heating to 80-150 DEG C, carrying out a reactionat a constant temperature for 3-10 hours, and replacing gas in the high-pressure reactor with nitrogen after the reaction is finished; wherein the dosage of sodium is 0.5-2.0% of the mass of carbazole; and (2) after the reaction is finished, distilling the reaction liquid under normal pressure at the temperature of 80-90 DEG C, stopping distilling until the volume is 40-60%, recovering the distilled solvent, cooling to 68-80 DEG C, filtering when the solution is still hot, finally, carrying out reduced pressure distillation at the temperature of 90-110 DEG C under the vacuum degree of less than 1 mmHg, and drying to obtain N-ethyl carbazole. The method has the advantages of simple process, recyclable solvent, high yield, high purity and the like.
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Paragraph 0026-0028
(2021/01/25)
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- Design and synthesis of aryl-functionalized carbazole-based porous coordination cages
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A subset of coordination cages have garnered considerable recent attention for their potential permanent porosity in the solid state. Herein, we report a series of functionalized carbazole-based cages of the structure type M12(R-cdc)12 (M = Cr, Cu, Mo) where the functional groups include a range of aromatic substituents. Single-crystal X-ray structure determinations reveal a variety of intercage interactions in these materials, largely governed by pi-pi stacking. Density functional theory for a subset of these cages was used to confirm that the nature of the increased stability of aryl-functionalized cages is a result of inter-cage ligand interactions. This journal is
- Rowland, Casey A.,Lorzing, Gregory R.,Bhattacharjee, Rameswar,Caratzoulas, Stavros,Yap, Glenn P. A.,Bloch, Eric D.
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supporting information
p. 9352 - 9355
(2020/10/02)
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- Butterfly-Shaped Thiophene-Pyridine Hybrids: Green Electroluminescence and Large Third-Order Optical Nonlinearities
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A set of four symmetric, butterfly-shaped 4-(4-(decyloxy)phenyl)-2,6-di(thiophen-2-yl)pyridine (TPY) derivatives 2TPA-TPY (TPY center and triphenylamine end groups), 2CBZ-TPY (TPY center and N-ethyl carbazole end groups), 2TPY-TPA (triphenylamine center and TPY at the periphery) and 2TPY-CBZ (N-ethyl carbazole center and TPY at the periphery) was synthesized. The molecules show reverse saturable absorption (RSA) which is consistent with two-photon absorption (2PA) associated with excited-state absorption (ESA) when excited using a 532 nm laser beam. The molecules 2TPA-TPY and 2TPY-TPA possess extremely low limiting thresholds of 1.73 and 2.68 J cm?2, respectively. An organic light-emitting diode (OLED) fabricated from 2TPA-TPY exhibits green emission with a maximum luminance of 207 cd m?2, a current efficiency (ηCE) of 1.51cd A?1, a maximum power efficiency (ηPmax) of 0.46 lm W?1 and an external quantum efficiency (ηEQE) of 0.48 % at 100 cd m?2.
- Chandrasekharan, Keloth,Dalimba, Udaya Kumar,Darshan, Vibhu,Gangadharappa, Sathish Chatnahalli,Kakekochi, Viprabha,Narayanan Unni, K. N.,Nikhil, P. P.
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p. 1762 - 1777
(2020/09/02)
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- Carbazolyl compounds alkylated in 9 position in position, as well as preparation method and application of carbazole compound (by machine translation)
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The invention provides a carbazole compound capable 9 of being alkylated in a-position manner, a preparation, method of the carbazole compound and a chemical structural formula of the carbazole compound as shown in the specification. The carbazolyl, R compounds C2-C9 of the present disclosure which have a straight-chain alkyl. group according to one AIE of, the above TNT-mentioned aspect of the. present disclosure not only have a higher index of refraction, but also have a sensitivity higher than the sensitivity of the detection. (by machine translation)
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Paragraph 0046-0049
(2020/02/20)
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- The aggregation induced fluorescence effect enhanced by a reasonable length of carbon chain
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Six different barbituric acid derivatives using ethyl, propyl, butyl, pentyl, hexyl and heptyl groups as hydrophobic substituents were prepared. Molecular dynamics simulation was carried out to study the effect of different carbon chain lengths on the aggregation-induced emission process. Among the compounds, the CB-5 containing a hexyl substituent exhibited the strongest Aggregation induced emission (AIE) effect, not the CB-6 with longest carbon chain. The aggregates of CB-5 was used to detect the 2, 4, 6-trinitrotoluene (TNT) in aqueous media, exhibiting a maximum quenching constant of 3.1 × 105 M? 1. The paper sensor based on CB-5 showed a superior sensitivity toward TNT both in vapor and solution. This provided a clear strategy for designing compounds that utilize the hydrophobic interaction of long-chain alkyl chains to enhance the AIE effect.
- Zhang, Hanjun,Tao, Furong,Cui, Yuezhi,Xu, Zhen
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- Synthesis and Optical Properties of New Chalcones Containing a 3,4-Ethylenedioxythiophene Fragment
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Abstract: A new series of chalcones bearing two or more 3,4-ethylenedioxythiophene fragments were synthesized, and their optical properties were studied. The Stokes shifts (Δλ) and band gaps (Egopt) were calculated on the basis of the absorption and emission spectra. The largest Stokes shift (115 nm) was found for a symmetrical product of the terephthalaldehyde and 3,4-ethylenedioxythiophene-2-carbaldehyde condensation, and the smallest band gap (1.93 eV) is characteristic of a chalcone that contains a 2,2',5',2''-ter(3,4-ethylenedioxythiophene). Correlations were established between the band gap and mutual arrangement of the 3,4-ethylenedioxythiophene fragments in the prepared chalcones.
- Ignashevich,Shavrina,Shklyaeva,Abashev
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p. 1920 - 1928
(2021/01/13)
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- Redox-neutral decarboxylative photocyclization of anthranilic acids
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A mild metal-, catalyst-, and oxidant-free photoredox neutral system has been found to efficiently enable intramolecular decarboxylative cyclization of anthranilic acids. This facile protocol provides an alternative method for the synthesis of carbazoles. Mechanistic studies reveal a key photoinduced 6π-electrocyclization process and formic acid was released as the sole byproduct.
- Huang, Huawen,Deng, Kun,Deng, Guo-Jun
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p. 8243 - 8247
(2020/12/29)
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- Dearomatization-Rearomatization Strategy for Synthesizing Carbazoles with 2,2′-Biphenols and Ammonia by Dual C(Ar)-OH Bond Cleavages
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Carbazole is an essential building block in various pharmaceuticals, agrochemicals, natural products, and materials. For future sustainability, it is highly desirable to synthesize carbazole derivatives directly from renewable resources or cheap raw materials. Phenolic compounds are a class of degradation products of lignin. On the other hand, ammonia is a very cheap industrial inorganic chemical. Herein, an efficient dearomatization-rearomatization strategy has been developed to directly cross-couple 2,2′-biphenols with ammonia by dual C(Ar)-OH bond cleavages. This strategy provides a greener pathway to synthesize valuable carbazole derivatives from phenols.
- Cao, Dawei,Yu, Jing,Zeng, Huiying,Li, Chao-Jun
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p. 13200 - 13205
(2020/12/18)
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- Rh(III)-Catalyzed N-Nitroso Directed C-H Arylation for Facile Construction of Diverse N-Hetero Biaryl Compounds
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A Rh(III)-catalyzed C?H arylation reaction of N-nitrosoanilines has been developed in which arylboronic acids were used as arylation reagents. It provides an efficient strategy for the synthesis of N-nitroso-[1,1′-biphenyl]-2-amine, which is an important starting material for the synthesis of N-hetero biaryl compounds, such as 2-amine-1,1′-biphenyl, carbazole, phenanthridone. This protocol can be applied to various N-alkyl substituted N-nitrosoanilines and N-nitrosoanilines with substituents on the phenyl ring. Arylboronic acids with both electron-donating and electron-withdrawing groups are tolerated.
- Wang, Pei-Long,Wang, Yan,Li, Yan,Wang, Xi-Sheng
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p. 3825 - 3828
(2020/10/22)
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- Novel carbazole-stilbene hybrids as multifunctional anti-Alzheimer agents
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Molecules capable of engaging with multiple targets associated with pathological condition of Alzheimer's disease have proved to be potential anti-Alzheimer's agents. In our goal to develop multitarget-directed ligands for the treatment of Alzheimer's disease, a novel series of carbazole-based stilbene derivatives were designed by the fusion of carbazole ring with stilbene scaffold. The designed compounds were synthesized and evaluated for their anti-AD activities including cholinesterase inhibition, Aβ aggregation inhibition, antioxidant and metal chelation properties. Amongst them, (E)-1-(4-(2-(9-ethyl-9H-carbazol-3-yl)vinyl)phenyl)-3-(2-(pyrrolidin-1-yl)ethyl)thiourea (50) appeared to be the best candidate with good inhibitory activities against AChE (IC50 value of 2.64 μM) and BuChE (IC50 value of 1.29 μM), and significant inhibition of self-mediated Aβ1–42 aggregation (51.29% at 25 μM concentration). The metal chelation study showed that compound (50) possessed specific copper ion chelating property. Additionally, compound (50) exhibited moderate antioxidant activity. To understand the binding mode of 50, molecular docking studies were performed, and the results indicated strong non-covalent interactions of 50 with the enzymes in the active sites of AChE, BuChE as well as of the Aβ1-42 peptide. Additionally, it showed promising in silico ADMET properties. Putting together, these findings evidently showed compound (50) as a potential multitarget-directed ligand in the course of developing novel anti-AD drugs.
- Chaudhary, Bharat N.,Gandhi, Pallav M.,Joshi, Prashant D.,Kanhed, Ashish M.,Patel, Dushyant V.,Patel, Kirti V.,Patel, Kishan B.,Patel, Nirav R.,Patel, Sagar P.,Prajapati, Navnit K.,Teli, Divya M.,Yadav, Mange Ram
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- A carbazole-hemicyanine dye based ratiometric fluorescent probe for selective detection of bisulfite (HSO3 ?) in cells and C. elegans
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Bisulfite (HSO3 ?) is an important sulfur dioxide (SO2) derivative, which plays a major role in many physiological processes and is also closely associated with a variety of diseases. Thus the development of highly selective and sensitive fluorescent probes is essential to detect HSO3ˉ in living cells. In this work, we report the synthesis and analysis of a ratiometric fluorescent probe for selective detection of HSO3ˉ based on the 1,4-nucleophilic addition reaction with the carbazole as an electron donor (D) and aldehyde group as an electron acceptor (A). The addition of HSO3ˉ and other ions to our probe can be observed by UV - vis and fluorescence spectrometry. Our investigation proved that the probe is highly selective and sensitive for HSO3ˉ and ratiometric changes. Moreover, the probe has good cell permeability and was successfully applied to the detection of exogenous HSO3ˉ in Hela cells and C. elegans.
- Bi, Keying,Tan, Rui,Hao, Ruiting,Miao, Lanxi,He, Yanqi,Xianghua, Wu,Zhang, Junfeng,Rui, Xu
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supporting information
p. 545 - 548
(2018/12/11)
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- Ratio type fluorescent probe for detecting sulfur dioxide and application of ratio type fluorescent probe
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The invention provides a ratio type fluorescent probe for detecting sulfur dioxide. The chemical structure formula of the ratio type fluorescent probe is shown in the specification. The probe is capable of detecting existence of sulfate radicals hydrogen sulfite radicals in solutions, cells or living bodies, is very rapid in recognition speed, and is capable of meeting a balance state within a short time. In addition, the probe is successfully applied to cell imaging, is also applied to mouse imaging, and has great superiority in living body analysis and detection.
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Paragraph 0017
(2019/09/16)
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- MODIFIED CARBAZOLES AS THERAPEUTIC AGENTS
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This disclosure relates to compounds that target microtubules, pharmaceutical compositions comprising them, and methods of using the compounds and compositions for treating diseases. More particularly, this disclosure relates to modified carbazole compounds and pharmaceutical compositions thereof, methods of targeting microtubules with these compounds, and methods of treating diseases affected by microtubule disruption.
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Paragraph 0175
(2020/01/08)
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- Design and synthesis of a fluorescent probe with a large stokes shift for detecting thiophenols and its application in water samples and living cells
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A turn-on florescent probe (probe-KCP) was developed for highly selective detection of thiophenols based on a donor-excited photo-induced electron transfer mechanism. Herein, the synthesis of the probe, a chalcone derivative, through a simple straightforward combination of a carbazole-chalcone fluorophore with a 2,4-dinitrophenyl functional group. In a kinetic study of the probe-KCP for thiophenols, the probe displayed a short response time (~30 min) and significant fluorescence enhancement. In selection and competition experiments, the probe-KCP exhibited excellent selectivity for thiophenols over glutathione (GSH), cysteine (Cys), sodium hydrosulfide (NaSH), and ethanethiol (C2H5SH) in addition to common anions and metal ions. Using the designed probe, we successfully monitored and quantified thiophenols, which are highly toxic. This turn-on fluorescence probe features a remarkably large Stokes shift (130 nm) and a short response time (30 min), and it is highly selective and sensitive (~160-fold) in the detection of thiophenols, with marked fluorescence in the presence of thiophenols. probe-KCP responds to thiophenols with a good range of linearity (0–15 μM) and a detection limit of 28 nM (R2 = 0.9946) over other tested species mentioned including aliphatic thiols, thiophenol analogues, common anions, and metal ions. The potential applications of this carbazole-chalcone fluorescent probe was successfully used to determine of thiophenols in real water samples and living cells with good performance and low cytotoxicity. Therefore, this probe has great potential application in environment and biological samples.
- Liu, Hua,Guo, Chuanlong,Guo, Shuju,Wang, Lijun,Shi, Dayong
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- Method for catalyzing reduction of iminodibenzyl carbon-based derivative
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The invention relates to a method for catalyzing reduction of an iminodibenzyl carbon-based derivative. For the first time, non-transition metal compound sodium triethylborohydride is used as a catalyst, the reduction reaction of the iminodibenzyl carbon-based derivative with an inexpensive and easily available organoboron reagent can be catalyzed conveniently under mild conditions to prepare an iminodibenzyl product. Compared with a traditional method, the method generally has the advantages that the catalyst is cheap and easy to obtain, operation is convenient and reaction is safe. For the first time, the selective reduction reaction of the iminodibenzyl carbon-based derivative with the organoboron reagent is catalyzed by a non-transition metal catalyst, and a practical and novel reaction strategy is provided for the laboratory preparation or industrial production of the iminodibenzyl product.
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Paragraph 0017-0020
(2019/11/12)
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- Microwave-assisted synthesis method for ethylation reaction
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The invention relates to a microwave-assisted synthesis method for an ethylation reaction. The method is characterized in that a reaction substrate is in an organic solvent, trifluoroacetic acid ethyl ester is taken as an ethylation reagent, in the presence of an alkali, microwave-assisted heating is carried out for 2 minutes, and a corresponding ethylation product can be obtained. The invention provides a new method for the ethylation reaction. The reaction rate of the method is several times higher than that of a traditional method, the operation is simple and convenient, the cost is low, the reaction time is short, the application range of the substrate is wide, the use of the expensive or hypertoxic ethylation reagent can also be avoided, and the method has higher application value.
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Paragraph 0012
(2019/10/05)
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- Catalytic protodeboronation of pinacol boronic esters: Formal anti-Markovnikov hydromethylation of alkenes
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Pinacol boronic esters are highly valuable building blocks in organic synthesis. In contrast to the many protocols available on the functionalizing deboronation of alkyl boronic esters, protodeboronation is not well developed. Herein we report catalytic protodeboronation of 1°, 2° and 3° alkyl boronic esters utilizing a radical approach. Paired with a Matteson-CH2-homologation, our protocol allows for formal anti-Markovnikov alkene hydromethylation, a valuable but unknown transformation. The hydromethylation sequence was applied to methoxy protected (-)-Δ8-THC and cholesterol. The protodeboronation was further used in the formal total synthesis of δ-(R)-coniceine and indolizidine 209B.
- Clausen, Florian,Kischkewitz, Marvin,Bergander, Klaus,Studer, Armido
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p. 6210 - 6214
(2019/06/27)
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- Pd-Catalyzed Intramolecular Chemoselective C(sp2)-H and C(sp3)-H Activation of N-Alkyl- N-arylanthranilic Acids
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A controllable palladium-catalyzed intramolecular C-H activation of N-alkyl-N-arylanthranilic acids has been developed. The methodology allows selective synthesis of 1,2-dihydro-(4H)-3,1-benzoxazin-4-ones and carbazoles from the same starting materials and palladium catalyst. The selectivity is controlled by the oxidant. Silver oxide promotes C(sp3)-H activation/C-O cyclization to provide 1,2-dihydro-(4H)-3,1-benzoxazin-4-ones, while copper acetate contributes to C(sp2)-H activation/decarboxylative arylation to afford carbazoles. This protocol is demonstrated by its wide substrate scope and good functional group tolerance.
- Hu, Zhe-Yao,Zhang, Yan,Li, Xin-Chang,Zi, Jing,Guo, Xun-Xiang
-
supporting information
p. 989 - 992
(2019/05/16)
-
- Construction of a Nanoporous Highly Crystalline Hexagonal Boron Nitride from an Amorphous Precursor for Catalytic Dehydrogenation
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Hexagonal boron nitride (h-BN) is regarded as a graphene analogue and exhibits important characteristics and vast application potentials. However, discovering a facile method for the preparation of nanoporous crystalline h-BN nanosheets (h-BNNS) is still a challenge. Herein, a novel and simple route for the conversion of amorphous h-BN precursors into highly crystalline h-BNNS was achieved through a successive dissolution–precipitation/crystallization process in the presence of magnesium. The h-BNNS has high crystallinity, high porosity with a surface area of 347 m2 g?1, high purity, and enhanced thermal stability. Improved catalytic performance of crystalline h-BNNS was evidenced by its much higher catalytic efficiency in the dehydrogenation of dodecahydro-N-ethylcarbazole, compared with its amorphous h-BN precursor, as well as other precious-metal-loaded heterogeneous catalysts.
- Chen, Hao,Yang, Zhenzhen,Zhang, Zihao,Chen, Zitao,Chi, Miaofang,Wang, Song,Fu, Jie,Dai, Sheng
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p. 10626 - 10630
(2019/07/09)
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- The carbazole compound manufactured by the manufacturing method in the carbazole compound.
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PROBLEM TO BE SOLVED: To provide a more simple method of manufacturing carbazoles which can be used industrially.SOLUTION: There is provided a manufacturing method of carbazoles including reacting 2-aminobiphenyls of which an amino group is represented by the formula (1), -NHR(1), where Rrepresents S(=O)R, C(=O)Ror an alkyl group having 1 to 3 carbon atoms, where Rrepresents a phenyl group may be substituted by an alkyl group having 1 to 2 carbon atoms or a nitro group, or an alkyl group having 1 to 3 carbon atoms, Rrepresents an alkyl group having 1 to 5 carbon atoms, with a sulfur-based solvent and oxygen in a presence of a heterogeneous catalyst carrying palladium, for example [P9-Type][UL-Type][P60-Type] provided by N.E. CHEMCAT CORPORATION and the like, at 110 to 130°C.
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-
Paragraph 0037-0040
(2020/10/19)
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- Fluorescent probe of reversible sulfur dioxide/sulphurous acid (hydrogen) salt
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The invention provides a fluorescent probe of reversible sulfur dioxide/sulphurous acid (hydrogen) salt, with the chemical name of 7-diethylin-2-(9-ethyl-9H-carbazole-3) benzo iso-pyran oxonium ion. The fluorescent probe can detect sulfur dioxide/sulphurous acid (hydrogen) salt in a solution, cells, tissues or a living body, wherein the living body includes fish, mice, rat, guinea pig and rabbit;and reversibility is realized by formaldehyde. The fluorescent probe is simple in synthesis steps, easily available in material, high in yield and suitable for industrial application.
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Paragraph 0025
(2018/06/16)
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- Modified carbazoles destabilize microtubules and kill glioblastoma multiform cells
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Small molecules that target microtubules (MTs) represent promising therapeutics to treat certain types of cancer, including glioblastoma multiform (GBM). We synthesized modified carbazoles and evaluated their antitumor activity in GBM cells in culture. Modified carbazoles with an ethyl moiety linked to the nitrogen of the carbazole and a carbonyl moiety linked to distinct biaromatic rings exhibited remarkably different killing activities in human GBM cell lines and patient-derived GBM cells, with IC50 values from 67 to >10,000 nM. Measures of the activity of modified carbazoles with tubulin and microtubules coupled to molecular docking studies show that these compounds bind to the colchicine site of tubulin in a unique low interaction space that inhibits tubulin assembly. The modified carbazoles reported here represent novel chemical tools to better understand how small molecules disrupt MT functions and kill devastating cancers such as GBM.
- Diaz, Philippe,Horne, Eric,Xu, Cong,Hamel, Ernest,Wagenbach, Michael,Petrov, Ravil R.,Uhlenbruck, Benjamin,Haas, Brian,Hothi, Parvinder,Wordeman, Linda,Gussio, Rick,Stella, Nephi
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- Targeting G-quadruplex DNA structures in the telomere and oncogene promoter regions by benzimidazole?carbazole ligands
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Recent studies support the idea that G-quadruplex structures in the promoter regions of oncogenes and telomere DNA can serve as potential therapeutic targets in the treatment of cancer. Accordingly, several different types of organic small molecules that stabilize G-quadruplex structures and inhibit telomerase activity have been discerned. Here, we describe the binding of benzimidazole-carbazole ligands to G-quadruplex structures formed in G-rich DNA sequences containing the promoter regions of human c-MYC, c-KIT1, c-KIT2, VEGF and BCL2 proto-oncogenes. The fluorescence spectroscopic data indicate that benzimidazole-carbazole ligands bind and stabilize the G-quadruplexes in the promoter region of oncogenes. The molecular docking studies provide insights into the mode and extent of binding of this class of ligands to the G-quadruplexes formed in oncogene promoters. The high stability of these G-quadruplex structures was validated by thermal denaturation and telomerase-catalyzed extension of the 3' end. Notably, benzimidazole-carbazole ligands suppress the expression of oncogenes in cancer cells in a dose-dependent manner. We anticipate that benzimidazole-carbazole ligands, by virtue of their ability to stabilize G-quadruplex structures in the promoter regions of oncogenes, might reduce the risk of cancer through the loss of function in the proteins encoded by these genes.
- Kaulage, Mangesh H.,Maji, Basudeb,Pasadi, Sanjeev,Ali, Asfa,Bhattacharya, Santanu,Muniyappa
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p. 178 - 194
(2018/02/20)
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- Alkyl Chain Introduction: In Situ Solar-Renewable Colorful Organic Mechanoluminescence Materials
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Mechanoluminescence (ML) materials are environmentally friendly and emit light by utilizing mechanical energy. This has been utilized in light sources, displays, bioimaging, and advanced sensors. Organic ML materials are strongly limited to application by in situ unrepeatable ML. Now, in situ solar-renewable organic ML materials can be formed by introducing a soft alkyl chain into an ML unit. For the first time, the ML from these polycrystalline thin films can be iteratively produced by simply recrystallizing the fractured crystal in situ after a contactless exposure to sunlight within a short time (≤60 s). Additionally, their ML color and lifetime can be also easily tuned by doping with organic luminescent dyes. Therefore, large-area sandwich-type organic ML devices can be fabricated, which can be repeatedly used in a colorful piezo-display, visual handwriting monitor, and sensitive optical sensor, showing a lowest pressure threshold for ML of about 5 kPa.
- Li, Wenlang,Huang, Qiuyi,Mao, Zhu,Li, Qi,Jiang, Long,Xie, Zongliang,Xu, Rui,Yang, Zhiyong,Zhao, Juan,Yu, Tao,Zhang, Yi,Aldred, Matthew P.,Chi, Zhenguo
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supporting information
p. 12727 - 12732
(2018/09/14)
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- A carbazole-based turn-on fluorescent probe for the detection of hydrazine in aqueous solution
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A carbazole-based fluorescent probe, 2-(9-ethyl-9H-carbazol-3-yl) isoindoline-1,3-dione, with a low detection limit (2.673 × 10?6 M) for the detection of hydrazine is designed and synthesized based on Gabriel reaction. The probe responds selectively to hydrazine over other amino compounds with marked fluorescence enhancement. Moreover, test paper experiments indicated its great potential in the environment monitoring of hydrazine in aqueous solution.
- Wang, Wei-Dong,Hu, Yang,Li, Qiao,Hu, Sheng-Li
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p. 206 - 211
(2018/04/02)
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- Preferential intermolecular interactions lead to chiral recognition: Enantioselective gel formation and collapse
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Interesting self-assembly of an amino acid based molecular material into a hydrogel in the presence of selective enantiomeric chiral amines leading to chiral recognition has been demonstrated. Moreover, collapse of a metallogel formed from the same material in the presence of selective enantiomers validated its enantioselective affinity. Importantly, in addition to relevant experimental techniques, DFT studies have been successfully explored to establish chiral recognition through enantioselective gelation.
- Gambhir, Diksha,Kumar, Sunil,Dey, Gourab,Krishnan, Venkata,Koner, Rik Rani
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supporting information
p. 11407 - 11410
(2018/10/20)
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- Transfer Hydrogenation of Alkenes Using Ethanol Catalyzed by a NCP Pincer Iridium Complex: Scope and Mechanism
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The first general catalytic approach to effecting transfer hydrogenation (TH) of unactivated alkenes using ethanol as the hydrogen source is described. A new NCP-type pincer iridium complex (BQ-NCOP)IrHCl containing a rigid benzoquinoline backbone has been developed for efficient, mild TH of unactivated C-C multiple bonds with ethanol, forming ethyl acetate as the sole byproduct. A wide variety of alkenes, including multisubstituted alkyl alkenes, aryl alkenes, and heteroatom-substituted alkenes, as well as O- or N-containing heteroarenes and internal alkynes, are suitable substrates. Importantly, the (BQ-NCOP)Ir/EtOH system exhibits high chemoselectivity for alkene hydrogenation in the presence of reactive functional groups, such as ketones and carboxylic acids. Furthermore, the reaction with C2D5OD provides a convenient route to deuterium-labeled compounds. Detailed kinetic and mechanistic studies have revealed that monosubstituted alkenes (e.g., 1-octene, styrene) and multisubstituted alkenes (e.g., cyclooctene (COE)) exhibit fundamental mechanistic difference. The OH group of ethanol displays a normal kinetic isotope effect (KIE) in the reaction of styrene, but a substantial inverse KIE in the case of COE. The catalysis of styrene or 1-octene with relatively strong binding affinity to the Ir(I) center has (BQ-NCOP)IrI(alkene) adduct as an off-cycle catalyst resting state, and the rate law shows a positive order in EtOH, inverse first-order in styrene, and first-order in the catalyst. In contrast, the catalysis of COE has an off-cycle catalyst resting state of (BQ-NCOP)IrIII(H)[O(Et)···HO(Et)···HOEt] that features a six-membered iridacycle consisting of two hydrogen-bonds between one EtO ligand and two EtOH molecules, one of which is coordinated to the Ir(III) center. The rate law shows a negative order in EtOH, zeroth-order in COE, and first-order in the catalyst. The observed inverse KIE corresponds to an inverse equilibrium isotope effect for the pre-equilibrium formation of (BQ-NCOP)IrIII(H)(OEt) from the catalyst resting state via ethanol dissociation. Regardless of the substrate, ethanol dehydrogenation is the slow segment of the catalytic cycle, while alkene hydrogenation occurs readily following the rate-determining step, that is, β-hydride elimination of (BQ-NCOP)Ir(H)(OEt) to form (BQ-NCOP)Ir(H)2 and acetaldehyde. The latter is effectively converted to innocent ethyl acetate under the catalytic conditions, thus avoiding the catalyst poisoning via iridium-mediated decarbonylation of acetaldehyde.
- Wang, Yulei,Huang, Zhidao,Leng, Xuebing,Zhu, Huping,Liu, Guixia,Huang, Zheng
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supporting information
p. 4417 - 4429
(2018/04/05)
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- Photoinduced Cross-Coupling of Amines with 1,2-Diiodobenzene and Its Application in the Synthesis of Carbazoles
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A facile and efficient process for the preparation of various tertiary aminobenzenes and carbazole derivatives via photoinduced cross-coupling of amines with 1,2-diiodobenzene is reported. Mechanistic investigations indicate that the transformation proceeds via nucleo-philic addition of an amine to the benzyne intermediate accompanied with a proton transfer process, followed by an oxidative cyclization of the generated diphenylamine to furnish the corresponding carbazole products.
- Zhao, Xinxin,Chen, Ming,Huang, Binbin,Yang, Chao,Gao, Yuan,Xia, Wujiong
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p. 2981 - 2989
(2018/05/15)
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- Synthesis, evaluation and molecular modelling studies of 2-(carbazol-3-yl)-2-oxoacetamide analogues as a new class of potential pancreatic lipase inhibitors
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A series of twenty four 2-(carbazol-3-yl)-2-oxoacetamide analogues were synthesized, characterized and evaluated for their pancreatic lipase (PL) inhibitory activity. Porcine PL was used against 4-nitrophenyl butyrate (method A) and tributyrin (methods B and C) as substrates during the PL inhibition assay. Compounds 7e, 7f and 7p exhibited potential PL inhibitory activity (IC50values of 6.31, 8.72 and 9.58 μM, respectively in method A; and Xi50of 21.85, 21.94 and 26.2, respectively in method B). Further, inhibition kinetics of 7e, 7f and 7p against PL, using method A, revealed their competitive nature of inhibition. A comparison of the inhibition profiles of the top three compounds in methods B and C, provided a preliminary idea of covalent bonding of the compounds with Ser 152 of PL. Molecular docking studies of the compounds 7a–x into the active site of human PL (PDB ID: 1LPB) was in agreement with the in vitro results, and highlighted probable covalent bond formation with Ser 152 apart from hydrophobic interactions with the lid domain. Molecular dynamics simulation of 7e complexed with PL, further confirmed the role of aromatic groups in stabilising the ligand (RMSD ? 4 ?). The present study led to the identification of 2-(carbazol-3-yl)-2-oxoacetamide analogues 7a–x as a new class of potential PL inhibitors.
- Sridhar,Ginson, George,Venkataramana Reddy,Tantak, Mukund P.,Kumar, Dalip,Paul, Atish T.
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p. 609 - 620
(2016/12/30)
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- Carbazole-Linked Near-Infrared Aza-BODIPY Dyes as Triplet Sensitizers and Photoacoustic Contrast Agents for Deep-Tissue Imaging
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Four new N-ethylcarbazole-linked aza-boron-dipyrromethene (aza-BODIPY) dyes (8 a,b and 9 a,b) were synthesized and characterized. The presence of the N-ethylcarbazole moiety shifts their absorption and fluorescence spectra to the near-infrared region, λ≈650–730 nm, of the electromagnetic spectrum. These dyes possess strong molar absorptivity in the range of 3–4×104 m?1 cm?1 with low fluorescence quantum yields. The triplet excited state and singlet oxygen generation of these dyes were enhanced upon iodination at the core position. The core-iodinated dyes 9 a,b showed excellent triplet quantum yields of about 90 and 75 %, with singlet oxygen generation efficiency of about 70 and 60 % relative to that of the parent dyes. Derivatives 8 a,b showed dual absorption profiles, in contrast to dyes 9 a,b, which had the characteristic absorption band of aza-BODIPY dyes. DFT calculations revealed that the electron density was spread over the iodine and dipyrromethene plane of 9 a,b, whereas in 8 a,b the electron density was distributed on the carbazole group and dipyrromethene plane of aza-BODIPY. The uniqueness of these aza-BODIPY systems is that they exhibit efficient triplet-state quantum yields, high singlet oxygen generation yields, and good photostability. Furthermore, the photoacoustic (PA) characteristics of these aza-BODIPY dyes was explored, and efficient PA signals for 8 a were observed relative to blood serum with in vitro deep-tissue imaging, thereby confirming its use as a promising PA contrast agent.
- Gawale, Yogesh,Adarsh, Nagappanpillai,Kalva, Sandeep Kumar,Joseph, Joshy,Pramanik, Manojit,Ramaiah, Danaboyina,Sekar, Nagaiyan
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p. 6570 - 6578
(2017/05/15)
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- Soluble oxime ester and aromatic alkone light polymerization initiator
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The invention relates to the technical field of optical radiation free radical polymerization novel materials, in particular to a novel compound of oxime ester and an aromatic ketone photo polymerization initiator, wherein the structural formula of the novel compound is shown as (I). The compound has excellent and practical dissolution performance and high light sensitivity, can be used as a photo initiator independently in the filed of the optical radiation free radical polymerization novel materials in an olefin-containing unsaturated compound system, and can also be used as one of the photo initiators in the photo polymerization of an olefinic unsaturated compound mixture or an olefin-containing unsaturated compound mixture.
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Paragraph 0090
(2017/05/02)
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- Synthesis and Characterization of Diketopyrrolopyrrole-based D-π-A-π-D Small Molecules for Organic Solar Cell Applications
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Four new small molecules – CTDP, BCTDP, CFDP, and BCFDP having D-π-A-π-D molecular architecture, possessing carbazole and benzocarbazole as electron donors, diketopyrrolopyrrole core as acceptor and thiophene/furan acting as spacer/bridge between donor (carbazole and benzocarbazole) and acceptor (diketopyrrolopyrrole) units are synthesized. All the four compounds exhibited absorption in the range of 300 to 700 nm, and, in particular, more intense absorption found in the 500 to 660 nm region. The estimated band gaps are found to be 1.92 eV for CTDP, 1.92 eV for BCTDP, 1.94 eV for CFDP, and 1.92 eV for BCFDP from their intersection point of absorption and emission spectra. The electrochemical studies revealed that the highest occupied molecular orbital/lowest unoccupied molecular orbital energy levels of all the four compounds, CTDP (?5.03/?3.65 eV), BCTDP (?5.03/?3.65 eV), CFDP (?4.94/?3.65 eV), and BCFDP (?4.90/?3.62 eV) are well matched with PCBM and expected to be act as donor materials in small molecule bulk hetero junction organic solar cells. All the compounds are thermally stable up to 382–416°C.
- Sivakumar, Gangala,Sasikumar, Mayarambakam,Rao, Vaidya Jayathirtha
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p. 1983 - 1994
(2017/05/29)
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- Discovery of novel nitroimidazole enols as Pseudomonas aeruginosa DNA cleavage agents
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A series of nitroimidazole enols as new bacterial DNA-targeting agents were for the first time designed, synthesized and characterized by NMR, IR and HRMS spectra. The antimicrobial screening revealed that 2-methoxyphenyl nitroimidazole enol 3i possessed stronger anti-P. aeruginosa efficacy (MIC = 0.10 μmol/mL) than reference drugs Norfloxacin and Metronidazole. Time-kill kinetic assay manifested that the active molecule 3i could rapidly kill the tested strains. Molecular docking indicated that the interactions between compound 3i and topoisomerase II were driven by hydrogen bonds. Quantum chemical study was also performed on 3i to understand the structural features essential for activity. Further research found that compound 3i was not able to effectively intercalate into bacterial DNA but could cleave DNA isolated from the standard P. aeruginosa strain, which might block DNA replication to exert the efficient bioactivities, and this active molecule was also able to be stored and carried by human serum albumin via hydrophobic interactions and hydrogen bonds.
- Li, Zhen-Zhen,Gopala, Lavanya,Tangadanchu, Vijai Kumar Reddy,Gao, Wei-Wei,Zhou, Cheng-He
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p. 6511 - 6522
(2017/11/03)
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- Cyano-contained two-photon fluorescence dye, and preparation method and application thereof
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The invention relates to a cyano-contained two-photon fluorescence dye, and a preparation method and application thereof. The cyano-contained two-photon fluorescence dye has a general molecular formula as shown in (I), wherein R represents hydrogen, alkyl, hydroxyalkyl or ether group. The preparation method comprises the steps of firstly carrying out halogenating reaction on carbazole, and introducing the R group on nitrogen to generate substituted carbazole; carrying out vilsmeier reaction on the substituted carbazole and N,N-dimethylformamide to obtain a 3,6-dicarboxy-9-ethyl carbazole intermediate; carrying out Michael addition reaction on the 3,6-dicarboxy-9-ethyl carbazole intermediate and (4-cyano benzyl) diethyl phosphite to obtain the dye. The cyano-contained two-photon fluorescence dye provided by the invention can be applied in fluorescence imaging for vital cell staining, and not only has a good two-photon fluorescence activity absorption cross section and an excellent cell membrane permeability, but also has the characteristics of high development, good photostability and low toxicity.
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Paragraph 0026; 0027
(2017/10/13)
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- Novel alkyl chain-based fluorescent probes with large Stokes shifts used for imaging the cell membrane and mitochondria in different living cell lines
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Fluorescent dyes with large Stokes shifts play a key role in developing multi-purpose fluorescent probes for a wide variety of targets. In this study, we developed two novel alkyl chain-based fluorescent probes (CA-C12 and CA-C2) with large Stokes shifts. The alkyl chain length of the probes affect the membrane permeability, and hence both probes can be successfully applied for sensing the cell membrane and mitochondria in different living cell lines. Furthermore, the probes CA-C12 and CA-C2 exhibited large Stokes shifts and excellent photostability in the different cell lines. The fluorescent dyes with large Stokes shifts were expected to have broader applications for developing various fluorescent probes with excellent optical properties.
- Meng, Fangfang,Liu, Yong,Niu, Jie,Lin, Weiying
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p. 16087 - 16091
(2017/03/22)
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- p-TsOH-mediated, Versatile, and Efficient Approach for the Synthesis of Triazolyl-Carbazoles from Nitrovinylcarbazoles and Azide via 1, 3-Dipolar Cycloaddition
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An efficient method for the synthesis of N-alkylated 3-(1-benzyl-1H-1,2,3-triazole-4-yl)-9H-carbazoles (5, 6, 7, 8, 9, 10) and 9-ethyl-3,6-di(1H-1,2,3-triazole-4-yl)-9H-carbazole (13) has been developed from nitroolefines. The effects of catalyst and solvent on these reactions have been investigated. p-TsOH-THF was found to be the best system for this reaction. Various triazolyl-carbazoles were prepared in good to excellent yields.
- Avula, Vijay Kumar Reddy,Vallela, Swetha,Anireddy, Jaya Shree,Chamarthi, Naga Raju
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p. 1361 - 1368
(2017/03/27)
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- A Green Synthesis of 2-Amino-4-(9H-carbazole-3-yl)thiophene-3-carbonitriles by a Step-wise and One-pot Three-component Gewald Reaction
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An eco-friendly method has been developed for the synthesis of 2-amino-4-(9H-carbazole-3-yl)thiophene-3-carbonitriles from preliminary carbazole (1) through an intermediate of 2-(1-(9H-carbazole-3-yl)ethylidene)malononitriles using the Knoevenagel condensation followed by the Gewald reaction. On the other hand, the target compounds could also be prepared in a one-pot three-component manner by treating equimolar quantities of 1-(9H-carbazole-3-yl)ethanone (3), malononitrile, and elemental sulfur. The merits of this preparation are mild reaction conditions. The Gewald reaction is executed with inorganic base NaHCO3 (H2O) in tetrahydrofuran, easy work-up procedure with good yields.
- Avula, Vijay Kumar Reddy,Vallela, Swetha,Anireddy, Jaya Shree,Chamarthi, Naga Raju
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p. 2471 - 2482
(2017/07/25)
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- Use for RL intermediate condensation product synthesis process (by machine translation)
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The present invention discloses a use for RL intermediate condensation product synthesis process, the process comprises the steps of: carbazole alkylation N - ethyl carbazole made, by nitration, reduction to generate a 3 - amino - N - ethyl carbazole, then in the organic solvent in the condensation reaction, use for intermediate condensate obtained RL; in this invention the condensation reaction using an alcohol as a solvent to replace the traditional O-chlorobenzene, improves the 3 - amino - N - ethyl carbazole conversion rate, and improves the use for RL crude purity and yield, and the process is stable, simple operation, high safety factor. (by machine translation)
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Paragraph 0017
(2017/08/29)
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