- Synthesis, structure and metal compounds of a novel chromophoric cyanamide ligand
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The novel compound 2-cyanaminofluoren-9-one (HL) has been synthesized, and is readily deprotonated to form the corresponding cyanamide anion L-. This has been isolated as the Tl+L- and AsPh4+L- salts. The UV/visible spectra of HL and AsPh4+L- show the same amine to carbonyl charge transfer transition seen in other aminofluorenones, although at longer wavelengths. The compound AsPh4+L- undergoes the reversible one electron reduction typical of fluorenones, whilst HL undergoes an irreversible reduction. The crystal structure of AsPh4+L- was determined and related to the solvatochromic behaviour of the L- anion. Some simple EHMO calculations have been carried out on the L- anion of AsPh4+L-, which show the cyanamide based HOMO and carbonyl based LUMO involved in the aforementioned CT transition. The thallium salt Tl+L- has also been used as a transmetallating agent in reaction with trimethyltin chloride to produce the corresponding tin cyanamide complex [SnMe3L], and in reaction with (triphenylphosphine)gold chloride to produce the first reported gold cyanamide compound [AuL(PPh3)], whose crystal structure has been determined.
- Adams, Christopher J.
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- Palladated composite of Cu-BDC MOF and perlite as an efficient catalyst for hydrogenation of nitroarenes
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A novel composite of metal-organic framework and perlite is prepared through hydrothermal treatment of terephthalic acid and Cu(NO3)2·3H2O in the presence of perlite. The resulting composite was then utilized as a support for the immobilization of Pd nanoparticles. The obtained compound was characterized via XRD, TGA, ICP, FTIR, TEM, FE-SEM/EDS and elemental mapping analysis and applied as a catalyst for the hydrogenation of nitroarenes under mild reaction condition. The results approved that the catalyst could efficiently promote hydrogenation of various nitroarenes with different electronic densities and steric properties. Moreover, the catalyst showed high selectivity towards hydrogenation of nitro groups. Hot filtration test affirmed heterogeneous nature of catalysis. Furthermore, the present catalytic composite was highly recyclable with low Pd leaching. A comparative study also approved superior activity of the composite compared to palladated perlite and metal-organic framework.
- Koohestani, Fatemeh,Sadjadi, Samahe
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- Efficient hydrogenation catalyst designing via preferential adsorption sites construction towards active copper
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Based on the experimental and DFT calculation results, here for the first time we built preferential adsorption sites for nitroarenes by modification of the supported Cu catalysts surface with 1,10-phenathroline (1,10-phen), by which the yield of aniline via reduction of nitroarene is enhanced three times. Moreover, a macromolecular layer was in-situ generated on supported Cu catalysts to form a stable macromolecule modified supported Cu catalyst, i.e., CuAlOx-M. By applying the CuAlOx-M, a wide variety of nitroarene substrates react smoothly to afford the desired products in up to > 99% yield with > 99% selectivity. The method tolerates a variety of functional groups, including halides, ketone, amide, and C = C bond moieties. The excellent catalytic performance of the CuAlOx-M can be attributed to that the 1,10-phen modification benefits the preferential adsorption of nitrobenzene and slightly weakens adsorption of aniline on the supported nano-Cu surface.
- Dai, Xingchao,He, Dongcheng,Li, Teng,Shi, Feng,Wang, Hongli,Wang, Tao,Wang, Xinzhi
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p. 397 - 406
(2021/07/21)
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- Amphiphilic ligands for Cu-catalyzed aerobic oxidation to synthesize 9-fluorenones in water
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A series of amphiphilic PEG-functionalized nitrogen ligands were developed for the highly efficient copper-catalyzed aerobic oxidation of 9-fluorenes, with molecular oxygen as the sole oxidant in neat water. A broad range of functional groups are well tolerated and thus offer the opportunity for further functionalization.
- Li, Longjia,Liu, Zibo,Tang, Shanyu,Li, Jiao,Ren, Xuanhe,Yang, Guanyu,Li, Heng,Yuan, Bingxin
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- Method for synthesizing fluorenone ketone compound through molecular oxygen oxidation in water phase
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Aiming at the technical problems that in the prior art a method for synthesizing a fluorenone ketone compound has organic solvent pollution and byproducts can be generated, the invention provides a method for synthesizing a fluorenone ketone compound through molecular oxygen oxidation in a water phase. The method comprises the following steps: by taking a fluorenone compound as a substrate, dispersing into an alkali solution, and at 40-120 DEG C, in the presence of oxygen, and with a water-soluble transition metal compound as a catalyst, stirring to carry out reactions, thereby obtaining the fluorenone ketone compound. By adopting the method, molecular oxygen is adopted as an oxidant, and water is adopted as a solvent, so that an organic solvent is avoided, and the problem that multiple byproducts are generated because of peroxidation can be avoided.
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Paragraph 0067; 0069
(2019/08/20)
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- Hydrogenation of Functionalized Nitroarenes Catalyzed by Single-Phase Pyrite FeS2 Nanoparticles on N,S-Codoped Porous Carbon
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Catalytic hydrogenation of nitroarenes is an industrially very important and environmentally friendly process for the production of anilines; however, highly chemoselective reduction of nitroarenes decorated with one or more reducible groups in a nitroarene molecule remains a challenge. Herein, a novel hybrid non-noble iron-based nanocatalyst (named as FeS2/NSC) was developed, which was prepared from biomass as C and N source together with inexpensive Fe(NO3)3 as Fe source through high-temperature pyrolysis in a straightforward and cost-effective procedure. Comprehensive characterization revealed that single-phase pyrite FeS2 nanoparticles with precisely defined composition and uniform size were homogeneously dispersed on N,S-codoped porous carbon with large specific surface area, hierarchical porous channels, and high pore volume. The resultant catalyst FeS2/NSC demonstrated good catalytic activity for hydrogenation of functionalized nitroarenes with good tolerance of various functional groups in water as a sustainable and green solvent. Compared with bulk pyrite FeS2 and other non-noble metal-based heterogeneous catalysts reported in the literature, a remarkably enhanced activity was observed under mild reaction conditions. More importantly, FeS2/NSC displayed exclusive chemoselectivity for the reduction of nitro groups for nitroarenes bearing varying readily reducible groups.
- Duan, Yanan,Dong, Xiaosu,Song, Tao,Wang, Zhaozhan,Xiao, Jianliang,Yuan, Youzhu,Yang, Yong
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- Transition-metal-free C(sp3)–H oxidation of diarylmethanes
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An efficient direct C(sp3)–H oxidation of diarylmethanes has been demonstrated by this study. This method employs environment-friendly O2 as an oxidant and is promoted by commercially available MN(SiMe3)2 [M = K, Na or Li], which provides a facile method for the synthesis of various diaryl ketones in excellent yields. This protocol is metal-free, mild and compatible with a number of functional groups on substrates.
- Yang, Fan,Zhou, Bihui,Chen, Pu,Zou, Dong,Luo, Qiannan,Ren, Wenzhe,Li, Linlin,Fan, Limei,Li, Jie
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- With Wnt signal path to inhibit the active heterocyclic compounds (by machine translation)
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The invention relates to a signal path with Wnt inhibiting activity of a heterocyclic compound, including the compound and its pharmaceutically acceptable salt, various isotope, various isomers or various crystal structure, having the general formula I of the structure shown in: the invention relates to a compound and its joint application composition can effectively inhibit the Wnt signal path, can be used for the treatment or prevention of a disorder associated with a Wnt signal path. (by machine translation)
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- Improved synthetic method of 2-amino-9-fluorenone
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The invention discloses an improved synthetic method of 2-amino-9-fluorenone. The improved synthetic method comprises the following steps: (1) adding dimethyl sulfoxide which is used as a solvent and 2-amino fluorine which is used as a solute into a reactor under an alkaline condition, and adding an oxidizing agent; (2) stirring for 1 hour to 5 days under a room temperature; (3) fractionally filtering, thus obtaining a brown solid 2-amino-9-fluorenone product. According to the improved synthetic method disclosed by the invention, the technical scheme is simple and economic, raw materials are easy to obtain, the preparation time is short, the yield is up to 98 percent, the content of byproducts is smaller than or equal to 2 percent, the improved synthetic method is particularly suitable for a pilot scale test and a large scale production of the 2-amino-9-fluorenone, and a good industrial application prospect is obtained.
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Paragraph 0037; 0044; 0045
(2017/10/07)
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- NHC-Catalyzed Benzylic Csp3–H Bond Activation of Alkylarenes and N-Benzylamines for the Synthesis of 3H-Quinazolin-4-ones: Experimental and Theoretical Study
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An N-heterocyclic carbene catalyzed benzylic Csp3–H bond activation of alkylarenes and N-benzylamines under metal-free conditions was developed. This organocatalyzed oxidative transformation afforded the corresponding carbonyl derivatives in good to excellent yields. A variety of alkylarenes and N-benzylamines were tolerated under the optimized reaction conditions. The established method was further extended to the synthesis of biologically important 3H-quinazolin-4-ones in good yields. For example, NPS 53574, a potent calcium receptor antagonist, was successfully synthesized by using this oxidative protocol. DFT studies show that the benzylic C–H bond activation proceeds through the nucleophilic attack of the free carbene on the benzylic carbon atom.
- Alanthadka, Anitha,Devi, E. Sankari,Nagarajan, Subbiah,Sridharan, Vellaisamy,Suvitha, Ambigapathy,Maheswari, C. Uma
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supporting information
p. 4872 - 4880
(2016/10/13)
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- Chemoselective hydrogenation of functionalized nitroarenes using MOF-derived co-based catalysts
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The synthesis, characterization, and application of nitrogen-doped carbon supported Co catalysts in selective hydrogenation of nitroarenes are described. The cobalt-based catalysts are prepared by simple pyrolysis of ZIF-67, a typical MOF material, under inert atmosphere. Physicochemical properties of the Co/C-N catalysts have been investigated by X-ray diffraction, elemental analysis, atomic absorption spectroscopy, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The Co-based materials were found to be highly efficient in the chemoselective hydrogenation of nitroarenes. A broad range of substituted nitroarenes are converted to the corresponding anilines in excellent yields under industrially viable conditions with other reducing groups remaining intact. In situ ATR-IR and XPS characterizations reveal that the Co-N centers present in the catalyst favor the preferential adsorption of nitro groups, leading to this unique chemoselectivity. The kinetic parameters of 4-nitrostyrene hydrogenation over the Co/C-N catalyst were investigated.
- Wang, Xi,Li, Yingwei
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- Highly selective transfer hydrogenation of functionalised nitroarenes using cobalt-based nanocatalysts
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Anilines are important feedstock for the synthesis of a variety of chemicals such as dyes, pigments, pharmaceuticals and agrochemicals. The chemoselective catalytic reduction of nitro compounds represents the most important and prevalent process for the manufacture of functionalized anilines. Consequently, the development of selective catalysts for the reduction of nitro compounds in the presence of other reducible groups is a major challenge and is crucial. In this regard, herein we show that the cobalt oxide (Co3O4-NGr@C) based nano-materials, prepared by the pyrolysis of cobalt-phenanthroline complexes on carbon constitute highly selective catalysts for the transfer hydrogenation of nitroarenes to anilines using formic acid as a hydrogen source. Applying these catalysts, a series of structurally diverse and functionalized nitroarenes have been reduced to anilines with unprecedented chemo-selectivity tolerating halides, olefins, aldehyde, ketone, ester, amide and nitrile functionalities.
- Jagadeesh, Rajenahally V.,Banerjee, Debasis,Arockiam, Percia Beatrice,Junge, Henrik,Junge, Kathrin,Pohl, Marga-Martina,Radnik, J?rg,Brückner, Angelika,Beller, Matthias
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supporting information
p. 898 - 902
(2015/03/04)
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- Photochromism of dihydroindolizines: Part XIV. Synthesis and photophysical behavior of photochromic dihydroindolizine-tripodal linkers toward anchoring sensitizers to semiconductor nanoparticles
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Photochromic dihydroindolizines (DHIs) 4a,5-dihydropyrrolo[1,2-b]pyridazine based tripodal-linker systems with adamantane core and ethyl benzoate tripods as anchoring groups have been successfully synthesized. In addition, new spirocyclopropene precursors have been prepared through both chemical and photochemical processes. The photochromic properties of the newly synthesized DHIs derivatives have been optimized and fine-tuned by the incorporation of various substituents on the fluorene (region A) and pyridazine (region C) moieties. Several alternative routes for the synthesis of the DHIs under investigation have been established. The Sonogashira crosscoupling reaction was utilized for fragment coupling between DHIs and the phenylacetylene tether of the adamantane core. Several reaction conditions of this key reaction were surveyed to obtain optimal yields of a new series of coupling products targeted for anchoring to semiconductor nanoparticles. The chemical structures of the newly synthesized materials were elucidated by both analytical and spectroscopic tools. Irradiation of the photochromic DHIs with polychromatic light resulted in ring opened colored betaines which underwent cycloreversion reactions via thermal 1,5-electrocyclization processes. The kinetic of the thermal 1,5-electrocyclization was studied by using a UV/VIS/NIR spectrophotometer. The kinetic measurements showed the half-lives of the colored betaines to be in the second domain. A pronounced increase in the half-lives of betaines bearing dimethyl-substituted pyridazine was noted compared with non-substituted pyridazine betaines. A strong effect of solvent polarity on the λmax and half-lives of the betaines was observed. The further adjustment of the absorption maxima and the kinetic properties via the manipulation of substituents on the fluorene (region A) and pyridazine moieties (region C) should yield more refined systems for application as supports onto metal-oxide surfaces which remains an active area of our ongoing research. Copyright
- Ahmed, Saleh Abdel-Mgeed,Al-Raqa, Shaya Y.
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scheme or table
p. 173 - 184
(2011/10/02)
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- Facile synthesis of biologically active heterocycles by indium-induced reactions of aromatic nitro compounds in aqueous ethanol
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Indium/ammonium chloride-induced reduction of aromatic nitro compounds to aromatic amines in aqueous ethanol was developed. Useful chemoselectivity was observed in the reduction reaction. This method was extended to reductive cyclization and rearrangement toward the synthesis of various biologically active heterocycles, including quinoline, oxazines, quinalonones, and phenanthridine in excellent yield. The oxophilicity of indium metal influenced the reaction in aqueous ethanol. Metals like zinc and tin were not effective in promoting this kind of reactions under the present environmentally friendly conditions.
- Banik, Bimal K.,Banik, Indrani,Samajdar, Susanta,Wilson, Mary
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p. 283 - 296
(2007/10/03)
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- Reductions of nitro and 9-oxo groups of environmental nitrofluorenes by the rat mammary gland in vitro
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Nitrofluorenes and C-9-oxidized nitrofluorenes are widespread environmental genotoxins which may be relevant for breast cancer on the basis of their carcinogenicities, particularly of 2,7-dinitrofluorene (2,7-diNF), for the rat mammary gland. Since their metabolism to active carcinogens may involve nitroreduction, this study examined the reduction of 2-nitrofluorene (2-NF) and 2,7-diNF and their 9-oxo- and 9-hydroxy (OH) derivatives by the rat mammary gland. Cytosolic fractions catalyze NADH- and NADPH-dependent reductions of the 2-nitro and 9-oxo to the respective 2-amino and 9-OH compounds at rates 4- and ≥10-fold greater than those with microsomes. Rates of amine formation catalyzed by cytosol from 2,7-diNF are greater than the rate from 2-NF and increase for C-9-oxidized derivatives: 9-oxo-2-NF >> 9-OH-2-NF > 2-NF and 9-OH-2,7-diNF 9-oxo-2,7-diNF >> 2,7-diNF. Nitroreduction is inhibited by O2 or allopurinol (20 μM), dicoumarol (100 μM), and rutin (50 μM). 9-Oxoreduction is inhibited by rutin, dicoumarol, and indomethacin (100 μM), but not by O2 or allopurinol. Pyrazole or menadione does not inhibit nitro or 9-oxoreduction. Xanthine, hypoxanthine, 2-hydroxypyrimidine, and N'-methylnicotinamide support cytosol-catalyzed nitro, but not 9-oxo, reduction. The data suggest that the nitroreduction is catalyzed largely by a xanthine oxidase and partially by a diaphorase and 9-oxoreduction by a carbonyl reductase. The extents of the nitro and carbonyl reductions of the nitrofluorenes may determine their reactivities with DNA, and thus genotoxicities for the mammary gland.
- Ritter,Decker,Malejka-Giganti
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p. 793 - 800
(2007/10/03)
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- Indium/ammonium chloride mediated selective reduction of aromatic nitro compounds: Practical synthesis of 6-aminochrysene
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Reduction of aromatic and heteroaromatic nitro compounds to the corresponding amino compounds was achieved by indium/ammonium chloride induced reaction in aqueous ethanol. This method was extended for the preparation of large quantities of 6-aminochrysene in excellent yield.
- Banik,Suhendra,Banik,Becker
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p. 3745 - 3754
(2007/10/03)
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- Nitroreduction of nitrated and C-9 oxidized fluorenes in vitro
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Widespread environmental pollution with mutagenic and carcinogenic nitrofluorenes contributes to human health risks. Since nitroreduction leads to activation of many nitro compounds, nitroreduction of the nitrofluorene (NF) derivatives by one- and two-electron reductants was examined. Rates of nitroreduction catalyzed by xanthine oxidase (XO)/hypoxanthine and measured via stimulation of acetylated cytochrome c reduction increased with the number of nitro groups and oxidation at C-9: 9-oxo-2,4,7-triNF > 9-oxo-2,7- diNF > 2,7-diNF > 9-oxo-2-NF = 2,5-diNF > 9-hydroxy-2-NF > 2-NF. Ascorbate catalyzed one-electron reduction to nitro anion radicals which reacted with molecular O2 to yield superoxide. Rates of O2 uptake with 9-oxo-2,4,7- triNF and 9-oxo-2,7-diNF were 63 and 0.17 times those, respectively, with equivalent concentrations of nitrofurazone, a classical substrate. Superoxide formation was indicated by the ~75% regeneration of O2 upon addition of superoxide dismutase and catalase. 9-Oxo-2,4,7-triNF stimulated O2 uptake in the presence of XO/NADH with typical Michaelis-Menten kinetics with an apparent K(m) of 0.476 ± 0.054 μM versus a K(m) of 6.18 ± 0.719 μM for nitrofurazone. HPLC analyses of products from reduction catalyzed by XO or diaphorase of Clostridium with NADH showed the following trends for the rates of amine formation from 9-oxo-2,7-diNF > 2,7-diNF; 9-oxo-2-NF > 9-hydroxy-2- NF > 2-NF; 2,7-diNF > 2-NF; and 9-oxo-2,7-diNF > 9-oxo-2-NF. Little or no amine was formed in 95% O2, suggesting O2-labile intermediates. The data herein suggest that oxidation at C-9 and multiple nitro groups increase the potential for nitroreduction of the nitrofluorenes in vivo which may lead to genotoxic effects.
- Ritter, Clare L.,Malejka-Giganti, Danuta
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p. 1361 - 1367
(2007/10/03)
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- Process for the preparation of fluoroaromatic and fluoroheteroaromatic compounds
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Good yields of a range of fluoroaromatic and fluoroheteroaromatic compounds may be obtained by reacting an aromatic or a heteroaromatic amine with a nitrosyl polyfluoro salt in an inert solvent to form an intermediate aryl or heteroaryl diazonium polyfluoro salt and decomposing this aryl or heteroaryl diazonium polyfluoro salt in situ. The process described is especially suitable for the preparation in good yield of fluoroaromatic and fluoroheteroaromatic compounds with ortho substituents.
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