- Iron-catalyzed domino decarboxylation-oxidation of α,β-unsaturated carboxylic acids enabled aldehyde C-H methylation
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A practical and general iron-catalyzed domino decarboxylation-oxidation of α,β-unsaturated carboxylic acids enabling aldehyde C-H methylation for the synthesis of methyl ketones has been developed. This mild, operationally simple method uses ambient air as the sole oxidant and tolerates sensitive functional groups for the late-stage functionalization of complex natural-product-derived and polyfunctionalized molecules.
- Gong, Pei-Xue,Xu, Fangning,Cheng, Lu,Gong, Xu,Zhang, Jie,Gu, Wei-Jin,Han, Wei
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supporting information
p. 5905 - 5908
(2021/06/18)
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- Reusable, magnetic Raney nickel based palladium catalysts for the Heck coupling in aqueous media
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Hybrid materials based on Pd- and Cu-doped Raney nickel appeared to be highly efficient catalysts for the Heck reaction in aqueous media in the absence of organic cosolvents. The catalysts can be easily removed by an external magnet and reused without losing catalytic activity.
- Bumagin, N. A.
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p. 2034 - 2040
(2021/11/05)
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- Triptycene carbene palladium compound and application thereof
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The invention discloses a triptycene carbene palladium compound and an application thereof, the structural formula of the triptycene carbene palladium compound is represented by a formula I or a formula II; compared with a conventional metal palladium catalyst, the triptycene carbene palladium compound is simple and convenient to prepare, high in yield and suitable for various substrates, the usage amount of the catalyst can be reduced to one ten thousandth, and the triptycene carbene palladium compound has a good catalytic effect on various metal palladium catalytic reactions; and the triptycene carbene palladium compound has important application value for researching the progress and application of catalytic reaction.
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Paragraph 0092-0099
(2021/05/08)
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- Triptycene carbene allyl palladium compound and application thereof
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The invention relates to a triptycene carbene allyl palladium compound and application thereof. The structural formula of the triptycene carbene allyl palladium compound is a formula I or a fotmula II. Compared with a conventional metal palladium catalyst, the triptycene carbene allyl palladium compound is easy and convenient to prepare, high in yield and suitable for various substrates, the use amount of a catalyst can be reduced to one ten thousandth, and the compound has a good catalytic effect on various metal palladium catalytic reactions. The compound has important application value for researching the progress and application of catalytic reaction.
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Paragraph 0054-0061
(2021/06/02)
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- Triptycene carbene palladium pyridine complex and application thereof
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The invention relates to a triptycene carbene palladium pyridine complex and application thereof. The structural formula of the triptycene carbene palladium pyridine complex is shown as a formula I. The complex provided by the invention is correct in detection. Based on the defects that a metal catalyst used for organic reaction at the present stage cannot be suitable for various substrates, the catalyst in use amount and cost and is difficult to preserve for a long time, the invention provides the triptycene carbene palladium pyridine complex used as a catalyst, wherein the preparation is simple and convenient, the yield is high, the triptycene carbene palladium pyridine complex is suitable for various substrates, the usage amount of the catalyst can be reduced to one ten thousandth, and the triptycene carbene palladium pyridine complex has a better catalytic effect on various metal palladium catalytic reactions. The triptycene carbene palladium pyridine complex has important application value for researching the progress and application of catalytic reaction.
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Paragraph 0052-0058
(2021/06/12)
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- Triptycene carbene tridentate metal coordination compound and application thereof
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The invention relates to a triptycene carbene tridentate metal coordination compound, wherein the structural formula of the triptycene carbene tridentate metal coordination compound is shown in the specification. According to the invention, the compound is correct in detection; based on the problems that a metal catalyst used in an organic reaction at the present stage cannot be suitable for various substrates, the catalyst content is high, the cost is high, long-time storage is difficult, and the like, the triptycene carbene tridentate metal coordination compound provided by the invention is used as a catalyst, the preparation is simple and convenient, the yield is high, the triptycene carbene tridentate metal coordination compound is suitable for various substrates, the usage amount of the catalyst can be reduced to one ten thousandth, and the triptycene carbene tridentate metal coordination compound has a better catalytic effect on various metal catalytic reactions, and has important application value for researching the progress and application of catalytic reaction.
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Paragraph 0059-0067
(2021/06/22)
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- Oxime-derived palladacycle Immobilized in an Ionic Liquid Brush as an Efficient and Reusable Catalyst for Mozoroki-Heck Reaction in Neat Water
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An efficient and reusable heterogeneous catalyst with oxime-derived palladacycle immobilized in an ionic liquid brush has been synthesized and an environmentally-friendly procedure have been developed for coupling aryl iodides and bromides with acrylic acid. These reactions were conducted in neat water under aerobic conditions with water-insoluble or even solid aryl halides and they proceeded smoothly and cleanly without any organic co-solvent or other additives. The ionic liquid brush could be easily recovered and reused at least five times without significant loss of activity. The protocol has the advantages of excellent yields, environmental friendliness, and catalyst recyclability.
- Wang, Rong,Li, Shan,Li, Jing,Wei, Junfa
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- Transition-metal-free C-P bond formation via decarboxylative phosphorylation of cinnamic acids with P(O)H compounds
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A novel, transition-metal-free phosphorylation of cinnamic acids with P(O)H compounds has been developed via radical-promoted decarboxylation under mild conditions. This method provides simple, efficient, and versatile access to valuable (E)-alkenylphosphine oxides in satisfactory yields with a wide variety of substrates.
- Liu, Lixin,Zhou, Dan,Dong, Jianyu,Zhou, Yongbo,Yin, Shuang-Feng,Han, Li-Biao
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p. 4190 - 4196
(2018/04/14)
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- Noble metal-free catalytic decarboxylation of oleic acid to n-heptadecane on nickel-based metal-organic frameworks (MOFs)
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Nickel based metal organic frameworks (Ni-MOFs) were successfully synthesized using new conjugated carboxylic acid linkers. These conjugated carboxylic acid linkers were synthesized using mild Heck coupling that led to the incorporation of functional groups not possible by traditional synthetic methods. Control of linker size allows for porosity tuning of the crystalline network and high surface area, that, in theory, results in the increased accessibility to Ni metal centers for catalysis. The resultant crystalline Ni-MOFs displayed BET areas as high as ~314 m2 g-1. To investigate their catalytic activity for conversion of oleic acid to liquid hydrocarbons, Ni-MOFs were grown on zeolite 5A beads that served as catalytic supports. The resultant catalysts displayed heptadecane selectivity as high as ~77% at mild reaction conditions, one of the highest yields for non-noble metal containing catalysts. The catalytic activity correlated to the concentration of acid sites. A slight decrease in catalytic activity was observed after catalysts recycling.
- Yang,McNichols,Davidson,Schweitzer,Gómez-Gualdrón,Trewyn,Sellinger,Carreon
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p. 3027 - 3035
(2017/08/01)
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- Recyclable glucose-derived palladium(0) nanoparticles as in situ-formed catalysts for cross-coupling reactions in aqueous media
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In situ-generated, glucose-derived palladium(0) nanoparticles were shown to be convenient and effective catalysts for aqueous Mizoroki-Heck, Sonogashira and Suzuki-Miyaura cross-coupling reactions. The addition of only 4-10 mol% glucose to the reaction mixture lead to a significant increase in yield of the desired products in comparison to processes that omitted the renewable sugar. Interestingly, the Mizoroki-Heck reaction was observed to proceed in good yield even as the reaction reached acidic pH levels. Extensive analysis of the size and morphology of the in situ-formed palladium nanoparticles using advanced analytical techniques showed that the zero valent metal was surrounded by hydrophilic hydroxyl groups. The increased aqueous phase affinity afforded by these groups allowed for facile recycling of the catalyst.
- Camp, Jason E.,Dunsford, Jay J.,Dacosta, Oliver S. G.,Blundell, Rebecca K.,Adams, James,Britton, Joshua,Smith, Robert J.,Bousfield, Thomas W.,Fay, Michael W.
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p. 16115 - 16121
(2016/02/20)
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- A highly active nickel-fibre complex as a catalyst for the Heck reaction
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A new amidoxime fibre-nickel catalyst (AOFs-Ni(0)) was synthesised by a coordination and reduction reaction. The X-ray diffraction patterns indicated that the Ni(II) ions were reduced to Ni(0). The scanning electron microscope image showed that the Ni(0) particles which were reduced in situ had a diameter of about 300 nm. This catalyst demonstrated high activity in the Heck coupling reaction of aryl iodine and conjugated alkenes without the protection of an inert atmosphere.
- Wu, Zhi-Chuan,Yang, Quan,Chen, Meng,Liu, Li,Tao, Ting-Xian
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p. 164 - 166
(2016/04/20)
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- Unravelling the structural and molecular basis responsible for the anti-biofilm activity of zosteric acid
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The natural compound zosteric acid, or p-(sulfoxy)cinnamic acid (ZA), is proposed as an alternative biocide-free agent suitable for preventive or integrative anti-biofilm approaches. Despite its potential, the lack of information concerning the structural and molecular mechanism of action involved in its anti-biofilm activity has limited efforts to generate more potent anti-biofilm strategies. In this study a 43-member library of small molecules based on ZA scaffold diversity was designed and screened against Escherichia coli to understand the structural requirements necessary for biofilm inhibition at sub-lethal concentrations. Considerations concerning the relationship between structure and anti-biofilm activity revealed that i) the para-sulfoxy ester group is not needed to exploit the anti-biofilm activity of the molecule, it is the cinnamic acid scaffold that is responsible for anti-biofilm performance; ii) the anti-biofilm activity of ZA derivatives depends on the presence of a carboxylate anion and, consequently, on its hydrogen-donating ability; iii) the conjugated aromatic system is instrumental to the anti-biofilm activities of ZA and its analogues. Using a protein pull-down approach, combined with mass spectrometry, the herein-defined active structure of ZA was matrix-immobilized, and was proved to interact with the E. coli NADH:quinone reductase, WrbA, suggesting a possible role of this protein in the biofilm formation process.
- Cattò, Cristina,Dell'Orto, Silvia,Villa, Federica,Villa, Stefania,Gelain, Arianna,Vitali, Alberto,Marzano, Valeria,Baroni, Sara,Forlani, Fabio,Cappitelli, Francesca
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- Magnetic polymer nanocomposite-supported Pd: An efficient and reusable catalyst for the Heck and Suzuki reactions in water
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A novel type of magnetically responsive polymer nanocomposite Fe3O4@poly(undecylenic acid-co-4-vinyl pyridine-co-sodium acrylate) (Fe3O4@PUVS) was synthesized by the free radical polymerization of 4-vinyl pyridine (4-VP) with sodium acrylate (SAA) and Fe3O4@undecylenic acid. Pd2+ was then immobilized on this magnetic nanocomposite to form the magnetic Fe3O4@PUVS-Pd catalyst. This catalyst exhibited excellent catalytic activity for the Heck and Suzuki coupling reactions in water, and could be simply separated by using a permanent magnet. The supported catalyst could be used consecutively for six runs without significant loss of catalytic activity.
- Wang, Dongfang,Liu, Wendong,Bian, Fengling,Yu, Wei
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p. 2052 - 2059
(2015/03/18)
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- Oxidative cleavage of olefins by in situ-generated catalytic 3,4,5,6-tetramethyl-2-iodoxybenzoic acid/oxone
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Oxidative cleavage of a variety of olefins to the corresponding ketones/carboxylic acids is shown to occur in a facile manner with 3,4,5,6-tetramethyl-2-iodobenzoic acid (TetMe-IA)/oxone. The simple methodology involves mere stirring of the olefin and catalytic amount (10 mol %) of TetMe-IA and oxone in acetonitrile-water mixture (1:1, v/v) at rt. The reaction mechanism involves initial dihydroxylation of the olefin with oxone, oxidative cleavage by the in situ-generated 3,4,5,6-tetramethyl-2-iodoxybenzoic acid (TetMe-IBX), and oxidation of the aldehyde functionality to the corresponding acid with oxone. Differences in the reactivities of electron-rich and electron-poor double bonds have been exploited to demonstrate chemoselective oxidative cleavage in substrates containing two double bonds.
- Moorthy, Jarugu Narasimha,Parida, Keshaba Nanda
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p. 11431 - 11439
(2015/02/05)
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- Transition-metal-free and chemoselective NaOtBu-O 2-mediated oxidative cleavage reactions of vic-1,2-diols to carboxylic acids and mechanistic insight into the reaction pathways
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A method for efficient oxidative cleavage of vic-1,2-diols using a NaO tBu-O2 system resulted in the formation of carboxylic acids in high yields. The present protocol is an eco-friendly alternative to a conventional transition-metal-based method. This new strategy allows large-scale production with nonchromatographic purification while also suppressing competitive reaction pathway such as benzilic acid rearrangement.
- Kim, Sun Min,Kim, Dong Wan,Yang, Jung Woon
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p. 2876 - 2879
(2014/06/23)
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- A luminescent dye@MOF platform: Emission fingerprint relationships of volatile organic molecules
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Self-assembly of luminescent moieties into porous metal-organic frameworks (MOFs) has generated many luminescent platforms for probing volatile organic molecules (VOMs). However, most of those explored thus far have only been based on the luminescence intensity of one transition, which is not efficient for probing different VOMs. We have synthesized a luminescent MOF material containing 1D nanotube channels, and further developed a luminescent dye@MOF platform to realize the probing of different VOMs by tuning the energy transfer efficiency between two different emissions. The dye@MOF platform exhibits excellent fingerprint correlation between the VOM and the emission peak-height ratio of ligand to dye moieties. The dye@MOF sensor is self-calibrating, stable, and instantaneous, thus the approach should be a very promising strategy to develop luminescent materials with unprecedented practical applications. Got the glow: A 3D coordination network with large hexagonal nanotube channels based on 1D infinite rod-shaped metal-carboxylate chains is reported. This material can absorb Rhodamine B dye into its pores to form a luminescent platform for visually probing different small molecules. Copyright
- Dong, Ming-Jie,Zhao, Min,Ou, Sha,Zou, Chao,Wu, Chuan-De
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p. 1575 - 1579
(2014/03/21)
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- Synthesis of Am80 (tamibarotene) prodrug candidates, congeners and metabolites
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Compound 1 (IT-M-07000) was previously reported as a candidate prodrug of Am80 (Tamibarotene; used to treat acute promyelocytic leukemia), and shown to be efficiently metabolized to Am80 via β-oxidation. Here, we describe in detail the synthesis of 1, together with another tetradeuterated candidate prodrug, IT-YA-00616 (2), as well as two congeners, and several metabolic intermediates of 1 previously detected in mouse plasma.
- Muratake, Hideaki,Amano, Yohei,Toda, Takahiro,Sugiyama, Kiyoshi,Shudo
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p. 846 - 852
(2013/09/12)
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- Palladium supported on a magnetic microgel: An efficient and recyclable catalyst for Suzuki and Heck reactions in water
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A novel heterogeneous Pd catalyst was synthesized by anchoring palladium(ii) onto poly(undecylenic acid-co-N-isopropylacrylamide-co-potassium 4-acryloxyoylpyridine-2,6-dicarboxylate)-coated Fe3O4 (Fe3O4@PUNP) magnetic microgel. The catalyst (Fe 3O4@PUNP-Pd) was characterized by FT-IR, TEM, VSM, XRD and XPS, and the loading level of Pd in Fe3O4@PUNP-Pd catalyst was measured to be 0.330 mmol g-1 by AAS. This catalyst exhibits excellent catalytic activity for the Suzuki and Heck reactions in water. In addition, the Fe3O4@PUNP-Pd catalyst can be easily separated and recovered with an external permanent magnet, and the reuse experiment shows that it can be used consecutively six times without significant loss in catalytic activity.
- Yang, Jianhua,Wang, Dongfang,Liu, Wendong,Zhang, Xi,Bian, Fengling,Yu, Wei
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p. 3429 - 3437
(2013/12/04)
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- A PdCl2-ionic liquid brush assembly: An efficient and reusable catalyst for Mizoroki-Heck reaction in neat water
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An efficient and reusable heterogeneous catalytic assembly of PdCl 2 held in ionic liquid brushes has been synthesized and an environmentally-friendly procedure was developed for coupling aryl iodides with acrylic acid. These reactions were conducted in water under aerobic conditions with water-insoluble or even solid aryl iodides and they proceeded smoothly and cleanly without any organic co-solvent or other additives. A 0.5 mol% (based on Pd atom) dose of the catalyst was found to be sufficient for Mizoroki-Heck reaction. The catalyst is easily recovered post reaction, via simple filtration, and reused at least eight times without a noticeable loss of activity. The protocol has the advantages of excellent yield, environmental friendliness, and catalyst recyclability. Copyright
- Shi, Xianying,Han, Xiaoyan,Ma, Wenjuan,Fan, Juan,Wei, Junfa
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experimental part
p. 16 - 20
(2012/03/26)
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- Control of interpenetration and gas-sorption properties of metal-organic frameworks by a simple change in ligand design
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In metal-organic framework (MOF) chemistry, interpenetration greatly affects the gas-sorption properties. However, there is a lack of a systematic study on how to control the interpenetration and whether the interpenetration enhances gas uptake capacities or not. Herein, we report an example of interpenetration that is simply controlled by the presence of a carbon-carbon double or single bond in identical organic building blocks, and provide a comparison of gas-sorption properties for these similar frameworks, which differ only in their degree of interpenetration. Noninterpenetrated (SNU-70) and doubly interpenetrated (SNU-71) cubic nets were prepared by a solvothermal reaction of [Zn(NO3)2]·6 H2O in N,N-diethylformamide (DEF) with 4-(2-carboxyvinyl)benzoic acid and 4-(2-carboxyethyl)benzoic acid, respectively. They have almost-identical structures, but the noninterpenetrated framework has a much bigger pore size (ca. 9.0×9.0 A) than the interpenetrated framework (ca. 2.5×2.5 A). Activation of the MOFs by using supercritical CO 2 gave SNU-70' and SNU-71'. The simulation of the PXRD pattern of SNU-71' indicates the rearrangement of the interpenetrated networks on guest removal, which increases pore size. SNU-70' has a Brunauer-Emmett-Teller (BET) surface area of 5290 m2 g-1, which is the highest value reported to date for a MOF with a cubic-net structure, whereas SNU-71' has a BET surface area of 1770 m2 g-1. In general, noninterpenetrated SNU-70' exhibits much higher gas-adsorption capacities than interpenetrated SNU-71' at high pressures, regardless of the temperature. However, at P2 at 77 K and CO2 at 195 K are higher for noninterpenetrated SNU-70' than for interpenetrated SNU-71', but the capacities for H2 and CH4 are the opposite; SNU-71' has higher uptake capacities than SNU-70' due to the higher isosteric heat of gas adsorption that results from the smaller pores. In particular, SNU-70' has exceptionally high H2 and CO2 uptake capacities. By using a post-synthetic method, the C=C double bond in SNU-70 was quantitatively brominated at room temperature, and the MOF still showed very high porosity (BET surface area of 2285 m2 g -1). Copyright
- Prasad, Thazhe Kootteri,Suh, Myunghyun Paik
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supporting information; experimental part
p. 8673 - 8680
(2012/08/28)
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- In situ generation of palladium nanoparticles: Reusable, ligand-free heck reaction in PEG-400 assisted by focused microwave irradiation
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A rapid and efficient Heck coupling reaction of aryl iodides with terminal olefins was conducted in PEG-400 at 120 °C in the presence of potassium carbonate and palladium nanoparticles formed in situ from palladium chloride under focused microwave irradiation. High to excellent product yields were achieved. The reaction medium and catalyst could be easily recycled at least five times without significant loss in reactivity. Georg Thieme Verlag Stuttgart New York.
- Du, Zhengyin,Zhou, Wanwei,Bai, Lin,Wang, Fen,Wang, Jin-Xian
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supporting information; experimental part
p. 369 - 372
(2011/04/22)
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- Unravelling the olefin cross metathesis on solid support. Factors affecting the reaction outcome
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Olefin cross metathesis on solid support under a variety of conditions is described. A comprehensive analysis considering diverse factors governing the reaction outcome gives a series of patterns for the application of this useful methodology in organic synthesis. If the intrasite reaction is not possible, homodimerization of the soluble olefin is crucial. When the homodimer is less reactive than its monomer, reaction outcome depends on the homodimerization rate, which, in turn, depends on the precatalyst used and the reaction conditions. If the site-site interaction is a feasible process, the cross metathesis product is obtained exclusively when the newly-formed double bond is resilient to further metathetic events. Taking into account these considerations, we have demonstrated that excellent results in terms of cross metathesis coupling can be obtained under the optimized conditions, and that microwave irradiation is also an interesting alternative for the development of a practical and energy-efficient cross metathesis on solid support.
- Poeylaut-Palena, Andres A.,Mata, Ernesto G.
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experimental part
p. 3947 - 3956
(2010/09/17)
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- Solid-supported cross metathesis and the role of the homodimerization of the non-immobilized olefin
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(Chemical Equation Presented) We have prepared immobilized olefins as models for the cross metathesis using different olefin partners in the presence of second generation Grubbs and Hoveyda-Grubbs precatalysts. We have demonstrated that solid-phase cross metathesis is strongly dependent on the degree of homodimerization of the non-immobilized olefin and the reactivity of such a homodimer. As in the homogeneous phase, the Hoveyda-Grubbs precatalyst was better for immobilized α,β-unsaturated carbonyl compounds.
- Poeylaut-Palena, Andres A.,Testero, Sebastian A.,Mata, Ernesto G.
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p. 2024 - 2027
(2008/09/19)
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- Recyclable polymer bound Pd(O) phosphine catalyst for effecting sp 2-sp2 and sp2-sp carbon-carbon coupling reactions in aqueous medium
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Aqueous Heck type coupling reactions between aryl iodides and terminal alkenes or alkynes have been effected in good yields using a recyclable catalyst system that consists of poly(N-isopropyl acrylamide) bound Pd(O) phosphine and an anionic surfactant, potassium lauryl sulphate.
- Koshti, Nirmal,Parab, Bharat,Naik, Shubhangi
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p. 154 - 159
(2008/02/09)
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- Silica-supported poly-γ-aminopropylsiloxane palladium (Pd 2+)-transition metal (Cu2+) complex: A new catalyst system for Heck reaction
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A new silica-supported poly-γ-aminopropysiloxane transition metal (Cu2+) and palladium (Pd2+) catalyst has been prepared from organic silica via immobilization on fumed silica, followed by treatment with Cu(OAc)2 and PdCl2 in ethanol. The catalyst is efficient for Heck arylation of aryl iodides with alkene. The effects of reaction temperature and Pd2+ content on catalytic properties have also been studied. Pd2+ has been found to improve the catalytic performance, reducing the reaction temperature (70°C) and the induction period. It provides an economic way to synthesize unsymmetrical trans-stilbenes.
- Zhao, Shao Fen,Zhou, Ren Xian,Zheng, Xiao Ming
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p. 2215 - 2217
(2007/10/03)
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- The fabrication of reactive hollow polysiloxane capsules and their application as a recyclable heterogeneous catalyst for the Heck reaction
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The fabrication of hollow polysiloxane capsule-supported palladium complexes has been investigated. Capsule-supported cyano-palladium(0) complexes were firstly prepared and their catalytic performance in the Heck arylation of alkenes was studied. Generally the method involves the consecutive cocondensation of 4-(triethoxysilyl)butyronitrile and dimethyldimethoxysilane monomers onto a microemulsion of preformed polydimethylsiloxane and the subsequent removal of the templated polydimethylsiloxane by exposure to solvents, and then the above product is reacted with palladium acetate in anhydrous toluene and reduced with KBH4 in ethanol to produce the hollow polysiloxane capsule-supported palladium complex. UV-VIS spectra and FT-IR spectra indicated that the capsules chelated with the palladium and the results of TEM and AFM measurements show that a hollow polysiloxane capsule-supported palladium complex has been prepared. These complex are highly active and stereoselective for the Heck reaction and can be easily separated from the reaction mixture. Moreover, these polysiloxane capsule-supported palladium(0) catalysts can be retrieved and reused with high catalytic stability. The Royal Society of Chemistry.
- Wang, Huigang,Zheng, Xuming,Chen, Ping,Zheng, Xiaoming
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p. 4701 - 4705
(2007/10/03)
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- Organic silica ligated to palladium (0) complex: A highly active and stereoselective catalyst for Heck reaction
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Organic silica ligated to palladium(0) complex has been prepared from poly-γ-cyanopropyl triethoxysilane and fumed silica, followed by treatment with palladium chloride in ethanol and then the reduction with KBH4 in ethanol. This catalyst is highly active and stereoselective for Heck reaction at 90°C or 1O0°C.
- Zhao,Zhou,Yang,Zheng
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p. 2274 - 2276
(2007/10/03)
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- Palladium catalysed heck and enantioselective allylic substitution reactions using reverse phase silica supports
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The use of reverse phase controlled-pore glass beads in Heck reactions affords the products with low levels of palladium leaching. Additionally, an enantioselective palladium catalysed allylic substitution reaction has been achieved with high enantiomeric excess and a low level of leaching.
- Anson, Michael S.,Mirza, Amin R.,Tonks, Louise,Williams, Jonathan M.J.
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p. 7147 - 7150
(2007/10/03)
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- Synthesis and photochemical reactions of main-chain polymers containing cinnamoyl groups
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Poly(amide-imide)s containing 4-carboxycinnamic acid as a photoreactive building block were prepared by direct polycondensation at 160°C of 1,6-diisocyanatohexane (HMDI), trimellitic anhydride and 4-carboxycinnamic acid (PCCA) in N-methyl-pyrrolidone (NMP) in the presence of organic bases as catalyst. Transparent and flexible films could be cast onto quartz plates from polymer solutions. Upon irradiation of the polymers in solution and in solid state (films), the cinnamoyl chromophores undergo (2 + 2) photocycloaddition. Decrease in cinnamoyl moieties based on photodimerization between cinnamoyl moieties during the UV irradiation was evaluated from the change in absorption spectra.
- Onciu, Marioara,Chiriac, Constantin I.,Timpu, Daniel,Ioan, Cǎtǎlina,Grigoriu, George
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p. 265 - 271
(2007/10/03)
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- Systematically cross-linked human hemoglobin: Functional effects of 10 ? spans between beta subunits at lysine-82
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The structure and properties of hemoglobin are altered by the introduction of cross-links of defined structure between specific residues. The bis methyl phosphates and bis 3,5-dibromosalicylates of 4-carboxy-trans-cinnamic acid as well as the bis methyl phosphate of 2,6-naphthalenedicarboxylic acid produce a 10 ? cross-link between the ε-amino groups of each β-lys-82 of human hemoglobin. The oxygen affinity of the modified proteins fits the correlation interpolated from those for shorter and longer cross-links. The oxygen binding curve shows a high degree of cooperativity. These results support the idea that the length of the semirigid cross-link in a structurally homogeneous series constrains the relaxation of the protein upon oxygen binding by a mechanism that is specifically reflected in the oxygen affinity, while interactions between hemes that affect cooperativity are not diminished.
- Kluger, Ronald,Shen, Lixin,Xiao, Hong,Jones, Richard T.
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p. 8782 - 8786
(2007/10/03)
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- PHOTOSYNTHESIS OF HETEROPOLYCYCLIC QUINOLONES
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Four new anilidoquinolones; 9-anilidobenzothienoquinolin-6(5H)-one (6), 9-N'-methylanilidobenzothieno-5-N-methylquinolin-6-one (7), 9-anilidothienothienylquinolin-6(5H)-one (16), and 9-N'-methylanilidothienothienyl-5-N-methylquinolin-6-one (17) were prepared by photochemical dehydrohalogenation from the dianilides (4,5,14 and 15).Photochemical dehydrogenation of the anilides to produce multicondensed diquinolones did not occur.
- Dogan, Jasna,Karminski-Zamola, Grace M.,Boykin, David W.
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p. 1659 - 1666
(2007/10/03)
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- Synthesis of substituted cinnamic acids and cinnamonitriles via palladium catalyzed coupling reactions of aryl halides with acrylic acid and acrylonitrile in aqueous media
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The palladium-catalysed coupling reactions of aryl halides with acrylic acid and acrylonitrile in the presence of a base (NaHCO3 or K2CO3) in water provide a novel and efficient and very simple method for the synthesis of substituted cinnamic acids and cinnamonitriles in high yields.NaHCO3 or K2CO3 effectively acts as a base in the reaction at elevated temperature (80-100 deg C).The reaction can be carried out with higher velocity and at low temperature (50-60 deg C), using CH3COOK as a base.
- Bumagin, N. A.,More, P. G.,Beletskaya, I. P.
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p. 397 - 402
(2007/10/02)
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- Fluorogenic 2-oxy-3(2H)-furanone materials
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Compounds of the formula SPC1 Wherein R1 is lower alkyl or phenyl lower alkyl; R2 is phenyl or substituted phenyl; and R3 is substituted or unsubstituted phenyl, naphthyl or indolyl; Are fluorogenic reagents which react wi
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