- Preparation method of monohalogenated phenylboronic acid
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The invention relates to the technical field of chemical synthesis, and particularly discloses a preparation method of monohalogenated phenylboronic acid. The preparation method comprises the following steps of: by taking dihalogenated benzene as a raw material and a mixture of lithium salt and alkaline ionic liquid as a catalyst, carrying out Grignard exchange with R1MgCl to generate monohalogenated phenyl magnesium chloride, reacting with B (OR) 3 to generate monohalogenated phenyl borate, and hydrolyzing under acidic conditions to obtain monohalogenated phenylboronic acid. The HPLC (High Performance Liquid Chromatography) content of the monohalogenated phenylboronic acid prepared by the method is greater than 99.5%; the total yield of the product is greater than 80%, the contents of monohalogenated phenylboronic acid and phenyldiboronic acid impurities of another halogen are both less than 0.003%, the requirements of modern fine chemical synthesis are completely met, the raw materials are easily available, the operation is simple, the safety is high, and the industrial production of monohalogenated phenylboronic acid is realized.
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Paragraph 0084-0087
(2020/09/20)
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- Ligand-Less Iron-Catalyzed Aromatic Cross-Coupling Difluoromethylation of Grignard Reagents with Difluoroiodomethane
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Iron-catalyzed cross-coupling difluoromethylations of the Grignard reagents with difluoroiodomethane provide various aromatic difluoromethyl products in good yields, not employing sterically demanding ligands. Difluoromethylations proceed within 30 min at -20 °C with 2.0 equiv of the Grignard reagents and FeCl3 or Fe(acac)3 (2.5 mol %). Mechanistic investigations clarify difluoromethyl radical intervention; Fe(0) ate is initially generated. Single-electron transfer from Fe(0) ate to difluoroiodomethane takes place. Recombination with aryl groups gives Ar-CF2Hs. The catalyst can be regenerated by the Grignard reagents.
- Motohashi, Hirotaka,Kato, Miki,Mikami, Koichi
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p. 6483 - 6490
(2019/05/16)
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- A novel graphite-like stacking structure in a discrete molecule and its molecular recognition behavior
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A graphite-like stacking structure was nicely reproduced in a discrete molecule that was prepared by 2+2 macrocyclic Schiff base formation. In the crystal structure, two hexabenzocoronene planes are closely stacked with displacement, yielding the intramolecular stacking structure similar to an AB- or ABC-stacking pattern in natural graphite. This molecule showed a recognition ability toward electron-deficient aromatic molecules in solution.
- Akine, Shigehisa,Onuma, Takahiro,Nabeshima, Tatsuya
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supporting information
p. 9369 - 9372
(2018/06/18)
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- An efficient method for the hydrolysis of potassium organotrifluoroborates promoted by montmorillonite K10
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An efficient and non-expensive method for conversion of diverse potassium organotrifluoroborates to their corresponding boronic acids promoted by montmorillonite K10 using water as the reaction solvent is described. Further interconversion of potassium organotrifluoroborates to their corresponding boronic esters, via boronic acid intermediates was also successfully accomplished. The products were obtained in good yields, being the rate of hydrolysis influenced by the type of substituent present in the boronic acid.
- Silva, Renato L.,Santos, Cosme S.,Santos, Jonh A. M.,Oliveira, Roberta A.,Menezes, Paulo H.,Freitas, Juliano C. R.
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p. 1777 - 1785
(2018/09/04)
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- Flow Chemistry on Multigram Scale: Continuous Synthesis of Boronic Acids within 1 s
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The benefits and limitations of a simple continuous flow setup for handling and performing of organolithium chemistry on the multigram scale is described. The developed metalation platform embodies a valuable complement to existing methodologies, as it combines the benefits of Flash Chemistry (chemical synthesis on a time scale of 1 s) with remarkable throughput (g/min) while mitigating the risk of blockages.
- Hafner, Andreas,Meisenbach, Mark,Sedelmeier, Joerg
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supporting information
p. 3630 - 3633
(2016/08/16)
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- Asymmetric Arylation of Imines Catalyzed by Heterogeneous Chiral Rhodium Nanoparticles
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Asymmetric arylation of aldimines catalyzed by heterogeneous chiral rhodium nanoparticles has been developed. The reaction proceeded in aqueous media without significant decomposition of the imines by hydrolysis to afford chiral (diarylmethyl)amines in high yields with outstanding enantioselectivities. This catalyst system exhibited the highest turnover number (700) in heterogeneous catalysts reported to date for these reactions. The reusability of the catalyst was also demonstrated.
- Yasukawa, Tomohiro,Kuremoto, Tatsuya,Miyamura, Hiroyuki,Kobayashi, Sh?
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supporting information
p. 2716 - 2718
(2016/06/15)
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- Novel organic semiconductor compound and organic light emitting device using the same
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The present invention relates to a novel organic semiconductor compound, and an organic electroluminescent device using the same. More particularly, the organic semiconductor compound according to the present invention is an azasiline derivative with a rigid structure having an electron doner and an electron acceptor in the molecule, and can embody excellent oxidation stability and light emitting characteristics. The organic electroluminescent device using the same has a high purity blue color having high quantum efficiency. The organic semiconductor compound is represented by chemical formula 1.
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Paragraph 0169-0173
(2016/10/10)
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- Phototautomerization in Pyrrolylphenylpyridine Terphenyl Systems
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[4-(2-Pyrrolyl)phenyl]pyridines 2-4 were synthesized and their photophysical properties and reactivity in phototautomerization reactions investigated by fluorescence spectroscopy and laser flash photolysis (LFP). The pKa for the protonation of the pyridine nitrogen in 2-4 was determined by UV-vis and fluorescence titration (pKa = 5.5 for 4). On excitation in polar protic solvents, 2-4 populate charge-transfer states leading to an enhanced basicity of the pyridine (pKa? ≈ 12) and enhanced acidity of pyrrole (pKa? ≈ 8-9) enabling excited-state proton transfer (ESPT). ESPT gives rise to phototautomers and significantly quenches the fluorescence of 2-4. Phototautomers 2-T and 4-T were detected by LFP with strong transient absorption maxima at 390 nm. Phototautomers 2-T and 4-T decayed by competing uni- and bimolecular reactions. However, at pH 11 the decay of 4-T followed exponential kinetics with a rate constant of 4.2 × 106 s-1. The pyridinium salt 4H+ forms a stable complex with cucurbit[7]uril (CB[7]) with 1:1 stoichiometry (β11 = (1.0 ± 0.2) × 105 M-1, [Na+] = 39 mM). Complexation to CB[7] increased the pKa for 4H+ (pKa = 6.9) and changed its photochemical reactivity. Homolytic cleavage of the pyrrole NH leads to the formation of an N-radical because of the decreased acidity of the pyrrole in the inclusion complex. (Figure Presented).
- Basari?, Nikola,Thomas, Suma S.,Bregovi?, Vesna Bla?ek,Cindro, Nikola,Bohne, Cornelia
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p. 4430 - 4442
(2015/05/13)
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- COMPOUND FOR ORGANIC ELECTRONIC ELEMENT, ORGANIC ELECTRONIC ELEMENT USING THE SAME, AND AN ELECTRONIC DEVICE THEREOF
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The present invention provides a novel compound capable of improving light emitting efficiency, stability and lifespan of an element, an organic electronic element using the same and an electronic device thereof.(110) Substrate(120) Positive electrode(130) Hole injection layer(140) Hole transfer layer(141) Buffer layer(150) Light emitting layer(151) Light-emitting assisting layer(160) Electron transfer layer(170) Electron injection layer(180) Negative electrodeCOPYRIGHT KIPO 2016
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Paragraph 0180-0183
(2016/10/07)
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- Methanol-promoted borylation of arylamines: A simple and green synthetic method to arylboronic acids and arylboronates
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A Sandmeyer borylation of arylamines via a SN2Ar pathway promoted by methanol with sodium nitrite and hydrochloric acid as diazotization agent has been developed, which provide a simple and green synthetic method to arylboronic acids and arylboronates. Georg Thieme Verlag Stuttgart New York.
- Zhao, Cong-Jun,Xue, Dong,Jia, Zhi-Hui,Wang, Chao,Xiao, Jianliang
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p. 1577 - 1584
(2014/07/08)
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- An easy route to (hetero)arylboronic acids
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An unprecedented spontaneous reactivity between diazonium salts and diboronic acid has been unveiled, leading to a versatile arylboronic acid synthesis directly from (hetero)arylamines. This fast reaction (35 min overall) tolerates a wide range of functional groups and is carried out under very mild conditions. The radical nature of the reaction mechanism has been investigated.
- Erb, William,Hellal, Akila,Albini, Mathieu,Rouden, Jacques,Blanchet, Jerome
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p. 6608 - 6612
(2014/06/09)
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- Sequential one-pot access to molecular diversity through aniline aqueous borylation
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On the basis of our recently reported aniline aqueous borylation, molecular diversity was achieved in a one-pot process by combining other reactions such as esterification, Suzuki-Miyaura coupling, hydrogenolysis, or Petasis borono-Mannich.
- Erb, William,Albini, Mathieu,Rouden, Jacques,Blanchet, Jrme
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p. 10568 - 10580
(2015/01/08)
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- Mn-catalyzed aromatic C-H alkenylation with terminal alkynes
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The first manganese-catalyzed aromatic C-H alkenylation with terminal alkynes is described. The procedure features an operationally simple catalyst system containing commercially available MnBr(CO)5 and dicyclohexylamine (Cy2NH). The reaction occurs readily in a highly chemo-, regio-, and stereoselective manner delivering anti-Markovnikov E-configured olefins in high yields. Experimental study and DFT calculations reveal that (1) the reaction is initiated by a C-H activation step via the cooperation of manganese and base; (2) manganacycle and alkynylmanganese species are the key reaction intermediates; and (3) the ligand-to-ligand H-transfer and alkynyl-assisted C-H activation are the key steps rendering the reaction catalytic in manganese.
- Zhou, Bingwei,Chen, Hui,Wang, Congyang
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p. 1264 - 1267
(2013/03/14)
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- Synthesis-guided structure revision of the sarcodonin, sarcoviolin, and hydnellin natural product family
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A sweeping structural revision of the sarcodonin natural product family (published structures 1a-13a) is proposed after extensive studies aimed at their chemical synthesis. Key features of revised structure 1b include replacement of the N,N-dioxide moiety with an oxime, ring-opening of the central diketopiperazine, and transposition of the terphenyl wing from the 1β-2β position of 1a to the 2β-3β position of 1b. This structure revision arose from the serendipitous synthesis of a benzodioxane aminal (44) whose structure was unambiguously determined by X-ray crystallography and whose spectral properties bore considerable resemblance to the published data for the sarcodonins. A versatile new method for O-arylation of hydroxamic acids is also reported herein, as well as a manganese(III)- mediated α-oxidation of hydroxamic acids to aminals.
- Lin, David W.,Masuda, Takeshi,Biskup, Moritz B.,Nelson, Jonathan D.,Baran, Phil S.
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supporting information; experimental part
p. 1013 - 1030
(2011/04/15)
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- Measurement of long-range interatomic distances by solid-state tritium-NMR spectroscopy
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(Chemical Equation Presented) For the structural determination of a ligand bound to an amorphous macromolecular system, solid-state NMR can be used to provide interatomic distances. It is shown here that selective labeling in discrete locations with tritium enables accurate measurement of long-range distances owing to the high gyromagnetic ratio of this nucleus, without structural modification of the molecule. This approach gives access to the largest NMR distance ever measured between two nuclei (14.4 A). 3H MAS NMR appears to be a promising tool for structural applications in the biological and material sciences. Copyright
- Yuen, Alexander K. L.,Lafon, Olivier,Charpentier, Thibault,Roy, Myriam,Brunet, Francine,Berthault, Patrick,Sakellariou, Dimitrios,Robert, Bruno,Rimsky, Sylvie,Pillon, Florence,Cintrat, Jean-Christophe,Rousseau, Bernard
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supporting information; experimental part
p. 1734 - 1735
(2010/04/25)
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- A recyclable Au(I) catalyst for selective homocoupling of arylboronic acids: Significant enhancement of nano-surface binding for stability and catalytic activity
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Au nanoparticles stabilized by polystyrene-co-polymethacrylic acid microspheres (PS-co-PMAA) were prepared and characterized via X-ray diffraction (XRD), and transmission electron microscope (TEM). The Au nanoparticles supported on the microspheres showed highly selective catalytic activity for homo-coupling reactions of arylboronic acids in a system of aryl-halides and arylboronic acids. X-ray photoelectron spectroscopy (XPS) spectra of the catalyst shows large amounts of Au(l) complexes band to the surface of the Au nanoparticles, which contributes to the selective homocoupling of the arylboronic acids. More importantly, this supported Au complex is a highly recyclable catalyst. The supported Au catalyst can be recycled and reused at least 6 times for a phenylboronic acid reactant, whereas the parent complex shows very low catalytic activity for this compound. The high catalytic activity of this material is attributed to: (1) the high surface to volume ratio which leads to more active sites being exposed to reactants; (2) the strong surface binding of the Au nanoparticle to the Au(1) complexes, which enhances both the stability and the catalytic activity of these complexes. Copyright
- Zhang, Xin,Zhao, Haitao,Wang, Jianhui
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experimental part
p. 5153 - 5160
(2011/12/15)
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- Efficient hydrolysis of organotrifluoroborates via silica gel and water
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(Chemical Equation Presented) A general, mild, and efficient method for the hydrolysis of organotrifluoroborates to unveil boronic acids using silica gel and H2O was developed. This method proved to be tolerant of a broad range of aryl-, heteroaryl-, alkenyl-, and alkyltrifluoroborates as well as structurally diverse aminomethylated organotrifluoroborates.As anticipated, electron-rich substrates provided the corresponding boronic acids more readily than electron-poor substrates, owing to the resonance-stabilized difluoroborane intermediate. The method developed was expanded further for the conversion of organotrifluoroborates to the corresponding boronate esters. 2009 American Chemical Society.
- Molander, Gary A.,Cavalcanti, Livia N.,Canturk, Belgin,Pan, Po-Shen,Kennedy, Lauren E.
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supporting information; experimental part
p. 7364 - 7369
(2010/01/16)
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- Asymmetric construction of chiral C-N axes through rhodium-catalyzed 1,4-addition
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Catalytic asymmetric construction of chiral C-N axes has been developed through a rhodium-catalyzed asymmetric 1,4-addition reaction. Both central chirality and axial chirality have been controlled at the same time using Rh/(R,R)-Ph-bod* catalyst with high enantio- and diastereoselectivity. This method has also been applied to the preparation of a planar-chiral ferrocene derivative. The resulting chiral C-N axis can be used as a good template to control the stereochemistry in the subsequent transformations such as alkylation and Diels-Alder reactions.
- Duan, Wei-Liang,Imazaki, Yusuke,Shintani, Ryo,Hayashi, Tamio
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p. 8529 - 8536
(2008/02/09)
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- Formation of boroxine: Its stability and thermodynamic parameters in solution
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Condensation of three boronic acids proceeding at room temperature gave their corresponding boroxines; NMR spectral measurements revealed that the reaction was reversible at room temperature, that electron-donating groups supported the formation of boroxine, and that entropically driven forces promoted the formation of boroxine in solution.
- Tokunaga, Yuji,Ueno, Hiroki,Shimomura, Youji,Seo, Toshihiro
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p. 787 - 790
(2007/10/03)
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- Cedranediolborane as a borylating agent for the preparation of boronic acids: Synthesis of a boronated nucleoside analogue
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Cedranediolborane can be cross-coupled with aryl iodides under Pd(0) catalysis to yield aryl boronates which can easily be deprotected to form the corresponding free boronic acids. The application of this methodology has led to the preparation of a boronated nucleoside indole analogue.
- Song,Morin
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p. 266 - 268
(2007/10/03)
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- The use of a modified Suzuki reaction for the synthesis of monoarylferrocenes
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A modification of the Suzuki cross-coupling reaction proved to be a clean and useful method for the preparation of monosubstituted arylferrocenes. Iodoferrocene was reacted with a series of substituted arylboronic acids in the presence of sodium carbonate and palladium acetate in aqueous ethanol at room temperature to produce a range of substituted monoarylferrocenes. A systematic investigation undertaken to determine optimal reaction conditions indicated that scrupulous deoxygenation of the solvent is critical. The use of stronger bases such as barium hydroxide and potassium carbonate is favourable and gives rise to better yields of monoarylferrocenes. The reactions also proceed efficiently in aqueous DMF, broadening the scope of the reaction allowing efficient reactions with boronic acids that show low solubility in organic solvents.
- Imrie, Christopher,Loubser, Christa,Engelbrecht, Pieter,McCleland, Cedric W.
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p. 2513 - 2523
(2007/10/03)
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- SYNTHESIS OF ARYLBORONIC ACIDS VIA THE REACTION OF BORANE WITH ARYLMAGNESIUM HALIDES
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The reaction of borane complexes with arylmagnesium halides produces the corresponding arylborohydrides in high yield.The arylborohydrides are readily hydrolyzed to the arylboronic acids.The syntheses are conveniently carried out in one pot.The reaction mechanism was clarified via a boron-11 NMR study.
- Kabalka, George W.,Sastry, Usha,Sastry, K.A.R.,Knapp, Furn F.,Srivastava, Prem C.
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p. 269 - 274
(2007/10/02)
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