- A green environmental protection of the bromobenzene [...] preparation method (by machine translation)
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The present invention provides a green environmental protection of the bromobenzene [...] preparation method, comprises the following steps: sulfuric acid and [...] aniline added in a reaction kettle, stirring cooling to 5 - 10 °C, thermal insulation and slowly instillment bromide, dropping after the completion of the slow heating to 15 - 20 °C, thermal insulation and dropping hydrogen peroxide solution, the constant temperature reaction, again lowering the temperature to 0 - 5 °C, thermal insulation and dropping nitroso sulfuric acid, thermal insulation reaction, slow heating to 35 - 40 °C, thermal insulation and dropping isopropyl alcohol and water mixture, after dropping the stirring, heating up to 55 - 60 °C, thermal insulation, layered, separation [...] and oil reservoir; the oil reservoir is arranged in the rectification apparatus, first heating up to 65 - 70 °C, after the heat preservation, heating up to 83 - 85 °C, distillation separation, to obtain [...] bromobenzene and 3, 5 - dibromide fluoride; the water through distillation, obtained from the isopropyl alcohol, a mixture of water and acetone and sulfuric acid, the isopropanol, water and the mixture for catalytic hydrogenation, to obtain the isopropanol-water solution. (by machine translation)
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Paragraph 0025-0056
(2018/11/26)
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- Preparation method of 3-bromofluorobenzene
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The invention relates to the field of organic synthesis and in particular relates to a preparation method of 3-bromofluorobenzene. The preparation method of the 3-bromofluorobenzene, provided by the invention, comprises the following steps: 1) enabling o-fluoroaniline to react with sulfuric acid and a bromination reagent to prepare 2-fluoro-4-bromoaniline sulfate; 2) enabling the 2-fluoro-4-bromoaniline sulfate to react with sodium nitrite in the presence of a reducing agent and a catalyst under an acidic condition, so as to prepare the 3-bromofluorobenzene. The preparation method of the 3-bromofluorobenzene, provided by the invention, has the advantages of cheap and easy-to-obtain raw materials, simple technology, feasibility in post-treatment and high yield and is extremely applicable toindustrialization; acid water produced by diazo deamination reaction can be used repeatedly; after the acid water is repeatedly used for a plurality of times, enriched low-boiling-point solvents including isopropyl alcohol, acetone and the like in the acid water can be removed by distillation and then the acid water can be continually used repeatedly; in a diazo deamination process, hypophosphorous acid in a traditional technology is replaced with low-grade alcohol, so that water eutrophication caused by the fact that the phosphorus content in water exceeds the standard is avoided.
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Paragraph 0069; 0070; 0071; 0072; 0073; 0074; 0075-0081
(2018/05/16)
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- An intramolecular: Ortho -assisted activation of the silicon-hydrogen bond in arylsilanes: An experimental and theoretical study
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An intramolecular activation of the Si-H bond in arylsilanes by selected ortho-assisting functional groups based on boron, carbon and phosphorus was investigated experimentally and by means of theoretical calculations. The major conclusion drawn is that the presence of a negatively charged oxygen atom in the functional group is essential for providing effective chelation to the silicon atom which in turn results in the increased hydridic character of a resulting five-coordinated species. In contrast, an intermolecular attack of hydroxide on the silicon atom in aryldimethylsilane results in the activation of the silicon-aryl bond. This increased reactivity of the Si-H bond in intramolecularly coordinated arylsilanes can be ascribed to a significant trans effect which operates in the preferred configuration. Hydrolytic cleavage of the Si-H bond results in dihydrogen elimination and the formation of various silicon heterocyclic systems such as benzosiloxaboroles, spiro-bis(siloxa)borinate, benzosilalactone and benzophosphoxasilole. In addition, intermolecular reduction of benzaldehydes with ortho-boronated arylsilane was observed whereas compounds bearing other reducible functional groups (COMe, COOEt, CN and NO2) were inert under comparable conditions. Specifically, an intramolecular reduction of the CN group in an ortho-silylated benzonitrile derivative was observed. The mechanism of Si-H bond activation was investigated by the DFT theoretical calculations. The calculations showed that the intramolecular coordination of the silicon atom effectively prevents the cleavage of the Si-aryl bond. Furthermore, the reaction is favored in anionic systems bearing COO-, B(OH)3- or CH2O- groups, while in the case of neutral functional groups such as PO(OEt)2 the process is much slower.
- Durka, Krzysztof,Urban, Mateusz,Czub, Maja,D?browski, Marek,Tomaszewski, Patryk,Luliński, Sergiusz
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p. 3705 - 3716
(2018/03/21)
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- Reactions of aromatic compounds with xenon difluoride
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Reactions of substituted benzenes C6H5R (R = Me, F, Cl, Br, CF3, NO2) with xenon difluoride in the presence of boron trifluoride–diethyl ether complex in weakly acidic (1,1,1,3,3-pentafluorobutane) and weakly basic media (acetonitrile) have been studied. These reactions lead to the formation of fluorobenzene derivatives FC6H4R (isomer mixture) together with isomeric difluorobenzenes and fluorinated and non-fluorinated biphenyls. The results have been compared with previously reported data obtained in other solvents using other catalysts.
- Bardin,Adonin, N. Yu.
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p. 1400 - 1407
(2016/11/29)
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- Fluorination of aromatic compounds with xenon difluoride in the presence of boron trifluoride etherate
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Fluorination of benzene with the XeF2 - BF3?Et2O system in acetonitrile at low temperatures affords fluorobenzene in 18% yield, the conversion of benzene being 92%. The rest products are di-, tri-, tetra-, and polyphenyls with different fluorination pattern. Toluene and chloro- and bromobenzenes are fluorinated predominantly at the ortho and para positions. Fluorination of 4-nitroanisole affords 2-fluoro-4-nitroanisole in 73% yield.
- Fedorov,Zubarev,Mortikov, V. Yu.,Rodinovskaya,Shestopalov
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p. 1049 - 1052
(2016/02/09)
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- Halogen exchange via a halogenation of diaryliodonium salts with cuprous halide
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An efficient halogenation reaction has been developed with diaryliodonium salts and cuprous halides. Various diaryliodonium salts 1 could perform the reaction with readily available CuBr or CuCl in CH3CN at 80°C, assembling bromoarenes or chloroarenes in up to 92% yields. This provides us a method for the transformation from iodoarenes to other haloarenes.
- Li, Jian,Liu, Li,Ding, Dong,Sun, Jiang-Tao
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p. 541 - 548
(2014/01/06)
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- Development of a large scale asymmetric synthesis of the glucocorticoid agonist BI 653048 BS H3PO4
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The development of a large scale synthesis of the glucocorticoid agonist BI 653048 BS H3PO4 (1·H3PO4) is presented. A key trifluoromethyl ketone intermediate 22 containing an N-(4-methoxyphenyl)ethyl amide was prepared by an enolization/bromine-magnesium exchange/electrophile trapping reaction. A nonselective propargylation of trifluoromethyl ketone 22 gave the desired diastereomer in 32% yield and with dr = 98:2 from a 1:1 diastereomeric mixture after crystallization. Subsequently, an asymmetric propargylation was developed which provided the desired diastereomer in 4:1 diastereoselectivity and 75% yield with dr = 99:1 after crystallization. The azaindole moiety was efficiently installed by a one-pot cross coupling/indolization reaction. An efficient deprotection of the 4-methoxyphenethyl group was developed using H3PO4/anisole to produce the anisole solvate of the API in high yield and purity. The final form, a phosphoric acid cocrystal, was produced in high yield and purity and with consistent control of particle size.
- Reeves, Jonathan T.,Fandrick, Daniel R.,Tan, Zhulin,Song, Jinhua J.,Rodriguez, Sonia,Qu, Bo,Kim, Soojin,Niemeier, Oliver,Li, Zhibin,Byrne, Denis,Campbell, Scot,Chitroda, Ashish,Decroos, Phil,Fachinger, Thomas,Fuchs, Victor,Gonnella, Nina C.,Grinberg, Nelu,Haddad, Nizar,Jaeger, Burkhard,Lee, Heewon,Lorenz, Jon C.,Ma, Shengli,Narayanan, Bikshandarkoil A.,Nummy, Larry J.,Premasiri, Ajith,Roschangar, Frank,Sarvestani, Max,Shen, Sherry,Spinelli, Earl,Sun, Xiufeng,Varsolona, Richard J.,Yee, Nathan,Brenner, Michael,Senanayake, Chris H.
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p. 3616 - 3635
(2013/06/04)
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- Synthesis of aryl fluorides on a solid support and in solution by utilizing a fluorinated solvent
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(Figure Presented) F for fast: The perfluorinated solvent C 6F14 is the key to a new variant of the BalzSchiemann reaction for the synthesis of fluorinated arenes. Triazenes are converted into fluoroarenes under mild con-ditions on a support and in solution (see scheme). The method is straightforward and inexpensive, and yields previously difficult-to-prepare fluoroarenes in high purity.
- Doebele, Marion,Vanderheiden, Sylvia,Jung, Nicole,Braese, Stefan
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supporting information; experimental part
p. 5986 - 5988
(2010/10/01)
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- Route to prepare 4-bromo-1-oxypentafluorosulfanylbenzene
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A process for preparing bromo-1-oxypentafluorosulfanylbenzene is provided, the process including the step of brominating pentafluorosulfanyloxybenzene with a bromination agent to provide the bromo-1-oxypentafluorosulfanylbenzene. The process is more effective than prior art processes for preparing such compounds.
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Page/Page column 4
(2008/06/13)
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- Method for producing tetrakis ( fluoroaryl) borate-magnesium compound
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Fluoroaryl magnesium halide is reacted with a boron compound so that a molar ratio of the fluoroaryl magnesium halide to the boron compound is not less than 3.0 and not more than 3.7, so as to produce a tetrakis (fluoroaryl) borate·magnesium compound. With this method, there occurs no hydrogen fluoride which corrodes a producing apparatus and requires troublesome waste water treatment.
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- Process for preparation of substituted aromatic compound
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A substituted aromatic compound substituted with Q is obtained by reacting a phosphazenium compound represented by formula (1) (in the formula, Q?represents an anion in a form derived by elimination of a proton from an inorganic acid, or an active hydrogen compound having an active hydrogen on an oxygen atom, a nitrogen atom or a sulfur atom; a, b, c and d, each independently, is 0 or 1, but all of them are not 0 simultaneously; and R groups represent the same or different hydrocarbon groups having 1 to 10 carbon atoms, or two Rs on each common nitrogen atom may be bonded together to form a ring structure) with a halogenated aromatic compound having halogen atoms; whereby, at least one halogen atom in the halogenated aromatic compound is substituted with Q (where, Q represents an inorganic group or an organic group in a form derived by elimination of one electron from Q?in formula (1)).
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- Preparation process of fluorine substituted aromatic compound
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A preparation process of a fluorine substituted aromatic compound comprising reacting an alkali metal or alkali earth metal salt of an aromatic compound having a hydroxy group with an organic fluorinating agent is disclosed. As a representative fluorinating agent, a bis-dialkylamino-difluoromethane compound, for example, 2,2′-difluoro-1,3-dimethylimidazolidine, is exemplified. According to the process, an industrially useful fluorinated aromatic compound, for example, a fluorobenzene, a fluorine substituted benzophenone, a fluorine substituted diarylsulfone can be prepared with ease in economy without specific equipment.
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- Exchange of halogens between aromatic compounds in the presence of Cu-HZSM-5 zeolite
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The reactions between various haloaromatics in binary mixtures which were approximately equimolar, were studied in gas-phase (673 K, atmospheric: pressure) in the presence of a 2 wt % Cu-HZSM-5 zeolite. The exchange of halogens (ipso substitution) between the two compounds was assumed to occur either through a radical mechanism involving an electron transfer between an atom of copper (I) and one aromatic molecule or through a nucleophilic substitution involving arylcopper complexes as intermediates.
- Imhaoulne,Imhaoulene,Vivier,Guisnet,Petot,Perot,Gubelmann
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p. 12913 - 12922
(2007/10/02)
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- Photochemical Bromination of Simple Arenes
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Photochemical bromination of benzene, fluorobenzene, chlorobenzene, t-butylbenzene, α,α,α-trifluorotoluene, and (in tetrachloromethane) biphenyl and naphthalene gives substitution products and adducts such as 1,2,3,4,5,6-hexabromocyclohexane (1).The decomposition of (1) and of the analogous chlorobenzene adduct (3) under photochemical conditions gives the parent arene, the monobrominated halogenobenzene, and bromine which may be scavenged by toluene to give benzyl bromide or by benzene to give bromobenzene and dibromobenzenes.Addition is a kinetically controlled process, so that the mechanism of formation of these aryl bromides must be largely through the reversible formation of these adducts.This is consistent with the unusual orientation of apparent attack by bromine upon the arene substrates, since the relative amounts of the isomeric aryl bromides is a consequence of the relative stabilities and ease of elimination of HBr and Br2 from a family of adducts. The range of isomer distribution found within the reaction of each arene with bromine is consistent with two competing processes involved in the formation of the aryl bromides; one of these might by the direct homolytic substitution by bromine atoms upon the arene.
- Bolton, Roger,Bhangar, Muhammad Iqbal,Williams, Gareth H.
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p. 893 - 896
(2007/10/02)
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- Substrate Selectivity and Orientation in Aromatic Substitution by Molecular Fluorine
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Direct elemental fluorination of representative aromatic substrates, including PhH, PhCH3, PhF, PhCl, PhBr, PhNO2, PhCN, and PhOCH3, has been investigated in inert solvents, e.g., CCl3F and other fluorocarbons, over the temperature range -154 to 40 deg C.In order to achieve the necessary control of the extremely reactivve electrophile, and to minimize unwanted modifications of the reaction environment, the fluorination has been carried out at extremely low rate and correspondingly low conversions, generally below 0.01percent, using as a reagent gaseous mixtures of F2 highly diluted (+ constants for all the substituents investigated, giving a ρ+ value of -2.45 for aromatic substitution by elemental fluorine with a correlation coefficient of 0.993.These results characterize F2 as a highly reactive, and correspondently unselective, reagent, and support a polar electrophilic substitution mechanism that is discussed and compared with other plausible fluorination pathways.
- Cacace, F.,Giacomello, P.,Wolf, A. P.
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p. 3511 - 3515
(2007/10/02)
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