104-92-7Relevant articles and documents
Dehydroxymethyl Bromination of Alkoxybenzyl Alcohols by Using a Hypervalent Iodine Reagent and Lithium Bromide
Shibata, Ayako,Kitamoto, Sara,Fujimura, Kazuma,Hirose, Yuuka,Hamamoto, Hiromi,Nakamura, Akira,Miki, Yasuyoshi,Maegawa, Tomohiro
, p. 2275 - 2278 (2018)
We describe the dehydroxymethylbromination of alkoxybenzyl alcohol by using a hypervalent iodine reagent and lithium bromide in F 3 CCH 2 OH at room temperature. Selective monobromination or dibromination was possible by adjusting the molar ratios of hypervalent iodine reagent and lithium bromide.
Gold-catalyzed halogenation of aromatics by N-halosuccinimides
Mo, Fanyang,Yan, Jerry Mingtao,Qiu, Di,Li, Fei,Zhang, Yan,Wang, Jianbo
, p. 2028 - 2032 (2010)
(Chemical Equation Presented) Golden bromination: A highly efficient and mild AuCl3-catalyzed bromination of aromatic rings with Nbromosuccinimide (NBS) has been developed. This method works with a low catalyst loading (down to 0.01 mol %) and can be combined with transition metal catalyzed transformations to deliver various aryl products.
Applications of Selenonium Cations as Lewis Acids in Organocatalytic Reactions
He, Xinxin,Wang, Xinyan,Tse, Ying-Lung (Steve),Ke, Zhihai,Yeung, Ying-Yeung
, p. 12869 - 12873 (2018)
The use of trisubstituted selenonium salts as organic Lewis acids in electrophilic halogenation and aldol-type reactions has been developed. The substrate scope is broad. The reaction conditions are mild and compatible with various functionalities. This study opens a new avenue for the development of nonmetallic Lewis acid catalysis.
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Uemura et al.
, p. 147 (1974)
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Efficient one-pot transformation of aminoarenes to haloarenes using halodimethylisulfonium halides generated in situ
Baik, Woonphil,Luan, Wanqiang,Lee, Hyun Joo,Yoon, Cheol Hun,Koo, Sangho,Kim, Byeong Hyo
, p. 213 - 219 (2005)
Halodimethylsulfonium halide 1, which is readily formed in situ from hydrohaloic acid and DMSO, is a good nucleophilic halide. This activated nucleophilic halide rapidly converts aryldiazonium salt prepared in situ by the same hydrohaloic acid and nitrite ion to aryl chlorides, bromides, or iodides in good yield. The combined action of nitrite ion and hydrohaloic acid in DMSO is required for the direct transformation of aromatic amines, which results in the production of aryl halides within 1 h. Substituted compounds with electron-donating or -withdrawing groups or sterically hindered aromatic amines are also smoothly transformed to the corresponding aromatic halides. The only observed by-product is the deaminated arene (usually 7%). The isolated aryldiazonium salts can also be converted to the corresponding aryl halides using 1. The present method offers a facile, one-step procedure for transforming aminoarenes to haloarenes and lacks the environmental pollutants that usually accompany the Sandmeyer reaction using copper halides.
An efficient, rapid and regioselective nuclear bromination of aromatics and heteroaromatics with NBS using sulfonic-acid-functionalized silica as a heterogeneous recyclable catalyst
Das, Biswanath,Venkateswarlu, Katta,Krishnaiah, Maddeboina,Holla, Harish
, p. 8693 - 8697 (2006)
A simple, efficient and rapid method has been developed for high-yielding regioselective nuclear monobromination of aromatic and heteroaromatic compounds using NBS in the presence of sulfonic-acid-functionalized silica at room temperature. The catalyst works under heterogeneous conditions and can be recycled.
Solvent effect in the free-radical oxidation and electrophilic ipso and hydrogen displacement of p-methoxybenzyl alcohol and N-(p-methoxybenzyl)acetamide by Br2
Bravo, Anna,Fontana, Francesca,Dordi, Barbara,Minisci, Francesco
, p. 3880 - 3881 (2000)
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Green halogenation reactions for (hetero)aromatic ring systems in alcohol, water, or no solvent
Kajorinne, Jessie K.,Steers, Jennifer C.M.,Merchant, Marnie E.,MacKinnon, Craig D.
, p. 1087 - 1091 (2018)
A new method of brominating aromatic and heteroaromatic ring systems is investigated. The combination of hydrobromic acid as the halogen source, hydrogen peroxide as the oxidant, and ethanol, water, or no solvent are evaluated as greener conditions than those that have been previously published. The new conditions give high yields and good regioselectivity for a variety of substrates when the ring is activated by electron-donating groups or heteroatoms. Phenols, anisole, thiophenes, and pyrrole give comparable or superior results when compared to a traditional bromination by N-bromosuccinimide in tetrahydrofuran. Other nitrogen-containing heterocycles do not react under the conditions because they are protonated and hence deactivated; similarly, substrates with electron-withdrawing groups are not brominated. The reaction is very tolerant of a variety of functional groups.
Catalytic Sandmeyer bromination
Beletskaya, Irina P.,Sigeev, Alexander S.,Peregudov, Alexander S.,Petrovskii, Pavel V.
, p. 2534 - 2538 (2007)
An efficient catalyst system for Sandmeyer bromination is proposed. Aryl bromides and dibromides can be obtained with excellent yield by this synthetic protocol. Georg Thieme Verlag Stuttgart.
Bis(sym-collidine)bromine(I) hexafluorophosphate as oxidant
Rousseau,Robin
, p. 8881 - 8885 (2000)
Primary and secondary alcohols in solution in methylene chloride are oxidised with bis(sym-collidine)bromine(I) hexafluorophosphate in good yields to the carbonyl compounds. For secondary and tertiary alcohols in which one of the substituents is a 4-methoxyphenyl group the oxidation takes place by cleavage of the phenyl-sp3 carbon bond and formation of bromoanisole and carbonyl compounds. (C) 2000 Elsevier Science Ltd.
One-pot synthesis of 4-aryl-2-aminothiazoles from styrenes and thioureas promoted by tribromoisocyanuric acid
de Andrade, Vitor S.C.,de Mattos, Marcio C.S.
, (2020)
A simple and efficient one-pot protocol has been developed for the conversion of styrenes into 4-aryl-2-aminothiazoles using readily available starting materials. Tribromoisocyanuric acid was successfully used for the co-bromination and oxidation of styrenes to give phenacyl bromides, which in the presence of thioureas produced the corresponding 4-aryl-2-aminothiazoles in 48–70% yield. The protocol involves three reactions in one process: a tandem (formation of phenacyl bromides from styrenes) followed by a telescoped (conversion to thiazole) reaction.
Brominations with Pr4NBr9 as a solid reagent with high reactivity and selectivity
Beck, Thorsten M.,Haller, Heike,Streuff, Jan,Riedel, Sebastian
, p. 740 - 747 (2014)
Tetrapropylammonium nonabromide (Pr4NBr9) is introduced as a room-temperature solid reagent for rapid bromination reactions of various substrates. The reagent exhibits reactivity similar to that of elemental bromine, but shows higher selectivity and it is easier and safer to store and to handle. Georg Thieme Verlag Stuttgart · New York.
Aromatic Halogenation Using N-Halosuccinimide and PhSSiMe3 or PhSSPh
Hirose, Yuuka,Yamazaki, Mirai,Nogata, Misa,Nakamura, Akira,Maegawa, Tomohiro
, p. 7405 - 7410 (2019)
We developed a mild aromatic halogenation reaction using a combination of N-halosuccinimide and PhSSiMe3 or PhSSPh. Less reactive aromatic compounds, such as methyl 4-methoxybenzoate, were brominated with PhSSiMe3 or PhSSPh and N-bromosuccinimide in high yields. No reaction was observed in the absence of PhSSiMe3 or PhSSPh. This method is also applicable to chlorination reactions using N-chlorosuccinimide and PhSSPh.
Iodine(I) reagents in hydrochloric acid-catalyzed oxidative iodination of aromatic compounds by hydrogen peroxide and iodine
Bedrac, Leon,Iskra, Jernej
, p. 1243 - 1248 (2013)
Hydrochloric acid activates the oxidative iodination of aromatic compounds with the iodine- hydrogen peroxide system through the formation of an iodine(I) compound as the iodinating reagent. Activation with hydrochloric acid is more powerful than that with sulfuric acid. The formation of dichloroiodic(I) acid (HICl2) with various forms of hydrogen peroxide was followed using UV spectroscopy. The HICl2 was used as the iodinating reagent. In the preparative oxidative iodinaton of various aromatic compounds, hydrochloric acid was used in a catalytic amount and the iodine(I) reagent was formed in situ with 0.5 equiv. hydrogen peroxide and 0.5 equiv. molecular iodine. Two types of reactivity were observed in oxidative iodination with iodine(I) species catalyzed by hydrochloric acid: in the iodination of anisole 1a better yields of iodination were observed with a smaller amount of hydrochloric acid, while on the contrary 4-tert-butyltoluene 1b gave better yields of iodination upon increasing the amount of hydrochloric acid. Reactivity was further manipulated by the choice of the solvent (MeCN, trifluoroethanol, hexafluoro-2-propanol). Copyright
Selective halogenation of aromatics by dimethyldioxirane and halogen ions
Bovicelli,Mincione,Antonioletti,Bernini,Colombari
, p. 2955 - 2963 (2001)
The oxidation of halogen anions by dimethyldioxirane (DMD) produced reactive species which led, in acidic media, to the halogenation of activated aromatic rings. The reaction can be efficiently controlled to obtain selective and mixed halogenated species.
Direct halogenation of organic compounds with halides using oxone in water - A green protocol
Firouzabadi,Iranpoor,Kazemi
, p. 1675 - 1681 (2009)
Direct bromination and iodination of various aromatic compounds with NaBr and NaI using oxone (2KHSO5·KHSO4·K 2S04) in water was accomplished successfully in high-to-excellent yields. The main benefit of this protocol is the performance of the reactions in water in the presence of a harmless oxidant without the use of any organic cosolvents. Using NaBr and NaI as the safe sources of halogens is another advantage of the protocol. This method is easily applicable to the large-scale operations. We have also applied this method successfully for the iodocyclization of an unsaturated alcohol and an unsaturated carboxylic acid.
RADICAL DECARBOXYLATIVE BROMINATION OF AROMATIC ACIDS
Barton, Derek H.R.,Lacher, Brigitte,Zard, Samir Z.
, p. 5939 - 5942 (1985)
Thiohydroxamic esters (mixed anhydrides) of aromatic and α,β-unsaturated carboxylic acids undergo clean decarboxylative bromination on treatment with bromotrichloromethane in the presence of a radical initiator.
Oxidative bromination reaction using vanadium catalyst and aluminum halide under molecular oxygen
Kikushima, Kotaro,Moriuchi, Toshiyuki,Hirao, Toshikazu
, p. 340 - 342 (2010)
The vanadium-catalyzed oxidative bromination reaction of arenes, alkenes, and alkynes was performed in the presence of AlBr3 to provide an alternative method for conventional bromination using hazardous bromine. The catalytic cycle is formed under molecular oxygen, which is more advantageous to vanadium bromoperoxidase (VBrPO) requiring hydrogen peroxide as a terminal oxidant.
An efficient regioselective NBS aromatic bromination in the presence of an ionic liquid
Pingali, Subramanya R.K.,Madhav, Monika,Jursic, Branko S.
, p. 1383 - 1385 (2010)
A simple, efficient, and rapid method was developed for high-yielding regioselective monobromination of activated aromatic compounds using NBS in combination with ionic liquid 1-butyl-1-methylimidazolium bromide ([Bmim]Br) or dioxane. The ionic liquid is recyclable and can be reused with minimal loss in the catalytic efficiency if the ionic liquid is rapidly microwaved prior to reactions.
An efficient vanadium-catalyzed bromination reaction
Moriuchi, Toshiyuki,Yamaguchi, Mitsuaki,Kikushima, Kotaro,Hirao, Toshikazu
, p. 2667 - 2670 (2007)
An efficient catalytic oxidative bromination of arenes, alkenes, and alkynes in aqueous media was achieved under relatively mild conditions by using NH4VO3 catalyst combined with H2O2, HBr, and KBr. Dodecyltrimethylammonium bromide was found to serve as an efficient surfactant to facilitate the NH4VO3-catalyzed bromination in aqueous media.
Metal- and base-free synthesis of aryl bromides from arylhydrazines
Phuc Tran, Dat,Nomoto, Akihiro,Mita, Soichiro,Dong, Chun-ping,Kodama, Shintaro,Mizuno, Takumi,Ogawa, Akiya
, (2020)
An efficient method was developed to synthesize brominated aromatic compounds from arylhydrazine hydrochlorides by using BBr3 in DMSO/CPME (cyclopentyl methyl ether) under air at 80 °C for 1 h without the use of bases or metal catalysts. In particular, this method could be carried out satisfactorily using electron-withdrawing groups to afford aryl bromides in a moderate to excellent yields.
An intriguing effect of lithium perchlorate dispersed on silica gel in the bromination of aromatic compounds by N-bromosuccinimide
Bagheri, Mojtaba,Azizi, Najmedin,Saidi, Mohammad R.
, p. 146 - 149 (2005)
A convenient and efficient procedure for electrophilic aromatic bromination has been developed by mixing of N-bromosuccinimide and an aromatic compound at room temperature on the surface of silica gel mixed with solid anhydrous LiClO4. All of the substrates examined underwent clean electrophilic aromatic bromination in reaction times of a few minutes to afford the corresponding bromoarenes under neutral conditions in excellent yield. In the case of thiophenol, no substitution reaction occurred, and the corresponding disulfide was obtained in excellent yield.
The X-ray crystal structures and computational analysis of NH...π hydrogen bonded banana-shaped carbazole derivatives and thermal analysis of higher mesogenic homologues
Belloni, Maura,Manickam,Ashton, Peter R.,Kariuki, Benson M.,Preece, Jon A.,Spencer, Neil,Wilkie, John
, p. 17 - 35 (2001)
The synthesis of a series of banana-shaped mesogenic structures has been carried out, in which the bend unit is formed by the 3,6-substitution of carbazole by 4-alkoxyphenyl moieties. The crystal structures of the methoxy and propyloxy derivatives are reported with an analysis of the N-H...π interactions that are observed in the crystalline state. This analysis was aided by semi-empirical molecular orbital calculations. Additionally, the thermal analysis of the complete series has been carried out in order to investigate the phase properties of these materials. The 4-nonyloxyphenyl derivative displays two melting points by DSC and normal light microscopy, but yields non-birefringent liquids. The incorporation of photorefractive molecular units, such as carbazole. into anisotropic materials may offer many advantages over conventional electrical poling of photorefractive polymers.
Anodically-Generated Br-Cl Composite Halogenating Reagents
Fukui, Kouta,Nonaka, Tsutomu
, p. 943 - 948 (1992)
The halogenating power of Br-Cl composite species (termed "BC-reagent" in this article) generated anodically from mixtures of Br- and Cl- in CH2Cl2 was examined in an ex-cell manner toward some organic compounds.The BC-reagent brominated methoxybenzenes, and the brominating power could be precisely controlled by means of the amount of electricity charged and by varying the ratio of Cl-/Br-.The power of the reagent was less controllable during the bromination of aniline.The reaction of olefins with the BC-reagent led to dibromination and bromochlorination, the product- selectivity of which could be also controlled.The theoretically calculated chemical composition of the BC-reagent agreed fairly well with the experimentally confirmed value in some cases.
Methanolysis of 4-bromobenzenediazonium ions. Effects of acidity, [MeOH] and temperature on the formation and decomposition of diazo ethers that initiate homolytic dediazoniation
Fernandez-Alonso, Alejandra,Bravo-Diaz, Carlos
, p. 4004 - 4011 (2008)
We have investigated the effects of solvent composition, acidity and temperature on the dediazoniation of 4-bromobenzenediazonium (4BrBD) ions in MeOH-H2O mixtures by employing a combination of spectrometric and chromatographic techniques. The kinetic behaviour is quite complex; in the absence of MeOH, dediazoniations follow first-order kinetics with a half-life t1/2 ? 3000 min (T = 45 °C), but addition of small concentrations of MeOH lead to more rapid but non-first-order kinetics, suggestive of a radical mechanism, with t1/2 ? 125 min at 25% MeOH. Further increases in the MeOH concentration slow down the rate of dediazoniation and reactions progressively revert to first-order behaviour, and at percentages of MeOH higher than 90%, t1/2 ? 1080 min. Analyses of reaction mixtures by HPLC indicate that three main dediazoniation products are formed depending on the particular experimental conditions. These are 4-bromophenol (ArOH), 4-bromoanisole (ArOMe), and bromobenzene (ArH). At acidities (defined as -log[HCl]) a turnover in the reaction mechanism takes place under acidic conditions. At any given MeOH content, the plot of kobs or t1/2 values against acidity is S-shaped, the inflexion point depending upon the MeOH concentration and the temperature. Similar S-shaped variations are found when plotting the dediazoniation product distribution against the acidity. The acid-dependence of the switch between the homolytic and heterolytic mechanisms suggests the homolytic dediazoniation proceeds via transient diazo ethers. The complex kinetic behaviour can be rationalized by assuming two competitive mechanisms: (i) the spontaneous heterolytic dediazoniation of 4BrBD, and (ii) an O-coupling mechanism in which the MeOH molecules capture ArN2 + to yield a highly unstable Z-adduct which undergoes homolytic fragmentation initiating a radical process. Analyses of the effects of temperature on the equilibrium constant for the formation of the diazo ether and on the rate of splitting of the diazo ether allowed, for the first time, estimation of relevant thermodynamic parameters for the formation of diazo ethers under acidic conditions. The 2008 Royal Society of Chemistry.
AUTOMATED DIAZOMETHANE GENERATOR, REACTOR AND SOLID PHASE QUENCHER
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Page/Page column 17-18, (2022/03/09)
An automated apparatus (Diazo-M-pen and Diazo-M-cube) for production, utilization and quenching of highly toxic diazomethane comprising of integrated pumps, tubular flow reactor, liquid-liquid micro-separator, solid MOF quencher etc.
Green bromination method
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Paragraph 0032-0034, (2021/06/13)
The invention discloses a green bromination method, and belongs to the field of green organic chemistry. Under the conditions of room temperature, opening and neutrality, reaction raw materials are aromatic hydrocarbon, olefin, alkyne, tryptamine, tryptophane and derivatives thereof with different functional groups, a bromine source is MBrx (M is Fe , Fe , Ce and the like, and x is 2-3), and the unique oxidant is H2O2. Brominated alkanes, alkenes, aromatic hydrocarbons, pyrrolo-indolines and furo-indolines and derivatives thereof can be produced. The bromination reaction is carried out by using easily available and cheap reagents (such as FeBr2, CeB3 and H2O2) in the market and the solvent, and the method has the characteristics of mild reaction conditions, wide substrate application range, simple steps, easiness in operation and no need of separation, is a green, environment-friendly and safe bromination reaction method, and has a good application prospect.
Bis-selenonium Cations as Bidentate Chalcogen Bond Donors in Catalysis
He, Xinxin,Wang, Xinyan,Tse, Ying-Lung Steve,Ke, Zhihai,Yeung, Ying-Yeung
, p. 12632 - 12642 (2021/10/21)
Lewis acids are frequently employed in catalysis but they often suffer from high moisture sensitivity. In many reactions, catalysts are deactivated because of the problem that strong Lewis acids also bond to the products. In this research, hydrolytically stable bidentate Lewis acid catalysts derived from selenonium dicationic centers have been developed. The bis-selenonium catalysts are employed in the activation of imine and carbonyl groups in various transformations with good yields and selectivity. Lewis acidity of the bis-selenonium salts was found to be stronger than that of the monoselenonium systems, attributed to the synergistic effect of the two cationic selenonium centers. In addition, the bis-selenonium catalysts are not inhibited by strong bases or moisture.