615-58-7Relevant academic research and scientific papers
Halogenated method of aromatic compound
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Paragraph 0205-0207, (2021/11/10)
The invention belongs to the field of organic synthesis, and particularly relates to synthesis of aromatic halogens, in particular to arylamine. The invention discloses a synthesis method of a corresponding ortho-halogenated product from aromatic compounds such as carbazole and phenol. The method comprises the following steps: adding a metal sulfonate salt catalyst, aromatic amine, carbazole, phenol and other hydrogen - heteroatom-containing aromatic compound reaction substrates, a halogenation reagent and a reaction solvent at a specific reaction temperature. After the drying agent is dried, the yield of the reaction product and the nuclear magnetic characterization determining structure are determined by column chromatography. The reaction product yield is determined by gas chromatography. By adopting the method, under the cheap metal salt catalyst, a plurality of ortho-substituted brominated and chloro products can be obtained with moderate to excellent yield.
Preparation method of monobrominated aromatic hydrocarbon compound
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Paragraph 0068-0070, (2020/11/23)
The invention discloses a preparation method of a monobrominated aromatic hydrocarbon compound, which comprises the following steps: by using an aromatic hydrocarbon compound as a raw material, wateras a solvent and liquid bromine as a bromine source, reacting at room temperature for 4.5 hours, and after the reaction is finished, carrying out aftertreatment on the obtained reaction mixed solutionto obtain the monobrominated target product. According to the method, a high-selectivity bromination method is realized on the aromatic hydrocarbon compound under the action of water, and the monobrominated aromatic hydrocarbon compound is prepared. The method is high in reaction applicability, mild in condition, high in yield, green and environment-friendly.
Regioselective monobromination of phenols with KBr and ZnAl–BrO3?–layered double hydroxides
Wang, Ligeng,Feng, Chun,Zhang, Yan,Hu, Jun
supporting information, (2020/02/22)
The regioselective mono-bromination of phenols has been successfully developed with KBr and ZnAl–BrO3?–layered double hydroxides (abbreviated as ZnAl–BrO3?–LDHs) as brominating reagents. The para site is much favorable and the ortho site takes the priority if para site is occupied. This reaction featured with excellent regioselectivity, cheap brominating reagents, mild reaction condition, high atom economy, broad substrate scope, and provided an efficient method to synthesize bromophenols.
A convenient and efficient H2SO4-promoted regioselective monobromination of phenol derivatives using N-bromosuccinimide
Wu, Yong-Qi,Lu, Hai-Jia,Zhao, Wen-Ting,Zhao, Hong-Yi,Lin, Zi-Yun,Zhang, Dong-Feng,Huang, Hai-Hong
supporting information, p. 813 - 822 (2020/02/15)
A convenient, rapid H2SO4-promoted regioselective monobromination reaction with N-bromosuccinimide was developed. The desired para-monobrominated or ortho-monobrominated products of phenol derivatives were obtained in good to excellent yields with high selectivity. Regioselective chlorination and iodination were also achieved in the presence of H2SO4 using N-chlorosuccinimide and N-iodosuccinimide, respectively.
Mild and Regioselective Bromination of Phenols with TMSBr
Ma, Xiantao,Yu, Jing,Jiang, Mengyuan,Wang, Mengyu,Tang, Lin,Wei, Mengmeng,Zhou, Qiuju
supporting information, p. 4593 - 4596 (2019/07/05)
In this work, an unexpected promoting effect of by-product thioether was observed, leading to a mild and regioselective bromination of phenols with TMSBr. This method can tolerate a series of functional groups such as the reactive methoxyl, amide, fluoro, chloro, bromo, aldehyde, ketone and ester groups, and has the potential to recycle the by-product thioether and isolate the desired product under column chromatography-free conditions. Mechanism studies revealed that O–H···S hydrogen bond may be formed between phenol and by-product thioether. Possibly owing to the steric hindrance effect from by-product thioether, the electrophilic bromination at para-position of phenols is much favorable.
A phenol compound high regioselective bromination method
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Paragraph 0031; 0032; 0033, (2019/06/05)
The invention discloses a phenol compound high regioselective bromination of the method, the method to trimethyl silane as brominating agent, in order to aryl sulfoxide as activator, with the phenol compound in the 0 - 50 °C lower, in a solvent, the reaction is stirred under an atmosphere of nitrogen at 1 - 12 hours, to realize the phenol compound high regioselective bromination, filtered, extraction columns chromatography separation to obtain the bromo phenol compound. This invention adopts the aryl sulfoxide as activator, sulfoxide substituted Kiev, on the one hand so that the phenol compound bromo the higher selectivity of the reaction region, and when the phenol compound hydroxy alignment not substituted basetime, regional selective para - bromo product, when the phenol compound hydroxy position there is substituted basetime, selective ortho - bromo product obtained; on the other hand if it through the filter, the extraction can be realized at the same time the isolation and purification of the recycling of the by-product, compared with column chromatography, reduces the separation and purification cost.
Preparation method of tris(2, 4-dibromophenyl)phosphate
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Paragraph 0027-0029; 0034-0037; 0040-0043; 0046-0049, (2018/10/11)
The invention relates to a preparation method of tris(2, 4-dibromophenyl)phosphate. The preparation method is capable of solving technical problems in the prior art that tris(2, 4-dibromophenyl)phosphate (BPP) product yield is low, impurity content is high, technology operation is complex, and cost is high. According to the preparation method, a halogenated hydrocarbon and a low fatty alcohol aremixed so as to obtain a mixed solvent, strong acid catalysis is adopted to prepared high purity 2,4-dibromophenol, a weak base is adopted for neutralization of an obtained system to protect phenolic hydroxyl groups from reaction with alkaline substances, an anti-oxidant is adopted to avoid oxidation of the phenolic hydroxyl groups by the air, so that high yield high transparency 2,4-dibromophenolis obtained. In the synthesis process of tris(2, 4-dibromophenyl)phosphate, under solvent free conditions, temperature segment reaction is carried out under Lewis acid catalytic effect, so that product yield is increased greatly; the cooperation of water and an emulsifier is capable of realizing applications of products in the field of transparent material flame resistance. The preparation methodis widely used in the field of fire retardant synthesis.
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 (2018/11/25)
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.
Bromine formation in solid NaBr/KNO3 mixture and assay of this reaction via bromination of activated aromatics
Rahu, Ida,Keki?ev, Ott,J?rv, Jaak,Burk, Peeter
, p. 2893 - 2898 (2018/08/23)
Bromine formation in the mixture of solid NaBr and KNO3 was observed and the process was studied in different acidified organic solvent–water mixtures by monitoring the bromination of acetanilide and other compounds, containing activated aromatic substituents. This assay is based on fast bromination reaction of these aromatic compounds, as differently from the assay of Br2, the brominated aromatics can be easily determined by conventional gas chromatography–mass spectrometry (GC–MS) methods. It was found that bromine was generated autocatalytically on the surface of salt crystals and the reaction was characterized by a lag period, the duration of which depended on reaction conditions, and importantly on the type of the organic solvent in the reaction mixture. As the bromine formation could be easily controlled by reaction conditions, it was suggested that the studied reaction might have practical applications as an environmentally friendly and economically feasible bromination method. It was also shown that the bromination of aromatics followed the mechanism of classical electrophilic aromatic substitution reaction.
A bromo-capped diruthenium(i,i) N-heterocyclic carbene compound for in situ bromine generation with NBS: Catalytic olefin aziridination reactions
Sengupta, Gargi,Pandey, Pragati,De, Subhabrata,Ramapanicker, Ramesh,Bera, Jitendra K.
supporting information, p. 11917 - 11924 (2018/09/10)
A bromo-capped metal-metal bonded diruthenium(i,i) complex Ru2(CO)4(PIN)2Br2 (1) (PIN = 1-isopropyl-3-(5,7-dimethyl-1,8-naphthyrid-2-yl)imidazol-2-ylidene) generates bromine with N-bromosuccinimide (NBS) at room temperature. Cycloalkene and stilbene are readily brominated by stoichiometric reactions with 1 and NBS. An analysis of the dibrominated products suggests the formation of cyclic bromonium intermediates indicating in situ Br2 generation. Complex 2, an iodide analogue of 1, is also synthesized. The reaction of 2 with N-iodosuccinimide releases I2, which is confirmed by the starch-iodine test. The catalytic utility of 1 is examined for the bromination of phenol. Catalyst 1, in combination with NBS and base, exhibits regioselectivity towards monobrominated products. Furthermore, efficient olefin aziridination is demonstrated utilizing catalyst 1 in the presence of NBS, K2CO3 and TsNH2.
