615-58-7Relevant academic research and scientific papers
Halogenated method of aromatic compound
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, (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.
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.
Preparation method of monobrominated aromatic hydrocarbon compound
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Paragraph 0071-0074, (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.
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.
1,1,2,2-Tetrahydroperoxy-1,2-Diphenylethane: An efficient and high oxygen content oxidant in various oxidative reactions
Khosravi, Kaveh,Naserifar, Shirin
supporting information, p. 6584 - 6592 (2018/10/05)
Several oxidative approaches namely thiocyanation of aromatic compounds, epoxidation of alkenes, amidation of aromatic aldehydes, epoxidation of α β-unsaturated ketones, oxidation of sulfides to sulfoxides and sulfones, bayer-villeger reaction, bromination and iodation of aniline and phenol derivatives oxidative esterification, oxidation of pyridines and oxidation of secondary, allylic and benzyllic alcohols were carried out using 1,1,2,2-Tetrahydroperoxy-1,2-Diphenylethane as the potential solid oxidant which can be stored for several months without any loss in its activity. All of the procedures were accomplished via mild reaction conditions and the products were afforded in high yields and short reaction times.
Synthesis, kinetics, and mechanism of bromophenols by N-bromophthalimide in aqueous acetic acid
Anjaiah, Birla,Prameela, Kethavath,Srinivas, Pabba,Rajanna, Kamatala Chinna
, p. 804 - 812 (2018/09/11)
The kinetics and mechanism of bromination of phenol and its substituents, viz. 4-chlorophenol, 4-bromophenol, 4-methylphenol, and 4-methoxyphenol by N-bromophthalimide (NBP) in the presence of mercuric acetate in the temperature range of 303–318?K in aqueous acetic acid medium have been investigated. The reaction follows first-order dependence on [NBP] and fractional order dependence of rate on [Phenol]. The activation parameters have been evaluated, and based on the observed kinetic results the probable mechanism has been proposed. Observed kinetic features and Hammett's reaction constant (ρ) suggests that bromination occurs through electrophilic substitution of bromonium ion (Br+) into the aromatic ring in the transition state. Large negative entropy of activation values probably suggests the rigid nature of transition state.
Ultrasonically assisted halogenation of aromatic compounds using isoquinolinium bound hypervalent chromium and tetrabutylammonium halides in PEG-600 solutions under acid free and solvent-free conditions
Sambashiva Rao,Ramesh, Kola,Rajanna,Chakrvarthi
, p. 1892 - 1896 (2018/07/10)
Isoquinolinium bound Cr(VI) reagents like isoquinolinium dichromate (IQDC) and isoquinolinium chlorochromate (IQCC) have been successfully accomplished as efficient reagents for oxidative halogenation of aromatic compounds using tetrabutylammonium halide (TBAX) as halogenating agents in aqueous polyethylene glycol (PEG-600) under acid free conditions. Tetrabutylammonium bromide (TBAB) has been used for bromination and tetrabutylammonium iodide (TBAI) for iodination. The halogenation reactions that occurred smoothly in 2 to 7 h under conventional conditions are accelerated magnificently under sonication with few minutes (25 to 70 min) of reaction time and fairly good yields. The reactions occurred at moderate temperature under mild and environmentally safe conditions with simple work up.
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.
