99-28-5Relevant academic research and scientific papers
Quinazoline derivative and preparation method and application thereof
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Paragraph 0066-0068, (2020/07/15)
The invention discloses a novel compound 4-(3 '-R substituted-5'-R substituted-4 '-hydroxyanilino) quinazoline derivative and a preparation method and application thereof. The structural formulas of the compound are shown as formulas I and II. The compound has good activity of preventing and treating chicken coccidiosis and can be used as a therapeutic agent for preventing and treating chicken coccidiosis in the field of preparation of medicines for preventing and treating chicken coccidiosis.
Method for photocatalytic synthesis of polybrominated phenol compound in water phase
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Paragraph 0012; 0034, (2019/08/30)
The invention discloses a method for photocatalytic synthesis of a polybrominated phenol compound in a water phase, comprising the following steps: adding a catalytic amount of a radical initiator, aphenol derivative and low-toxic and cheap bromide salt and water into a reaction vessel, reacting at room temperature at 5 W power in a photocatalytic reactor for a certain period, extracting with ethyl acetate and then re-crystallizing to obtain a polybrominated phenol compound. The above radical initiator is eosin, azobisisobutanol, sodium persulfate, ammonium persulfate or potassium persulfate.The free radical initiator and the bromine salt are cheap and easily available, and the method is an ideal synthesis method of the polybrominated phenol compound. According to the method, low-toxicity bromine salt instead of liquid bromine is used to carry out a bromination reaction, unstable and explosive hydrogen peroxide is replaced with the cheap and easily-available free radical initiator, and an emerging photocatalytic method is used. The polybrominated phenol compound can be obtained in a high yield by only using a 5W power lamp for the reaction, the reaction selectivity is high, by-products are less, and the post-treatment is simple.
A quick, mild and efficient bromination using a CFBSA/KBr system
Jiang, Pan-Pan,Yang, Xian-Jin
, p. 90031 - 90034 (2016/10/09)
Bromination is a fundamental transformation in organic chemistry and brominated compounds as building blocks are of paramount importance in organic synthesis. In our study, we have developed an efficient method of bromination by using a CFBSA/KBr system at room temperature in a short reaction time. Notably, this approach has been proven to be applicable to a range of substrates including 1,3-diketones and β-keto esters, phenols, aromatic amines and heteroarenes with good to excellent yields.
Rapid and total bromination of aromatic compounds using TsNBr2 without any catalyst
Saikia, Indranirekha,Chakraborty, Pranita,Sarma, Manas Jyoti,Goswami, Mridusmita,Phukan, Prodeep
, p. 211 - 217 (2015/10/29)
N,N-Dibromo-p-toluenesulfonamide (TsNBr2) has been found to be a new reagent for bromination of aromatic compounds. The reaction is extremely fast and goes into completion instantaneously at ambient temperature to produce exclusively the corresponding polybrominated product. This procedure is applicable to various phenols, anisole, and anilines to give corresponding polybrominated compound as a single product in excellent yield.
A simple protocol for the visual discrimination of natural cyclodextrins in aqueous solution using perichromic probes
Nandi, Leandro G.,Nicoleti, Celso R.,Stock, Rafaela I.,Barboza, Tainá A.,Andreaus, Jürgen,Machado, Vanderlei G.
, p. 1600 - 1606 (2015/02/19)
(Graph Presented) Three synthesized compounds, 4-(4-nitrostyryl)phenol, 2,6-dibromo-4-(2,4-dinitrobenzylideneamino) phenol and 2,6-dichloro-4-(2,4-dinitrobenzylideneamino)phenol, were deprotonated to generate the perichromic dyes 2b, 3b and 4b, respectively. These dyes were used as probes to investigate the micropolarity of natural cyclodextrins (CyDs) and it was observed that they interact differently with the CyDs according to the molecular structure of the dye and the diameter of the CyD. The solvatochromic bands of the dyes that interacted with the CyDs were bathochromically shifted, suggesting that the probes were transferred to the hydrophobic interior of the CyD in aqueous solution. Dyes 2b and 4b were found to be very selective for α-CyD and γ-CyD, respectively, while β- and γ-CyD changed the color of the solution of compound 3b. These dyes were then successfully used in a simple assay that allows the naked-eye discrimination of natural CyDs in aqueous solution, without the need for expensive techniques.
Green halogenation of aromatic heterocycles using ammonium halide and hydrogen peroxide in acetic acid solvent
D'Aleo, Danielle N.,Allard, Sheena R.,Foglia, Cassandra C.,Parent, Shawna L.M.,Rohr, David J.,Gottardo, Christine,MacKinnon, Craig D.
, p. 679 - 683 (2013/08/23)
The green generation of X+ (X = Br, I) using hydrogen peroxide in aqueous acetic acid allows access to aromatic heterocyclic halides in yields and purities comparable to syntheses employing N-bromosuccinimide. In activated and unsubstituted thiophene rings, regioselectivity is quantitative for positions α to the sulfur; pyrroles also give quantitative reactions, at least initially. Deactivated rings, including furans and thiazoles, as well as thiophenes with strongly electron-withdrawing groups showed little to no reactivity under the conditions investigated. The reaction shows remarkable functional group tolerance (to alcohol, nitro, alkyl, halo, and carbonyl groups), as shown through reaction with substituted phenols. In all bromination reactions, reaction yields and regiochemistry were very similar to reactions involving N-bromosuccinimide in tetrahydrofuran solvent.
An instant and facile bromination of industrially-important aromatic compounds in water using recyclable CaBr2-Br2 system
Kumar, Lalit,Mahajan, Tanu,Agarwal
experimental part, p. 2187 - 2196 (2011/09/16)
Various industrially-important brominated intermediates have been instantly synthesized using aq. CaBr2-Br2 system as an efficient and recyclable brominating reagent under aqueous conditions at room temperature without the need for metal catalysts or acidic additives. Structurally-diverse phenol and aniline derivatives with strong electron-withdrawing groups such as carboxylic, nitro and formyl show remarkable reactivity to the brominating reagent and brominated in 92-98% yield with high purity (>99%) in a very short reaction time. Organic solvent-free conditions, a feature of the green chemistry, were successively used not only for the reactions but also for the isolation of products at the end of the reaction. The recycling of HBr by its neutralization, thereby generating additional amounts of industrially-important CaBr2 has been designed and developed. The brominating reagent has been recycled and regenerated, and the process was repeated up to 4 cycles after the fresh batch using the regenerated brominating reagent having almost identical selectivity and isolated yields, which seems to be the most promising methodology from the viewpoint of the green approach to organic synthesis.
Environmentally benign electrophilic and radical bromination 'on water': H2O2-HBr system versus N-bromosuccinimide
Podgor?ek, Ajda,Stavber, Stojan,Zupan, Marko,Iskra, Jernej
experimental part, p. 4429 - 4439 (2009/10/09)
A H2O2-HBr system and N-bromosuccinimide in an aqueous medium were used as a 'green' approach to electrophilic and radical bromination. Several activated and less activated aromatic molecules, phenylsubstituted ketones and styrene were efficiently brominated 'on water' using both systems at ambient temperature and without an added metal or acid catalyst, whereas various non-activated toluenes were functionalized at the benzyl position in the presence of visible light as a radical activator. A comparison of reactivity and selectivity of both brominating systems reveals the H2O2-HBr system to be more reactive than NBS for benzyl bromination and for the bromination of ketones, while for electrophilic aromatic substitution of methoxy-substituted tetralone it was higher for NBS. Also, higher yields of brominated aromatics were observed when using H2O2-HBr 'on water'. Bromination of styrene reveals that not just the structure of the brominating reagent but the reaction conditions: amount of water, organic solvent, stirring rate and interface structure, play a key role in defining the outcome of bromination (dibromination vs bromohydroxylation). In addition, mild reaction conditions, a straightforward isolation procedure, inexpensive reagents and a lower environment impact make aqueous brominating methods a possible alternative to other reported brominating protocols.
Rearrangements during nitrosodecarboxylation of isomeric dibromohydroxybenzoic acids
Shishkin,Fadin
experimental part, p. 688 - 692 (2009/04/07)
The reaction of 3,5-dibromo-4-hydroxybenzoic acid, its sodium salt, and also sodium 3,5-dibromo-2-hydroxybenzoate with NaNO2 in a glacial acetic acid at room temperature led to the formation of a mixture of dibromonitrophenol resulting from nitrosodecarboxylation accompanied by a rearrangement processes and followed by oxidation of the arising nitrosophenols.
1-Benzyl-4-aza-1-azoniabicyclo[2.2.2]octane tribromide as a regenerable and useful reagent for bromination of phenols under mild conditions
Hajipour, Abdol R.,Pourmousavi, Seied A.,Ruoho, Arnold E.
, p. 796 - 800 (2007/10/03)
1-Benzyl-4-aza-1-azoniabicyclo[2.2.2]octane tribromide has been examined over several phenolic compounds under mild conditions. The reaction gives brominated phenols in good to excellent yields. Straightforward work-up of the reaction yields pure products in several cases.
