3652-89-9Relevant articles and documents
Preparation method of 4-bromocarbazole
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Paragraph 0041-0057; 0060-0063, (2020/12/08)
The invention discloses a preparation method of 4-bromocarbazole, and belongs to the technical field of chemistry. According to the preparation method of 4-bromocarbazole, o-bromoaniline and m-dibromobenzene are subjected to a C-N coupling and C-C coupling cascade reaction under the action of a catalyst, a ligand and alkali, 4-bromocarbazole is synthesized in one step through a one-pot method, m-dibromobenzene is a reactant and also serves as a reaction solvent at the same time, and residual m-dibromobenzene can be recycled after the reaction is finished. According to the preparation method, o-bromoaniline and m-dibromobenzene, which are cheap and easy to obtain, are used as raw materials, the product 4-bromocarbazole is obtained by one step through a one-pot method cascade reaction, and compared with the prior art, the step of nitro reduction cyclization is avoided, namely the reaction step is shortened, and the preparation method has the advantages of low production cost, environmental friendliness and the like.
4-bromocarbazole preparation method
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Paragraph 0053; 0054; 0057, (2019/10/17)
The invention discloses a 4-bromocarbazole preparation method. The method includes: in a reaction bottle, mixing 2-bromo-6-fluoronitrobenzene with aniline, adding triethylamine, starting stirring, performing reflux reaction for 8h, after reaction is finished, adding water to perform quenching reaction, and carrying out suction filtration to obtain brownish red solid namely 2-nitro-3-bromo-1,1'-biphenyl; mixing 2-nitro-3-bromo-1,1'-biphenyl with ethyl alcohol, adding ferric trichloride and activated carbon, starting stirring, dropwise adding 80% hydrazine hydrate, then stirring for 6h under a reflux state, and performing filtering, extracting, layering, washing and distilling to obtain off-white solid namely 2-amino-3-bromo-1,1'-biphenyl. By adoption of cheap and easily-acquirable raw materials, a target compound is obtained through three-step reaction of fluorine nucleophilic substitution, reduction and diazonium cyclization, and the total yield of products is high. In addition, a process is simple in operation, suitable for large-scale production and beneficial to product market competitiveness.
4-bromo-9H-carbazole synthesizing method
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Paragraph 0019; 0023; 0024; 0027; 0028; 0031, (2019/02/04)
The invention discloses a 4-bromo-9H-carbazole synthesizing method and belongs to the field of organic synthesis. According to the method, o-chloronitrobenzene is utilized as a starting material, 2,2'-dinitrobiphenyl is synthesized through high-temperature coupling reaction under copper powder catalysis, then 4-nitro carbazole is obtained through triethyl phosphite ring closure reaction, diazoniumsalt is prepared from 4-nitro carbazole through zinc powder reduction and diazotization reaction under the acid condition, and then the diazonium salt reacts with cuprous bromide to synthesize a product of 4-bromo-9H-carbazole. According to the method, the raw materials are easy to obtain, the production cost is low, and the yield can reach 70% or more; the method has easiness in industrial production and provides basis for industrialization of 4-bromo-9H-carbazole and follow-up derivatives of 4-bromo-9H-carbazole.