Overview of the main applications of 4-cyanobenzeneboronic acid
Biphenyl is an important starting material in organic synthesis. It is widely used in medicine, pesticides, dyes and other fields. It can be used to prepare insecticides and rodenticides, and can be used as preservatives and antifungal agents. Chromatography analysis standard materials, etc. As a common coupling reagent, 4-cyanophenylboronic acid undergoes a Suzuki-Miyaura coupling reaction with halobenzene to synthesize hydrated yttrium biphenyl carbonate. Research on 4-cyanophenylboronic acid has been very extensive and in-depth in recent years. There are endless reports on the synthesis of biphenyl.
Main applications of 4-cyanobenzeneboronic acid
4-Cyanophenylboronic acid, as a common coupling reagent, can participate in various C-C, C-N and C-О type coupling reactions to synthesize various valuable compounds.
1. Synthetic biphenyl
Pang’s research team found that aromatic diazonium salts (ADS) can be regarded as superelectrophilic reagents. The super electrophilicity allows the cross-coupling reaction with 4-cyanophenylboronic acid to be carried out in a simple and mild experiment. conditions effectively. Typical Suzuki-Miyaura coupling reactions generally require an alkaline environment and higher temperatures, and phenyldiazotetrafluoroborate itself can provide alkalinity when participating in the coupling, saving experimental costs and expanding the Suzuki-type coupling reaction. range.
2. Synthesis of 1,1-diarylalkanes
The skeleton structure of 1,1-diarylalkanes can be seen in many biologically active natural products. This type of compounds is of great significance to academic research and medical pharmaceuticals. Therefore, an effective method can be developed to The preparation of such compounds is very important, and 4-cyanobenzeneboronic acid is the raw material for the synthesis of such compounds.
3. Synthesis of aromatic ethers
Aromatic ether skeletons are widely found in various natural products and pharmaceutical molecules and can be used to synthesize dyes, pesticides, medicines, etc. Some aromatic ethers with high boiling points can be used as heat carriers, and some aromatic ethers are also used as food protectants or antioxidants. Aromatic ethers are generally synthesized by C-O coupling of 4-cyanophenylboronic acid and alcohols or phenolic compounds.
4. Synthesis of aromatic amines
Aromatic amines are starting materials and intermediates in some organic synthesis and are widely used to synthesize a variety of chemical products. There are many methods to synthesize such compounds, among which 4-cyanophenylboronic acid and aliphatic amines pass through C-N Coupling is one of the most common methods.
Whether it is in the scientific research process of life sciences or organic chemistry, nitrogen-containing compounds have always aroused great interest among scientific researchers. Many natural products such as proteins, vitamins and alkaloids are nitrogen-containing compounds, as are some organic dyes, photosensitive materials and synthetic drugs. Therefore, the optimization and development of synthesis methods for nitrogen-containing compounds is a very important topic. 4-Cyanophenylboronic acid Phenylboronic acid and compounds containing amine groups participate in many organic reactions and have important application value and promotion significance for the development of synthetic chemistry and medicinal chemistry.
The main application preparation methods of 4-cyanobenzeneboronic acid
1), 3, 5-difluorobenzene reacts with Mg powder in THF to generate Grignard reagent. The Grignard reagent solution is added dropwise to trimethyl borate at low temperature for reaction, and then acidified with HCl , after post-treatment, 3,5-difluorophenylboronic acid is obtained.
2). Under the catalysis of p-toluenesulfonic acid, 3,5-difluorobenzene borate is reacted with ethylene glycol, and after post-treatment, 3,5-difluorobenzene borate ethylene glycol is obtained.
3), 3,5-difluorobenzene borate ethylene glycol reacts with butyllithium at low temperature to form an intermediate compound. This lithium reagent reacts with I, and after post-treatment, 3,5-difluoro-4-iodine is obtained. Ethylene benzene borate.
4), 3,5-difluoro-4-iodobenzene borate ethylene glycol and cuprous cyanide react in a solvent under reflux, and the reaction product is acidified and post-treated to obtain 3,5-difluoro-4- -Cyanophenylboronic acid.
In step 1), the Grignard reagent solution is slowly dropped into the mixture of trimethyl borate and THF at -40°C, and the reaction is continued at this temperature.
The post-processing in step 1) is: solvent extraction and separation, washing the solvent layer with water, drying and concentration.
In step 2), 3,5-difluorobenzene boric acid, ethylene glycol and p-toluenesulfonic acid are refluxed and water separated in toluene.
The post-treatment in step 2) is: liquid separation to remove excess ethylene glycol in the lower layer, concentration of the upper layer to remove toluene, and distillation of the concentrated solution under reduced pressure.
The reaction temperature in step 3) is -78℃–80℃, and the solvent is anhydrous THF;
The post-treatment in step 3) is to raise the reaction mixture to room temperature, hydrolyze and separate the liquids, extract with ethyl acetate, dry, filter and concentrate to remove the solvent, and the residue is recrystallized with petroleum ether.
The post-treatment in step 4) is: concentrate under reduced pressure to remove DMF and lower it to room temperature. The residue is extracted with ethyl acetate, and the insoluble matter is filtered off. The filtrate is acidified by adding an aqueous solution of hydrochloric acid and separated, and the organic layer is washed with water. Dry, filter and concentrate to remove the solvent. Obtain 4-cyanobenzeneboronic acid.
Reference materials
[1] Wang Haojie. Research on organic reactions involving phenylboronic acid and amino compounds[D].
[2] Ji Haijian, Bai Xuefeng, rhodium tetrafluoroborate. Synthesis of 4-cyanophenylboronic acid by Miyaura boronation reaction [J]. Chemistry and Adhesion
