Background and overview of the preparation method of 4-aminophenylboronic acid pinacol ester
4-Aminophenylboronic acid pinacol ester is used as an intermediate in the synthesis of drugs and organic light-emitting materials (LEDs). Arylboronic acid can be used as a safe and environmentally friendly new arylation reagent and is widely used in the scientific research and production of various fine chemicals containing aryl structures such as medicines, pesticides, and advanced materials. The reaction of arylboronic acids and halogenated compounds plays a decisive role in today’s drug synthesis. This type of reaction was first proposed by the Japanese scientist Suzuki’s team and won the Nobel Prize in Chemistry in 2010.
Preparation method of 4-aminophenylboronic acid pinacol ester
Report on the preparation method of 4-aminophenylboronic acid pinacol ester 1.
To a stirred solution of 4-bromoaniline (1.0 g, 5.8 mmol) and bis(pinacolato)diboron (1.78 g, 7.0 mmol) in dioxane (15.0 mL) was added potassium acetate (1.71g, 17.4mmol). The reaction mixture was degassed with nitrogen for 30.0 min, and PdCl2(dppf) (0.21 g, 0.3 mmol) was added. The reaction was allowed to stir at 100 °C for 6 h. The reaction progress was monitored by TLC. After the reaction was completed, methyltetrahydrofuran was used to distill off dioxane from the reaction mixture, and the residue was quenched with water, and the compound was extracted with ethyl acetate. The organic layer was concentrated under reduced pressure to give a crude compound, which was purified by Combi-flashTM column chromatography (4.0 g column), eluting with 20% ethyl acetate in hexane, to give 4- as a pale yellow solid. Aminophenylboronic acid pinacol ester (0.65g, 5 mica 0.78%). MS: 220.20[M+1].
Preparation method report 2 of 4-aminophenylboronic acid pinacol ester,
Add 20g 4-aminobenzene borate hydrochloride, 19.2g pinacol, and 46.6g anhydrous magnesium sulfate into a 500ml round-bottomed flask, add 250ml tetrahydrofuran, stir and react at room temperature for 5 hours, and filter after the reaction is completed. The organic phase was washed twice with saturated sodium chloride, dried with anhydrous sodium sulfate, and finally spun dry to obtain 21.5 g of white solid 4-aminophenylboronic acid pinacol ester, with a yield of 76%.
Preparation method report 3 of 4-aminophenylboronic acid pinacol ester.
Add p-phenylenediamine (0.5mmol) and 2.0mL (50mmol) methanol into the reaction tube. After the aniline is completely dissolved, add 0.5mL 3mol/L hydrochloric acid and stir for two minutes. Add 35mg sodium nitrite solid to 0.25 mL of distilled water, then slowly add it into the reaction tube with a syringe, stir for 30 minutes at 0 to 5°C, then add (1.5 mmol) divaleryl diboron to the reaction tube, stir for 1 hour at room temperature, and wait for reaction At the end, add 10 mL of distilled water to the mixture, and then extract it with 50 mL of methylene chloride three times. Collect the organic phase, dry it with anhydrous Na2SO4, filter with suction, and use The dichloromethane was removed with a rotary evaporator to obtain 4-aminophenylboronic acid pinacol ester as a white solid, with a yield of 53%.
References
[1][Invented in China] CN201780022556.2 Thiazolopyridine derivatives as GPR119 agonists
[2][Chinese invention, Chinese invention authorization] CN201410190653.0 Method for producing arylboronic acid and arylboronic acid ester by boronation reaction of aromatic amine under alcohol promotion
[3][Chinese invention] CN201610280781.3 A bis-aryl urea compound with anti-tumor activity and its preparation method and application
