Preparation method of 3-phenoxyphenylboronic acid_Kain Industrial Additive

Background and overview^[1]

3-Phenoxyphenylboronic acid is an organic intermediate that can be used to prepare luminescent materials. It can be prepared from phenol and 1-bromo-2-iodobenzene through a two-step reaction.

Preparation method^[1]

Step 1, synthesis of intermediate 1-bromo-2-phenoxybenzene (A-1):

Take 0.1 mol of phenol, dissolve it in 100 mL of anhydrous tetrahydrofuran, stir, accurately weigh 0.4 mol of sodium hydride and add it to the reaction bottle in batches, not too fast to prevent too many bubbles from being generated. After the addition, the solution will turn yellow , then add 0.11 mol of 1-bromo-2-iodobenzene (added in batches) and react at room temperature overnight; filter the reaction product to remove the solid matter, spin the filtrate to dryness, add dichloromethane to dissolve, and pass through the column with petroleum ether: acetic acid Ethyl ester = 1:5 (volume ratio) was washed through the column to obtain 1-bromo-2-phenoxybenzene (intermediate A-1) (0.05 mol, y = 50%). Mass spectrum: 249.97.

Step 2, synthesis of 2-phenoxyphenylboronic acid (B-1):

Dissolve 0.018 mol of 1-bromo-2-phenoxybenzene in 100 ml of dry THF, then add it to a dried 500 ml three-necked bottle, and react at -78°C under the protection of N₂ 30min, slowly add 0.027mol of n-butyllithium dropwise, and after the dropwise addition is completed, keep the reaction at -78°C for 3 hours, then slowly add 0.02mol of triisopropyl borate dropwise, and after the dropwise addition, keep the reaction at -78°C for 2h, and slowly The temperature was raised to room temperature and the reaction was carried out overnight. After TLC monitoring of the reaction, the reaction solution was slowly quenched with water, extracted and evaporated to dryness to obtain 0.0144 mol of 2-phenoxyphenylboronic acid (B-1) with a yield of 80%. Mass spectrum: 214.06.

Apply^[1]

As shown in the table below, 3-phenoxyphenylboronic acid can be used as a reactant in a coupling reaction with a halogenated aromatic hydrocarbon to produce intermediate C14, C14 bromine, which can be further made into boric acid, and then coupled to prepare a luminescent substrate.