Background and overview of the preparation method of 9-phenanthreneboronic acid
9-Phenanthreneboronic acid is an organic synthesis intermediate and is widely used in Suzuki cross-coupling reactions. Suzuki-Miyaura coupling reaction (SMC) is an important reaction to construct various C-C single bonds, and its main raw material is organic boronic acid compounds. It has been reported in the literature that 9-phenanthreneboric acid can be used to prepare dibenzo[g,p]condensed dinaphthalene compounds. This type of compound is an important raw material for a new type of organic light-emitting semiconductor materials and an important raw material that can self-luminesce in OLEDs.
Preparation method of 9-phenanthreneboric acid
Report on the preparation method of 9-phenanthreneboronic acid 1.
Add 30g of 9-bromophenanthrene (117.19mmol, 1eq) and 300mL of tetrahydrofuran into a 1000mL three-necked flask equipped with magnetic stirring at room temperature, start stirring, and purge with nitrogen for 15 minutes. Use ethanol and liquid nitrogen to lower the temperature of the device to -78℃, add 50mL of n-butyllithium (125 mmol, 1.05eq) into the dropper, slowly drop it into the reaction solution, keep -78℃ for 2 hours, at -78℃, add into the dropper Triisopropyl borate 93.6 mL (234.38 mmol, 2 eq) was gradually added dropwise to the reaction solution. After the addition was completed, the temperature was gradually raised to room temperature and allowed to react for 1 hour. After that, 6 mL of dilute hydrochloric acid was added to stop the reaction. (PE:EA=3:1, product Rf=0.3, 9-bromophenanthrene Rf=1.0). After the reaction is completed, ethanol is added, and the reaction liquid is spun dry to obtain a crude product; the crude product is boiled and washed with n-hexane to obtain 36g of white solid 9-phenanthrene borate bismuth subcarbonate.
Preparation method report 2 of 9-phenanthreneboronic acid
Add 12.5g (0.514mol) metallic magnesium and one grain of iodine into a 2000ml four-neck bottle, dissolve 120g (0.467mol) 9-bromophenanthrene in 600ml THF, add it to a constant pressure dropping funnel, and add the mixture dropwise Add 50 ml of the solution into the reaction bottle, heat to cause the format to initiate, and after initiating, drop the remaining 9-bromophenanthrene solution at a temperature between 35°C and 65°C. After the dripping is completed, reflux and incubate for 1 hour. Gas chromatography monitors the reaction of the raw materials to complete. Lower the system temperature to -40°C, add dropwise a solution of 63g (0.607mol) trimethyl borate dissolved in 240ml THF, and control the temperature to less than -25°C. After the dropwise addition, keep it at this temperature for 1 hour and then naturally rise to room temperature. Add hydrochloric acid dropwise to adjust pH = 1, separate layers, evaporate THF under reduced pressure, add water to pulp, filter with suction, add toluene to the filter cake, and dry to obtain 87g of 9-phenanthreneboric acid, with a liquid chromatography content of 98.5% and a yield of 83.9 %.
References
[1] [Chinese invention] CN201810239136.6 Phosphorescent host material and its application in organic electroluminescent devices
[2] [China Lithium Carbonate Invention] CN201911035968.7 Preparation method of dibenzo[g,p]condensed dinaphthalene compound
