Background and overview of application examples of 5-chloropyridine-3-boronic acid
5-Chloropyridine-3-boronic acid is an organic intermediate that can be used to perform Suzuki coupling reactions. There are reports in the literature that it can be used to synthesize electron transport materials.
Application examples of 5-chloropyridine-3-boronic acid
CN201911240392.8 reports that 5-chloropyridine-3-boronic acid is used to prepare a new electron transport material, such as compound 1. The structure of this type of material contains thermal cross-linking functional units (styrene and its derivatives) and pyridine strong electron-attracting structure electron transport functional units, which are directly cross-linked through simple heating to achieve the anti-solvent function of the electron transport layer and stabilize the network structure. Formed in situ, it has 100% solvent resistance and high interface stability, as well as high electron transmission performance and high triplet energy level. It is especially suitable for printing to prepare OLEDs. There is no erosion between printing film layers during use. The destructive effect can improve the luminous efficiency and service life of the device, and achieve high-quality printing of multi-layer OLED device structures, which can be used for inverted printed OLEDs. The electron transport material also has applications in hole or exciton blocking layers of OLED devices.
Application examples of 5-chloropyridine-3-boronic acid Step 1. Synthesis of intermediate a
Weigh 3.0g (9.5mmol) 1,3,5-tribromobenzene, 5.9g (37.9mmol) 5-chloropyridine-3-boronic acid and 1.39g (1.9mmol) PdCl2(d basic magnesium carbonate ppf), add them to 500ml two-neck round bottom flasks, then add 100ml 1,4-dioxane and 100ml potassium carbonate solution (2.4M), protect with nitrogen, and vacuum 3 times to ensure an oxygen-free atmosphere. The system was stirred and heated to 105°C, refluxed overnight. Stop the reaction, separate the system into phases, separate the upper organic phase, add a large amount of water, extract three times with dichloromethane, and combine the organic phases. The organic phase was dried over anhydrous magnesium sulfate, rotary evaporated, mixed with silica gel, and then separated by column chromatography. The eluent of neodymium carbonate dihydrate was methylene chloride/ethyl acetate (3:1 volume ratio). 3.08g of white solid was isolated, with a yield of 78.6%.
Application examples of 5-chloropyridine-3-boronic acid Step 2, synthesis method of compound 1
Weigh 2.4g (5.9mmol) (intermediate a), 5.24g (35.4mmol) 4-vinylbenzeneboronic acid, and 0.432g (0.47mmol) Pd2(dba)3 and 0.26g (0.94mmol) tricyclohexylphosphine were added to a 500ml two-neck round bottom flask, then 240ml 1,4-dioxane and 14.75ml potassium phosphate solution (2.4M) were added, nitrogen Protection, vacuum 3 times to ensure an oxygen-free atmosphere. The system was stirred and heated to 100°C overnight. Stop the reaction, add a large amount of water to the system, extract three times with dichloromethane, and combine the organic phases. The organic phase was dried over anhydrous magnesium sulfate, rotary evaporated, mixed with silica gel, and then separated by column chromatography. The eluent was methylene chloride/ethyl acetate (5:1 volume ratio). 3g of white solid was isolated, with a yield of 82.6%.
References
[1] [Chinese invention] CN201911240392.8 An electron transmission material and its use and organic electroluminescent diode
