Preparation method of 7H-benzo[C]carbazole_Kain Industrial Additive

Background and overview^[1]

Carbazole derivatives are typical electron-rich groups, so carbazole derivatives have good hole transport capabilities and high luminescence capabilities. Moreover, due to their large rigid planar structure, group movement is difficult and can effectively Increase the glass transition temperature (Tg) of the compound. Therefore, carbazole derivatives are a type of material with high Tg, high luminescence intensity and good hole transport properties, and can be used as hole transport materials and luminescent materials. 7H-benzo[C]carbazole is an important organic light-emitting material intermediate that can further synthesize organic optoelectronic materials, which have been widely used in organic light-emitting diodes (OLEDs).

Preparation^[1]

7H-Benzo[C]carbazole is prepared as follows:

A: Add 260g 2-naphthol and 520g hydrazine hydrate (80%) into a clean and dry 1000mL four-neck reaction flask, stir, raise the temperature to reflux, and insulate for 20 hours. After the reaction is completed, cool to 90°C and add 500g Clear water, stir and crystallize at room temperature, filter with suction, and wash twice with clean water to obtain an off-white solid. After the solid is dissolved by heating with 750 ml of toluene, carefully add 100 ml of concentrated hydrochloric acid dropwise between 60-70°C. After the dripping is completed, cool to Room temperature, suction filtration, rinse the solid with a small amount of toluene, and dry to obtain 296.5g of light red white solid, HPLC: 98.2%.

B: Add 164g 2-naphthylhydrazine hydrochloride and 968ml methanol into a clean and dry 3000mL four-neck reaction bottle, stir at room temperature, control the temperature of the reaction material at 20-25°C, add 91g cyclohexanone dropwise, and After the addition is completed, stir at room temperature for another 2 hours. A white solid precipitates during the reaction. After the reaction is completed, cool to 0°C, filter with suction, rinse the solid with 250 ml of cold methanol, collect the solid, and dry it to collect white needles. Solid 141g, HPLC: 99.7%.

C: Into a clean and dry 2000mL four-neck reaction bottle equipped with a stirrer, thermometer and condenser tube, add 98.3g of 5, 6, 7, 8-tetrahydro-3, 4-benzocarbazole and 700ml Toluene, after stirring and dissolving, add 201.9g DDQ in batches at room temperature. After the addition is completed, raise the temperature to reflux and keep the reaction for 2 hours. HPLC traces the reaction of 5, 6, 7, 8-tetrahydro-3, 4-benzocarbazole. , after the reaction is completed, cool the material to room temperature, remove the insoluble matter by suction filtration, rinse the solid with an appropriate amount of toluene, combine the filtrate, and recover the toluene under reduced pressure of the filtrate, add 200ml of ethanol, heat to dissolve, stir and crystallize at room temperature, and filter through suction Afterwards, an off-white solid 7H-benzo[C]carbazole was obtained. After drying, 70.4 g was obtained. HPLC: 99.5%.

Main reference materials

[1] CN201910346950.2 A preparation method of 10-bromo-7H-benzo[c]carbazole