Description
Carbazole derivatives are widely used for OFETs, OLED, PLED. 9-(heptadecan-9-yl)-2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9H-carbazole is one of the popular intermediates used for the synthesis of either small molecules or polymers (that are made into devices for display technology or photovoltaic solar cells).
Synthesis
The general procedure for the synthesis of 9-(1-octylnonyl)carbazole-2,7-bis(boronic acid pinacol ester) from isopropanol pinacol borate and 2,7-dibromo-9-(1-octylnonyl)-9H-carbazole was as follows: 2,7-dibromo-9-(1-octylnonyl)-9H-carbazole (5.0 g, 9.0 mmol) was placed in a vacuumed round-bottomed flask and evacuated for 4 hours. Anhydrous THF (150 mL) was added to dissolve. The mixture was stirred under argon protection for 2 h, followed by slow dropwise addition of n-butyllithium (2.0 M in hexane, 11.26 mL) at -78 °C. After the dropwise addition, the reaction was continued at -78 °C for 2 hours. Then, isopropanol pinacol borate (5.52 mL) was slowly added and the reaction mixture was gradually warmed to room temperature and the reaction continued with stirring for 40 hours. Upon completion of the reaction, the reaction was quenched with methanol and then extracted with dichloromethane. The organic layer was dried with anhydrous magnesium sulfate (MgSO4), filtered and the solvent was removed by rotary evaporation. The crude product was purified by column chromatography to afford 9-(1-octylnonyl)carbazole-2,7-bis(boronic acid pinacol ester) (Yield: 70%) using ethyl acetate-hexane (1:9 to 9:1) as eluent.
References
[1] Macromolecules, 2012, vol. 45, # 21, p. 8658 - 8664
[2] Patent: KR101495152, 2015, B1. Location in patent: Paragraph 0164; 0180-0181
[3] Journal of Polymer Science, Part A: Polymer Chemistry, 2012, vol. 50, # 24, p. 5011 - 5022
[4] Journal of the American Chemical Society, 2012, vol. 134, # 46, p. 19035 - 19042
[5] New Journal of Chemistry, 2011, vol. 35, # 6, p. 1327 - 1334
