Synthesis
General procedure for the synthesis of 2,7-dibromo-9-ethyl-9H-carbazole from bromohexane and 2,7-dibromocarbazole: A mixture of 2,7-dibromo-9H-carbazole (10 mmol), ethidium bromide (10.5 mmol), benzyltriethylammonium chloride (0.227 g, 1 mmol), toluene (20 mL), and a 50% w/v aqueous sodium hydroxide (0.42 g 10.5 mmol) The mixture was stirred at 80 °C for 14 hours. Upon completion of the reaction, the mixture was cooled to room temperature, poured into 50 mL of water and acidified with 10% hydrochloric acid to pH ≈ 2. The organic layer was separated and the aqueous phase was further extracted with toluene (2 × 10 mL). The organic phases were combined, washed with water (2 x 25 mL), dried over anhydrous sodium sulfate, filtered and concentrated to dryness. The crude product was purified by column chromatography to afford the target compound 2,7-dibromo-9-ethyl-9H-carbazole.
References
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