Synthesis
General procedure for the synthesis of 9-(prop-2-yn-1-yl)-9H-carbazole from carbazole and 3-bromopropyne: A mixture of carbazole (4.175 g, 25 mmol) and sodium metal (0.575 g, 25 mmol) in dioxane (20 mL) was refluxed under an inert atmosphere until the sodium metal was completely dissolved. Subsequently, 3-bromopropyne (3.38 mL, 39 mmol) was slowly added to the reaction system. Upon completion of the reaction, the mixture was cooled to room temperature and stirred continuously for 18 hours. After the reaction was terminated, an appropriate amount of water was added and extracted with dichloromethane (CH2Cl2). The organic phases were combined, dried over anhydrous sodium sulfate (Na2SO4) and filtered to remove the desiccant. The solvent was removed by distillation under reduced pressure and the resulting crude product was purified by column chromatography (eluent ratio of 10:1 hexane/ethyl acetate) to give the final target compound 9-(prop-2-yn-1-yl)-9H-carbazole in 76% yield.
References
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