Synthesis
The general procedure for the synthesis of 2-iodobenzothiazole from benzothiazole was as follows: benzothiazole (1 mmol, 135.9 mg) and perfluorobutyl iodide (1.1 mmol, 380.5 mg) were placed in a 10 mL round bottom flask. 5 mL of N,N-dimethylformamide and sodium tert-butoxide (0.5 mmol, 48.1 mg) were added. The reaction mixture was stirred at room temperature for 20 min and the progress of the reaction was monitored by thin layer chromatography (TLC). After completion of the reaction, the mixture was poured into water and extracted with dichloromethane. The organic phase was collected and dried with anhydrous sodium sulfate, followed by removal of dichloromethane by rotary evaporator to give the crude product. The crude product was purified by silica gel column chromatography using petroleum ether and ethyl acetate (v/v=30:1) as eluents to give 2-iodobenzothiazole (white solid, 257.6 mg, 99% yield). In addition, the crude product can also be purified by recrystallization: the crude product was first washed with cold water, filtered, and dissolved in ethanol (2 mL). After heating until complete dissolution, it was left to stand and slowly cooled to induce precipitation of crystals.
References
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