Synthesis
General procedure for the synthesis of 2-bromobenzothiazole from benzothiazole: Benzothiazole (1 mmol, 135.9 mg), carbon tetrabromide (1.1 mmol, 364.8 mg), 5 mL of N,N-dimethylformamide, and sodium tert-butoxide (4.0 mmol, 384.4 mg) were sequentially added to a 10 mL round-bottom flask. The reaction mixture was stirred at room temperature for 3 hours, during which time 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 phases were combined and dried with anhydrous sodium sulfate. Subsequently, the dichloromethane was removed by rotary evaporator to obtain 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-bromobenzothiazole (light yellow oily liquid, 199 mg, 93% yield).
References
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[2] Patent: CN107501023, 2017, A. Location in patent: Paragraph 0051; 0052
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[4] Journal of Organic Chemistry, 2009, vol. 74, # 21, p. 8309 - 8313
[5] European Journal of Organic Chemistry, 2013, # 9, p. 1644 - 1648
