53218-26-1

533-30-2

53218-26-1

The general procedure for the synthesis of 6-bromobenzothiazole from 6-aminobenzothiazole was as follows: aqueous (1.0 mL) solution of sodium nitrite (0.147 g, 2.1 mmol) was slowly added dropwise to a mixture of 6-aminobenzothiazole (0.30 g, 2.0 mmol) suspended in a 48% aqueous hydrobromic acid solution (3 mL) at 0 °C. After the dropwise addition was completed, the reaction mixture was stirred at room temperature for 30 minutes. Subsequently, the resulting solution was slowly added to a hydrochloric acid solution (concentration not specified, 5 mL) of copper (I) bromide (0.435 g, 3.0 mmol) at 0 °C. After addition, the reaction system was warmed to 60 °C and stirred for 1.5 hours. Upon completion of the reaction, the reaction mixture was cooled, alkalized with excess ammonia and extracted with ether. The organic phases were combined, washed sequentially with water and saturated saline, dried anhydrous and concentrated. Purification by Combiflash fast chromatography afforded 6-bromobenzothiazole (0.26 g). This product was subsequently converted to the target compound using a similar procedure as in Example 1 , with mass spectrometry (ESI) detection showing (M + H)+ = 413.1.