808755-67-1

2-Bromo-6-methoxybenzo[d]thiazole (555 mg, 2.28 mmol) was dissolved in dichloromethane (10 mL) under argon protection and at room temperature. Subsequently, a 1 M solution of boron tribromide in dichloromethane (4 mL) was slowly added to this solution. The reaction mixture was stirred at room temperature under argon atmosphere for 7 hours. Upon completion of the reaction, the mixture was poured into ice water and extracted with chloroform (3 x 30 mL). The organic phases were combined and dried with anhydrous sodium sulfate, followed by removal of the solvent by reduced pressure distillation. The crude product was purified by silica gel column chromatography (silica gel 80 g, eluent hexane: ethyl acetate = 3:1) to give 2-bromobenzo[d]thiazol-6-ol (521 mg, 99% yield) as a brown solid. The physical properties of the product were determined as follows.

[1] Patent: JP6095208, 2017, B2. Location in patent: Paragraph 0030; 0031; 0032
[2] Chemistry - A European Journal, 2016, vol. 22, # 27, p. 9330 - 9337
[3] Patent: WO2013/40183, 2013, A1. Location in patent: Paragraph 0062
[4] Patent: WO2016/161572, 2016, A1. Location in patent: Page/Page column 50
[5] Patent: WO2004/108663, 2004, A1. Location in patent: Page 100