22514-58-5

66947-92-0

22514-58-5

General procedure for the synthesis of 2-bromobenzothiazole-6-carboxylic acid from methyl 2-aminobenzothiazole-6-carboxylate: to a mixed solution of methyl 2-bromobenzothiazole-6-carboxylate (1.256 g, 4.39 mmol) in tetrahydrofuran (THF, 60 mL) and water (H2O, 20 mL) was added at 0 °C lithium hydroxide monohydrate (920 mg, 21.9 mmol). The reaction mixture was stirred at room temperature overnight. Upon completion of the reaction, the pH was adjusted to 2 with 1N hydrochloric acid (HCl) solution, followed by extraction with ethyl acetate. After the organic phase was washed with saturated saline, the solvent was removed by distillation under reduced pressure, and the crude product obtained could be used directly in the next step of the reaction without further purification. Mass Spectrometry (ESI) m/z: 257.9 (M + 1)+.