反应详情

To a solution of concentrated H2SO4 (3 mL) and hydrobromic acid (6 mL of 48%) was added 3-(5-amino-4-benzothiazol-2-yl-2H-pyrazol-3-yl)-propan-1-ol (810 mg, 3.0 mmol). The resulting mixture was refluxed for 2 hrs. The mixture was cooled to room temperature, poured into ice water, and adjusted to pH 3-4 using 5% NaOH solution. The resulting sticky solid was isolated by filtration, washed with water and air-dried to yield 815 mg (80%) of 4-benzothiazol-2-yl-5-(3-bromopropyl)-2H-pyrazol-3-ylamine as a cream coloured solid. The crude material was used in the subsequent step without further purification. MS (m/z, ES+): 337.1 (Br79M+1, 61%), 339.1 (Br81M+1, 59%), 257.2 (M-HBr, 100%).

1. temperatureThe resulting mixture was refluxed for 2 hrs
2. customThe resulting sticky solid was isolated by filtration
3. washwashed with water
4. customair-dried