Synthesis
0.1 mole of p-aminoanisole and 0.1 mole of potassium thiocyanate (KCNS) were dissolved in 100 mL of glacial acetic acid (AcOH) and the mixture was cooled and stirred in an ice bath for 10-20 minutes. Subsequently, 0.1 mol of bromine in glacial acetic acid solution was slowly added dropwise, with the rate of dropwise acceleration controlled to maintain the reaction temperature below 10 °C. After the dropwise addition was completed, the reaction mixture was stirred at room temperature for 2-4 hours. After completion of the reaction, the resulting hydrobromide (HBr) salt was separated by filtration, washed with glacial acetic acid and dried. The dried salt was dissolved in hot water and alkalized by adjusting the pH to 11.0 with ammonia solution (NH4OH). The precipitate precipitated was filtered, washed with water and dried to give the target product 2-amino-6-methoxybenzothiazole. The reaction process was monitored by thin layer chromatography (TLC) using toluene: acetone (8:2) as unfolding agent.
References
[1] Synlett, 2012, vol. 23, # 15, p. 2219 - 2222
[2] Synlett, 2009, # 16, p. 2682 - 2684
[3] Heterocyclic Communications, 2018, vol. 24, # 5, p. 255 - 258
[4] Phosphorus, Sulfur and Silicon and the Related Elements, 2008, vol. 183, # 5, p. 1124 - 1133
[5] European Journal of Medicinal Chemistry, 2008, vol. 43, # 5, p. 1114 - 1122
