16252-88-3

874-37-3

5-Nitrobenzo[c][1,2,5]thiadiazole (Compound 16, 2 g, 11.04 mmol) was used as a raw material, which was dissolved in a mixed solvent of ethanol and water (2:1, 3 mL, v/v) with NH4Cl (2.34 g, 44.20 mmol). The reaction mixture was placed in an oil bath at 90°C and refluxed for 30 min. Subsequently, iron powder (2.47 g, 44.20 mmol) was added to the reaction system and the reaction continued to be stirred under reflux conditions for 3 hours. After the completion of the reaction was monitored by TLC, the hot reaction mixture was filtered and the residue was washed with ethanol. The filtrates were combined, neutralized with saturated NaHCO3 solution and then extracted with ethyl acetate. The organic phase was dried with anhydrous sodium sulfate and concentrated to give the target product 2,1,3-benzothiazol-5-amine (Compound 17, 1.5 g, 90.3% yield).