4-aminophenyl ethyl imino ether hydrochloride(3.0 g) was added to a solution of ammonia (12g) in ethanol(150ml, ~8% mass percent) with stirring at room temperature for 24 hours. The reaction mixture was filtered and concentrated in vacuo, and acidated with hydrochloric acid (5ml, 63%). Absorbent charcoal was used to purify. The mixture was filtered, and concentrated and dried in vacuo at room temperature to give 5.0 g(86%) of 4-aminobenzamidine hydrochloride was obtained as a bright yellow solid.