Step 1: Thiourea (10.0g,0.13mol) was dissolved in anhydrous ethanol (30mL), ethidium bromide (15.8g, 0.14mol) was added, and the temperature was raised to 40 until the reaction was completely soluble, and then stirred at 50 overnight. Cooled to room temperature, evaporated the solvent under reduced pressure to obtain ethylisothiourea hydrobromide (crude 26g).
Step 2: Ethylisothiourea hydrobromide (24g of crude) and morpholine (13.6g, 0.156mol) were dissolved in water (100mL) and stirred at reflux at 110 for 4 hours. The reaction solution was cooled to room temperature, concentrated under reduced pressure and brought to water twice with ethanol, then washed with methyl tert-butyl ether to give morpholinecarboximidamide hydrobromide (27 g, 96%). m/z=130 [M+1]+ MS (ESI+).
