607740-08-9

56990-02-4

1670-14-0

98-86-2

607740-08-9

3,5-dibromobenzaldehyde (1.0 g, 40 mmol), acetophenone (4.81 g, 40 mmol) were used as raw materials, which were dissolved in ethanol (80 mL), followed by addition of sodium hydroxide (0.16 g, 4 mmol). The reaction mixture was stirred at room temperature for 8 hours. Upon completion of the reaction, benzylcarbamidine hydrochloride (4.70 g, 30 mmol), sodium hydroxide (1.60 g, 40 mmol) and ethanol (40 mL) were added to the system and the reaction mixture was heated to reflux and the reaction was continued for 8 hours. At the end of the reaction, the resulting white solid was collected by filtration and washed with ethanol until the filtrate was colorless. The solid product was further washed with water and ethanol and finally dried under vacuum to give intermediate N (5.20 g, yield: 56%).