To a solution of 3-methoxy-4-(methylaminocarbonyloxy)benzaldehyde (1.0 g) in 1,2-dichloroethane (20 ml) was added 4′-piperazinoacetophenone (0.98 g), followed by sodium triacetoxyborohydride (1.53 g), with stirring. The reaction mixture was stirred overnight at ambient temperature, poured into saturated sodium carbonate solution (75 ml) and extracted with dichloromethane. The combined organic layers were washed with water and brine, dried over anhydrous sodium sulfate, filtered, and the filtrate was concentrated. The residue was dissolved in dichloromethane and flash chromatographed (silica gel and dichloromethane), eluting with the same solvent system, followed by 1% methanol:dichloromethane. The appropriate fractions were combined and concentrated. The residue was recrystallized from ethyl acetate to give product, mp 120-123° C.
