To a solution of 2-[4-(2-pyrimidinyl)-1-piperazinyl]ethylamine (2.46 g, 0.012 mol) in methanol (45 mL) was added acetone (0.9 mL, 0.012 mol) and zinc chloride/sodium cyanoborohydride solution in dichloromethane (24 mL, containing 0.006 mol zinc chloride and 0.012 mol sodium cyanoborohydride) at room temperature. The resulting mixture was stirred at room temperature for 1 hour, and then an additional portion of the zinc chloride/cyanoborohydride solution (2 mL) was added. The mixture was then stirred at room temperature for 2 days. To the reaction mixture was added 1M aqueous sodium hydroxide solution (18 mL). The methanol was removed on a rotary evaporator, and the residue was partitioned between dichloromethane (100 mL) and brine solution (100 mL). The organic layer was dried over anhydrous magnesium sulfate and concentrated on a rotary evaporator. The desired intermediate, N-(1-methylethyl)-2-[4-(2-pyrimidinyl)-1-piperazinyl]ethylamine (TLC on silica gel using 30% methanol in ethyl acetate, Rf=0.31 ), was isolated as a colorless oil by cttromatography on 250 gm of silica gel using 30% methanol/ethyl acetate as the eluant (1.28 g, 50% yield).
