4-[1-[3-(Isopropylamino)-2-pyridyl]piperazin-4-yl-carbonyl]benzoic acid methyl ester (1.8 g) and (S)-(+)-2-amino-1-propanol (0.71 g) were dissolved in methanol (30 ml) and heated to reflux for 12 hours. The reaction mixture was cooled and with the slow addition of excess of water at 40° C. to precipitate the crystals, the mixture was cooled again and stirred at 20° C. for 1 hour. Following with filtration and washing with water, the filtered solid was recrystallized using isopropanol and ether, filtered and dried to give 1.66 g (yield: 83%) of the desired compound.
