Propylamine → 2-Amino-4-propylamino-6-methylpyrimidine

Under a nitrogen atmosphere, a solution of 17.0 grams (0.12 mole) of 2-amino-4-chloro-6-methylpyrimidine (commercially available) and 20 mL (0.24 mole) of n-propylamine was stirred, and 25 mL of ethanol was added. Upon completion of addition, the reaction mixture was stirred at ambient temperature for one hour. After this time, the reaction mixture was heated to reflux where it stirred for 2.5 hours. An additional five mL of n-propylamine was added to the reaction mixture, then it was allowed to stir at ambient temperature for about 18 hours. The reaction mixture was concentrated under reduced pressure, and the residue was dissolved in 250 mL of 10% methanol in methylene chloride. The cloudy solution was filtered through 300 grams of basic alumina (deactivated with 18 mL of water) using 10% methanol in methylene chloride as the eluant. The product-containing fractions were combined and concentrated under reduced pressure, yielding about 21 grams of 2-amino-4-propylamino-6-methylpyrimidine. The NMR spectrum was consistent with the proposed structure.