General procedure for the synthesis of 6-chloro-N4,N4-dimethylpyrimidine-2,4-diamine from 2-amino-4,6-dichloropyrimidine and dimethylamine: to an acetonitrile solution of 2-amino-4,6-dichloropyrimidine (2.0 g, 12.2 mmol) was added sequentially N,N-diisopropylethylamine (Hunig base, 2.34 mL, 13.4 mmol) and dimethylamine ( 6.7 mL, 13.4 mmol). The reaction mixture was stirred at 50°C for 1.5 hours. Upon completion of the reaction, the mixture was cooled to 0 °C and poured into a mixture of dichloromethane and water. The organic layer was separated, washed with saturated saline, and the organic phase was concentrated to afford 6-chloro-N4,N4-dimethylpyrimidine-2,4-diamine (2.2 g, 94% yield) as an off-white solid.LC-MS (electrospray ionization) m/z = 173,175 [M + H]+.
