The general procedure for the synthesis of 2-methyl-4-aminopyrimidine from trimethyl orthoacetate and 3-methoxyacrylonitrile was as follows: in a 10 mL stainless steel pressure-resistant reactor, 1.0 g (12 mmol) of 3-methoxyacrylonitrile, 3.9 g (32 mmol) of trimethyl orthoacetate, and 4.0 g (56 mmol) of 24 wt% ammonia-methanol solution were added in sequence. The reaction mixture was stirred at 130°C for 8 hours. After completion of the reaction, 20 mL of hexane was added to the reaction mixture, stirred thoroughly and filtered to afford 0.94 g (isolated yield: 72%) of the target product 2-methyl-4-aminopyrimidine as yellow crystals. 2-methyl-4-aminopyrimidine was characterized physically as follows: 1H-NMR (DMSO-d6, δ/ppm): 2.29 (3H, s), 6.22 (1H, dd, J = 5.9), 4.0 g (56 mmol) of 24 wt% ammonia-methanol solution. dd, J = 5.9, 0.5 Hz), 6.69 (2H, brs), 7.94 (1H, d, J = 5.9 Hz); CI-MS (m/e): 109 (M + 1).
