The general procedure for the synthesis of ethyl 2-aminopyrimidine-5-carboxylate from ethyl 2-methylsulfonyl-5-pyrimidinecarboxylate was as follows: ethyl 2-(methylsulfonyl)pyrimidine-5-carboxylate (2.15 g, 9.34 mmol) was dissolved in acetonitrile (11.7 mL) and stirred at room temperature. Subsequently, 32% aqueous ammonium hydroxide solution (11.36 mL, 93 mmol) was added slowly and dropwise. The reaction mixture transformed into a white suspension within seconds. The acetonitrile was removed by rotary evaporator and the remaining aqueous phase suspension was filtered through a Brinell funnel. The resulting solid was washed with distilled water (20 mL) and dried to give ethyl 2-aminopyrimidine-5-carboxylate as a white solid (1.192 g, 7.13 mmol, 76% yield, MS/ESI+ 168.1 [MH]+).
