Synthesis
Methyl 3-aminopyrazine-2-carboxylate (100 g, 0.653 mol) was used as starting material, which was co-dissolved with N-chlorosuccinimide (NCS, 87.2 g, 0.653 mol) in acetonitrile (500 mL) in a 1 L three-neck flask. The reaction mixture was heated to 82 °C and the reaction was maintained at this temperature with stirring for 12 h to ensure complete reaction. Upon completion of the reaction, the acetonitrile solvent was removed by distillation under reduced pressure. The resulting crude product was purified by recrystallization using mixed petroleum ether/ethyl acetate solvent, and the final bright green crystalline target product, methyl 3-amino-6-chloropyrazine-2-carboxylate (112.7 g, 92% yield) was obtained.
