Step 1: Hydrogenation reaction. 5-Ethynyl-2-aminopyrazine (18 mg, 0.151 mmol) was dissolved in ethyl acetate (500 μL) under stirring conditions and triethylamine (63 μL, 0.45 mmol) and Pd(OH)2/carbon catalyst (0.01 mmol, 20% wt on carbon) were added sequentially. The reaction system was placed in a hydrogen atmosphere at 45 psi and the reaction was shaken for 6 hours. Upon completion of the reaction, the catalyst was removed by filtration and the filtrate was concentrated under reduced pressure to afford the off-white solid product 2-amino-5-ethylpyrazine in 84% yield.
