At 0 , to 5-bromopyrazine-2-amine (5736.8mg, 32.97mmol) in CH2Cl2 (80mL) solution was added 4-DMAP (403.2mg, 3.30mmol); then at 0 drop two A solution of di-tert-butyl carbonate (11.4ml, 3.30mmol) in CH2Cl2; the mixture was stirred at room temperature; after the completion of the reaction was monitored by TLC, the solution was washed with brine, dried over Na2SO4, filtered, and concentrated in vacuo; the crude product was chromatographed on a silica gel column Method, purified with ethyl acetate/petroleum ether (1/2) to obtain a white solid product (7250.4 mg, yield 80.2%).
