反应详情

温度

50 °C

Ammonium chloride (558 mg, 10.4 mmol) was suspended in benzene (5 ml) and 2M-trimethylaluminum toluene solution (5.2 ml, 10.4 mmol) was added dropwise at 0° C. After stirring for 1 hr, a solution of methyl 5-chloropyrazine-2-carboxylate (600 mg, 3.48 mmol) in benzene (5 ml) was added. The reaction mixture was heated to 50° C., and stirred overnight. After cooling, the reaction mixture was poured into water, and neutralized with saturated aqueous sodium hydrogen carbonate solution. The mixture was extracted with ethyl acetate, and the organic layer was washed with water and saturated brine, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The residue was purified by silica gel column chromatography (dichloromethane:methanol=100:0→98:2) to give 5-chloropyrazine-2-carboxamide (236 mg, yield 43%) as a white solid.

1. stirringstirred overnight
2. temperatureAfter cooling
3. extractionThe mixture was extracted with ethyl acetate
4. washthe organic layer was washed with water and saturated brine
5. dry with materialdried over anhydrous sodium sulfate
6. concentrationconcentrated under reduced pressure
7. customThe residue was purified by silica gel column chromatography (dichloromethane:methanol=100:0→98:2)