反应详情

In 100 ml of concentrated sulfuric acid is dissolved 17.00 g of methyl 6-bromo-3-amino-2-pyrazinecarboxylate obtained according to the method described in literature [J. Am. Chem. Soc., 2798-2800 (1949)]. At an ice-cooled temperature, 10.11 g of sodium nitrite is added to the suspension, which is stirred for 30 minutes. The reaction mixture is poured into 920 mL of methanol, and heated under reflux for 5 hours. The reaction mixture is cooled and then concentrated under reduced pressure. The residue thus obtained is added to a mixture of 500 mL of ice water and 600 mL of chloroform and separated into layers. The organic layer is washed successively with saturated aqueous solution of sodium hydrogen carbonate, water and saturated aqueous solution of sodium chloride and dried over anhydrous magnesium sulfate. Then, the solvent is distilled off under reduced pressure to obtain 6.30 g of methyl 6-bromo-3-methoxy-2-pyrazinecarboxylate.

1. customobtained
2. additionis added to the suspension, which
3. temperatureheated
4. temperatureunder reflux for 5 hours
5. temperatureThe reaction mixture is cooled
6. concentrationconcentrated under reduced pressure
7. customThe residue thus obtained
8. customseparated into layers
9. washThe organic layer is washed successively with saturated aqueous solution of sodium hydrogen carbonate, water and saturated aqueous solution of sodium chloride
10. dry with materialdried over anhydrous magnesium sulfate
11. distillationThen, the solvent is distilled off under reduced pressure