反应详情

While keeping 285 ml of 97% sulfuric acid at 5-12° C. by cooling it with ice, 28.5 g of 3-amino-6-fluoro-2-pyrazinecarboxamide was added thereto to form a uniform solution. After adding 18.9 g of sodium nitrite to the solution at 5-12° C., the mixture thus obtained was stirred for 1.5 hours while cooling it with ice. While keeping the reaction mixture at a temperature not exceeding 10° C., the reaction mixture was dropwise added to 1.4 L of ice water, and the mixture thus formed was extracted first with one 850 mL portion and then two 200 mL portions of ethyl acetate. The organic layers thus obtained were united, 400 mL of water was added, then 160 mL of saturated aqueous solution of sodium hydrogen carbonate was added, pH was adjusted to 3.0, and the organic layer was separated. The organic layer thus obtained was washed with saturated aqueous solution of sodium chloride and dried on anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. The residue thus obtained was washed with a mixture of diisopropyl ether and ethyl acetate to obtain 22.4 g of 6-fluoro-3-hydroxy-2-pyrazinecarboxamide as a solid product.

1. customat 5-12° C.
2. additionwas added
3. customto form a uniform solution
4. customthe mixture thus obtained
5. temperaturewhile cooling it with ice
6. customexceeding 10° C.
7. customthe mixture thus formed
8. extractionwas extracted first with one 850 mL portion
9. customThe organic layers thus obtained
10. customthe organic layer was separated
11. customThe organic layer thus obtained
12. washwas washed with saturated aqueous solution of sodium chloride
13. dry with materialdried on anhydrous magnesium sulfate
14. customthe solvent was removed under reduced pressure
15. customThe residue thus obtained
16. washwas washed with a mixture of diisopropyl ether and ethyl acetate