[F:1][C:2]1[N:7]=[C:6]([C:8](OC)=[O:9])[C:5](=[O:12])[NH:4][CH:3]=1.[NH3:13].C(OCC)(=O)C.C(=O)([O-])O.[Na+]>CO.O>[F:1][C:2]1[N:7]=[C:6]([C:8]([NH2:13])=[O:9])[C:5]([OH:12])=[N:4][CH:3]=1
In 3.0 mL of methanol was dissolved 0.12 g of methyl 6-fluoro-3-oxo-3,4-dihydro-2-pyrazinecarboxylate. Then, gaseous ammonia was introduced into the solution at an ice-cooled temperature for a period of 10 minutes, after which the mixture thus obtained was allowed to stand at room temperature for 2 days. The solvent was removed under reduced pressure, the residue thus obtained was added to a mixture of 30 mL of ethyl acetate and 30 ml of water, pH was adjusted to 7.5 with saturated aqueous solution of sodium hydrogen carbonate, and the organic layer was separated. After adding 30 mL of ethyl acetate to the remaining aqueous layer, pH was adjusted to 1.0 with 1 mol/L hydrochloric acid, and the whole mixture was extracted with two 15 mL portions of ethyl acetate. The organic layers thus obtained were united, washed successively with 15 mL of water and 15 mL of saturated aqueous solution of sodium chloride and dried on anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. The solid product thus obtained was washed with diisopropyl ether to obtain 0.015 g of 6-fluoro-3-hydroxy-2-pyrazinecarboxamide as a yellow-colored solid product.
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