Cl[C:2]1[N:3]=[C:4]([CH3:13])[C:5]([C:9]([O:11][CH3:12])=[O:10])=[N:6][C:7]=1[Cl:8].CO.[C:16](=O)([O-])[O-:17].[K+].[K+]>>[Cl:8][C:7]1[N:6]=[C:5]([C:9]([O:11][CH3:12])=[O:10])[C:4]([CH3:13])=[N:3][C:2]=1[O:17][CH3:16]To a solution of methyl 5,6-dichloro-3-methylpyrazine-2-carboxylate (6.17 g, 27.9 mmol) in anhydrous methanol (100 ml, 2.47 mol) at 0° C. was added potassium carbonate (4.30 g, 31.1 mmol) slowly. The suspension was stirred at 0° C. for 30 minutes and warmed to ambient temperature in 1 h. The solid was filtered and the filtrate was concentrated to give crude methyl 6-chloro-5-methoxy-3-methylpyrazine-2-carboxylate (6.2 g, 103% yield) which was used in next step without further purification.
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