[NH2:1][C:2]1[C:3]([C:8]2[CH:17]=[CH:16][C:11]([C:12]([O:14][CH3:15])=[O:13])=[C:10]([F:18])[CH:9]=2)=[N:4][CH:5]=[CH:6][N:7]=1.C1C(=O)N([Br:26])C(=O)C1.C(=O)(O)[O-].[Na+]>C(#N)C>[NH2:1][C:2]1[C:3]([C:8]2[CH:17]=[CH:16][C:11]([C:12]([O:14][CH3:15])=[O:13])=[C:10]([F:18])[CH:9]=2)=[N:4][C:5]([Br:26])=[CH:6][N:7]=1To a suspension of methyl 4-(3-aminopyrazin-2-yl)-2-fluorobenzoate (31.5 g, 127 mmol) in acetonitrile (430 mL) at 0° C. was added NBS (23.9 g, 134 mmol). The reaction mixture was stirred in ice bath for 1 h, sat. sodium bicarbonate was added, stirred 30 min and product was extracted with ethylacetate. The organic extracts were combined, washed with brine, dried over sodium sulfate, filtered and evaporated. The crude product was recrystallized in EtOAc and heptane to give methyl 4-(3-amino-6-bromopyrazin-2-yl)-2-fluorobenzoate as brown color solid in 96% yield. LCMS (m/z): 326.0/328.0 (MH+), 0.87 min.
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