[C:1]([C:4]([NH:9][CH2:10][C:11]1[N:19]=[CH:18][C:17]([CH2:20][CH3:21])=[CH:16][C:12]=1[C:13]([OH:15])=[O:14])([CH3:8])[CH:5]([CH3:7])[CH3:6])(=[O:3])[NH2:2].C([O-])(=O)C.[Na+].BrBr>C(O)(=O)C>[CH2:20]([C:17]1[CH:18]=[N:19][C:11]([C:10]2[NH:2][C:1](=[O:3])[C:4]([CH:5]([CH3:7])[CH3:6])([CH3:8])[N:9]=2)=[C:12]([CH:16]=1)[C:13]([OH:15])=[O:14])[CH3:21]A mixture of 0.8 g of 2-{[(1-carbamoyl-1,2-dimethylpropyl)amino]methyl}-5-ethylnicotinic acid (2.7 mmol) and 0.56 g sodium acetate (6.8 mmol) in 10 mL acetic acid is warmed until homogeneous and cooled to room temperature. The solution is treated with 0.88 g bromine (5.45 mmol), and the reaction is stirred at 25° C. for 16 hours, then at 75° C. for three days. The reaction mixture is partitioned between CH2Cl2 and water, and the organic phase is dried and concentrated in vacuo. The residue is recrystallized from ethyl acetate-hexanes to afford 0.4 g of the title product having mp 172°-175° C.
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