C([O:3][C:4](=[O:22])[C:5]1[CH:10]=[CH:9][C:8]([NH:11][C:12]2[C:13]3[N:14]([CH:19]=[CH:20][N:21]=3)[CH:15]=[C:16]([Br:18])[N:17]=2)=[CH:7][CH:6]=1)C.[OH-].[Na+]>C(O)C>[Br:18][C:16]1[N:17]=[C:12]([NH:11][C:8]2[CH:7]=[CH:6][C:5]([C:4]([OH:22])=[O:3])=[CH:10][CH:9]=2)[C:13]2[N:14]([CH:19]=[CH:20][N:21]=2)[CH:15]=1A mixture of 4-(6-Bromo-imidazo[1,2-a]pyrazin-8-ylamino)-benzoic acid ethyl ester (30 mmol), 1N aqueous sodium hydroxide (50 mL), and ethanol (80 mL) is heated at reflux for 1.5 hr. The mixture is cooled and the ethanol removed in vacuo. The residue is diluted with iN sodium hydroxide (30 mL) and washed with ethyl acetate (2×100 mL). The aqueous layer is brought to pH 6 with 3N HCl, and the mixture filtered to give 4-(6-Bromo-imidazo[1,2-a]pyrazin-8-ylamino)-benzoic acid (7) as a light orange solid.
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