[O:1]=[C:2]([CH3:19])[CH2:3][CH2:4][C:5]1[CH:10]=[CH:9][N:8]2[C:11]([C:14]([O:16]CC)=[O:15])=[CH:12][N:13]=[C:7]2[CH:6]=1.[Li+].[OH-].C(O)(=O)CC(CC(O)=O)(C(O)=O)O>C1COCC1.CO>[O:1]=[C:2]([CH3:19])[CH2:3][CH2:4][C:5]1[CH:10]=[CH:9][N:8]2[C:11]([C:14]([OH:16])=[O:15])=[CH:12][N:13]=[C:7]2[CH:6]=1A stirring mixture of ethyl 7-(3-oxobutyl)imidazo[1,2-a]pyridine-3-carboxylate (85) (90 mg, 0.346 mmol) and 2N LiOH (0.5 mL) in THF:MeOH (4:1, 3 mL) was heated at 60° C. for 45 minutes. The reaction was cooled to room temperature and the pH was adjusted between 3-5 with 10% citric acid. The solvent was partially concentrated and the crude product was purified by reverse phase preparative HPLC to yield 7-(3-oxobutyl)imidazo[1,2-a]pyridine-3-carboxylic acid (86). MS m/z 233.08 (M+1)+.
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