[NH2:1][C:2]1[C:3]([CH3:13])=[C:4]([C:9]([F:12])=[CH:10][CH:11]=1)[C:5]([O:7][CH3:8])=[O:6].[C:14]([O:17]C(=O)C)(=O)[CH3:15].[N:21]([O-])=O.[Na+].C(=O)([O-])[O-].[K+].[K+]>C(O)(=O)C>[C:14]([N:1]1[C:2]2[CH:11]=[CH:10][C:9]([F:12])=[C:4]([C:5]([O:7][CH3:8])=[O:6])[C:3]=2[CH:13]=[N:21]1)(=[O:17])[CH3:15]
Methyl 3-amino-6-fluoro-2-methylbenzoate (7.50 g, 0.041 mol) was dissolved in 150 mL of acetic acid. To this was added acetic anhydride (14.6 g, 0.143 mol) and the mixture was warmed to 75° C. Sodium nitrite (11.3 g, 0.164 mol) was added in portions to the reaction mixture (evolution of an gas observed). The mixture was stirred at 75° C. for 16 hours, then allowed to cool to ambient temperature, and then poured into cold 10% aqueous potassium carbonate solution. This material was extracted twice with EtOAc, the extracts dried over sodium sulfate and concentrated under reduced pressure. Column chromatography (1:1 EtOAc/Hexanes) afforded 0.48 g of methyl 1-acetyl-5-fluoro-1H-indazole-4-carboxylate. The crude material was then added to 5 mL of 4M HCl/dioxane and 15 mL of methanol in a pressure tube and heated to 60° C. for 2 hours. The mixture was concentrated under reduced pressure and the resulting solids were taken up in 10% aqueous potassium carbonate/EtOAc. The organic layer was isolated, dried over sodium sulfate and concentrated under reduced pressure to give 0.483 g (5%) of the title compound.
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