[NH2:1][C:2]1[C:3]([C:14]([OH:16])=[O:15])=[N:4][C:5]([O:12][CH3:13])=[C:6]([C:8]([F:11])([F:10])[F:9])[CH:7]=1.OS(O)(=O)=O.O.[C:23]([O-])(O)=O.[Na+]>CO>[NH2:1][C:2]1[C:3]([C:14]([O:16][CH3:23])=[O:15])=[N:4][C:5]([O:12][CH3:13])=[C:6]([C:8]([F:9])([F:10])[F:11])[CH:7]=13-Amino-6-methoxy-5-trifluoromethyl-pyridine-2-carboxylic acid (Int. B) 5.5 g, 23.29 mmol) was dissolved in MeOH (90 ml). H2SO4 (6.21 ml, 116 mmol) was added dropwise and the solution was heated to reflux for 4 hours. The reaction mixture was reduced in vacuo to approx. 15 ml and water (15 ml) was added. The pH was adjusted to pH 9 by careful addition of solid NaHCO3. Water (100 ml) was added and the mixture was extracted with DCM. The combined organic extracts were concentrated in vacuo to afford the title compound.
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