[CH3:1][C:2]1[N:7]=[CH:6][C:5]([O:8][C:9]([CH3:16])([CH3:15])[C:10]([O:12]CC)=[O:11])=[CH:4][CH:3]=1.[OH-].[K+].C(O)=O>CS(C)=O.O>[CH3:1][C:2]1[N:7]=[CH:6][C:5]([O:8][C:9]([CH3:16])([CH3:15])[C:10]([OH:12])=[O:11])=[CH:4][CH:3]=1To a solution of ethyl 2-(6-methyl-3-pyridyloxy)-2-methylpropionate (Step A, 2.0 g, 8.9 mmol) in DMSO (20 mL) was added potassium hydroxide (1.0 g, 20 mmol) in 2 mL water. After stirring at room temperature for 2 h, the reaction was quenched by addition of formic acid (85%, 10 mmol) and poured into water (200 mL). The product was extracted with EtOAc (2×100 mL), and the combined extracts were dried over anhydrous sodium sulfate, filtered and concentrated to dryness to give the title compound contaminated with DMSO (molar ratio 1:5, determined by NMR). 1H NMR (500 MHz, CD3OD): δ 8.06 (d, 1H), 7.38-7.22 (m, 2H), 2.47 (s, 3H), 1.58 (s, 6H).
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