CC([O:5][CH2:6][C:7]1[C:11]([C:12]([O:14][CH3:15])=[O:13])=[C:10]([CH:16]([CH3:18])[CH3:17])[O:9][N:8]=1)(C)C.FC(F)(F)C(O)=O>ClCCl>[OH:5][CH2:6][C:7]1[C:11]([C:12]([O:14][CH3:15])=[O:13])=[C:10]([CH:16]([CH3:18])[CH3:17])[O:9][N:8]=1To a solution of methyl 3-{[(1,1-dimethylethyl)oxy]methyl}-5-(1-methylethyl)-4-isoxazolecarboxylate (500 mg, 1.96 mmol) in dichloromethane (97 mL) was added trifluoroacetic acid (97 mL, 1.25 mol). The solution was stirred at ambient temperature for approximately 45 minutes and then concentrated. The residue was taken up with ethyl acetate and poured into saturated sodium bicarbonate. Solid sodium bicarbonate followed by solid sodium carbonate were added until the pH was basic. The aqueous layer was extracted with ethyl acetate and the combined organic layers were dried over magnesium sulfate, concentrated and purified by chromatography (silica gel, 25% ethyl acetate in hexanes) to afford the methyl 3-(hydroxymethyl)-5-(1-methylethyl)-4-isoxazolecarboxylate (304 mg, 78%). 1H-NMR (400 MHz, DMSO-d6) δ 5.29 (t, J=6 Hz, 1H), 4.62 (d, J=6 Hz, 2H), 3.77 (s, 3H), 3.68 (septet, J=7 Hz, 1H), 1.25 (d, J=7 Hz, 6H).
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