N-(1-Ethyl-1H-pyrazol-5-yl)-2-(2-formyl-3-(methoxymethoxy)phenoxy)-N-isopropylacetamide (0.38 g, 1.01 mmol) was dissolved in THF (10 ml), purged with N2 gas and stirred in an ice bath. HCl (concentrated, 0.34 ml, 4.05 mmol) was slowly added and the solution stirred to 25° C. More HCl (0.3 ml) was added over 4 h with warming (40° C.) to reach completion of reaction. 10% Sodium bicarbonate solution (20 ml) was added and the mixture was extracted with ethyl acetate (3×75 ml). The combined organic phases were washed with a saturated aqueous sodium chloride solution (50 ml) and dried over sodium sulfate. After evaporation the resulting solid was purified by silica gel chromatography (5-80% ethyl acetate/hexanes) to give 0.179 g (53%) of N-(1-ethyl-1H-pyrazol-5-yl)-2-(2-formyl-3-hydroxyphenoxy)-N-isopropylacetamide as a white solid. 1H NMR (400 MHz, CDCl3) δ 11.90 (s, 1H), 10.35 (s, 1H), 7.50 (s, 1H), 7.43 (t, J=8.43 Hz, 1H), 6.67 (d, J=8.53 Hz, 1H), 6.39 (d, J=8.27 Hz, 1H), 6.32-6.27 (m, 1H), 6.12 (d, J=7.30 Hz, 1H), 5.65 (s, 1H), 4.25-4.13 (m, 3H), 1.46 (t, J=7.23 Hz, 3H), 1.22 (d, J=6.54 Hz, 3H), 1.14 (d, J=6.51 Hz, 3H). MS (ESI) m/z 332 [M+H]+. MP 179-182° C.
