反应详情

To a stirred solution of [4-(5-Cyano-2-methyl-6-oxo-1,6-dihydro-pyridin-3-yl)phenoxy]-acetic acid ethyl ester (7, 1.3 g, 4.16 mmol) in a mixture of 1,4-dioxane (25 mL) and water (25 mL) was added lithium hydroxide mono hydrate (700 mg, 16.7 mmol). The reaction mixture was stirred for 2 h at ambient temperature, diluted with water (50 mL), washed with diethylether (2×25 mL), cooled to 0° C. and acidified to pH 2 with aqueous hydrochloric acid (5 N). After standing at ambient temperature overnight the formed precipitate was filtered off with suction, washed with water and dried under vacuum to give [4-(5-Cyano-2-methyl-6-oxo-1,6-dihydro-pyridin-3-yl)-phenoxy]-acetic acid (8) as light yellow crystalline solid (758 mg, 64% yield, 97% pure by LC-MS and 1H NMR), 1H NMR (400 MHz; CDCl3): δ 7.70 (d, 1H); 7.20 (m, 2H); 6.73 (m, 2H); 4.88 (s, 2H); 1.71 (s, 3H).

1. washwashed with diethylether (2×25 mL)
2. temperaturecooled to 0° C.
3. waitAfter standing at ambient temperature overnight
4. filtrationthe formed precipitate was filtered off with suction
5. washwashed with water
6. customdried under vacuum