反应详情

To a solution of (S)-2-[4-(2,6-difluoro-phenoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-butyric acid methyl ester (0.119 g, 0.38 mol) in tetrahydrofuran:water (1:1, 8 mL) was added lithium hydroxide monohydrate (0.050 g 1.19 mmol). The mixture was stirred at room temperature for 2 h. The reaction mixture was poured into water and washed with diethyl ether and the ether layer discarded. The aqueous phase was acidified with 1N aqueous hydrochloric acid (pH <2), and extracted with ethyl acetate (2×30 mL). The combined ethyl acetate layers were dried over magnesium sulfate, filtered and concentrated to afford (S)-2-[4-(2,6-difluoro-phenoxy)-2-oxo-2,5-dihydro-pyrrol-1-yl]-butyric acid (0.090 g, 83%) as an off-white solid. 1H NMR (300 MHz, DMSO-d6) δ ppm 0.87 (t, J=7.4 Hz, 3H), 1.60-2.06 (m, 2H), 4.23 (d, J=18.7 Hz, 1H), 4.31 (d, J=18.7 Hz, 1H), 4.43 (dd, J=10.7, 5.0 Hz, 1H), 5.05 (s, 1H), 7.21-7.54 (m, 3H), 12.94 (br. s., 1H).

1. washwashed with diethyl ether
2. extractionextracted with ethyl acetate (2×30 mL)
3. dry with materialThe combined ethyl acetate layers were dried over magnesium sulfate
4. filtrationfiltered
5. concentrationconcentrated