反应详情

To a stirred solution of the ester from step 1 (260 mg, 0.79 mmol) in 2:1:1 tetrahydrofuran/methanol/water (8 mL) is added lithium hydroxide (140 mg, 3.3 mmol). The reaction mixture is stirred at room temperature for 2 h, and concentrated under reduced pressure. The residue is partitioned between water (10 mL) and diethyl ether (10 mL). The aqueous layer is acidified to pH 4–5 with 1 N hydrochloric acid and extracted with 3:1 chloroform/2-propanol (3×30 mL). The combined organic layers are dried (sodium sulfate), filtered, and concentrated under reduced pressure to provide the title compound. 1H NMR (300 MHz, CD3OD) δ 8.64 (s, 1H), 8.10 (s, 1H), 8.01 (s, 1H), 7.28 (s, 2H), 3.52 (m, 2H), 3.26 (m, 2H), 1.75 (m, 2H), 1.59 (m, 2H), 1.02 (t, J=7 Hz, 3H), 0.75 (t, J=7 Hz, 3H).

1. concentrationconcentrated under reduced pressure
2. customThe residue is partitioned between water (10 mL) and diethyl ether (10 mL)
3. extractionextracted with 3:1 chloroform/2-propanol (3×30 mL)
4. dry with materialThe combined organic layers are dried (sodium sulfate)
5. filtrationfiltered
6. concentrationconcentrated under reduced pressure