反应详情

To a stirred solution of the ethyl ester (Step 1) (0.090 g, 0.231 mmol) in THF:EtOH:H2O (7:2:1) (4 mL) was added aqueous NaOH solution (0.11 mL, 2.5 M). After stirring 16 hours, the reaction was partially concentrated in vacuo to remove the organic solvents, diluted with H2O, and washed with diethyl ether. The resulting aqueous phase was acidified with concentrated HCl, extracted with diethyl ether, dried over MgSO4, filtered and concentrated in vacuo yielding an oil. The oil was purified by flash chromatography (silica, hexanes-ethyl acetate, 3:1 with 5% acetic acid). This procedure yielded the title acid (0.020 g, 24%) as a white powder: mp 162.3–164.7° C. 1H NMR (acetone-d6/300 MHz) 8.05 (s, 1H), 7.90 (s, 1H), 7.74 (d, 1H, J=8.7 Hz), 7.29 (d, 1H, J=8.7 Hz), 5.97 (q, 1H, J=6.8 Hz). FABLRMS m/z 361 (M−H). ESHRMS m/z 361.0111 (M−H, Calc'd 361.0094).

1. concentrationthe reaction was partially concentrated in vacuo
2. customto remove the organic solvents
3. additiondiluted with H2O
4. washwashed with diethyl ether
5. extractionextracted with diethyl ether
6. dry with materialdried over MgSO4
7. filtrationfiltered
8. concentrationconcentrated in vacuo
9. customyielding an oil
10. customThe oil was purified by flash chromatography (silica, hexanes-ethyl acetate, 3:1 with 5% acetic acid)
11. customThis procedure yielded the title acid (0.020 g, 24%) as a white powder