反应详情

A solution of compound 4 (4.0 g, 11.83 mmol) in acetone (50 mL) was treated with 10% HCl solution (50 mL) and the resulting mixture was stirred for over night (16 h). Acetone was evaporated, crude was basified with 2 N NaOH solution and product was extracted into CH2Cl2 (3×25 mL). The combined CH2Cl2 layer was washed with brine (20 mL) and dried (Na2SO4). The solvent was evaporated and the crude product was purified by column chromatography on silica gel (ethyl acetate:hexanes, 1:4) to obtain compound 5 (2.9 g, 83%) as a solid. 1H NMR (CDCl3) δ 7.15 (d, J=6.6 Hz, 2H), 6.32 (d, J=8.7 Hz, 1H), 3.81 (tt, J=7.2, 23.4 Hz, 1H), 3.37 (t, J=16.8 Hz, 2H), 2.95 (t, J=16.5 Hz, 2H), 2.51-2.41 (m, 4H), 2.18-2.11 (m, 2H), 1.92-1.78 (m, 2H). MS-ESI (m/z, %): 296 (96), 294 (M+, 100), 200 (30).

1. customAcetone was evaporated
2. extractionwas extracted into CH2Cl2 (3×25 mL)
3. washThe combined CH2Cl2 layer was washed with brine (20 mL)
4. dry with materialdried (Na2SO4)
5. customThe solvent was evaporated
6. customthe crude product was purified by column chromatography on silica gel (ethyl acetate:hexanes, 1:4)