反应详情

A solution of potassium hydroxide (2.27 g, 0.040 mol, 1.3 eq) in water (45 mL) was added drop wise to a solution of 1a (6 g, 0.031 mol, 1 eq) in methanol (15 mL) (see FIG. 4). The mixture was stirred at room temperature for 15 h. The solution was then concentrated under vacuum. The aqueous phase was washed with ether (2×100 mL), acidified with 6N aqueous HCl solution and extracted with ether (3×100 mL). The combined organic extracts were washed with brine (100 mL) and dried over sodium sulfate. Evaporation of the solvent afforded a colorless oil which crystallized upon standing. The desired product 9a was obtained as a solid (5.34 g, 96%). Rf 0.26 (hexane/EtOAc=6:4).). 1H NMR δ (DMSO-d6) 5.41 (s, 1H), 5.61 (s, 1H), 5.93 (s, 1H), 6.15 (s, 1H), 7.22 (m, 5H), 12.45 (s, 1H). [M−H]− 177.2: tR=1.28 min; purity: 88%.

1. concentrationThe solution was then concentrated under vacuum
2. washThe aqueous phase was washed with ether (2×100 mL)
3. extractionextracted with ether (3×100 mL)
4. washThe combined organic extracts were washed with brine (100 mL)
5. dry with materialdried over sodium sulfate
6. customEvaporation of the solvent
7. customafforded a colorless oil which
8. customcrystallized