反应详情

温度

0 °C

To a cooled (0° C.) suspension of 2-methyl-1,3-benzoxazol-5-ol (Fujita, et al., Synthesis (1982):62-9) (10.3 g, 68.9 mmol) in anhydrous tetrahydrofuran (150 mL) was added isopropylmagnesium chloride (34.4 mL, 2.0 M solution in tetrahydrofuran, 68.9 mmol). The reaction mixture was stirred at 0° C. for 0.5 h, and 1-benzhydrylindoline-2,3-dione (18.8 g, 59.9 mmol) and anhydrous dichloromethane (150 mL) were added. The reaction mixture was heated at reflux for 6 days and was allowed to cool to ambient temperature. The reaction mixture was diluted with a saturated aqueous solution of ammonium chloride (200 mL) and ethyl acetate (200 mL) and the phases were separated. The aqueous phase was extracted with ethyl acetate (2×200 mL) and the combined organic solution was washed with brine (2×200 mL), dried over anhydrous sodium sulfate, filtered and concentrated in vacuo. The crude product was purified by column chromatography with hexanes/ethyl acetate (3/1), followed by recrystallization from hexanes/ethyl acetate to afford 1-(diphenylmethyl)-3-hydroxy-3-(5-hydroxy-2-methyl-1,3-benzoxazol-6-yl)-1,3-dihydro-2H-indol-2-one (3.10 g, 10%) as an off-white solid: 1H NMR (300 MHz, CDCl3) δ8.41 (br s, 1H), 7.63-7.60 (m, 2H), 7.47-7.32 (m, 10H), 7.15 (s, 1H), 7.04-6.96 (m, 1H), 6.96-6.88 (m, 1H), 6.87 (d, J=9.0 Hz, 1H), 6.41 (d, 7.8 Hz, 1H), 4.58 (br s, 1H), 2.44 (s, 3H); MS (ES+) m/z 445.2 (M−17).

1. temperatureTo a cooled
2. temperatureThe reaction mixture was heated
3. temperatureat reflux for 6 days
4. temperatureto cool to ambient temperature
5. customthe phases were separated
6. extractionThe aqueous phase was extracted with ethyl acetate (2×200 mL)
7. washthe combined organic solution was washed with brine (2×200 mL)
8. dry with materialdried over anhydrous sodium sulfate
9. filtrationfiltered
10. concentrationconcentrated in vacuo
11. customThe crude product was purified by column chromatography with hexanes/ethyl acetate (3/1)
12. customfollowed by recrystallization from hexanes/ethyl acetate