反应详情

The product of Example 91B (1.746 g, 9.1798 mmol) dissolved in a 2:1:1 v/v/v mixture of water/acetic acid/concentrated sulfuric acid (24 mL) was heated at reflux for 3 days. The reaction was cooled, poured onto ice water (80 mL) and adjusted to pH12 with 6N aqueous sodium hydroxide. The reaction was washed with ethyl ether (3×50 mL). The aqueous phase was acidified to pH 2 with concentrated hydrochloric acid and extracted with ethyl ether (2×75 mL). The ethereal extracts were dried over magnesium sulfate, filtered, and concentrated by rotary evaporation. The residue was co-concentrated with methylene chloride (5 mL)/hexanes (100 mL) three times and dried on high vacuum to afford the title compound as an off-white solid (1.402 g, 6.702 mmol, 73%). 1H NMR (300 MHz, DMSO-D6) δ ppm 1.23 (d, J=6.62 Hz, 6 H) 2.88-3.23 (m, 1 H) 7.66 (dd, J=8.09, 1.84 Hz, 1 H) 7.80 (d, J=7.72 Hz, 1 H) 7.83 (d, J=1.47 Hz, 1 H) 13.70 (br s, 1 H).

1. temperaturewas heated
2. temperatureat reflux for 3 days
3. temperatureThe reaction was cooled
4. additionpoured onto ice water (80 mL)
5. washThe reaction was washed with ethyl ether (3×50 mL)
6. extractionextracted with ethyl ether (2×75 mL)
7. dry with materialThe ethereal extracts were dried over magnesium sulfate
8. filtrationfiltered
9. concentrationconcentrated by rotary evaporation
10. customdried on high vacuum