反应详情

Methanol (3L) was added to thoroughly dried Compound IV (427.5 g, 1.42 mol) under argon. To this stirred suspension concentrated sulfuric acid (100 mL) was added and heated at reflux for 20 h under argon. Methanol was evaporated under reduced pressure at 30° C. The residue was taken up in ethyl acetate (3 L) and washed with water (2×1 L), saturated aqueous Na HCO3 (pH 8, 2×1 L), saturated aqueous sodium chloride solution (2×1 L). Organic layer was dried on anhydrous magnesium sulfate, filtered and the solvent was evaporated. The crude product obtained was dried thoroughly under high vacuum and used as such in the next step. Yield: white solid, 433.6 g (97%). 1HNMR(CDCl3): δ 7.72(s, 1H), 7.06(d, J=7.9 Hz, 2H), 6.77(d, J=7.9 Hz, 2H), 6.33(t, J=2.2 Hz, 1H), 6.26 (d, J=2.2 Hz, 2H), 5.74(s, 1H), 3.81(s, 3H), 3.60(s, 6H).

1. temperatureheated
2. temperatureat reflux for 20 h under argon
3. customMethanol was evaporated under reduced pressure at 30° C
4. washwashed with water (2×1 L), saturated aqueous Na HCO3 (pH 8, 2×1 L), saturated aqueous sodium chloride solution (2×1 L)
5. dry with materialOrganic layer was dried on anhydrous magnesium sulfate
6. filtrationfiltered
7. customthe solvent was evaporated