反应详情

Methanol (3.0 L) was added to a thoroughly dried 7 (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 nitrogen. Methanol was evaporated under reduced pressure at 30° C. The residue was taken up in ethyl acetate (3.0 L) and washed with water (2×1.0 L), saturated aqueous Na HCO3 (2×1.0 L), brine (2×1.0 L). The organic layer was dried on anhydrous magnesium sulfate, filtered and the solvent was evaporated. The residue obtained was dried thoroughly under high vacuum as white solid, (433.6 g 97%): mp 106-108° C.; 1HNMR(360 MHz, 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); MS (EI) m/z 315[M]+; Anal. (C18H18O5) C, H.

1. temperatureheated
2. temperatureat reflux for 20 h under nitrogen
3. customMethanol was evaporated under reduced pressure at 30° C
4. washwashed with water (2×1.0 L), saturated aqueous Na HCO3 (2×1.0 L), brine (2×1.0 L)
5. dry with materialThe organic layer was dried on anhydrous magnesium sulfate
6. filtrationfiltered
7. customthe solvent was evaporated
8. customThe residue obtained
9. customwas dried thoroughly under high vacuum as white solid, (433.6 g 97%)