反应详情

To a stirred solution of 3-bromo-4,5-dihydroxybenzaldehyde (10.50 g, 48.38 mmol) in DMF (145 mL) was added anhydrous KF (14.02 g, 241.9 mmol, dried for 24 hours under high vacuum/P2O5). After 15 minutes CH2Br2 was added all at once and the resulting mixture heated to 100–105° C. for 4 hours. The mixture was evaporated under reduced pressure and the residue was taken up in ether and water. The layers were separated, the aqueous layer was washed with ether (3×). The combined ether layers were washed with water (2×), brine and dried over anhydrous magnesium sulfate. After filtration, the mixture was concentrated under reduced pressure to give 8.42 g of 3-bromo-4,5-methylenedioxybenzaldehyde (76%) as a brownish solid. 1H NMR (500 MHz; CDCl3): δ 6.16 (s, 2H); 7.26 (s, 1H); 7.55 (s, 1H); 9.77 (s, 1H).

1. temperatureheated to 100–105° C. for 4 hours
2. customThe mixture was evaporated under reduced pressure
3. customThe layers were separated
4. washthe aqueous layer was washed with ether (3×)
5. washThe combined ether layers were washed with water (2×), brine
6. dry with materialdried over anhydrous magnesium sulfate
7. filtrationAfter filtration
8. concentrationthe mixture was concentrated under reduced pressure