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ChemicalBook CAS DataBase List 4-Bromo-2,5-dimethoxybenzaldehyde
31558-41-5

4-Bromo-2,5-dimethoxybenzaldehyde synthesis

5synthesis methods
2,5-Dimethoxybenzaldehyde

93-02-7

4-Bromo-2,5-dimethoxybenzaldehyde

31558-41-5

At 0 °C, 2,5-dimethoxybenzaldehyde (1.0 g, 6.02 mmol) was dissolved in glacial acetic acid (7 mL) and a solution of bromine (0.34 mL, 6.62 mmol) in glacial acetic acid (3 mL) was slowly added. The reaction mixture was gradually warmed to room temperature and stirred continuously for 1 hour. Upon completion of the reaction, water (30 mL) was added to quench the reaction and the resulting white precipitate was collected by filtration. The precipitate was redissolved in water (30 mL) and dichloromethane (30 mL) for liquid-liquid separation. The aqueous phase was extracted with dichloromethane (3 x 25 mL), and all organic phases were combined, washed with brine (25 mL), dried over anhydrous sodium sulfate, filtered, and concentrated under reduced pressure to give the crude product. The crude product was purified by silica gel column chromatography (eluent: 20% ethyl acetate/hexane) to afford 4-bromo-2,5-dimethoxybenzaldehyde as a light yellow solid (0.83 g, 3.37 mmol, 56% yield).

-

Yield:31558-41-5 87%

Reaction Conditions:

with titanium tetrachloride in dichloromethane at -78; for 1 h;

Steps:

1
2,5-Dimethoxybromobenzene (5) (7.0 ml :47 mmol) was dissolved in 160 ml of dichloromethane. The solution was added with 13 ml (0.12 mol) of titanium chloride (IV) under argon atmosphere at -78°C, subsequently with 8.2 ml (0.14 mol ) of dichloromethylmethy ether, and stirred at -78°C for one hour. The reaction mixture was gradually added to 600 ml of ice water and extracted with dichloromethane. The dichloromethane layer was washed with an aqueous saturated sodium hydrogencarbonate solution, water, and saturated brine, and then dried over sodium sulfate. The dichloromethane was evaporated under reduced pressure, and the residue was purified by silica gel column to obtain 9.9 g of Compound (6) (yield 87 %).1H-NMR (CDCl3, 300 MHz): 10.40 (s, 1H), 7.34 (s, 1H), 7.25 (s, 1H), 3.91 (s, 3H), 3.90 (s, 3H)

References:

Daiichi Pure Chemicals Co. Ltd.;Nagano, Tetsuo EP1403268, 2004, A1 Location in patent:Page 10

FullText

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