5-Bromovanillin → 5-Bromo-3,4-dihydroxybenzaldehyde

To a solution of 3-bromo-4-hydroxy-5-methoxybenzaldehyde (12.1 g, 0.52 mol) in dichloromethane (200 ml) was added 1.0 M boron tribromide in dichloromethane (2.2 eq, 115 ml) at 0°. The reaction was stirred at 0° for 20 min, then at ambient temperature for 2.5 h. The reaction was then cooled to 0°, and quenched by the slow addition of methanol. The solvents were removed under reduced pressure and the trimethyl borate was removed by azeotropation with added methanol. Drying in vacuo yielded the desired product (11.51 g, 100%).

1. waitat ambient temperature for 2.5 h
2. temperatureThe reaction was then cooled to 0°
3. customquenched by the slow addition of methanol
4. customThe solvents were removed under reduced pressure
5. customthe trimethyl borate was removed by azeotropation with added methanol
6. customDrying in vacuo

ORD record

ord-822645d3364e415f8723a94d458026a1

Source dataset

uspto-grants-2010_06

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US07732461B2