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

HRID 639030Notes

Reaction equation

HRID 639030 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]([CH:7]=[C:8]([O:11]C)[C:9]=1[OH:10])[CH:5]=[O:6].B(Br)(Br)Br>C(Cl)Cl>[Br:1][C:2]1[CH:3]=[C:4]([CH:7]=[C:8]([OH:11])[C:9]=1[OH:10])[CH:5]=[O:6]

Participants

4

Reactant 2

HCID 180995-BromovanillinHCID 25134Boron tribromide

Product 1

HCID 854055-Bromo-3,4-dihydroxybenzaldehydeYield 100%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

To a solution of the compound of Example (a) (12.1 g, 0.52 mol) in CH2Cl2 (200 mL) was added 1.0 M boron tribromide in CH2Cl2 (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. Vacuum drying yielded a dark green-brown solid (11.51 g, 100%) which was used without further purification: MS (ES) m/z 217.2. (M+H)+.

Workup

  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. customVacuum drying

Sources & evidence

ORD record
ord-a32ff4cd51e64803988ebfffc21646b2
Source dataset
uspto-grants-2010_04
Patent number
US07691850B2

Reaction notes

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