Carbon tetrabromide → 4-Bromo-1-(bromomethyl)-2-methylbenzene

HRID 603128Notes

Reaction equation

HRID 603128 reaction equation
[Br:1][C:2]1[CH:7]=[CH:6][C:5]([CH2:8]O)=[C:4]([CH3:10])[CH:3]=1.C(Br)(Br)(Br)[Br:12].C1C=CC(P(C2C=CC=CC=2)C2C=CC=CC=2)=CC=1.C1(P(=O)(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1>C(Cl)Cl.CCCCCC.CCOC(C)=O>[Br:1][C:2]1[CH:7]=[CH:6][C:5]([CH2:8][Br:12])=[C:4]([CH3:10])[CH:3]=1

Participants

7

Reactant 4

HCID 11205Carbon tetrabromideHCID 11776TriphenylphosphineHCID 13097Triphenylphosphine OxideHCID 22280088(4-Bromo-2-methylphenyl)methanol

Product 1

HCID 225690184-Bromo-1-(bromomethyl)-2-methylbenzeneYield 97.1%

Reagents, catalysts & solvents 2

HCID 6344DichloromethaneSolventHCID 21226206Ethyl acetate hexaneSolvent

Conditions

Temperature
2.5 °C

Procedure

(4-Bromo-2-methylphenyl)methanol (10.4 g, 51.6 mmol) is dissolved in anhydrous CH2Cl2 (150 mL) and CBr4 (18.8 g, 56.8 mmol) added. The reaction mixture is cooled to 0-5° C. and PPh3 (14.9 g, 56.8 mmol) is added. The reaction mixture is stirred overnight then hexane/EtOAc (9:1) (250 mL) is added with vigorous stirring. The triphenylphosphine oxide that forms during the reaction is filtered off and the filtrates are concentrated in vacuo. The resulting oil is purified on a silica gel pad with hexane/EtOAc (8:2). The solvent are removed on a rotary evaporator and the bromoform is removed by vacuum distillation (15 mm Hg, bp: 40-50° C.) to provide the expected product 1-Bromo-4-(bromomethyl)-3-methylbenzene (13.23 g, 97%) as a yellow oil.

Workup

  1. filtrationis filtered off
  2. concentrationthe filtrates are concentrated in vacuo
  3. customThe resulting oil is purified on a silica gel pad with hexane/EtOAc (8:2)
  4. customThe solvent are removed on a rotary evaporator
  5. customthe bromoform is removed by vacuum distillation (15 mm Hg, bp: 40-50° C.)

Sources & evidence

ORD record
ord-1c1f0a5326fb4c089196b01ec65c5a1d
Source dataset
uspto-grants-2011_03
Patent number
US07906654B2

Reaction notes

Loading…