2-Methylbenzoic acid → 5-Bromo-2-methylbenzoic acid

HRID 2227711Notes

Reaction equation

HRID 2227711 reaction equation
[C:1]1([CH3:10])[C:2]([C:7]([OH:9])=[O:8])=[CH:3][CH:4]=[CH:5][CH:6]=1.[Br:11]Br>C(Cl)Cl.[Fe]>[Br:11][C:4]1[CH:5]=[CH:6][C:1]([CH3:10])=[C:2]([CH:3]=1)[C:7]([OH:9])=[O:8]

Participants

5

Reactant 2

HCID 83732-Methylbenzoic acidHCID 24408Bromine

Product 1

HCID 3460045-Bromo-2-methylbenzoic acidYield 32.5%

Reagents, catalysts & solvents 2

HCID 23925IronCatalystHCID 6344DichloromethaneSolvent2×

Procedure

A mixture of o-toluic acid (28 g, 206 mmol), iron powder (0.74 g, 13 mmol), and Br2 (42 g, 260 mmol) were stirred at 0° for 2 hr. At this point the reaction, which had proceeded ˜40%, was diluted with 25 mL of CH2Cl2 to facilitate stirring. The reaction was then heated at 45° for 16 hr to drive to completion. Upon cooling, the reaction was diluted with CH2Cl2, washed 2× with 10% NaHSO3, 1× with brine prior to drying over Na2SO4. After removal of the volatiles, the residue comprising a 2:1 mixture of 5-bromo to 3-bromotoluic acid was recrystallized from 95% EtOH to yield 14.4 g of 5-bromo-2-methylbenzoic acid.

Workup

  1. customAt this point the reaction, which
  2. stirringto facilitate stirring
  3. temperatureThe reaction was then heated at 45° for 16 hr
  4. temperatureUpon cooling
  5. washwashed 2× with 10% NaHSO3, 1× with brine
  6. dry with materialto drying over Na2SO4
  7. customAfter removal of the volatiles
  8. additiona 2:1 mixture of 5-bromo to 3-bromotoluic acid
  9. customwas recrystallized from 95% EtOH

Sources & evidence

ORD record
ord-2f28dd3b240b4052b63474fbfdf2abf5
Source dataset
uspto-grants-2002_07
Patent number
US06414126B1

Reaction notes

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