Carbon Dioxide → 4-Bromo-2,5-dimethylbenzoic acid

HRID 1017777Notes

Reaction equation

HRID 1017777 reaction equation
C([Li])CCC.Br[C:7]1[CH:12]=[C:11]([CH3:13])[C:10]([Br:14])=[CH:9][C:8]=1[CH3:15].[C:16](=[O:18])=[O:17].Cl>CCCCCC>[Br:14][C:10]1[C:11]([CH3:13])=[CH:12][C:7]([C:16]([OH:18])=[O:17])=[C:8]([CH3:15])[CH:9]=1

Participants

6

Reactant 4

HCID 280Carbon DioxideHCID 313Hydrochloric AcidHCID 66175Benzene, 1,4-dibromo-2,5-dimethyl-HCID 178418339Butyllithium

Product 1

HCID 27534794-Bromo-2,5-dimethylbenzoic acid

Reagents, catalysts & solvents 1

HCID 8058HexaneSolvent

Procedure

At −78° C., 100 ml (0.16 mol) of a 1.6 molar n-butyl lithium solution in hexane is added dropwise to a solution of 43.63 g (0.162 mol) of 2,5-dibromo-p-xylene, and stirred for one hour. Then dry carbon dioxide is passed into the solution for 4 hours. It is slowly heated to ambient temperature and stirred for 16 hours. After the slow addition of 210 ml of 2N hydrochloric acid, the phases are separated, the aqueous phase is extracted 2× with 200 ml ether, the combined organic phases are washed with conc. NaCl solution and dried with Na2SO4. After the solvent has been eliminated in vacuo the crude product is mixed with 200 ml of 2N NaOH and the brown solution obtained is extracted 3× with 100 ml of diethyl ether. The aqueous phase is acidified with conc. HCl and the precipitate which then forms is suction filtered, washed with ice water and dried.

Workup

  1. stirringstirred for 16 hours
  2. customthe phases are separated
  3. extractionthe aqueous phase is extracted 2× with 200 ml ether
  4. washthe combined organic phases are washed with conc. NaCl solution
  5. dry with materialdried with Na2SO4
  6. additionis mixed with 200 ml of 2N NaOH
  7. customthe brown solution obtained
  8. extractionis extracted 3× with 100 ml of diethyl ether
  9. filtrationfiltered
  10. washwashed with ice water
  11. customdried

Sources & evidence

ORD record
ord-e09049177e444e8aac3e2a747e1ede35
Source dataset
uspto-grants-2002_11
Patent number
US06479524B1

Reaction notes

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