Nitric Acid → 2,5-Dibromo-4-methylbenzoic acid

HRID 1667327Notes

Reaction equation

HRID 1667327 reaction equation
[N+]([O-])(O)=[O:2].[Br:5][C:6]1[CH:11]=[C:10]([CH3:12])[C:9]([Br:13])=[CH:8][C:7]=1[CH3:14].[OH2:15]>>[Br:5][C:6]1[CH:11]=[C:10]([CH3:12])[C:9]([Br:13])=[CH:8][C:7]=1[C:14]([OH:2])=[O:15]

Participants

4

Reactant 3

HCID 944Nitric AcidHCID 962WaterHCID 66175Benzene, 1,4-dibromo-2,5-dimethyl-

Product 1

HCID 232948852,5-Dibromo-4-methylbenzoic acid

Procedure

To a mixed solution of nitric acid (45 ml, 70-71%) and water (55 ml) was added portionwise 2,5-dibromo-p-xylene 802 (13.2 g, 50 mmol). The resulting mixture was heated to reflux and continued to reflux for 6 days. The mixture was cooled to room temperature and the white solid was collected by filtration. The solid was placed into a mixture of ethyl acetate (100 ml) and water (100 ml), to which was added sodium carbonate portion wise (ca 10-12 g) over a 2 hour period until all the solid dissolved. The organic layer was separated and the aqueous layer was made strongly acidic by the addition of concentrated HCl to pH 2-3. A white solid was collected by filtration and dried in vacuum to give 2,5-dibromo-4-methylbenzoic acid: 9.6 g (65%).

Workup

  1. temperatureThe resulting mixture was heated
  2. temperatureto reflux
  3. temperatureto reflux for 6 days
  4. filtrationthe white solid was collected by filtration
  5. additionThe solid was placed into a mixture of ethyl acetate (100 ml) and water (100 ml), to which
  6. additionwas added sodium carbonate portion wise (ca 10-12 g) over a 2 hour period until all the solid
  7. dissolutiondissolved
  8. customThe organic layer was separated
  9. additionthe aqueous layer was made strongly acidic by the addition of concentrated HCl to pH 2-3
  10. filtrationA white solid was collected by filtration
  11. customdried in vacuum

Sources & evidence

ORD record
ord-f0dc163dcca84f189779dbc2b42cf162
Source dataset
uspto-grants-2011_10
Patent number
US08044212B2

Reaction notes

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