Hydrogen Bromide → 2-Bromo-4-chlorobenzoic acid

HRID 1297172Notes

Reaction equation

HRID 1297172 reaction equation
[N+]([O-])([O-])=O.[Na+].N[C:7]1[CH:15]=[C:14]([Cl:16])[CH:13]=[CH:12][C:8]=1[C:9]([OH:11])=[O:10].[BrH:17]>O.[Cu](Br)Br>[Br:17][C:7]1[CH:15]=[C:14]([Cl:16])[CH:13]=[CH:12][C:8]=1[C:9]([OH:11])=[O:10]

Participants

6

Reactant 3

HCID 260Hydrogen BromideHCID 24268Sodium NitrateHCID 666462-Amino-4-chlorobenzoic acid

Product 1

HCID 331262-Bromo-4-chlorobenzoic acidYield 59%

Reagents, catalysts & solvents 2

HCID 24611Copper bromide (CuBr2)CatalystHCID 962WaterSolvent3×

Procedure

An aqueous solution of sodium nitrate (2.21 g) in water (15 mL) is added dropwise to a stirred, ice-cooled mixture of 2-amino-4-chlorobenzoic acid (5.00 g, 29.1 mmol) and 48% hydrobromic acid (150 mL) in water (150 mL). The resultant mixture is stirred for 2 hr at 0° C. Then it is treated dropwise with an aqueous solution of copper bromide (7.81 g) in water (20 mL). Upon the completion of the addition, the reaction mixture is allowed to warm to ambient temperature where it is stirred overnight. After extraction with ethyl acetate/hexanes (3:1; 2×400 mL), the combined organic layers are washed with brine (200 mL), dried, concentrated, and chromatographed on silica (1% methyl alcohol and 0.5% acetic acid in chloroform) to give the title compound (4.04 g, 59% yield). mp 154-155° C.; ES(−)MS m/z 233, (M−H)− consistent with 1 Br and 1 Cl.

Workup

  1. temperaturecooled
  2. additionUpon the completion of the addition
  3. extractionAfter extraction with ethyl acetate/hexanes (3:1; 2×400 mL)
  4. washthe combined organic layers are washed with brine (200 mL)
  5. customdried
  6. concentrationconcentrated
  7. customchromatographed on silica (1% methyl alcohol and 0.5% acetic acid in chloroform)

Sources & evidence

ORD record
ord-21f62644e44f4b40b688f3789f793f7a
Source dataset
uspto-grants-2007_07
Patent number
US07250430B2

Reaction notes

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