Water → 2-Chloro-4-hydroxybenzoic acid

HRID 1072891Notes

Reaction equation

HRID 1072891 reaction equation
N[C:2]1[CH:10]=[CH:9][C:5]([C:6]([OH:8])=[O:7])=[C:4]([Cl:11])[CH:3]=1.N([O-])=[O:13].[Na+].O>S(=O)(=O)(O)O>[Cl:11][C:4]1[CH:3]=[C:2]([OH:13])[CH:10]=[CH:9][C:5]=1[C:6]([OH:8])=[O:7]

Participants

5

Reactant 3

HCID 962WaterHCID 171544-Amino-2-chlorobenzoic acidHCID 23668193Sodium Nitrite

Product 1

HCID 918212-Chloro-4-hydroxybenzoic acid

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Conditions

Temperature
70 °C

Procedure

4-Amino-2-chlorobenzoic acid (10.01 g) was homogeneously dissolved in 12.5% sulfuric acid (400 ml) by heating the mixture to 70° C. and cooled with ice. An aqueous solution of sodium nitrite (4.24 g/water 12 ml) was dropwise added to this suspension over 5 min at a temperature of not more than 8° C. Five minutes later, this solution was gradually poured into water (500 ml) at 80° C., upon which vigorous bubbling occurred and the solution turned red. The reaction mixture was further stirred at 80° C. for 1 hr. After cooling, the resulting product was extracted three times with ether. The organic layers were combined, washed successively with diluted hydrochloric acid, water and saturated brine, and dried over anhydrous magnesium sulfate. The solvent was evaporated and a small amount of diisopropyl ether was added to allow crystallization, whereby the objective compound (6.32 g) was obtained as an orange powder.

Workup

  1. temperaturecooled with ice
  2. customvigorous bubbling
  3. temperatureAfter cooling
  4. extractionthe resulting product was extracted three times with ether
  5. washwashed successively with diluted hydrochloric acid, water and saturated brine
  6. dry with materialdried over anhydrous magnesium sulfate
  7. customThe solvent was evaporated
  8. additiona small amount of diisopropyl ether was added
  9. customcrystallization, whereby the objective compound (6.32 g)
  10. customwas obtained as an orange powder

Sources & evidence

ORD record
ord-360859a2f0b64f86ad2c9a81c341bc3c
Source dataset
uspto-grants-2005_06
Patent number
US06911469B2

Reaction notes

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