Sulfuric Acid → 2-Hydroxy-4-iodobenzoic acid

HRID 1160789Notes

Reaction equation

HRID 1160789 reaction equation
N[C:2]1[CH:10]=[CH:9][CH:5]([C:6]([OH:8])=[O:7])[C:4]([OH:12])(O)[CH:3]=1.S(=O)(=O)(O)O.N([O-])=O.[Na+].[I-:22].[K+]>O>[OH:12][C:4]1[CH:3]=[C:2]([I:22])[CH:10]=[CH:9][C:5]=1[C:6]([OH:8])=[O:7]

Participants

6

Reactant 4

HCID 1118Sulfuric AcidHCID 4875Potassium IodideHCID 23668193Sodium NitriteHCID 67036043HCID 67036043, compound

Product 1

HCID 728742-Hydroxy-4-iodobenzoic acid

Reagents, catalysts & solvents 1

HCID 962WaterSolvent3×

Conditions

Temperature
70 °C

Procedure

A sample of 4-amino-2-hydroxysalicylic acid (10 g, 65.3 mmol) is charged to a 2 liter Erlenmeyer flask equipped with a large stir bar, cooled in an ice/water bath and treated with concentrated sulfuric acid (20 mL) and enough water to make a free flowing suspension (˜50 mL). After stirring for 20 minutes, the reaction is treated with a solution of sodium nitrite (4.55 g, 66.0 mmol) in water (20 mL) over the course of 10 minutes. After stirring an additional 3 minutes, the reaction is treated with a solution of potassium iodide (16.9 g, 101 mmol) in water (30 mL) over the course of 15 minutes. The cooling bath is removed and the reaction is carefully monitored and stirred as it generates a significant amount of nitrogen gas. After the reaction subsides, it is briefly heated to 70° C. after which it is allowed to cool to room temperature and sit overnight. The resulting solid is collected by filtration, washed with water and dried to give crude 2-hydroxy-4-iodo-benzoic acid that is used in the next reaction without further purification: ESMS m/z 265.0 (M+H+).

Workup

  1. customequipped with a large stir bar
  2. temperaturecooled in an ice/water bath
  3. stirringAfter stirring an additional 3 minutes
  4. customThe cooling bath is removed
  5. stirringstirred as it
  6. customAfter the reaction subsides, it
  7. temperatureto cool to room temperature
  8. waitsit overnight
  9. filtrationThe resulting solid is collected by filtration
  10. washwashed with water
  11. customdried

Sources & evidence

ORD record
ord-3155d567b4ee405182b90bd849f3ad39
Source dataset
uspto-grants-2010_10
Patent number
US07816542B2

Reaction notes

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