Sulfuric Acid → 3-Hydroxy-2-methylbenzoic Acid

HRID 356704Notes

Reaction equation

HRID 356704 reaction equation
N([O-])=O.[Na+].N[C:6]1[C:7]([CH3:15])=[C:8]([CH:12]=[CH:13][CH:14]=1)[C:9]([OH:11])=[O:10].S(=O)(=O)(O)[OH:17]>O>[OH:17][C:6]1[C:7]([CH3:15])=[C:8]([CH:12]=[CH:13][CH:14]=1)[C:9]([OH:11])=[O:10]

Participants

5

Reactant 3

HCID 1118Sulfuric Acid2×HCID 27336993-Amino-2-methylbenzoic acidHCID 23668193Sodium Nitrite

Product 1

HCID 2520233-Hydroxy-2-methylbenzoic Acid

Reagents, catalysts & solvents 1

HCID 962WaterSolvent2×

Conditions

Temperature
80 °C

Procedure

Alternatively, the desired subtitled compound was prepared by adding 22.6 g (0.33 mol) of sodium nitrite in small portions to a cooled (-10° C.) solution of 45 g (0.30 mol) of 3-amino-2-methylbenzoic acid and 106 g (58 mL; 1.08 mol) of concentrated sulfuric acid in 400 mL of water, while maintaining the temperature below 7° C. The resultant reaction mixture was surrey for approximately 30 minutes at -10° C., poured into a solution of 240 mL of concentrated sulfuric acid in 1.2 L water, and then slowly heated to 80° C. (heavy gas evolution occurs between the temperatures of 40°-60° C.). When the gas evolution stopped, the reaction mixture was cooled to room temperature and the subtitled compound was extracted five times with ethyl acetate (600 mL). The combined organic phases were combined with 500 mL of an aqueous saturated sodium carbonate solution. The resultant layers were separated and the aqueous layer was acidified to pH 2 with concentrated hydrochloric acid. The titled compound was then extracted using ethyl acetate (500 mL) and the combined organic phases were washed with brine, dried over sodium sulfate, filtered and then concentrated under reduced pressure to provide a crude material. This material was purified using two recrystallizations from a ethyl acetate/chloroform mixture to provide 23.2 g of a light orange powder.

Workup

  1. temperaturewhile maintaining the temperature below 7° C
  2. customThe resultant reaction mixture
  3. customoccurs between the temperatures of 40°-60° C.
  4. temperaturethe reaction mixture was cooled to room temperature
  5. extractionthe subtitled compound was extracted five times with ethyl acetate (600 mL)
  6. customThe resultant layers were separated
  7. extractionThe titled compound was then extracted
  8. washthe combined organic phases were washed with brine
  9. dry with materialdried over sodium sulfate
  10. filtrationfiltered
  11. concentrationconcentrated under reduced pressure
  12. customto provide a crude material

Sources & evidence

ORD record
ord-0e31b2e112484972a4018d0fafc4fc50
Source dataset
uspto-grants-1998_11
Patent number
US05837710

Reaction notes

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