Sulfuric Acid → 3-Hydroxy-2-methylbenzoic Acid

HRID 400185Notes

Reaction equation

HRID 400185 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 stirrer 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 soluton. 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. Yield: 52%.

Workup

  1. temperaturewhile maintaining the temperature below 7° C
  2. customThe resultant reaction mixture
  3. customfor approximately 30 minutes
  4. customat -10° C.
  5. customoccurs between the temperatures of 40°-60° C.
  6. temperaturethe reaction mixture was cooled to room temperature
  7. extractionthe subtitled compound was extracted five times with ethyl acetate (600 mL)
  8. customThe resultant layers were separated
  9. extractionThe titled compound was then extracted
  10. washthe combined organic phases were washed with brine
  11. dry with materialdried over sodium sulfate
  12. filtrationfiltered
  13. concentrationconcentrated under reduced pressure
  14. customto provide a crude material

Sources & evidence

ORD record
ord-2df99759803545c997f597fcb83ad483
Source dataset
uspto-grants-1998_10
Patent number
US05827859

Reaction notes

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