Sulfuric Acid → 3-Hydroxy-2-methylbenzoic Acid

HRID 1459009Notes

Reaction equation

HRID 1459009 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
-10 °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 70° C. The resultant reaction mixture was stirred 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 70° C
  2. customThe resultant reaction mixture
  3. temperatureslowly heated to 80° C. (heavy gas evolution
  4. customoccurs between the temperatures of 40°-60° C.
  5. temperaturethe reaction mixture was cooled to room temperature
  6. extractionthe subtitled compound was extracted five times with ethyl acetate (600 mL)
  7. customThe resultant layers were separated
  8. extractionThe titled compound was then extracted
  9. washthe combined organic phases were washed with brine
  10. dry with materialdried over sodium sulfate
  11. filtrationfiltered
  12. concentrationconcentrated under reduced pressure
  13. customto provide a crude material

Sources & evidence

ORD record
ord-632378d238264717b66d5310dd2482ee
Source dataset
uspto-grants-1998_12
Patent number
US05852043

Reaction notes

Loading…