Sulfuric Acid → Methyl 5-hydroxy-2-methylbenzoate

HRID 2120495Notes

Reaction equation

HRID 2120495 reaction equation
N[C:2]1[CH:3]=[C:4]([C:9]([CH3:12])=[CH:10][CH:11]=1)[C:5]([O:7][CH3:8])=[O:6].S(=O)(=O)(O)[OH:14].N([O-])=O.[Na+].C(OCC)C>C1COCC1.O.CO>[OH:14][C:2]1[CH:3]=[C:4]([C:9]([CH3:12])=[CH:10][CH:11]=1)[C:5]([O:7][CH3:8])=[O:6]

Participants

8

Reactant 4

HCID 1118Sulfuric Acid3×HCID 3283Diethyl EtherHCID 15049977Methyl 5-Amino-2-methylbenzoateHCID 23668193Sodium Nitrite

Product 1

HCID 13929055Methyl 5-hydroxy-2-methylbenzoate

Reagents, catalysts & solvents 3

HCID 887MethanolSolventHCID 962WaterSolvent3×HCID 8028TetrahydrofuranSolvent

Procedure

4.6 g (28 mmol) of methyl 3-amino-6-methylbenzoate are dissolved in 50 ml of THF and 50 ml of 1M sulphuric acid and then the reaction medium is cooled to 0° C. A solution of sodium nitrite (2.3 g, 33.6 mmol) in 10 ml of water is then added dropwise and then the medium is stirred for 20 minutes. 15 ml of pure sulphuric acid are then added and the reaction medium is heated under reflux for 2 hours, poured into 500 ml of water and extracted with ethyl ether. The organic phases are dried, concentrated under reduced pressure and the residue obtained is dissolved in 100 ml of methanol. 3 ml of sulphuric acid are added and the reaction medium is heated under reflux for 14 hours, cooled, treated with water and ethyl ether. After extraction with ethyl ether, the organic phases are combined, dried over magnesium sulphate and concentrated under reduced pressure. After purification on a silica column (ethyl acetate 30-heptane 70), a brown oil is obtained (m=1.2 g; Y=25%).

Workup

  1. temperaturethe reaction medium is heated
  2. temperatureunder reflux for 2 hours
  3. extractionextracted with ethyl ether
  4. customThe organic phases are dried
  5. concentrationconcentrated under reduced pressure
  6. customthe residue obtained
  7. temperaturethe reaction medium is heated
  8. temperatureunder reflux for 14 hours
  9. temperaturecooled
  10. extractionAfter extraction with ethyl ether
  11. dry with materialdried over magnesium sulphate
  12. concentrationconcentrated under reduced pressure
  13. customAfter purification on a silica column (ethyl acetate 30-heptane 70)
  14. customa brown oil is obtained (m=1.2 g; Y=25%)

Sources & evidence

ORD record
ord-017550dee6f84f4f97f1cb62b8708f49
Source dataset
uspto-grants-2004_02
Patent number
US06689922B1

Reaction notes

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