3-Amino-2-methylbenzoic acid methyl ester → 3-Hydroxy-2-methylbenzoic Acid

HRID 1859814Notes

Reaction equation

HRID 1859814 reaction equation
N[C:2]1[C:3]([CH3:12])=[C:4]([CH:9]=[CH:10][CH:11]=1)[C:5]([O:7]C)=[O:6].N([O-])=[O:14].[Na+]>CC(O)=O.OS(O)(=O)=O.O>[OH:14][C:2]1[C:3]([CH3:12])=[C:4]([CH:9]=[CH:10][CH:11]=1)[C:5]([OH:7])=[O:6]

Participants

6

Reactant 2

HCID 38010253-Amino-2-methylbenzoic acid methyl esterHCID 23668193Sodium Nitrite

Product 1

HCID 2520233-Hydroxy-2-methylbenzoic AcidYield 94.5%

Reagents, catalysts & solvents 3

HCID 176Acetic AcidSolventHCID 962WaterSolvent2×HCID 1118Sulfuric AcidSolvent2×

Procedure

A solution of 20.6 g (0.125 mol) of methyl 3-amino-2-methylbenzoate in 150 mL of HOAc and 25 mL of conc. H2SO4 was cooled in ice and diazotized by the dropwise addition of a solution of 8.7 g (0.125 mol) of NaNO2 in 50 mL of H2O. After stirring for 15 minutes, the diazonium solution was added dropwise to a boiling solution of 200 mL of 50% H2SO4, and the refluxing continued for 15 minutes after the addition was complete. The mixture was diluted with H2O and extracted twice with Et2O. The Et2O was washed 5 times with H2O, then with saturated NaCl. Drying over MgSO4 and removal of the solvent under reduced pressure left 17.98 g (94.4% yield) of the product as a tan solid, mp 137-140° C. The structure was confirmed by NMR spectroscopy.

Workup

  1. waitthe refluxing continued for 15 minutes
  2. additionafter the addition
  3. extractionextracted twice with Et2O
  4. washThe Et2O was washed 5 times with H2O
  5. dry with materialDrying over MgSO4 and removal of the solvent under reduced pressure

Sources & evidence

ORD record
ord-0c07a8f2bbf24f4899281bf1dd40e604
Source dataset
uspto-grants-2003_03
Patent number
US06528535B2

Reaction notes

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