Acetyl chloride → 2-Methyl-1,3-benzoxazol-6-ol

HRID 366443Notes

Reaction equation

HRID 366443 reaction equation
Cl.[NH2:2][C:3]1[CH:9]=[CH:8][C:6]([OH:7])=[CH:5][C:4]=1[OH:10].[C:11](Cl)(=O)[CH3:12].C1(C)C=CC(S([O-])(=O)=O)=CC=1.[NH+]1C=CC=CC=1>C(N(CC)CC)C>[CH3:11][C:12]1[O:10][C:4]2[CH:5]=[C:6]([OH:7])[CH:8]=[CH:9][C:3]=2[N:2]=1

Participants

5

Reactant 3

HCID 6367Acetyl chlorideHCID 466102Benzenesulfonic acid, 4-methyl-, compd. with pyridine (1:1)2×HCID 134088224-Aminobenzene-1,3-diol hydrochloride

Product 1

HCID 6765042-Methyl-1,3-benzoxazol-6-ol

Reagents, catalysts & solvents 1

HCID 8471TriethylamineSolvent

Procedure

4-Aminoresorcinol hydrochloride (2.0 g, 12.4 mM), acetyl chloride (1.0 g, 12.6 mM), triethylamine (1.38 g, 13.6 mM) and pyridinium-p-toluenesulfonate (PPTS, 800 mg, 3.2 mM) were refluxed in xylenes (50 mL) for about 18 hours. Additional PPTS (300 mg) was added and the mixture was then refluxed about 48 hours. The reaction mixture was concentrated and the residue dissolved in ethyl acetate (200 mL) and washed with H2O (3×150 mL). The combined aqueous layer was back extracted with ethyl acetate (200 mL) and the combined organic layers were dried over MgSO4. Filtration and concentration provided 1.36 g. Filtration through a silica gel column eluted with 10% methanol/methylene chloride provided an orange solid, 0.3 g; m.p., 94-96° C.

Workup

  1. temperaturethe mixture was then refluxed about 48 hours
  2. concentrationThe reaction mixture was concentrated
  3. dissolutionthe residue dissolved in ethyl acetate (200 mL)
  4. washwashed with H2O (3×150 mL)
  5. extractionThe combined aqueous layer was back extracted with ethyl acetate (200 mL)
  6. dry with materialthe combined organic layers were dried over MgSO4
  7. filtrationFiltration and concentration
  8. customprovided 1.36 g
  9. filtrationFiltration through a silica gel column
  10. washeluted with 10% methanol/methylene chloride
  11. customprovided an orange solid, 0.3 g
  12. customm.p., 94-96° C.

Sources & evidence

ORD record
ord-4c0c8dfd619f4eaa8e6958e37f837331
Source dataset
uspto-grants-2000_10
Patent number
US06130217

Reaction notes

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