O-Xylene → [2-(4-Pyridyl)-benzoxazol-7-yl]carboxylic acid

HRID 1393343Notes

Reaction equation

HRID 1393343 reaction equation
O[C:2]1[C:10]([NH:11][C:12](=[O:19])[C:13]2[CH:18]=[CH:17][N:16]=[CH:15][CH:14]=2)=[CH:9][CH:8]=[CH:7][C:3]=1[C:4]([OH:6])=[O:5].O.C1(C)C=CC(S(O)(=O)=O)=CC=1.C1(C)C(C)=CC=CC=1.C(=O)([O-])[O-].[K+].[K+]>C(OCC)(=O)C>[N:16]1[CH:15]=[CH:14][C:13]([C:12]2[O:19][C:2]3[C:3]([C:4]([OH:6])=[O:5])=[CH:7][CH:8]=[CH:9][C:10]=3[N:11]=2)=[CH:18][CH:17]=1

Participants

6

Reactant 4

HCID 7237O-XyleneHCID 11430Potassium CarbonateHCID 521998p-Toluenesulfonic acid monohydrate2×HCID 230338922-Hydroxy-3-isonicotinoylaminobenzoic acid

Product 1

HCID 23033871[2-(4-Pyridyl)-benzoxazol-7-yl]carboxylic acidYield 86.4%

Reagents, catalysts & solvents 1

HCID 8857Ethyl AcetateSolvent

Procedure

A mixture of methyl ester of 2-hydroxy-3-isonicotinoylamino-benzoic acid (500 mg, 1.84 mmol), p-toluenesulfonic acid mono-hydrate (349 mg, 1.84 mmol) and xylene (20 ml) was heated under reflux for 14 hrs. and then p-toluenesulfonic acid mono-hydrate (349 mg, 1.84 mmol) was further added and refluxed under heating for 2 hrs. The reaction mixture was cooled with ice, and ethyl acetate and 10% aqueous potassium carbonate solution were added thereto. The organic phase was separated, washed with water and brine in turn and then dried. The solvent was distilled off under reduced pressure, and the residue was triturated with a mixture of n-hexane/diisopropyl ether (4/1), filtered and dried to give methyl ester of [2-(4-pyridyl)-benzoxazol-7-yl]carboxylic acid (382 mg, 82%) as pale yellow crystals.

Workup

  1. temperaturewas heated
  2. temperatureunder reflux for 14 hrs
  3. temperaturerefluxed
  4. temperatureunder heating for 2 hrs
  5. additionwere added
  6. customThe organic phase was separated
  7. washwashed with water and brine in turn
  8. customdried
  9. distillationThe solvent was distilled off under reduced pressure
  10. customthe residue was triturated with a mixture of n-hexane/diisopropyl ether (4/1)
  11. filtrationfiltered
  12. customdried

Sources & evidence

ORD record
ord-158243f6eedb43f4a2709479679e4e2a
Source dataset
uspto-grants-2008_03
Patent number
US07345068B2

Reaction notes

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