Triethylamine → 6-Fluoro-3-methyl-1,2-benzoxazole

HRID 1274556Notes

Reaction equation

HRID 1274556 reaction equation
[F:1][C:2]1[CH:7]=[CH:6][C:5]([C:8](=O)[CH3:9])=[C:4]([OH:11])[CH:3]=1.C(N1C=CN=C1)([N:14]1C=CN=C1)=O.C(N(CC)CC)C>O1CCCC1>[F:1][C:2]1[CH:7]=[CH:6][C:5]2[C:8]([CH3:9])=[N:14][O:11][C:4]=2[CH:3]=1

Participants

5

Reactant 3

HCID 8471TriethylamineHCID 682631,1'-CarbonyldiimidazoleHCID 27373264'-Fluoro-2'-hydroxyacetophenone

Product 1

HCID 219784096-Fluoro-3-methyl-1,2-benzoxazole

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

A mixture of 4'-fluoro-2'-hydroxyacetophenone, oxime (47.0 g, 0.278 mol) in tetrahydrofuran is heated to just under reflux, treated with a solution of 1,1'-carbonyldiimidazole (55.0 g, 0.340 mol) and triethylamine (39.0 g, 0.390 mol) in tetrahydrofuran, refluxed for one hour, cooled, concentrated in vacuo, and poured into an ice-water mixture. The resultant aqueous mixture is extracted with ether. The organic extracts are combined, washed sequentially with saturated ammonium chloride solution and brine, dried over anhydrous magnesium sulfate, and concentrated in vacuo to obtain an oil. Column chromatography of the oil using silica gel and a methylene chloride/hexanes solution (1:1) gives the title product as a yellow oil which is identified by 1H NMR spectral analysis.

Workup

  1. temperatureis heated to just
  2. temperatureunder reflux
  3. temperaturerefluxed for one hour
  4. temperaturecooled
  5. concentrationconcentrated in vacuo
  6. additionpoured into an ice-water mixture
  7. extractionThe resultant aqueous mixture is extracted with ether
  8. washwashed sequentially with saturated ammonium chloride solution and brine
  9. dry with materialdried over anhydrous magnesium sulfate
  10. concentrationconcentrated in vacuo
  11. customto obtain an oil

Sources & evidence

ORD record
ord-a343bea2c6d243a6a5178eca8c4c7ad3
Source dataset
uspto-grants-2000_12
Patent number
US06156700

Reaction notes

Loading…