Dimethylformamide → 5-(5-Oxazolyl)-1H-pyrrole-2-carboxaldehyde

HRID 6428Notes

Reaction equation

HRID 6428 reaction equation
CN(C)[CH:3]=[O:4].P(Cl)(Cl)(Cl)=O.[NH:11]1[CH:15]=[CH:14][CH:13]=[C:12]1[C:16]1[O:20][CH:19]=[N:18][CH:17]=1.C([O-])(=O)C.[Na+]>ClCCCl.C(Cl)(Cl)Cl>[CH:3]([C:15]1[NH:11][C:12]([C:16]2[O:20][CH:19]=[N:18][CH:17]=2)=[CH:13][CH:14]=1)=[O:4]

Participants

7

Reactant 4

HCID 6228DimethylformamideHCID 24813Phosphorus oxychlorideHCID 517045Sodium AcetateHCID 19793758HCID 19793758, compound

Product 1

HCID 197937575-(5-Oxazolyl)-1H-pyrrole-2-carboxaldehydeYield 80%

Reagents, catalysts & solvents 2

HCID 111,2-DichloroethaneSolventHCID 6212ChloroformSolvent

Procedure

To an ice cooled 1 mL dimethylformamide was added 0.82 g (5.4 mmol) of phosphorus oxychloride while stirring under a nitrogen atmosphere. The mixture was stirred 20 minutes and then was added a solution of 0.60 g (4.5 mmol) of 5-(pyrrol-2-yl)oxazole in 15 mL of 1,2-dichloroethane while cooling in an ice bath. The reaction mixture was then heated under reflux for 20 minutes. After cooling to room temperature, 50 mL of chloroform was added followed by 60 mL of saturated aqueous sodium acetate. After heating under reflux for 20 minutes, the mixture was cooled to room temperature and the organic layer separated, washed with aqueous sodium carbonate and dried over anhydrous sodium sulfate. Following evaporation of the solvent at reduced pressure, the crude product was purified by column chromatography with chloroform elution to give 0.58 g (80%) of 5-(5-formylpyrrol-2-yl)oxazole as a white solid, m.p. 152°-153° C.; 1H-NMR (Acetone-d6) δ 6.68 (d, 1H, ArH), 7.09 (d, 1H, ArH), 7.61 (S, 1H, ArH), 8,22 (s, 1H, ArH), 9.57 (s, 1H, CHO).

Workup

  1. stirringThe mixture was stirred 20 minutes
  2. temperaturewhile cooling in an ice bath
  3. temperatureThe reaction mixture was then heated
  4. temperatureunder reflux for 20 minutes
  5. temperatureAfter heating
  6. temperatureunder reflux for 20 minutes
  7. temperaturethe mixture was cooled to room temperature
  8. customthe organic layer separated
  9. washwashed with aqueous sodium carbonate
  10. dry with materialdried over anhydrous sodium sulfate
  11. customevaporation of the solvent at reduced pressure
  12. customthe crude product was purified by column chromatography with chloroform elution

Sources & evidence

ORD record
ord-ca3b6b7778984b1dafee3bcd7b9942eb
Source dataset
uspto-grants-1993_09
Patent number
US05248782

Reaction notes

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