Phosphorus oxychloride → 5-Ethyl-2-(2-phenylethenyl)-1,3-oxazole-4-carboxylic acid

HRID 746023Notes

Reaction equation

HRID 746023 reaction equation
[C:1]([NH:11][CH:12]([C:17](=[O:20])[CH2:18][CH3:19])[C:13]([O:15]C)=[O:14])(=O)[CH:2]=[CH:3][C:4]1[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=1.P(Cl)(Cl)(Cl)=O>C1(C)C=CC=CC=1>[CH2:18]([C:17]1[O:20][C:1]([CH:2]=[CH:3][C:4]2[CH:5]=[CH:6][CH:7]=[CH:8][CH:9]=2)=[N:11][C:12]=1[C:13]([OH:15])=[O:14])[CH3:19]

Participants

4

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 53730131HCID 53730131, compound

Product 1

HCID 542006445-Ethyl-2-(2-phenylethenyl)-1,3-oxazole-4-carboxylic acid

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Conditions

Temperature
90 °C

Procedure

A mixture of methyl 2-cinnamoylamino-3-oxovalerate (8.25 g), phosphorus oxychloride (5.6 ml) and toluene (80 ml) was refluxed with stirring for 40 minutes. The solvent was then distilled off and the residue was neutralized with aqueous sodium hydrogen carbonate and extracted with ethyl ether. The ethyl ether layer was washed with water and dried over anhydrous magnesium sulfate. The solvent was distilled off and the oily residue was dissolved in ethanol (30 ml). To the solution was added 2N sodium hydroxide (30 ml) and the mixture was heated on a water bath at 90° C. for 5 minutes. After cooling, the reaction mixture was adjusted to pH 2 with 2N hydrochloric acid and diluted with water. The resulting crystalline precipitate was collected by filtration to give 5-ethyl-2-styryl-4oxazolecarboxylic acid; yield 7.12 g (97.7%). Recrystallization from ethanol gave colorless prisms melting at 143°-144° C.

Workup

  1. temperaturewas refluxed
  2. distillationThe solvent was then distilled off
  3. extractionextracted with ethyl ether
  4. washThe ethyl ether layer was washed with water
  5. dry with materialdried over anhydrous magnesium sulfate
  6. distillationThe solvent was distilled off
  7. dissolutionthe oily residue was dissolved in ethanol (30 ml)
  8. additionTo the solution was added 2N sodium hydroxide (30 ml)
  9. temperatureAfter cooling
  10. additiondiluted with water
  11. filtrationThe resulting crystalline precipitate was collected by filtration

Sources & evidence

ORD record
ord-436743f218314d56896e47de467eb1e0
Source dataset
uspto-grants-1986_07
Patent number
US04602027

Reaction notes

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