Boron trifluoride → Ethyl 3-(4-nitrophenyl)-1,2,4-oxadiazole-5-carboxylate

HRID 54543

Reaction equation

HRID 54543 reaction equation
[N+:1]([C:4]1[CH:13]=[CH:12][C:7]([C:8](=[N:10][OH:11])[NH2:9])=[CH:6][CH:5]=1)([O-:3])=[O:2].Cl[C:15](=O)[C:16]([O:18][CH2:19][CH3:20])=[O:17].B(F)(F)F>O1CCOCC1>[CH2:19]([O:18][C:16]([C:15]1[O:11][N:10]=[C:8]([C:7]2[CH:12]=[CH:13][C:4]([N+:1]([O-:3])=[O:2])=[CH:5][CH:6]=2)[N:9]=1)=[O:17])[CH3:20]

Participants

5

Reactant 3

HCID 6356Boron trifluorideHCID 20884Ethoxalyl chlorideHCID 3825473N-Hydroxy-4-nitrobenzimidamide

Product 1

HCID 2743197Ethyl 3-(4-nitrophenyl)-1,2,4-oxadiazole-5-carboxylate

Reagents, catalysts & solvents 1

HCID 312751,4-DioxaneSolvent

Procedure

A mixture of 4-nitrobenzamide oxime (4 g) and ethyl chlorooxoacetate (3.01 g) in dioxane (200 ml) was refluxed for 1 hour, and then borontrifluoride (1 ml) was added thereto. The whole mixture was refluxed for 12 hours. After being cooled to room temperature, the solvent was evaporated in vacuo. The residue was diluted with ethyl acetate (100 ml), washed with a saturated potassium carbonate aqueous solution, dried over magnesium sulfate and evaporated in vacuo. The residue was purified by column chromatography on silica gel with a mixture of dichloromethane and hexane (1:1) as eluent. The fractions containing the object product were collected and evaporated in vacuo to afford 5-ethoxycarbonyl-3-(4-nitrophenyl)-1,2,4-oxadiazole.

Workup

  1. temperaturewas refluxed for 1 hour
  2. temperatureThe whole mixture was refluxed for 12 hours
  3. customthe solvent was evaporated in vacuo
  4. additionThe residue was diluted with ethyl acetate (100 ml)
  5. washwashed with a saturated potassium carbonate aqueous solution
  6. dry with materialdried over magnesium sulfate
  7. customevaporated in vacuo
  8. customThe residue was purified by column chromatography on silica gel with a mixture of dichloromethane and hexane (1:1) as eluent
  9. additionThe fractions containing the object product
  10. customwere collected
  11. customevaporated in vacuo

Sources & evidence

ORD record
ord-2cdff5b8567042a49776887cdc18c53d
Source dataset
uspto-grants-1997_04
Patent number
US05622976

Linked notes

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