Phosphorus pentachloride → 5-Chloro-2-(4-methyl-1-piperazinyl)benzoxazole

HRID 1636847Notes

Reaction equation

HRID 1636847 reaction equation
[Cl:1][C:2]1[CH:3]=[CH:4][C:5]2[O:9][C:8](S)=[N:7][C:6]=2[CH:11]=1.P(Cl)(Cl)(Cl)(Cl)Cl.[CH3:18][N:19]1[CH2:24][CH2:23][NH:22][CH2:21][CH2:20]1>C1C=CC=CC=1>[Cl:1][C:2]1[CH:3]=[CH:4][C:5]2[O:9][C:8]([N:22]3[CH2:23][CH2:24][N:19]([CH3:18])[CH2:20][CH2:21]3)=[N:7][C:6]=2[CH:11]=1

Participants

5

Reactant 3

HCID 24819Phosphorus pentachlorideHCID 531671-MethylpiperazineHCID 178527795HCID 178527795, compound

Product 1

HCID 108483785-Chloro-2-(4-methyl-1-piperazinyl)benzoxazole

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Procedure

A 300 mg portion of 5-chloro-2-mercaptobenzoxazole was suspended in 50 ml of anhydrous benzene, and the suspension was mixed with 404 mg of phosphorus pentachloride and heated under reflux for 3 hours. The reaction solution was cooled in an ice bath and, with stirring, 1.6 g of 1-methylpiperazine was added thereto. After 30 minutes of stirring, the ice bath was removed to carry out 12 hours of stirring at room temperature, and then the reaction solution was mixed with saturated sodium bicarbonate aqueous solution and extracted with ethyl acetate. The organic layer was washed with saturated brine and dried with magnesium sulfate and then the solvent was evaporated under a reduced pressure. Thereafter, the thus obtained mixture was purified by a silica gel column chromatography (ethyl acetate:methanol=20:1) to obtain the title compound (121 mg) in light yellow color.

Workup

  1. temperatureheated
  2. temperatureunder reflux for 3 hours
  3. temperatureThe reaction solution was cooled in an ice bath
  4. stirringAfter 30 minutes of stirring
  5. customthe ice bath was removed
  6. stirringof stirring at room temperature
  7. additionthe reaction solution was mixed with saturated sodium bicarbonate aqueous solution
  8. extractionextracted with ethyl acetate
  9. washThe organic layer was washed with saturated brine
  10. dry with materialdried with magnesium sulfate
  11. customthe solvent was evaporated under a reduced pressure
  12. customThereafter, the thus obtained mixture was purified by a silica gel column chromatography (ethyl acetate:methanol=20:1)

Sources & evidence

ORD record
ord-00851cb9bed04865922935ddbe67e68e
Source dataset
uspto-grants-2000_03
Patent number
US06037342

Reaction notes

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