Pyridine → 3,5-Dichloro-1,2-benzoxazole

HRID 1739053Notes

Reaction equation

HRID 1739053 reaction equation
[Cl:1][C:2]1[CH:3]=[CH:4][C:5]2[O:9][N:8]=[C:7](O)[C:6]=2[CH:11]=1.N1C=CC=CC=1.P(Cl)(Cl)([Cl:20])=O>>[Cl:20][C:7]1[C:6]2[CH:11]=[C:2]([Cl:1])[CH:3]=[CH:4][C:5]=2[O:9][N:8]=1

Participants

4

Reactant 3

HCID 1049PyridineHCID 24813Phosphorus oxychlorideHCID 178518984HCID 178518984, compound

Product 1

HCID 135684483,5-Dichloro-1,2-benzoxazoleYield 92%

Procedure

To a suspension of 5-chloro-3-hydroxy-1,2-benzisoxazole (100 g) in phosphorus oxychloride (80 ml) was added pyridine (48 ml) dropwise over 1 hours with stirring at room temperature, and the mixture was then refluxed for 5 hours. The reaction mixture was added to ice water (500 ml) and extracted with ethyl acetate and the combined extracts were dried over anhydrous magnesium sulphate. The solvent was evaporated under reduced pressure and the title compound (102 g, 92%) was obtained by recrystallizng the residue from petroleum ether as a colorless needle.

Workup

  1. temperaturethe mixture was then refluxed for 5 hours
  2. extractionextracted with ethyl acetate
  3. dry with materialthe combined extracts were dried over anhydrous magnesium sulphate
  4. customThe solvent was evaporated under reduced pressure

Sources & evidence

ORD record
ord-f1b8beea89954a68a8ff835ea9d6b3dd
Source dataset
uspto-grants-1999_10
Patent number
US05965591

Reaction notes

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