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

HRID 1870278Notes

Reaction equation

HRID 1870278 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 recrystallizing 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-8bc43c0348544deb87d76d9f2f50235c
Source dataset
uspto-grants-2000_08
Patent number
US06096771

Reaction notes

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