Phosphorus oxychloride → 2,6-Dichloroimidazo[1,2-b]pyridazine

HRID 2051116Notes

Reaction equation

HRID 2051116 reaction equation
[Na].[Cl:2][C:3]1[CH:4]=[CH:5][C:6]2[N:7]([CH:9]=[C:10](O)[N:11]=2)[N:8]=1.P(Cl)(Cl)([Cl:15])=O>>[Cl:15][C:10]1[N:11]=[C:6]2[CH:5]=[CH:4][C:3]([Cl:2])=[N:8][N:7]2[CH:9]=1

Participants

4

Reactant 3

HCID 24813Phosphorus oxychlorideHCID 5360545SodiumHCID 229893296-Chloroimidazo[1,2-b]pyridazin-2-ol

Product 1

HCID 144223582,6-Dichloroimidazo[1,2-b]pyridazine

Procedure

Sodium salt of 6-chloro-2-hydroxyimidazo [1,2-b]pyridazine (16.0 g) is gradually added to 100 ml of phosphorus oxychloride and heated under reflux for 5 hours. The mixture is distilled under reduced pressure to remove about two-thirds amount of phosphorus oxychloride used, and the residue is poured into ice water, neutralized with aqueous ammonia and extracted with chloroform. The extract is dried over anydrous sodium sulfate and distilled to remove chloroform. The residue then is purified by silica gel chromatography (eluent: dichloromethane) to give 1.5 g of the title compound as crystals.

Workup

  1. temperatureheated
  2. temperatureunder reflux for 5 hours
  3. distillationThe mixture is distilled under reduced pressure
  4. customto remove about two-thirds amount of phosphorus oxychloride
  5. additionthe residue is poured into ice water
  6. extractionextracted with chloroform
  7. dry with materialThe extract is dried over anydrous sodium sulfate
  8. distillationdistilled
  9. customto remove chloroform
  10. customThe residue then is purified by silica gel chromatography (eluent: dichloromethane)

Sources & evidence

ORD record
ord-39587d5e98d34f5099748b9fd09c05e8
Source dataset
uspto-grants-1991_05
Patent number
US05017212

Reaction notes

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