Phosphorus oxychloride → 3,4,5-Trichloropyridazine

HRID 568307

Reaction equation

HRID 568307 reaction equation
[Cl:1][C:2]1[C:3](=O)[NH:4][N:5]=[CH:6][C:7]=1[Cl:8].P(Cl)(Cl)([Cl:12])=O>>[Cl:12][C:3]1[N:4]=[N:5][CH:6]=[C:7]([Cl:8])[C:2]=1[Cl:1]

Participants

3

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 732474,5-Dichloro-3-hydroxypyridazine

Product 1

HCID 701113,4,5-Trichloropyridazine

Procedure

A stirred solution of 20.0 grams of 4,5-dichloro-3-pyridazone in 150 ml of phosphorus oxychloride is heated under reflux for five hours. The excess phosphorus oxychloride is removed under reduced pressure, and the residue poured into ice water. The mixture is extracted with diethyl ether. The extract is dried with magnesium sulfate, filtered, and the filtrate concentrated to a residue. The residue is distilled under reduced pressure. A fraction, b.p. 117°-118° C./14-15 mm, 20 grams, solidifies on standing. The solid is recrystallized from acetone-water to yield 3,4,5-trichloropyridazine; m.p. 61° C.

Workup

  1. temperatureunder reflux for five hours
  2. customThe excess phosphorus oxychloride is removed under reduced pressure
  3. additionthe residue poured into ice water
  4. extractionThe mixture is extracted with diethyl ether
  5. dry with materialThe extract is dried with magnesium sulfate
  6. filtrationfiltered
  7. concentrationthe filtrate concentrated to a residue
  8. distillationThe residue is distilled under reduced pressure
  9. customThe solid is recrystallized from acetone-water

Sources & evidence

ORD record
ord-1b32c944f3204d678de1d668cb4a71fb
Source dataset
uspto-grants-1988_03
Patent number
US04728355

Linked notes

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