Phosphorus oxychloride → 2-(6-Chloro-3-pyridazinyl)phenol

HRID 1759360Notes

Reaction equation

HRID 1759360 reaction equation
P(Cl)(Cl)([Cl:3])=O.[OH:6][C:7]1[CH:12]=[CH:11][CH:10]=[CH:9][C:8]=1[C:13]1[CH:14]=[CH:15][C:16](=O)[NH:17][N:18]=1>CN(C)C=O>[Cl:3][C:16]1[N:17]=[N:18][C:13]([C:8]2[CH:9]=[CH:10][CH:11]=[CH:12][C:7]=2[OH:6])=[CH:14][CH:15]=1

Participants

4

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 30173466-(2-Hydroxyphenyl)-3(2H)-pyridazinone

Product 1

HCID 30187332-(6-Chloro-3-pyridazinyl)phenolYield 96%

Reagents, catalysts & solvents 1

HCID 6228DimethylformamideSolvent

Procedure

Dimethylformamide (85 ml.) was cooled to 5° and phosphorus oxychloride (115 ml.) was added slowly to maintain a solution temperature below 60°. 6-(2-Hydroxyphenyl)-3(2H)-pyridazinone (30 g., 0.16 m.) was added rapidly in several portions. The reaction mixture was heated to 85° and held at this temperature for 4.5 hours with stirring. The mixture was then cooled to 35° and poured into 1 liter of ice cold water keeping the quenched solution below 35°. The resulting precipitate was filtered off, washed with water and dried to give 30.8 g. (96% yield) of crude 3-chloro-6-(2-hydroxyphenyl)pyridazine.

Workup

  1. temperatureto maintain a solution temperature below 60°
  2. temperatureThe reaction mixture was heated to 85°
  3. temperatureThe mixture was then cooled to 35°
  4. filtrationThe resulting precipitate was filtered off
  5. washwashed with water
  6. customdried
  7. customto give 30.8 g

Sources & evidence

ORD record
ord-ebbaaadebd5940899d8e5e8d82fd931f
Source dataset
uspto-grants-1982_07
Patent number
US04340733

Reaction notes

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