Phosphorus oxychloride → 3,4-Dichloro-6-[3-(trifluoromethyl)phenyl]pyridazine

HRID 52778Notes

Reaction equation

HRID 52778 reaction equation
[Cl:1][C:2]1[CH:3]=[C:4]([C:8]2[CH:13]=[CH:12][CH:11]=[C:10]([C:14]([F:17])([F:16])[F:15])[CH:9]=2)[N:5]=[N:6][CH:7]=1.O=P(Cl)(Cl)[Cl:20]>C1(C)C=CC=CC=1>[Cl:20][C:7]1[N:6]=[N:5][C:4]([C:8]2[CH:13]=[CH:12][CH:11]=[C:10]([C:14]([F:17])([F:16])[F:15])[CH:9]=2)=[CH:3][C:2]=1[Cl:1]

Participants

4

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 117473005-Chloro-3-[3-(trifluoromethyl)phenyl]pyridazine

Product 1

HCID 199596853,4-Dichloro-6-[3-(trifluoromethyl)phenyl]pyridazineYield 76%

Reagents, catalysts & solvents 1

HCID 1140TolueneSolvent

Procedure

5-Chloro-3-[3-(trifluoromethyl)phenyl]pyridazine, 1-oxide (27 g, 0.098 mole, Compound No. 70) and POCl3 (16.9 g, 0.11 mole) were heated to 105° C. in toluene (250 mL) under N2 for 18 h. The solvent was then removed in vacuo and the mixture was partitioned between ethyl acetate and water. The organic layer was washed with brine, dried (MgSO4), filtered through silica gel and evaporated in vacuo. The crude solid was recrystallized from cyclohexane/ethyl acetate to give 3,4-dichloro-6-[3-(trifluoromethyl)phenyl]pyridazine (21.57 g, 76% yield, Compound No. 47) as a white solid.

Workup

  1. customThe solvent was then removed in vacuo
  2. customthe mixture was partitioned between ethyl acetate and water
  3. washThe organic layer was washed with brine
  4. dry with materialdried (MgSO4)
  5. filtrationfiltered through silica gel
  6. customevaporated in vacuo
  7. customThe crude solid was recrystallized from cyclohexane/ethyl acetate

Sources & evidence

ORD record
ord-053ae3e220b14fbea4328ad641e102fe
Source dataset
uspto-grants-1997_04
Patent number
US05616789

Reaction notes

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