Phosphorus oxychloride → 3-(p-Bromophenyl)-6-chloro-4-methylpyridazine

HRID 904123Notes

Reaction equation

HRID 904123 reaction equation
[Br:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[C:9]([CH3:15])=[CH:10][C:11](=O)[NH:12][N:13]=2)=[CH:4][CH:3]=1.P(Cl)(Cl)([Cl:18])=O>O>[Br:1][C:2]1[CH:7]=[CH:6][C:5]([C:8]2[N:13]=[N:12][C:11]([Cl:18])=[CH:10][C:9]=2[CH3:15])=[CH:4][CH:3]=1

Participants

4

Reactant 2

HCID 24813Phosphorus oxychlorideHCID 233336686-(p-bromophenyl)-5-methyl-3(2H)-pyridazinone

Product 1

HCID 203982893-(p-Bromophenyl)-6-chloro-4-methylpyridazine

Reagents, catalysts & solvents 1

HCID 962WaterSolvent

Procedure

A 10 g. portion of 6-(p-bromophenyl)-5-methyl-3(2H)-pyridazinone [J. Medicinal Chem. 17, 281 (1974)] and 100 ml. of phosphorus oxychloride are heated at steam bath temperature for 3 hours. The mixture is added dropwise to cold water while stirring. The resulting solid is filtered and washed with water to afford 3-(p-bromophenyl)-6-chloro-4-methyl pyridazine as a grey solid. A mixture of 1.5 g. of this compound, 0.64 g. of formylhydrazine and 25 ml. of n-butyl alcohol is stirred at reflux for 18 hours. The reaction mixture is cooled in an ice bath, filtered, and the solid is recrystallized from methyl alcohol giving 6-(p-bromophenyl)-7-methyl-1,2,4-triazolo[4,3-b]pyridazine.

Workup

  1. filtrationThe resulting solid is filtered
  2. washwashed with water

Sources & evidence

ORD record
ord-e12dba28d9b74bc4bea6597d2c4fc9ac
Source dataset
uspto-grants-1980_10
Patent number
US04230705

Reaction notes

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