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

Participants

Reaction Steps

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.

Provenance & Evidence