Phosphorus oxychloride → 3-(4-Bromophenyl)-6-chloropyridazine

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Reaction Steps

A mixture of 20.0 g. of 6-(p-bromophenyl)-3(2H)-pyridazinone (prepared as described in Example 1) in 100 ml. of phosphorus oxychloride is heated at reflux temperature for 41/2 hours. The excess phosphorus oxychloride is removed under reduced pressure and the residue is stirred with water-cracked ice to decompose the remaining phosphorus oxychloride. The product is recovered by filtration and recrystallized from dilute dimethylformamide yielding tan crystals, m.p. 201°-203° C.

Provenance & Evidence