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

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Reaction Steps

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.

Provenance & Evidence