Ici 109,081 → 6-[p-(2,2-dichlorocyclopropylcarbonylamino)-phenyl]-4,5-dihydro-5-methyl-3(2H)-pyridazinone

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Reaction Conditions

Reaction Steps

5.0 g (24.6 millimoles) of 6-(p-aminophenyl)-4,5-dihydro-5-methyl-3(2H)-pyridazinone are dissolved in 100 ml of absolute tetrahydrofuran by stirring and heating to 60° C. The solution is allowed to cool to room temperature, 5.15 g (29.7 millimoles) of 2,2-dichlorocyclopropanecarboxylic acid chloride, dissolved in 10 ml of absolute tetrahydrofuran, are added dropwise and the mixture is then stirred for 6 hours under reflux. Thereafter it is concentrated to about 50 ml and the product is filtered off at 10° C., washed with water and recrystallized from dimethylformamide/water. 5.0 g (60% of theory) of 6-[p-(2,2-dichlorocyclopropylcarbonylamino)-phenyl]-4,5-dihydro-5-methyl-3(2H)-pyridazinone are obtained as colorless crystals, of melting point 252°-253° C.

Provenance & Evidence