6-(4-Aminophenyl)-4,5-dihydropyridazin-3(2H)-one → 6-[p-(1-chlorocyclopropylcarbonylamino)-phenyl]-4,5-dihydro-3(2H)-pyridazinone

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Reaction Steps

A solution of 4.45 g (32.0 millimoles) of 1-chlorocyclopropanecarboxylic acid chloride in 20 ml of absolute tetrahydrofuran is added dropwise to a stirred suspension of 5.0 g (26.4 millimoles) of 6-(p-aminophenyl)-4,5-dihydro-3(2H)-pyridazinone in 100 ml of absolute tetrahydrofuran. The mixture is then stirred for 20 hours at room temperature followed by 1 hour under reflux. The product is filtered off at 10° C., washed first with tetrahydrofuran and then with water, and recrystallized from dimethylformamide/water. 6.3 g (82% of theory) of 6-[p-(1-chlorocyclopropylcarbonylamino)-phenyl]-4,5-dihydro-3(2H)-pyridazinone are isolated as colorless crystals, of melting point 231°-232° C.

Provenance & Evidence