1-Piperazinecarboxylic acid, ethyl ester → 6-[4-(4-ethoxycarbonyl-piperazin-1-yl)-3-nitro-phenyl]-4,5-dihydro-5-methyl-3(2H)-pyridazinone

Participants

Reaction Conditions

Reaction Steps

24.5 ml (168 mmol) of 1-ethoxycarbonylpiperazine are added to a solution of 15.0 g (56 mmol) of 6-(4-chloro-3-nitro-phenyl)-4,5-dihydro-5-methyl-3(2H)-pyridazinone in 50 ml of dimethyl formamide and the solution is stirred at a reaction temperature of 100° C. for 3 hours. When the reaction mixture is cold, it is poured out on 300 ml of ice water with vigorous stirring. The precipitated solid is suction filtered, washed with a small quantity of ethanol and diethyl ether and recrystallized from 500 ml of ethanol. 16.7 g (76%) of orange yellow crystals, m.p. 140° to 142° C., are obtained.

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