Studies on positive inotropic agents. II. Synthesis of (4-substituted 1-piperazinylcarbonyl)-2-(1H)-quinolinone derivatives.

Many (1-piperazinylcarbonyl)-2(1H)-quinolinone derivatives were synthesized and examined for positive inotropic activity on the canine heart. Among them, 3, 4-dihydro-6-[4-(3-oxo-3-phenylpropyl)-1-piperazinylcarbonyl]-2(1H)-quinolinone (XXIj) and 3, 4-dihydro-6-[4-(oxo-4-phenylbutyl)-1-piperazinylcarbonyl]-2(1H)-quinolinone (XXIl) were found to have potent activity.