Potent mammalian topoisomerase II inhibitors: 1-cyclopropyl-6,8-difluoro-1,4-dihydro-7-(2,6-dimethyl-4-pyridinyl)-4-substituted-quinolines

A series of novel 4-substituted-1,4-dihydro-quinolines 3 were prepared and found to exhibit moderate to excellent mammalian topo II inhibitory activity. Among the compounds prepared, in general, the nitrogen analogues are the most active compounds and the sulfur analogue is the least active one.