. . . "D75-4590" . "4-[2-(Diethylamino)ethylamino]-3-ethyl-2-methyl-4a,9-diaza-3,4-dihydrofluorene-1-carbonitrile" . . . . . . . . . . "D75-4590" . "1-{[2-(Diethylamino)ethyl]amino}-2-ethyl-3-methylpyrido[1,2-a]benzimidazole-4-carbonitrile" .