Cyclopent[f]isoindole-1,3,5,7(2H,6H)-tetrone, 6-[8-(dimethylamino)-3,4-dihydro-6-methyl-3-oxo-2-quinoxalinyl]-2-[2,4, 6-trimethyl-3-[2-(4-morpholinyl)ethoxy]phenyl]-