1 LHL 3-(2,6-dichlorophenyl)-7-({4-[2-(diethylamino)ethoxy]phenyl}amino)-1-methyl-3,4-dihydropyrimido[4,5-D]pyrimidin-2(1h)-one 1.000 2 FSS 3-(2,6-dichlorophenyl)-7-({4-[(diethylamino)methoxy]phenyl}amino)-1-methyl-3,4-dihydropyrimido[4,5-D]pyrimidin-2(1h)-one 0.725