Potent and selective inhibitors of platelet-derived growth factor receptor phosphorylation. Part 4: structure–activity relationships for substituents on the quinazoline moiety of 4-[4-(N-substituted(thio)carbamoyl)-1-piperazinyl]-6,7-dimethoxyquinazoline

Here, we investigated the structure–activity relationships of the 6,7-dimethoxyquinazoline moiety. With regard to exploration of positions and varieties of substituents on the quinazoline ring, 6,7-dialkoxy substitution was optimal. This study suggests the possibility of further modifications for this moiety.