Inhibition of Src kinase activity by 4-anilino-5,10-dihydro-pyrimido[4,5-b]quinolines

4-(2,4-Dichloro-5-methoxy)anilino-5,10-dihydropyrimido[4,5-b]quinolines are potent inhibitors of Src kinase and Src cellular activity while having no effect on Fyn cellular activity. The corresponding 4-(2,4-dichloro-5-methoxy)anilino-pyrimido[4,5-b]quinolines are much less effective Src inhibitors.