Selective inhibition of the tyrosine kinase pp60src by analogs of 5,10-dihydropyrimido[4,5-b]quinolin-4(1H)-one

7,8-Dimethoxy-5,10-dihydropyrimido[4,5-b]quinolin-4(1H)-one (1b) has been discovered to be a potent and selective inhibitor of the tyrosine-specific kinase activity associated with pp60c-src. Mole of inhibition studies reveal that this agent inhibits in a pure-mixed-noncompetitive mode with respect to nucleotide co-factor.