Discovery of novel purine derivatives with potent and selective inhibitory activity against c-Src tyrosine kinase.

We report here the discovery of novel purine derivatives with potent and selective inhibitory activity against c-Src tyrosine kinase by adopting a strategy integrating focused combinatorial library design, virtual screening, chemical synthesis, and bioassay. Thirty two compounds were selected and synthesized. All compounds showed potent inhibitory activity against c-Src kinase with IC₅₀ values ranging from 3.14 μM to 0.02 μM. Compound 5i was identified as one of the most potent agent with an IC₅₀ 120 times lower than those of the hits. The high hit rate (100%) and the potency of the new Src kinase inhibitors demonstrated the efficiency of the strategy for the focused library design and virtual screening. The novel active chemical entities reported here should be good leads for further development of purine-based anticancer drugs targeting Src tyrosine kinase.