The pyrimidine-2,4-diamine analogs exerted excellent activities in down-regulation of ALK phosphorylation. However, the prevalent drug-resistant site-mutation has gradually prevented the agents from being widely used. Herein, we conducted an exploration of high affinity moiety that bound to the solvent-front region (G1202R located) within the ATP binding site of ALK leading to the synthesis of thirty-five pyrimidine-2,4-diamine derivatives. Among these compounds, urea group was extensively derivatized which finally resulted in the identification of the 'semi-free urea' compound 39. All compounds were assayed cytotoxicity and enzymatic activities and 39 turned out to be the most potent one with IC50 values of 2.1, 0.91, 4.3 and 0.73 nM towards ALKwt, ALKL1196M, ALKG1202R and ROS1, respectively. The performances of 39 on ALK- & ROS1-dependent cell lines were in good accordance with enzymatic activities with IC50 values below 0.06 µM. Besides, 39 induced cell apoptosis in a dose-dependent manner in H2228 cells. Finally, the binding models of 39 with ALKwt, ROS1, ALKL1196M and ALKG1202R were ideally established which further clearly elucidated their mode of action within the active site.
Keywords: 4-Diamine; ALK & ROS1 inhibitors; Apoptosis-inducing; Mutation-combating; Pyrimidine-2; Solvent front.
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