Design, synthesis and biological evaluation N-(2-alkyoxy-6-aliphatic aminopyridin-3-yl)-2,4-diaminepyrimidine derivatives bearing acylamino or DBTD 'head' as potential ALK inhibitors.

Aiming to develop promising ALK inhibitors, two series of N-(2-alkyoxy-6-aliphatic aminopyridin-3-yl)-2,4-diaminepyrimidine derivatives (22a-x and 23a-d) were designed according to scaffold hopping and bioisosterism principles. All compounds were efficiently synthesized by concise reactions and anti-proliferative activities on ALK-addicted H2228, Karpas299 cells and EGFR-expressive A549 cell were evaluated by MTT assay. Several compounds exhibited potential cytotoxic activities with IC values below 0.10 μM. Five compounds (22g, 22h, 22l, 22s and 23a) were selected for further enzymatic determination, resulting in the discovery of 22l against ALK and ALK with IC values of 2.1 nM and 3.8 nM. Particularly, western blot and cell apoptosis assays identified 22l as a promising ALK inhibitor, which was capable of obviously inhibiting cellular ALK activity and inducing cell apoptosis. Eventually, molecular docking modes of 22l with ALK confirmed structural basis in accordance with the SARs analysis.