Discovery of 7-azaindole based anaplastic lymphoma kinase (ALK) inhibitors: wild type and mutant (L1196M) active compounds with unique binding mode.

We have identified a novel 7-azaindole series of anaplastic lymphoma kinase (ALK) inhibitors. Compounds 7b, 7 m and 7 n demonstrate excellent potencies in biochemical and cellular assays. X-ray crystal structure of one of the compounds (7 k) revealed a unique binding mode with the benzyl group occupying the back pocket, explaining its potency towards ALK and selectivity over tested kinases particularly Aurora-A. This binding mode is in contrast to that of known ALK inhibitors such as Crizotinib and NVP-TAE684 which occupy the ribose binding pocket, close to DFG motif.