Design, Synthesis, Crystallographic Studies and Preliminary Biological Appraisal of New Substituted Triazolo[4,3-b]pyridazin-8-amine Derivatives as Tankyrase Inhibitors.

Searching for selective tankyrases (TNKSs) inhibitors, a new small series of 6,8-disubstituted triazolo[4,3-b]piridazines has been synthesized and characterized biologically. Structure-based optimization of the starting hit compound NNL (3) prompted us to the discovery of 4-(2-(6-methyl-[1,2,4]triazolo[4,3-b]pyridazin-8-ylamino)ethyl)phenol (12), a low nanomolar selective TNKSs inhibitor working as NAD isostere as ascertained by crystallographic analysis. Preliminary biological data candidate this new class of derivatives as a powerful pharmacological tools in the unraveling of TNKS implications in physiopathological conditions.