Synthesis and Evaluation of Aminothiazole Derivatives as Hedgehog Pathway Inhibitors

A series of aminothiazole derivatives bearing the benzimidazole moiety were synthesized and evaluated in Gli luciferase reporter assays. Lead optimization led to the discovery of potent hedgehog pathway antagonist 18 (2-[3-(1H-benzimidazol-2-yl)-4-chloroanilino]-N-[4-(trifluoromethyl)phenyl]-1,3-thiazole-4-carboxamide), with IC₅₀ values in nanomolar range. The molecular basis ascribed to hindering sonic hedgehog-driven Smoothened (Smo) localization within the primary cilium (PC). Moreover, compound 18 inhibited Gli1 mRNA expression in mutant Smo cell line and displayed moderate cytotoxicity against DAOY cancer cell.