Synthesis and biological evaluation of 2-pyridyl-substituted pyrazoles and imidazoles as transforming growth factor-beta type 1 receptor kinase inhibitors.

A series of 2-pyridyl-substituted pyrazoles (16a-d, 17, 18, and 28a-e) and imidazoles (22 and 23) has been synthesized and evaluated for their ALK5 inhibitory activity in cell-based luciferase reporter assays. Among them, 3-(3-(6-methylpyridin-2-yl)-4-(quinolin-6-yl)-1H-pyrazole-1-carbothioamido)benzamide (28c) showed 96% and 93% inhibition at 0.1 microM in luciferase reporter assays using HaCaT cells transiently transfected with p3TP-luc reporter construct and ARE-luc reporter construct, respectively.