Design, synthesis, and structure-activity relationships of 1-ethylpyrazole-3-carboxamide compounds as novel hypoxia-inducible factor (HIF)-1 inhibitors.

Hypoxia-inducible factor (HIF)-1 is well known as a promising target for cancer chemotherapy. By screening an in-house chemical library using a hypoxia-responsive luciferase reporter gene assay, we identified CLB-016 (1) containing 1-ethylpyrazole-3-carboxamide as a HIF-1 inhibitor (IC50=19.1μM).