Discovery of (<i>S</i>)‑1-(1-(Imidazo[1,2‑<i>a</i>]pyridin-6-yl)ethyl)-6-(1-methyl‑1<i>H</i>‑pyrazol-4-yl)‑1<i>H</i>‑[1,2,3]triazolo[4,5‑<i>b</i>]pyrazine (Volitinib) as a Highly Potent and Selective Mesenchymal–Epithelial Transition Factor (c-Met) Inhibitor in Clinical Development for Treatment of

HGF/c-Met signaling has been implicated in human cancers. Herein we describe the invention of a series of novel triazolopyrazine c-Met inhibitors. The structure–activity relationship of these compounds was investigated, leading to the identification of compound 28, which demonstrated favorable pharmacokinetic properties in mice and good antitumor activities in the human glioma xenograft model in athymic nude mice.