Design, synthesis and biological evaluation of biphenyl urea derivatives as novel VEGFR-2 inhibitors

VEGFR-2 plays a critical role in vasculogenesis and VEGFR-2 inhibitors have been widely used in the treatment of cancer. In our continued efforts to search for potent and novel VEGFR-2 inhibitors as antitumor agents, we have identified a potent lead compound (HMQ-16) bearing a biphenyl scaffold. Rearrangement and replacement of arylcarbamoyl in HMQ-16 with a urea moiety generated a series of novel VEGFR-2 inhibitors. In order to enhance the affinity with VEGFR-2, the 4′-acetyl group was converted to an oxime group. Fourteen biphenyl urea derivatives were designed and synthesized as potent VEGFR-2 inhibitors. Six of them (T2, T5, T7, T9, T11, T14) exhibited potent VEGFR-2 inhibitory activity comparable to that of sorafenib. Compound T7 was the most potent with an IC ₅₀ value of 1.08 nM. The enzymatic and cellular assays suggested that T7 has potential as a valuable lead compound for further optimization.