A reversible, cell-permeable inhibitor of VEGFR2’s kinase activity (IC50 = 70 nM); less potently inhibits PDGFRβ (IC50 = 920 nM); blocks the growth of human umbilical vein endothelial cells stimulated with either VEGF or PDGF (IC50s = 110 nM and 2 µM, respectively).