4-(Azolylphenyl)-phthalazin-1-amines: Novel inhibitors of VEGF receptors I and II.

Novel potent derivatives of phthalazine are described as ATP-competitive inhibitors of vascular endothelial growth factor receptors I and II (VEGFR-1/2). A number of compounds display VEGFR-2 inhibitory activity reaching that of Vatalanib(TM)3 (IC50 < 100 nM) in an HTRF enzymatic assay. Several derivatives also show good potential for the development as VEGFR-2 specific inhibitors showing 15-20-fold selectivity over VEGFR-1.