inhibited the tyrosine phosphorylation in FGF, VEGF, and PDGF receptors and the activation of extracellular signal-regulated kinase (ERK), c-Jun-N-terminal-kinase (JNK) and AKT after the rhFGF-2 stimulation. The introduction of the phenyl hydrazide motif to the position 5 of the pyrido[2,3-d]pyrimidine scaffold led to the inhibitory effect in two signaling pathways: inhibition of AKT activation in the phosphatidyl