Polyhydroquinoline (1) interactedwithDMF-DMAto yield the corresponding aza-enamine derivative (2). Compound (2) reacted with a series of aromatic amines to afford the newfused pyridopyrimidines (5a-d).On the other hand, reaction of (2) with hydrazine hydrate and hydroxylamine hydrochloride yielded the pyrimidine derivatives (7) and (8), respectively. Refluxing of (2) with urea derivative in acetic acid yielded the final product (10a,b). Studying the behavior of (2) towards active methylene reagent afforded the adducts (11) and (12), respectively. The in vivo antitumor activity of compounds (5a-c), (8) and (10a)was evaluated against liver cancer cells (HEPG2), using Doxorubicine as a reference drug.Compound (5b) showed the highest potency mean while compounds (5c) and (8) showed limited activity against liver carcinoma cells (HEPG2).Also, the in vivo antitumor activity, compound (5b) exhibited high cytotoxic activity against breast cancer cells (MCF7).