Synthetic approach to a novel quinoline scaffold 4-amino-5,10-dihydropyrimido[4,5-b]quinolin-2(1H)-one with antiproliferative effects on HCT116 colon cancer cell lines

• A cytosine-based analog, compound 11 , was synthesized through a multistep process. • All intermediates were structurally validated by 2D NMR or X-ray crystallography. • HPLC-based assays confirmed cellular uptake of compound 11 . • Compound 11 exhibited antiproliferative effects in HCT116 cancer cells after 72 hours. • Pyrimido-quinoline derivatives are promising scaffolds for anticancer drug discovery. This study reports the synthesis and biological evaluation of novel pyrimido[4,5- b ]quinoline derivative 11 with potential anticancer activity. The initial compound (compound 1 ) was synthesized via a one-pot reaction involving aniline, benzaldehyde, and barbituric acid. Its structure was confirmed by 2D NMR and X-ray crystallography. To explore new scaffolds, the barbituric acid moiety was replaced with a cytosine unit, leading to the synthesis of compound 11 through a multistep process. The structure of the key intermediate was confirmed by 2D NMR and/or X-ray crystallography. HPLC-based uptake assays confirmed the cellular permeability of compound 11 . This compound exhibited antiproliferative effects in HCT116 cells after 72 h. These findings highlight pyrimido-quinoline derivatives as a promising scaffold for drug discovery.