A natural like O-glycoconjugate polycyclic compound 4 was obtained by a multistep procedure starting from N-(3-methyl-1-(4-nitrophenyl)-1H-pyrazol-5-yl)acetamide. The glycosyl derivative 4 showed antiproliferativeactivity against all the tumoral cell lines of the NCI panel in the range 0.47–5.43 μM. Cytofluorimetric analysis performed on MDA-MB231, a very aggressive breast cancer cell line, which