The compound “2-((4-nitrophenyl)amino)-7,8,9,10-tetrahydro cyclohepta[4,5]thieno[2,3-d][1,3,4]thiadiazolo[3,2-a]pyrimidin-11(6H)-one” and method of synthesizing it, wherein the compound is effective to inhibit the growth and proliferation of human liver cancer cells HepG2. The compound has a higher efficiency to inhibit the growth and proliferation of these cells as it has an inhibitory concentration value (IC50) of 0.7 μg, compared to reference medication Doxorubicin that has an (IC50) value of 1.2 μg. It further surpasses that reference medication at all tested concentrations. The method includes the steps of: preparing a first compound of cycloheptanone, ethylcyanoacetate, sulfur, ethanol and diethylamine; preparing a second compound by heating of the first compound with excess of hydrazine hydrate in absolute ethanol as solvent; preparing a third compound by heating the second compound with carbon disulphide in dry pyridine; and preparing the compound of the invention by reacting the third compound with 4-nitrophenylisothiocyanate in dry N,N-methylformamide as solvent.