This study describe the organic synthesis of 2-iodobenzamido (2-N-nitrobenzen-5, 6, 7, 8 tetrahydrobenzothieno [2, 3-d]) pyrimidine -4-(3H) one as an example for some pyrimidine derivative used a new series of as potential cancer chemotherapeutic agents. The precursor derivative is α-(2-iodobenzamido)-β -(4-nitrophenyl)-N-[3-ethoxy-carbonyl-4, 5, 6, 7-tetrahydrobenzothiophen-2-l] acrylic acid amide which react with hydrazine hydrate. The purification process was done via crystallization using solvent ethanol. The overall yield 78% the structure of the synthesized compound was confirmed by correct analytical and spectral data .Also, The synthesized compound was labeled with radioactive iodine -125 via nucleophilic substitution reaction ,in the presence cuprous chloride, the labeling process was carried out at 95oC for 60 min. the radiochemical yield was determined by using thin layer chromatography and the yield is equal to 80%.Preliminary in-vivo study was examined in normal mice were performed after intravenous injection through the tail vein and the data show the labeling compound was cleared quickly from most body organs. The radioiodinated compound showed high brain uptake .The results in this study suggest that radioiodinated pyrimidine derivative may be useful as cancer chemotherapeutic agents.