A series of 1,4-phenylene-bis-chalcones 3a-3h were synthesized by the reaction of terephthalaldehyde with substituted arylketones in this study. The novel 1,4-phenylene-bis-pyrimidine-2-amine derivatives 5a-5h were obtained by the addition of guanidine hydrochloride to 1,4-phenylene-bis-chalcone 3a-3h in ethanolic KOH under reflux conditions.The structure of the compounds was explained by means of IR, 1 H NMR, 13 C NMR, and elemental analyses. The anticancer activities of 3a-3h and 5a-5h were investigated against rat brain tumor cells and human uterus carcinoma in vitro . Activity tests were performed as dose-dependent assays at eight concentrations. The positive control was 5fluorouracil (5-FU). Compounds 3c and 3d were examined and they showed high activities as compared to 5-FU against C6 (rat brain tumor) and HeLa (human uterus carcinoma) cells. The anticancer activity of 5h was better than that of 5-FU at high concentrations cell-selectively against C6 cells.

Thiazolylpyrazoline derivatives were recently reported as potent anticancer agents. In this study, novel 1,4-phenylene-bis-N-thiocarbamoylpyrazoles (3a-h) and 1,4-phenylene-bis-pyrazolylthiazoles (5a-h) were prepared and screened for their anticancer activities against C6 (rat brain tumor cells) and HeLa (human uterus carcinoma). Anticancer activity studies were performed as a dose-dependent assay starting with eight concentrations. 5-Fluorouracil (5-FU) was used as a positive control. Compounds 3c, 3d, and 3h were examined and they revealed almost the same activities compared with 5-FU in terms of cell selectivity against C6 cells. Moreover, compounds 3a-h had lower cytotoxicity than 5-FU. The low cytotoxicity values of 3a-h as well as their high antiproliferative activity were encouraging, but further studies are required on the use of these molecules as anticancer drugs.