A variety of new pyrazolines, isoxazolines, and amide derivatives were designed, synthesized, and tested in vitro for their cytotoxic potential against the breast cancer cell line MCF-7. Nabumetone is a prodrug that is used as non-steroidal anti-inflammatory drug   (NSAID). Before synthesis, the Molecular docking program (GOLD suite v. 5.7.1) was used to evaluate the selectivity for ER-α receptor, which demonstrated good agreement with the in vitro findings. Specifically, compounds 1e and 2e that target the ER- α receptor had the greatest PLP fitness values of (75.61 and 73.36), respectively, when compared to the tamoxifen reference medication, which had a PLP fitness of (92.78). The IC50 values for the synthesized compounds revealed that compound (1e) has a high IC50 value of 19 µM against MCF-7, compared to tamoxifen, which has an IC50 value of (18.02) µM.