Benzazole–Carboxamide Hybrids as Potent Antiproliferative Agents Against Breast Cancer Cells

Breast cancer remains a leading cause of cancer-related mortality worldwide, and the development of novel small-molecule agents with improved efficacy and selectivity is still urgently needed. Although benzazole and benzamide scaffolds are individually recognized for their diverse pharmacological activities, systematic studies exploring hybrid N-(benzazol-2-yl)4-substituted benzamide derivatives as antiproliferative agents against breast cancer are limited. In this study, a series of N-(benzazol-2-yl)-4-substituted benzamide derivatives was synthesized and fully characterized by ¹H NMR, ¹³C NMR, and IR spectroscopy. The antiproliferative activities of the synthesized compounds were evaluated against the human breast cancer cell line MCF-7 and the normal fibroblast cell line L929 using the MTT assay. The compounds were obtained in good to excellent yields (70–85%). Several derivatives exhibited strong growth-inhibitory effects, with IC₅₀ values ranging from 3.11 to 12.39 µM. Among the tested molecules, compounds 6 and 11 demonstrated the most significant cytotoxic effects, and compound 6 emerged as the most promising candidate for further investigation. These findings provide preliminary structure–activity insights and highlight benzazole–benzamide hybrids as promising scaffolds for further anticancer drug development.