Biological Evaluation of Dipyrromethanes in Cancer Cell Lines: Antiproliferative and Pro‐apoptotic Properties

Functionalized dipyrromethanes were synthesized by hetero‐Diels–Alder reactions of nitroso‐ and azoalkenes and screened for their in vitro activity as anticancer agents. The studied dipyrromethanes were tested against leukemia and lymphoma cell lines, and showed GI50 values in the mid‐micromolar range. The pro‐apoptotic activities of two candidates, (E)‐1‐(2′‐ethoxycarbonylhydrazono‐1′‐benzyl‐1H‐tetrazol‐5‐yl)‐5,5′‐diethyldipyrromethane and (E)‐1‐(2′‐p‐nitrophenyl‐2′‐hydroxyiminoethyl)‐5‐phenyldipyrromethane, and their effects on the cell cycle are described. The latter compound was found to decrease the S‐phase cell population in a dose‐dependent manner and to irreversibly block cells in the G2/M phase.