Abstract
The Friedel-Crafts reaction between substituted indoles as nucleophiles with chalcones-based benzofuran and benzothiophene scaffolds was carried out by employing a highly efficient bimetallic iron-palladium catalyst system. This catalytic approach produced the desired bis-heteroaryl products with low catalyst loading, a simple procedure, and with acceptable yield. All synthesized indole scaffolds 3a-3s were initially evaluated for their cytotoxic effect against human fibroblast BJ cell lines and appeared to be non-cytotoxic. All non-cytotoxic compounds 3a-3s were then evaluated for their anticancer activities against cervical cancer HeLa, prostate cancer PC3, and breast cancer MCF-7 cell lines, in comparison to standard drug doxorubicin, with IC50 values 1.9 +/- 0.4 mu M, 0.9 +/- 0.14 mu M and 0.79 +/- 0.05 mu M, respectively, and appeared to be moderate to weak anticancer agents. Fluoro-substituted chalcone moiety-containing compounds, 3b appeared to be the most active member of the series against cervical HeLa (IC50 = 8.2 +/- 0.2 mu M) and breast MCF-7 cancer cell line (IC50 = 12.3 +/- 0.04 mu M), whereas 6-fluroindol-4-bromophenyl chalcone-containing compound 3e (IC50 = 7.8 +/- 0.4 mu M) appeared to be more active against PC3 prostate cancer cell line.