Ultrasound-assisted bismuth nitrate-induced green synthesis of novel pyrrole derivatives and their biological evaluation as anticancer agents

A series of novel N-substituted pyrrole derivatives have been designed and synthesized following ultrasound-assisted and bismuth nitrate-catalyzed eco-friendly route. This reaction has also provided a general method to prepare diverse varieties of N-substituted pyrroles with less nucleophilic polyaromatic amines. Based on ¹H NMR spectroscopy, a plausible mechanistic pathway has been advanced. Cytotoxicity of some selected N-substituted pyrrole derivatives has been evaluated in vitro in a panel of mammalian cancer cell lines which includes liver cancer cell lines (HepG2 and Hepa1-6), colon cancer cell lines (HT-29 and Caco-2), a cervical cancer cell line (HeLa) and NIH3T3 cells. Two compounds, 5-(1H-pyrrol-1-yl)-1,10-phenanthroline (9) and 1-(phenanthren-2-yl)-1H-pyrrole (10) have shown good cytotoxicity against some cancer cell lines. Furthermore, these compounds have exhibited cytotoxic specificity against liver cancer cell lines in vitro when compared with normal cultured primary hepatocytes.