A Novel and Different Approach for the Synthesis of Quinoline Derivatives Starting Directly from Nitroarenes and Their Evaluation as Anti-Cancer Agents

A series of new quinoline derivatives (6-phenyl-6H-chromeno, [4,3-b] quinoline) have been prepared by using 4-chloro-2-phenyl-2H-chromene-3-carbaldehyde and various substituted nitroarenes as starting materials in the presence of Tin (II) chloride dihydrate and ethanol. The conversion in this synthesis involves the following steps (i) reduction of nitroarenes to anilines, (ii) Coupling of the anilines, chromene aldehydes (iii) Cyclization of resulting species and (iv) dehydration of cyclic intermediates. Several new quinolones have been prepared. We screened eight compounds of this novel series (6a-r) in three different cancer cell lines (B16F10, MCF7 and A549). The screened compounds showed moderate anticancer activity on two of the studied cell lines with best IC50 values of compound 6i (6.10±1.23 µM) and 6m (8.21±2.31 µM) on MCF7 cells. The selected compounds 6i and 6m led to morphological changes after treatment on MCF7 cell line. Interestingly, detailed studies suggested that the compounds 6i and 6m induced apoptosis in MCF7 cells in an oxidative stress independent manner without causing necrosis. In addition, we found destabilization of mitochondrial membrane potential behind the observed anticancer activity. Our results clearly indicate the promising anticancer potential of this novel series. This method is operationally simple and works with a diverse range of substrates.