A Facile Synthesis of C2-Substituted Pyrrolo[2,3-f]quinolines with Cytotoxic Activity

An expeditious four-step synthesis of the 1H-pyrrolo[2,3-f]quinoline-2-carboxamides (5a-h) is described. Readily available 6-quinolinecarboxaldehyde is converted to the parent acid (6) by nucleophilic attack of the azido-ester (9) and intramolecular cyclization of (10) followed by hydrolysis of the methyl ester (11). The cytotoxicity of the target molecules (5a-h) was evaluated in four tumour cell lines in vitro. One compound (5d) showed sufficient activity (IC50 = 10.2 μM) in the human non-small cell lung cell line NSCLCN16- L16 to be worthy of further study.