Synthesis and cytotoxic activity of N-[2-(dimethylamino)ethyl] carboxamide derivatives of benzofuro[2,3-b]quinoline, 6H-quinindoline, indeno[2,1-b] quinoline and [1] benzothieno[2,3-b] quinoline

The acid precursors of the title compounds were prepared from methyl 2-amino-3-formylbenzoate (3), by Friedlander synthesis with o-methoxy- and o-nitro-phenylacetic acids, phenylpyruvic acid and benzo[b]thiophen-2-one, respectively. Except for the last example, cyclization of an initial 3-arylquinoline derivative was then required to give the tetracycle. Growth inhibition properties of the carboxamides in a series of cancer cell lines were measured for comparison with previous data for an isomeric series. In all cases, the present set were found to be less active.