An efficient one-step synthetic pathway to dihydroquinoline (DHQ) and benzodihydroquinoline (BDHQ) derivatives involving 1,2-Michael addition reaction between amino phenol/naphthol and two molecules of methyl propiolate followed by intramolecular cyclization and aromatization using cuprous iodide as a catalyst was successfully developed. The synthesized DHQ derivatives displayed highly selective fluorescence quenching in the presence of copper(II) with a very low detection limit (LOD for DHQ is 0.20 μM). Moreover, the mechanisms of both formation of the corresponding DHQ and the fluorescence quenching by copper(II) are proposed along with the evidence of X-ray diffraction data.
Key words
dihydroquinoline - benzodihydroquinoline - intramolecular cyclization - fluorescence chemosensor - detection of copper(II) ion - introduction
