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
