3-Amidocoumarins as chemodosimeters to trap cyanide through both Michael and intramolecular cyclization reaction

Two 3-amidocoumarin derivatives have been utilized as doubly activated Michael acceptors to selectively and sensitively trap cyanide with remarkable colorimetric and fluorescent response. Single-crystal structures of the cyanide adducts clearly confirm Michael additions taking place at the 4-position of coumarin, then an unexpected intramolecular cyclization reaction between the cyano and amido groups occurring.