Actions of Bisnucleophiles on (E)-3-[3-(2-Hydroxyaryl)-3-oxoprop- 1-en-1-yl]chromones: Versatile Transformations into Oxygen- and Nitrogen-Containing Heterocycles Ridha Hassaine.

The transformations of (E)-3-[3-(2-hydroxyaryl)-3-oxoprop-1 -en-1 -yl]chromones in the presence of methylhydrazine and aromatic bisnucleophiles are described. The reactions generally lead to chro-mone ring transformation via pyrone ring-opening and heterocycliza-tion to give novel diazoles and (Z)-3-aminomethylenechromanones, respectively. Piperazine catalyzes chromanone ring closure of the starting substrate to afford chromone-chromanone dyads. [ABSTRACT FROM AUTHOR]