Four-Component Domino Synthesis of Pyrazolo[3,4- h]quinoline-3-carbonitriles: "Turn-Off" Fluorescent Chemosensor for Fe3+ Ions.

The synthesis of novel pyrazolo[3,4- h]quinoline-3-carbonitriles has been achieved through a one-pot, four-component domino strategy under solvent-free microwave conditions. One of these compounds exhibited fluorescence under UV lamp and was found to be highly sensitive toward Fe3+ ions in DMSO against various metal ions with a detection limit of 8.6 × 10-7 M.