ZrCl4/[bmim]BF4-catalyzed condensation of salicylaldehydes and malononitrile: Single-step synthesis of 3-cyanocoumarin derivatives

Article abstract of DOI:10.1002/jhet.593

Figure represented. A versatile and efficient single-step route to 3-cyanocoumarins via Knoevenagel condensation of salicylaldehydes and malononitrile using ZrCl₄ as the catalyst (15 mol %) in ionic liquid 1-(n-butyl)-3-methylimidazolium tetrafluoroborate as reaction medium and catalyst is described. The novel procedure features single step, short reaction time, good yields, and simple workup.