Coumarin syntheses via Pechmann condensation in Lewis acidic chloroaluminate ionic liquid

1-Butyl-3-methylimidazolium chloroaluminate, [bmim]Cl . 2AlCl(3) ionic liquid is used as an alternative to conventional acid catalysts in the Pechmann condensation of phenols with ethyl acetoacetate leading to the formation of coumarin derivatives. The reaction time is reduced drastically even at ambient conditions. The ionic liquid plays the dual role of solvent and Lewis acid catalyst providing a quick and efficient route to the syntheses of cournarins. (C) 2001 Elsevier Science Ltd. All rights reserved.