Fast, Solvent-Free, Microwave-Promoted Friedländer Annulation with a Reusable Solid Catalyst

Abstract

A fast, solvent-free method is described for the synthesis of substituted quinoline derivatives via Friedländer cyclization, employing a reusable solid catalyst (silica-propylsulfonic acid). Although it worked best under microwave irradiation (with generally more than 90% isolated yields in 30 min), the reaction was also feasible under conventional heating (with fair to good yields in about 5 h).

Keywords:

• Friedländer synthesis
• microwaves
• quinoline
• solid catalyst
• solvent-free

ACKNOWLEDGMENTS

Support of this research by the University of Turin is gratefully acknowledged. Z. R. thanks the World Wide Style (WWS) Project. Part of this work comes from the degree thesis of Christian Speranza.