Rice husk ash supported FeCl2•2H2O: A mild and highly efficient heterogeneous catalyst for the synthesis of polysubstituted quinolines by Friedlander heteroannulation

Rice husk ash was used as a new, green, and cheap adsorbent for FeCl3. Characterization of the obtained reagent showed that rice husk ash supported FeCl2 center dot 2H(2)O was formed. This reagent is efficient at catalyzing the synthesis of multisubstituted quinolines by the Friedlander heteroannulation of o-aminoaryl ketones with ketones or beta-diketones under mild reaction conditions. This methodology allows for the synthesis of a broad range of substituted quinolines in high yields and with excellent regioselectivity in the absence of a solvent. (C) 2013, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.