Synthesis of novel trifluoromethyl-containing heterocycle-fused troponoid compounds

Abstract

A facile synthesis of novel trifluoromethyl-containing pyrano-, pyrazolo- and isoxazolo-fused tropone compounds 4a,b, 5a,b, and 6a,b, respectively, by cyclizations of (E)-3-[3-(trifluoromethylphenyl)acryloyl]tropolones 3a,b is described. The substrates 3a,b were prepared by Claisen-Schmidt condensation reaction of 3-acetyltropolone (1) with 3- or 4-(trifluoromethyl)benzaldehydes 2a,b.