Regiospecific Aza-Michael Addition of 4-Aryl-1H-1,2,3-triazoles to Chalcones: Synthesis of 2,4-Disubstituted 1,2,3-Triazoles in Basic Medium

Abstract

A novel metal-free and base-mediated method to display the donor ability of 1,2,3-triazoles for the synthesis of 2,4-disubstituted 1,2,3-triazoles has been developed. A DABCO-promoted aza-Michael addition of 4-aryl NH-1,2,3-triazoles to α,β-unsaturated ketones (chalcones) is presented. The reactions proceeded with complete regiospecificity in a 3:1 mixture of acetonitrile and methanol at 85 °C to provide 2,4-disubstituted 1,2,3-triazoles as Michael adducts, and the addition products 1,3-diaryl-(4-aryl-2H-1,2,3-triazol-2-yl)propan-1-ones were isolated in high yields.