Synthesis of 2,4,5-trisubstituted thiazoles via lawesson's reagent-mediated chemoselective thionation-cyclization of functionalized enamides

摘要

An efficient route to 2-phenyl/(2-thienyl)-5-(het)aryl/(methylthio)-4- functionalized thiazoles via one-step chemoselective thionation-cyclization of highly functionalized enamides mediated by Lawesson's reagent is reported. These enamide precursors are obtained by nucleophilic ring-opening of 2-phenyl/(2-thienyl)-4-[bis(methylthio)/(methylthio)(het)arylmethylene] -5-oxazolones with alkoxides and a variety of primary aromatic/aliphatic amines or amino acid esters, leading to the introduction of an ester, an N-substituted carboxamide, or a peptide functionality in the 4-position of the product thiazoles.