Synthesis of Thiazolo[3,2-b] [1,2,4]triazoles through Pd-Catalyzed Copper-Free Sonogashira Coupling Reaction

The synthesis of 2-substituted thiazolo[3,2-b] [1,2,4]triazoles is accomplished copper-free, Pd-catalyzed Sonogashira reaction of 6-(iodomethyl)-2-methylthiazolo[3,2-b][1,2,4]triazole with terminal alkynes in DMF at 70 degrees C. The coupling reaction of phenylacetylene and 4-ethynyltoluene gave the desired products in high yields. While, the Sonogashira reaction of alkynes such as 1-hexyne, 1-octyne, propargyl alcohols, and propargyl amines afforded the products in good yields.