Efficient Synthesis of Hybrid Compounds from 1,2,3-Triazoles, Benzimidazole, and Thiazolo[3,2-a]Benzimidazole Through Palladium-Catalyzed Coupling-Heteroannulation Reactions

Hybrid compounds are synthetic scaffolds of two or more pharmacophores that can be recognized as important reagents to increase the desired activity of biologically active compounds. This investigation develops an efficient and successful procedure for the synthesis of hybrid compounds based on 1,2,3-triazole scaffolds. Hybrid compounds include benzimidazole linked-1,2,3-triazole 9a-d and thiazolo[3,2-a] benzimidazole linked-1,2,3-triazoles 10a-d prepared from acetylenic benzimidazoles and substituted iodophenyl-1,2,3-triazoles with 75-90% yields, through Sonogashira coupling and heteroannulation. The reactions were carried out in DMF as the solvent and catalyzed by palladium(II) acetate/copper(I) iodide, in the presence of morpholine as an effective base at 70 °C. One-pot reaction conditions, high reaction yields, and simple reaction procedures are the advantages of this method.