Application of Suzuki Miyaura Cross Coupling Reaction for the Synthesis of Thiazole-Coumarin and Sulfonamide Derivatives Using Pd-PEPPSI Pre-Catalysts and Buchwald Ligands

Abstract

The thesis deals with the application of Suzuki cross coupling reaction for the derivatization of biologically important compounds. The Suzuki Miyaura cross coupling reaction condition for the thiazole-coumarin bromide and aryl sulfonamide with different boronic acid have been developed. The thiazole substituted coumarin-bromide required Pd-PEPPSI catalyst system. The aryl sulfonamide derivatives resulted in higher yields with Buchwald ligand Johnphos. The reaction conditions have been optimized for reaction temperature, solvent, reaction time, catalyst and ligand loading and base. Both of substrate display excellent functional group tolerance and allows the coupling of aryl boronic acids in good to excellent yield. Ten structurally diverse thiazole-coumarin and sulfonamide derivatives were prepared from commercially available boronic acids, using comparable catalyst loading (as low as 5.0 mol %). All the synthesized compounds have been characterized by physical and spectroscopic techniques including Proton and Carbon NMR.