An Improved Synthesis of Imidazo [4, 5??b] pyridines and Imidazo [4, 5??b] pyrazines by Palladium Catalyzed Amidation using Xantphos in a 1, 4??Dioxane: tert??Amyl …

AJ Rosenberg, I Ahmed, RJ Wilson…

Index: Wilson, Robert J.; Rosenberg, Adam J.; Kaminsky, Lauren; Clark, Daniel A. Journal of Organic Chemistry, 2014 , vol. 79, # 5 p. 2203 - 2212

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Abstract

Abstract: Herein an improved protocol for the synthesis of imidazoACHTUNGTRENNUNG [4, 5-b] pyridines and imidazoACHTUNGTRENNUNG [4, 5-b] pyrazines using a palladium- catalyzed amidation that utilizes Xantphos as an ancillary phosphine ligand is reported. The use of a binary solvent system comprised of 1, 4-dioxane and tert-amyl alcohol was crucial in eliminating unwanted by-products. Keywords: nitrogen heterocycles; P ligands; palladium