An Improved Synthesis of Imidazo[4,5-<i>b</i>]pyridines and Imidazo[4,5-<i>b</i>]pyrazines by Palladium Catalyzed Amidation using Xantphos in a 1,4-Dioxane:<i>tert</i>-Amyl Alcohol Solvent System
                                
                                    
                                        作者:Adam J. Rosenberg、Ijaz Ahmed、Robert J. Wilson、Theresa M. Williams、Lauren Kaminsky、Daniel A. Clark                                    
                                    
                                        DOI:10.1002/adsc.201400465
                                    
                                    
                                        日期:2014.11.3
                                    
                                    AbstractHerein an improved protocol for the synthesis of imidazo[4,5‐b]pyridines and imidazo[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.magnified image