Direct Access to 3-Aminoindazolesby Buchwald-Hartwig C-N Coupling Reaction

An efficient synthesis of various N-substituted 3-aminoindazolesusing Buchwald-Hartwig C-N coupling reaction isdescribed. Several parameters were varied, including the natureof the halogen atom and the protecting group of the starting materials,as well as the effects of the catalyst system, base, solvent, andreaction time. The efficiency of microwave versus conventional heatingwas also compared to test the outcome of the reaction. Thus, byapplying this recent knowledge about metal-catalyzed aminations,an alternative for the direct synthesis of primary 3-aminoindazoleshas been provided.