Palladium and Copper Cocatalyzed Intermolecular Cyclization Reaction: Synthesis of 5-Aminopyrazole Derivatives

A novel and efficient palladium and copper co-catalyzed intermolecular cyclization of acetonitriles with hydrazones has been developed for the synthesis of 5-aminopyrazoles through C-C and C N bond formation. The reaction has the advantages of easily available starting materials, simple manipulation and mild reaction conditions. The reaction involving various substituted acetonitriles and hydrazones proceeds smoothly and 5-aminopyrazoles are synthesized in good yields. In contrast to the aliphatic and heteroaromatic substrates, the aromatic substrates tend to have a higher degree of reactivity.