Pd-catalyzed tandem C-H azidation and N-N bond formation of arylpyridines: a direct approach to pyrido[1,2-b]indazoles.

A novel Pd-catalyzed nitrogenation of arylpyridines via C-H azidation has been developed. Direct C-N and N-N formations are achieved for this N-atom incorporation transformation using azides as the N-atom source. This method provides an alternatively concise approach for the construction of bioactively important pyrido[1,2-b]indazoles.