Regioselective and Guided C-H Activation of 4-Nitropyrazoles

A divergent and regioselective approach to 5-aryl-4-nitro-1H-pyrazoles was developed by guided transition-metal-catalyzed arylation of 4-nitro-1H-pyrazoles. This method provides a convenient tool for the functionalization of the pharmacologically relevant pyrazole scaffold. The scope and limitations of the methodology were studied.