Catalytic System for Inhibition of Amination‐Type Reaction and Palladium‐Catalysed Direct Arylation using Non‐Protected Pyrazole Derivatives

The palladium‐catalysed direct arylation at C‐4 of non‐protected 5‐aminopyrazoles was found to proceed in high yields using a variety of aryl bromides. The choice of potassium acetate as the base was found to be crucial to inhibit the amination reaction and to promote the direct arylation.