One-pot, telescoped synthesis of N-aryl-5-aminopyrazoles from anilines in environmentally benign conditions

An efficient synthetic approach to synthesize N-aryl-5-aminopyrazoles from anilines via a one-pot, telescoped reaction performed in entirely aqueous conditions has been developed. This protocol provides a rapid, convenient method to prepare N-aryl-5-aminopyrazoles, useful building blocks for the synthesis of several bicyclic nitrogen heterocycles, by avoiding the isolation of the toxic intermediate arylhydrazines and the use of a metallic reductant.