Metal-Free Synthesis of Pyrazoles from 1,3-Diarylpropenes and Hydrazines via Multiple Inter-/Intramolecular C–H Aminations

Abstract

A facile and metal-free access to pyrazoles from 1,3-diarylpropenes and hydrazines via multiple inter-/intramolecular C-H aminations was described. Under the neutral and mild 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) oxidative conditions, various disubstituted pyrazoles were synthesized in moderate to excellent yields. This method provides a pot- and step-economic strategy for the construction of pyrazoles, especially those for drug discovery. (Figure presented.).