Efficient Method for the Synthesis of Functionalized Pyrazoles by Catalyst-Free One-Pot Tandem Reaction of Nitroalkenes with Ethyl Diazoacetate.

The one-pot synthesis of multisubstituted pyrazole derivatives was achieved viacatalyst-free 1,3-dipolar cycloaddition of ethyl diazoacetate and nitroalkenes as the key step and elimination of the leaving group (NO2 or Br) followed by intramolecular proton transfer with satisfactory yields.