Cascade reaction to 1H-pyrazoles from hydrazones via sodium Ni-trite promoted dual C-C/C-N formation,annulation and aromatization with 1,2-dichloroethane

A novel route for tandem C-C/C-N formation,annulation and aromatization of hydrazones with 1,2-dichloroethane to synthesize 1 H-pyrazoles has been developed.Furthermore,the 1,2-dichloroethane serves as alkylation reagent in good to excellent yields.This methodology features mild reaction conditions and good functional group tolerance,providing a direct approach for the preparation of 1 Hpvrazoles.