N -Phenyl Benzohydrazonoyl Halides as an Excellent Precursor of Nitrile Imines for the Preparation of Heterocyclic Compounds

N-phenyl benzohydrazonoyl halide derivatives are important building blocks in the synthesis of a large number of heterocyclic compounds that include pyrazoles, pyridazine, etc. The main factor in the importance of hydrazonyl halide is the easy release of the nitrile imine when treated in an alkaline medium through the preparation process. Owing to the wide range of applications of these precursors, we will introduce a general overview for the synthesis and reactions of these types of compounds.