Nitrilimines or nitrile amides are a class of organic compounds sharing a common functional group with the general structure corresponding to the conjugate base of an amine bonded to the N-terminus of a nitrile. The dominant structure for the parent compound nitrilimine is that of the propargyl-like in scheme 1 with a C–N triple bond and with a formal positive charge on nitrogen and two lone pairs and a formal negative charge on the terminal nitrogen. Other structures such as hypervalent , allene-like , allylic and carbene are of lesser relevance. H-\!{\equiv}N=N-HH-C{:}\!-N=N-H
Nitrilimines were first observed in the thermal decomposition of 2-tetrazoles releasing nitrogen:
One alternative synthesis technique is an elimination reaction of hydrazoyl halides.Ulrich, H. The Chemistry of Imidoyl Halides; Plenum Press: New York, 1968; pp. 187–189.
Nitrilimines are linear 1,3-dipoles represented by structures and . A major use is in heterocyclic synthesis. E.g. with alkynes they generate pyrazoles in a 1,3-dipolar cycloaddition. Due to their high energy, they are usually generated in situ as a reactive intermediate.
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