Nitrilimine

Nitrilimines or nitrile amides are a class of organic compounds sharing a common functional group with the general structure R-CN-NR corresponding to an amine bonded to the N-terminus of a nitrile. The dominant structure for the parent compound nitrilimine is that of the propargyl-like 1 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 2, allene-like 3, allylic 4 and carbene 5 are of lesser relevance.

Nitrilimines were first observed in the thermal decomposition of 2-tetrazoles releasing nitrogen:^[1]

Nitrilimines are linear 1,3-dipoles in 1,3-dipolar cycloadditions and are represented by structures 1 and 3. With alkynes they generate pyrazoles.

References

1. ^ Communications: The Formation of Nitrile Imines in the Thermal Breakdown of 2,5-Disubstituted Tetrazoles Rolf Huisgen Michael Seidel, Juergen Sauer, James McFarland, Guenter WallbillichJ. Org. Chem.; 1959; 24(6); 892-893 Abstract