Imine

[8] The relationship of imines to amines having double and single bonds can be correlated with imides and amides, as in succinimide vs acetamide.

Imines are related to ketones and aldehydes by replacement of the oxygen with an NR group.

In recent years, several reagents such as Tris(2,2,2-trifluoroethyl)borate [B(OCH2CF3)3],[14] pyrrolidine[15] or titanium ethoxide [Ti(OEt)4][16] have been shown to catalyse imine formation.

The chief reaction of imines, often undesirable, is their hydrolysis back to the amine and the carbonyl precursor.

Very analogous to ketones and aldehydes, primary imines are susceptible to attack by carbanion equivalents.

The method allow for the synthesis of secondary amines:[29][30] This can be expanded to include enolisable carbons in the Mannich reaction, which is a straightforward and commonly used approach for producing β-amino-carbonyl compounds.

[35][36] Owing to their enhanced electrophilicity, iminium derivatives are particularly susceptible to reduction to the amines.

Since imines derived from unsymmetrical ketones are prochiral, their reduction defines a route to chiral amines.

Unhindered aldimines tend to cyclize, as illustrated by the condensation of methylamine and formaldehyde, which gives the hexahydro-1,3,5-triazine.

[37] The polymerisation reaction proceeds directly when the aldehyde and amine monomers are mixed together at room temperature.

Owing to the dynamic covalent nature of the imine bonds, polyimines can be recycled relatively easily.

Imines are intermediates in the alkylation of amines with formic acid in the Eschweiler-Clarke reaction.

A methylene transfer reaction of an imine by an unstabilised sulphonium ylide can give an aziridine system.