How are imines used in the body?
Many enzymes employ imines as part of their reaction mechanisms. An important biological reaction is the formation of an imine bond between an amino acid carbonyl group and the amine of the amino acid lysine. This is because they are highly reactive and can form adducts with other molecules.
Are imines more reactive than aldehydes?
Imines are less electrophilic than aldehydes and ketones The decreased electrophilicity of imines is readily accounted for by the lower electronegativity of nitrogen compared with that of oxygen.
How do imines react?
Imines are susceptible to hydrolysis to the corresponding amine and carbonyl compound. Imines participate in many reactions that are analogous to the reactions of aldehydes and ketones: An imine is reduced in reductive amination. An imine reacts with an amine to an aminal, see for example the synthesis of cucurbituril.
What is iminium salt?
Iminium salts hydrolyse to give the corresponding ketone or aldehyde: Iminium cations are readily reduced to the amines, e.g. by sodium cyanoborohydride. They are intermediates in the reductive amination of ketones and aldehydes.
Why are oximes more stable than imines?
This explains a commonly observed trend: imines (X = CH2) hydrolyze readily under aqueous conditions, whereas oximes and hydrazones are much more stable due to the negative inductive effect of the additional heteroatom (X = O or NH), with the former being the most stable conjugate in this series due to the high …
Can imines be isolated?
Imines are sometimes difficult to isolate and purify due to their sensitivity to hydrolysis. Consequently, other reagents of the type Y–NH2 have been studied, and found to give stable products (R2C=N–Y) useful in characterizing the aldehydes and ketones from which they are prepared.
Which reaction iminium ion is an intermediate of?
Iminium cations are readily reduced to the amines, e.g. by sodium cyanoborohydride. They are intermediates in the reductive amination of ketones and aldehydes.
How are iminium salts produced from amines and imines?
Iminium salts can commonly be prepared from the reaction of amines with aldehydes and ketones. In addition, iminium ions can be generated from enamines and imines by reaction with electrophiles such as H + < 55CI (L)1039 >.
How are iminium ions produced in a reaction?
Iminium ion cyclizations. The requisite iminium ions in these reactions are often readily available via the modified Polonovski reaction. Although two steps, N -oxide formation and reaction with trifluoroacetic anhydride, are involved, this approach is often preferable to the reaction of a tertiary amine with mercury (II) acetate,…
How are iminium cations reduced to amines in reductive amination?
Iminium cations are readily reduced to the amines, e.g. by sodium cyanoborohydride. They are intermediates in the reductive amination of ketones and aldehydes.
Which is the best way to prepare iminium?
Milder methods of iminium preparation, efficient modern strategies such as their use in tandem reaction procedures (e.g., aza-Cope Mannich cyclizations), and counter-nucleophile reactions demonstrate their increasing value as synthetic tools <89MI 310-01 >.