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The general structure of an imine. In organic chemistry, an imine (/ ɪ ˈ m iː n / or / ˈ ɪ m ɪ n /) is a functional group or organic compound containing a carbon–nitrogen double bond (C=N). The nitrogen atom can be attached to a hydrogen or an organic group (R). The carbon atom has two additional single bonds.
The Staudinger synthesis, also called the Staudinger ketene-imine cycloaddition, is a chemical synthesis in which an imine 1 reacts with a ketene 2 through a non-photochemical 2+2 cycloaddition to produce a β-lactam 3. [1] The reaction carries particular importance in the synthesis of β-lactam antibiotics. [2]
First, the nickel metal dehydrogenates the alcohol to form a ketone and Ni-H complex. Then, the ketone reacts with ammonia to form an imine. Finally, the imine reacts with Ni-H to regenerate catalyst and form primary amine. An example of a homogeneous catalytic system is the reductive amination of ketones done with an iridium catalyst. [20]
Apart from polyimine polymers that are formed directly via the condensation reaction from aldehydes and amines, it is also possible to incorporate imines in other existing polymer materials. Imines have, for example, been incorporated into recyclable epoxy-based thermosets [11] and polyesters. [12]
General structure of an imine. Schiff bases are imines in which R 3 is an alkyl or aryl group (not a hydrogen). R 1 and R 2 may be hydrogens General structure of an azomethine compound. In organic chemistry, a Schiff base (named after Hugo Schiff) is a compound with the general structure R 1 R 2 C=NR 3 (R 3 = alkyl or aryl, but not hydrogen).
Reactions between aldimines and α-methylene carbonyls are also considered Mannich reactions because these imines form between amines and aldehydes. The reaction is named after Carl Mannich. [2] [3] Scheme 1 – Ammonia or an amine reacts with formaldehyde and an alpha acidic proton of a carbonyl compound to a beta amino carbonyl compound.
The first N-sulfinyl imines in racemic form were formed by oxidation of p-toluene-sulfenyl imines with m-CPBA. [9] Enantiopure p-toluene-sulfinyl imines arise by the reaction of the commercially available Andersen reagent (menthyl p-toluenesulfinate) [10] with metallo-ketimines but is limited to ketone derived N-sulfinyl imines. [11]
If one or both of the nitrogen substituents is a hydrogen atom it is the tautomeric form of an imine. This usually will rearrange to the imine; however there are several exceptions (such as aniline). The enamine-imine tautomerism may be considered analogous to the keto-enol tautomerism. In both cases, a hydrogen atom switches its location ...