Imine


Imine

An imine is a functional group or chemical compound containing a carbonnitrogen double bond [March Jerry; (1985). "Advanced Organic Chemistry reactions, mechanisms and structure" (3rd ed.). New York: John Wiley & Sons, inc. ISBN 0-471-85472-7] . Due to their diverse reactivity, imines are common substrates in a wide variety of transformations. An imine can be synthesised by the nucleophilic addition of an amine to a ketone or aldehyde giving a hemiaminal -C(OH)(NHR)- followed by an elimination of water to yield the imine. (see alkylimino-de-oxo-bisubstitution for a detailed mechanism) However, the equilibrium in this reaction usually lies in favor of the free carbonyl compound and amine, so that azeotrope distillation or use of a dehydrating agent such as molecular sieves is required to push the reaction in favor of imine formation. Addition reactions with primary amines give imines that are stable under an inert atmosphere. In the presence of oxygen or water, such imines will quite readily hydrolyze or oligomerize. However, with an aryl group or certain stabilizing alkyl substituents on nitrogen, the imine formed is stable to oxygen and water and is called a Schiff base. In contrast, imine condensations using ammonia and a carbonyl compound do not lead to stable imines - the imine formed quickly oligomerizes such as in the reaction of formaldehyde and ammonia which gives hexamine instead of the corresponding imine. When a secondary amine is used, elimination of water from the hemiaminal leads to an iminium ion. This iminium ion can further react to form either an aminal, or enamine if there is an sp3-hybridized carbon in the alpha position. Addition of suitably activated carbonyl compounds to this imminium ion also leads to the corresponding Mannich base.

Imine synthesis

Several laboratory methods exist for the synthesis of imines.
* Condensation of amines with carbonyls in alkylimino-de-oxo-bisubstitution
* Condensation of carbon acids with nitroso compounds
* The rearrangement of trityl N-haloamines in the Stieglitz rearrangement
* Dehydration of hemiaminals [OrgSynth | author = W. J. Middleton and H. D. Carlson | title = Hexafluoroacetone imine | collvol = 6 | collvolpages = 664 | year = 1988 | prep = cv6p0664]
* By reaction of alkenes with hydrazoic acid in the Schmidt reaction
* By reaction of a nitrile, hydrochloric acid and an arene in the Hoesch reaction

Imine reactions

* An imine can be reduced to an amine.
* An imine can be hydrolysed with water to the corresponding amine and carbonyl compound.
* An imine reacts with an amine to an aminal, see for example the synthesis of cucurbituril.
* An imine reacts with dienes in the Aza Diels-Alder reaction to a tetrahydropyridine.
* An imine can be oxidized with meta-chloroperoxybenzoic acid (mCPBA) to give an oxaziridine
* An aromatic imine reacts with an enol ether to a quinoline in the Povarov reaction.
* A tosylimine reacts with an α,β-unsaturated carbonyl compound to an allylic amine in the Aza-Baylis-Hillman reaction.
* Imines are intermediates in the alkylation of amines with formic acid in the Eschweiler-Clarke reaction.
* A rearrangement in carbohydrate chemistry involving an imine is the Amadori rearrangement.
* A methylene transfer reaction of an imine by an unstabilised sulphonium ylide can give an aziridine system.

Amidates

.

Amidates are the corresponding amide enolates: R-N=C(O-)R and find use as ligands.

See also

* Other functional groups with a CN double bond: oximes, hydrazones
* Other functional groups with a CN triple bond: nitriles, isonitriles

References


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Look at other dictionaries:

  • imine — ● imine nom féminin (allemand Imine) Nom générique des composés de formule générale RR′C≅NR″, produits par la condensation des aldéhydes et des cétones RR′C≅O avec l ammoniac ou les amines primaires H2NR″. ⇒IMINE, subst. fém. CHIM. Amine… …   Encyclopédie Universelle

  • Imīne — Imīne, sekundäre Amine (Imidbasen), die sich vom Ammoniak (NH3) dadurch ableiten, daß 2 Atome Wasserstoff durch ein zweiwertiges Alkoholradikal ersetzt sind, z. B. NH.C2H4 Äthylenimin …   Meyers Großes Konversations-Lexikon

  • Imine —   [Kurzwort], Singular Imin das, s, im weiteren Sinn alle organische Verbindungen, in denen eine Iminogruppe, =NH vorliegt; im engeren Sinn organische Verbindungen, in denen formal das Sauerstoffatom einer Carbonylgruppe durch die Gruppe =NH… …   Universal-Lexikon

  • imine — IMÍNE s.f.pl. (chim.) Clasă de combinaţii organice rezultate prin înlocuirea a doi atomi de hidrogen din molecula de NH3 printr un radical organic bivalent. [< fr. imines]. Trimis de LauraGellner, 26.04.2005. Sursa: DN …   Dicționar Român

  • imine — [i mēn′; im′ēn΄, im′in] n. [arbitrary alteration of AMINE] a compound containing the divalent radical NH united to alkyl or other nonacid radicals …   English World dictionary

  • Imine — Structure de base des imines. Une imine est un composé organique caractérisé par une double liaison carbone azote. De plus, l azote est lié grâce à son troisième électron de valence à un second groupe alkyle ou à un hydrogène …   Wikipédia en Français

  • Imine — Strukturformel eines Imins mit blau markierter Imino Gruppe. Imine sind eine Gruppe chemischer Verbindungen, bei denen das Sauerstoff Atom eines Aldehyds oder Ketons durch ein Stickstoff Atom ersetzt ist. Das Stickstoff Atom trägt zudem noch ein… …   Deutsch Wikipedia

  • imine — im·ine im .ēn n a compound containing the NH group or its substituted form NR that is derived from ammonia by replacement of two hydrogen atoms by a hydrocarbon group or other nonacid organic group * * * (ĭ mēnґ) an organic compound… …   Medical dictionary

  • imine — iminas statusas T sritis chemija formulė R₂C=NR atitikmenys: angl. azomethine; imine rus. азометин; имин ryšiai: sinonimas – azometinas …   Chemijos terminų aiškinamasis žodynas

  • imine — iminas statusas T sritis chemija apibrėžtis Heterociklinis junginys. formulė Formulę žr. priede. priedas( ai) Grafinis formatas atitikmenys: angl. imine rus. имин …   Chemijos terminų aiškinamasis žodynas


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