Amination is the process by which an

amine In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of elec ...

group is introduced into an organic

molecule A molecule is a group of two or more atoms that are held together by Force, attractive forces known as chemical bonds; depending on context, the term may or may not include ions that satisfy this criterion. In quantum physics, organic chemi ...

. This type of reaction is important because organonitrogen compounds are pervasive.

Reactions

Aminase enzymes

Enzymes that

catalyse Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...

this reaction are termed aminases. Amination can occur in a number of ways including reaction with

ammonia Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...

or another

such as an

alkylation Alkylation is a chemical reaction that entails transfer of an alkyl group. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene (or their equivalents). Alkylating agents are reagents for effecting al ...

reductive amination Reductive amination (also known as reductive alkylation) is a form of amination that converts a carbonyl group to an amine via an intermediate imine. The carbonyl group is most commonly a ketone or an aldehyde. It is a common method to make amine ...

and the

Mannich reaction In organic chemistry, the Mannich reaction is a three-component organic reaction that involves the amino alkylation of an acidic proton next to a carbonyl () functional group by formaldehyde () and a primary or secondary amine () or ammonia () ...

Acid-catalysed hydroamination

Many alkyl amines are produced industrially by the amination of alcohols using ammonia in the presence of

solid acid Solid acids are acids that are insoluble in the reaction medium. They are often used as heterogeneous catalysts. Many solid acids are zeolites. A variety of techniques are used to quantify the strength of solid acids. Examples Examples of ino ...

catalysts. Illustrative is the production of ''tert''-butylamine: :NH₃ + CH₂=C(CH₃)₂ → H₂NC(CH₃)₃ The

Ritter reaction The Ritter reaction (sometimes called the Ritter amidation) is a chemical reaction that transforms a nitrile into an ''N''-alkyl amide using various electrophilic alkylating reagents. The original reaction formed the alkylation, alkylating agent u ...

isobutene Isobutylene (or 2-methylpropene) is a hydrocarbon with the chemical formula . It is a four-carbon branched alkene (olefin), one of the four isomers of butylene. It is a colorless flammable gas, and is of considerable industrial value. Productio ...

with

hydrogen cyanide Hydrogen cyanide (formerly known as prussic acid) is a chemical compound with the chemical formula, formula HCN and structural formula . It is a highly toxic and flammable liquid that boiling, boils slightly above room temperature, at . HCN is ...

is not useful in this case because it produces too much waste.

Electrophilic amination

Usually, the amine reacts as the

nucleophile In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they are ...

with another organic compound acting as the

electrophile In chemistry, an electrophile is a chemical species that forms bonds with nucleophiles by accepting an electron pair. Because electrophiles accept electrons, they are Lewis acids. Most electrophiles are positively Electric charge, charged, have an ...

. This sense of reactivity may be reversed for some electron-deficient amines, including

oxaziridine An oxaziridine is an organic molecule that features a three-membered heterocycle containing oxygen, nitrogen, and carbon. In their largest industrial application, oxaziridines are intermediates in the production of hydrazine. Oxaziridine deriv ...

hydroxylamine Hydroxylamine (also known as hydroxyammonia) is an inorganic compound with the chemical formula . The compound exists as hygroscopic colorless crystals.Greenwood and Earnshaw. ''Chemistry of the Elements.'' 2nd Edition. Reed Educational and Prof ...

oxime In organic chemistry, an oxime is an organic compound belonging to the imines, with the general Chemical formula, formula , where R is an organic Side chain, side-chain and R' may be hydrogen, forming an aldoxime, or another organic functional g ...

s, and other N–O substrates. When the amine is used as an electrophile, the reaction is called electrophilic amination. Electron-rich organic substrates that may be used as nucleophiles for this process include

carbanion In organic chemistry, a carbanion is an anion with a lone pair attached to a tervalent carbon atom. This gives the carbon atom a negative charge. Formally, a carbanion is the conjugate base of a carbon acid: : where B stands for the base (chemist ...

s and

enolate In organic chemistry, enolates are organic anions derived from the deprotonation of carbonyl () compounds. Rarely isolated, they are widely used as reagents in the Organic synthesis, synthesis of organic compounds. Bonding and structure Enolate ...

Miscellaneous methods

Alpha hydroxy acids Alpha hydroxy carboxylic acids, or α-hydroxy carboxylic acids (AHAs), are a group of carboxylic acids featuring a hydroxy group located ''one'' carbon atom away from the acid group. This structural aspect distinguishes them from beta hydroxy acid ...

can be converted into amino acids directly using aqueous ammonia solution, hydrogen gas and a heterogeneous metallic

ruthenium Ruthenium is a chemical element; it has symbol Ru and atomic number 44. It is a rare transition metal belonging to the platinum group of the periodic table. Like the other metals of the platinum group, ruthenium is unreactive to most chem ...

catalyst.

Metal-catalyzed hydroamination

hydroamination In organic chemistry, hydroamination is the formal Addition reaction, addition of an bond of an amine across an Carbon–carbon bond, carbon-carbon multiple bond of an alkene, alkyne, diene, or allene. In the ideal case, hydroamination is Atom eco ...

, amines add to

alkene In organic chemistry, an alkene, or olefin, is a hydrocarbon containing a carbon–carbon double bond. The double bond may be internal or at the terminal position. Terminal alkenes are also known as Alpha-olefin, α-olefins. The Internationa ...

s.Liangbin Huang, Matthias Arndt, Käthe Gooßen, Heinrich Heydt, and Lukas J. Gooßen "Late Transition Metal-Catalyzed Hydroamination and Hydroamidation" Chem. Rev., 2015, 115 (7), pp 2596–2697. When substituted amines add, the result is alkene carboamination.

References

{{Reflist Organic reactions