Amine

Amine

Overview

Amines are organic compound
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

s and functional group
Functional group
In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of...

s that contain a basic
Base (chemistry)
For the term in genetics, see base A base in chemistry is a substance that can accept hydrogen ions or more generally, donate electron pairs. A soluble base is referred to as an alkali if it contains and releases hydroxide ions quantitatively...

 nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

 atom
Atom
The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...

 with a lone pair
Lone pair
In chemistry, a lone pair is a valence electron pair without bonding or sharing with other atoms. They are found in the outermost electron shell of an atom, so lone pairs are a subset of a molecule's valence electrons...

. Amines are derivative
Derivative (chemistry)
In chemistry, a derivative is a compound that is derived from a similar compound by some chemical or physical process. In the past it was also used to mean a compound that can be imagined to arise from another compound, if one atom is replaced with another atom or group of atoms, but modern...

s of ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...

, wherein one or more hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 atoms have been replaced by a substituent
Substituent
In organic chemistry and biochemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon...

 such as an alkyl or aryl
Aryl
In the context of organic molecules, aryl refers to any functional group or substituent derived from an aromatic ring, be it phenyl, naphthyl, thienyl, indolyl, etc....

 group. Important amines include amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

s, biogenic amine
Biogenic amine
-Examples:Some prominent examples of biogenic amines include:* Histamine - a substance derived from the amino acid histidine that acts as a neurotransmitter mediating arousal and attention, as well as a pro-inflammatory signal released from mast cells in response to allergic reactions or tissue...

s, trimethylamine
Trimethylamine
Trimethylamine is an organic compound with the formula N3. This colorless, hygroscopic, and flammable tertiary amine has a strong "fishy" odor in low concentrations and an ammonia-like odor at higher concentrations...

, and aniline
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...

; see :Category:Amines for a list of amines. Inorganic derivatives of ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...

 are also called amines, such as chloramine (NClH2).

Compounds with the nitrogen atom attached to a carbonyl
Carbonyl
In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups....

 of the structure R-C(=O)NR'R'‌' are called amide
Amide
In chemistry, an amide is an organic compound that contains the functional group consisting of a carbonyl group linked to a nitrogen atom . The term refers both to a class of compounds and a functional group within those compounds. The term amide also refers to deprotonated form of ammonia or an...

s and have different chemical properties from amines.

Primary amines arise when one of three hydrogen atoms in ammonia is replaced by an alkyl.
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Primary amine Secondary amine Tertiary amine

Amines are organic compound
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

s and functional group
Functional group
In organic chemistry, functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. The same functional group will undergo the same or similar chemical reaction regardless of the size of the molecule it is a part of...

s that contain a basic
Base (chemistry)
For the term in genetics, see base A base in chemistry is a substance that can accept hydrogen ions or more generally, donate electron pairs. A soluble base is referred to as an alkali if it contains and releases hydroxide ions quantitatively...

 nitrogen
Nitrogen
Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

 atom
Atom
The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...

 with a lone pair
Lone pair
In chemistry, a lone pair is a valence electron pair without bonding or sharing with other atoms. They are found in the outermost electron shell of an atom, so lone pairs are a subset of a molecule's valence electrons...

. Amines are derivative
Derivative (chemistry)
In chemistry, a derivative is a compound that is derived from a similar compound by some chemical or physical process. In the past it was also used to mean a compound that can be imagined to arise from another compound, if one atom is replaced with another atom or group of atoms, but modern...

s of ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...

, wherein one or more hydrogen
Hydrogen
Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

 atoms have been replaced by a substituent
Substituent
In organic chemistry and biochemistry, a substituent is an atom or group of atoms substituted in place of a hydrogen atom on the parent chain of a hydrocarbon...

 such as an alkyl or aryl
Aryl
In the context of organic molecules, aryl refers to any functional group or substituent derived from an aromatic ring, be it phenyl, naphthyl, thienyl, indolyl, etc....

 group. Important amines include amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

s, biogenic amine
Biogenic amine
-Examples:Some prominent examples of biogenic amines include:* Histamine - a substance derived from the amino acid histidine that acts as a neurotransmitter mediating arousal and attention, as well as a pro-inflammatory signal released from mast cells in response to allergic reactions or tissue...

s, trimethylamine
Trimethylamine
Trimethylamine is an organic compound with the formula N3. This colorless, hygroscopic, and flammable tertiary amine has a strong "fishy" odor in low concentrations and an ammonia-like odor at higher concentrations...

, and aniline
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...

; see :Category:Amines for a list of amines. Inorganic derivatives of ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...

 are also called amines, such as chloramine (NClH2).

Compounds with the nitrogen atom attached to a carbonyl
Carbonyl
In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom: C=O. It is common to several classes of organic compounds, as part of many larger functional groups....

 of the structure R-C(=O)NR'R'‌' are called amide
Amide
In chemistry, an amide is an organic compound that contains the functional group consisting of a carbonyl group linked to a nitrogen atom . The term refers both to a class of compounds and a functional group within those compounds. The term amide also refers to deprotonated form of ammonia or an...

s and have different chemical properties from amines.

Aliphatic amines


Primary amines arise when one of three hydrogen atoms in ammonia is replaced by an alkyl. Important primary alkyl amines include methylamine
Methylamine
Methylamine is the organic compound with a formula of CH3NH2. This colourless gas is a derivative of ammonia, but with one H atom replaced by a methyl group. It is the simplest primary amine. It is sold as a solution in methanol, ethanol, THF, and water, or as the anhydrous gas in pressurized...

, ethanolamine
Ethanolamine
Ethanolamine, also called 2-aminoethanol or monoethanolamine , is an organic chemical compound that is both a primary amine and a primary alcohol . Like other amines, monoethanolamine acts as a weak base...

 (2-aminoethanol), and the buffering agent
Buffering agent
A buffering agent is a weak acid or base used to maintain the acidity of a solution at a chosen value. The function of a buffering agent is to prevent a rapid change in pH when acids or bases are added to the solution. Buffering agents have variable properties—some are more soluble than others;...

 tris
Tris
Tris is an abbreviation of the organic compound known as trisaminomethane, with the formula 3CNH2. Tris is extensively used in biochemistry and molecular biology. In biochemistry, tris is widely used as a component of buffer solutions, such as in TAE and TBE buffer, especially for solutions of...

. Secondary amines have two alkyl substituents bound to N together with one hydrogen. Important representatives include dimethylamine
Dimethylamine
Dimethylamine is an organic compound with the formula 2NH. This secondary amine is a colorless, flammable liquified gas with an ammonia-like odor. Dimethylamine is generally encountered as a solution in water at concentrations up to around 40%...

 and methylethanolamine.
In tertiary amines, all three hydrogen atoms are replaced by organic substituents. Examples include trimethylamine
Trimethylamine
Trimethylamine is an organic compound with the formula N3. This colorless, hygroscopic, and flammable tertiary amine has a strong "fishy" odor in low concentrations and an ammonia-like odor at higher concentrations...

, a distinctively fishy smell. Cyclic
Cyclic compound
In chemistry, a cyclic compound is a compound in which a series of atoms is connected to form a loop or ring.While the vast majority of cyclic compounds are organic, a few inorganic substances form cyclic compounds as well, including sulfur, silanes, phosphanes, phosphoric acid, and triboric acid. ...

 amines are either secondary or tertiary amines. Examples of cyclic amines include the 3-member ring aziridine
Aziridine
Aziridines are organic compounds containing the aziridine functional group, a three-membered heterocycle with one amine group and two methylene groups...

 and the six-membered ring piperidine
Piperidine
Piperidine is an organic compound with the molecular formula 5NH. This heterocyclic amine consists of a six-membered ring containing five methylene units and one nitrogen atom...

. N-methylpiperidine is a cyclic tertiary amine. It is also possible to have four alkyl substituents on the nitrogen. These compounds are not amines but are called quaternary ammonium cation
Quaternary ammonium cation
Quaternary ammonium cations, also known as quats, are positively charged polyatomic ions of the structure NR4+, R being an alkyl group or an aryl group. Unlike the ammonium ion and the primary, secondary, or tertiary ammonium cations, the quaternary ammonium cations are permanently charged,...

s, have a charged nitrogen center, and necessarily come with an anion.

Aromatic amines



Aromatic amines have the nitrogen atom connected to an aromatic ring as in aniline
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...

s. The aromatic ring decreases the alkalinity
Base (chemistry)
For the term in genetics, see base A base in chemistry is a substance that can accept hydrogen ions or more generally, donate electron pairs. A soluble base is referred to as an alkali if it contains and releases hydroxide ions quantitatively...

 of the amine, depending on its substituents. The presence of an amine group strongly increases the reactivity of the aromatic ring, due to an electron-donating effect.

Naming conventions


Amines are named in several ways. Typically, the compound is given the prefix "amino-" or the suffix: "-amine." The prefix "N-" shows substitution on the nitrogen atom. An organic compound with multiple amino groups is called a diamine, triamine, tetraamine and so forth.

Systematic names for some common amines:
Lower amines are named with the suffix -amine.



methylamine
Higher amines have the prefix amino as a functional group.



2-aminopentane
(or sometimes: pent-2-yl-amine or pentane-2-amine)

Physical properties


Hydrogen bonding significantly influences the properties of primary and secondary amines. Thus the boiling point
Boiling point
The boiling point of an element or a substance is the temperature at which the vapor pressure of the liquid equals the environmental pressure surrounding the liquid....

 of amines is higher than those of the corresponding phosphine
Phosphine
Phosphine is the compound with the chemical formula PH3. It is a colorless, flammable, toxic gas. Pure phosphine is odourless, but technical grade samples have a highly unpleasant odor like garlic or rotting fish, due to the presence of substituted phosphine and diphosphine...

s, but generally lower than those of the corresponding alcohol
Alcohol
In chemistry, an alcohol is an organic compound in which the hydroxy functional group is bound to a carbon atom. In particular, this carbon center should be saturated, having single bonds to three other atoms....

s. For example, methylamine and ethylamine
Ethylamine
Ethylamine is an organic compound with the formula CH3CH2NH2. This colourless gas has a strong ammonia-like odor. It is miscible with virtually all solvents and is considered to be a weak base, as is typical for amines. Ethylamine is widely used in chemical industry and organic...

 are gases under standard conditions, whereas the corresponding methyl alcohol and ethyl alcohols are liquids. Gaseous amines possess a characteristic ammonia smell, liquid amines have a distinctive "fishy" smell.

Also reflecting their ability to form hydrogen bonds, most aliphatic amines display some solubility in water. Solubility decreases with the increase in the number of carbon atoms. Aliphatic amines display significant solubility in organic solvent
Solvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...

s, especially polar organic solvents. Primary amines react with ketone
Ketone
In organic chemistry, a ketone is an organic compound with the structure RCR', where R and R' can be a variety of atoms and groups of atoms. It features a carbonyl group bonded to two other carbon atoms. Many ketones are known and many are of great importance in industry and in biology...

s such as acetone
Acetone
Acetone is the organic compound with the formula 2CO, a colorless, mobile, flammable liquid, the simplest example of the ketones.Acetone is miscible with water and serves as an important solvent in its own right, typically as the solvent of choice for cleaning purposes in the laboratory...

.

The aromatic amines, such as aniline
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...

, have their lone pair electrons conjugated
Conjugated system
In chemistry, a conjugated system is a system of connected p-orbitals with delocalized electrons in compounds with alternating single and multiple bonds, which in general may lower the overall energy of the molecule and increase stability. Lone pairs, radicals or carbenium ions may be part of the...

 into the benzene ring, thus their tendency to engage in hydrogen bonding is diminished. Their boiling points are high and their solubility in water low


Chirality


Amines of the type NHRR' and NRR'R" are chiral
Chirality (chemistry)
A chiral molecule is a type of molecule that lacks an internal plane of symmetry and thus has a non-superimposable mirror image. The feature that is most often the cause of chirality in molecules is the presence of an asymmetric carbon atom....

: the nitrogen atom bears four substituents counting the lone pair. The energy barrier for the inversion
Nitrogen inversion
In chemistry, a nitrogen compound like ammonia in a trigonal pyramid geometry undergoes rapid nitrogen inversion whereby the molecule turns inside out. This interconversion is a room temperature process because the energy barrier is relatively small. Contrast this to phosphine which does not show...

 of the stereocenter is relatively low, e.g., ~7 kcal/mol for a trialkylamine. The interconversion of the stereoisomers has been compared to the inversion of an open umbrella in to a strong wind. Because of this low barrier, amines such as NHRR' cannot be resolved optically and NRR'R" can only be resolved when the R, R', and R" groups are constrained in cyclic structures such as aziridines. Quaternary ammonium salts with four distinct groups on the nitrogen are capable of exhibiting optical activity.

Properties as bases


Like ammonia, amines are bases
Base (chemistry)
For the term in genetics, see base A base in chemistry is a substance that can accept hydrogen ions or more generally, donate electron pairs. A soluble base is referred to as an alkali if it contains and releases hydroxide ions quantitatively...

. Compared to alkali metal hydroxides, amines are weaker (see table for examples of conjugate acid
Conjugate acid
Within the Brønsted–Lowry acid-base theory , a conjugate acid is the acid member, HX, of a pair of two compounds that transform into each other by gain or loss of a proton. A conjugate acid can also be seen as the chemical substance that releases, or donates, a proton in the forward chemical...

 Ka values). The basicity of amines depends on:
  1. The electronic properties of the substituents (alkyl groups enhance the basicity, aryl groups diminish it).
  2. Steric hindrance offered by the groups on nitrogen.
  3. The degree of solvation of the protonated amine.


The nitrogen atom features a lone electron pair that can bind H+ to form an ammonium ion R3NH+. The lone electron pair is represented in this article by a two dots above or next to the N. The water solubility
Solubility
Solubility is the property of a solid, liquid, or gaseous chemical substance called solute to dissolve in a solid, liquid, or gaseous solvent to form a homogeneous solution of the solute in the solvent. The solubility of a substance fundamentally depends on the used solvent as well as on...

 of simple amines is largely due to hydrogen bonding between protons in the water molecules and these lone electron pairs.
  • Inductive effect
    Inductive effect
    In chemistry and physics, the inductive effect is an experimentally observable effect of the transmission of charge through a chain of atoms in a molecule by electrostatic induction...

     of alkyl groups

Ions of compound Kb
Ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...

 NH3
1.8·10−5 M
Propylamine
Propylamine
Propylamine, also known as n-propylamine, is an amine with the chemical formula C3H9N.Propylamine is a weak base with its Kb equaling 4.7 × 10-4.-Preparation:...

 CH3CH2CH2NH2
4.7·10−4 M
2-Propylamine (CH3)2CHNH2 3.4·10−4 M
Methylamine
Methylamine
Methylamine is the organic compound with a formula of CH3NH2. This colourless gas is a derivative of ammonia, but with one H atom replaced by a methyl group. It is the simplest primary amine. It is sold as a solution in methanol, ethanol, THF, and water, or as the anhydrous gas in pressurized...

 CH3NH2
4.4·10−4 M
Dimethylamine
Dimethylamine
Dimethylamine is an organic compound with the formula 2NH. This secondary amine is a colorless, flammable liquified gas with an ammonia-like odor. Dimethylamine is generally encountered as a solution in water at concentrations up to around 40%...

 (CH3)2NH
5.4·10−4 M
Trimethylamine
Trimethylamine
Trimethylamine is an organic compound with the formula N3. This colorless, hygroscopic, and flammable tertiary amine has a strong "fishy" odor in low concentrations and an ammonia-like odor at higher concentrations...

 (CH3)3N
5.9·10−5 M

+I effect of alkyl groups raises the energy of the lone pair of electrons, thus elevating the basicity. Thus the basicity of an amine may be expected to increase with the number of alkyl groups on the amine. However, there is no strict trend in this regard, as basicity is also governed by other factors mentioned above. Consider the Kb values of the methyl amines given above. The increase in Kb from methylamine to dimethylamine may be attributed to +I effect; however, there is a decrease from dimethylamine to trimethyl amine due to the predominance of steric hindrance offered by the three methyl groups to the approaching Brönsted acid.

  • Mesomeric effect
    Mesomeric effect
    The mesomeric effect or resonance effect in chemistry is a property of substituents or functional groups in a chemical compound. The effect is used in a qualitative way and describes the electron withdrawing or releasing properties of substituents based on relevant resonance structures and is...

     of aromatic systems

Ions of compound Kb
Ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...

 NH3
1.8·10−5 M
Aniline
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...

 C6H5NH2
3.8·10−10 M
4-Methylaniline 4-CH3C6H4NH2 1.2·10−9 M
2-Nitroaniline
2-Nitroaniline
2-Nitroaniline, also known as ortho-nitroaniline or o-nitroaniline, is an organic chemical compound that is chemically described as an aniline carrying a nitro functional group in position 2. It is classified as an aromatic amine. At ambient temperature and pressure, 2-nitroaniline is a powdered...

1.5·10−15 M
3-Nitroaniline
3-Nitroaniline
3-Nitroaniline, also known as 'meta'-nitroaniline and m-nitroaniline, is non-volatile stable solid commonly used as a raw material for dyes. 3-Nitroaniline is an aniline carrying a nitro functional group in position 3...

2.8·10−13 M
4-Nitroaniline
4-Nitroaniline
4-Nitroaniline, p-nitroaniline or 1-amino-4-nitrobenzene is an organic compound with the formula C6H6N2O2. It is an organic chemical compound, consisting of a phenyl group attached to an amino group which is para to a nitro group. The chemical structure of p-nitroaniline is shown at the right...

9.5·10−14 M

-M effect of aromatic ring delocalises the lone pair of electrons on nitrogen into the ring, resulting in decreased basicity. Substituents on the aromatic ring, and their positions relative to the amine group may also considerably alter basicity as seen above.


The of solvation of protonated amines changes upon their conversion to ammonium compounds. Typically salts of ammonium compounds exhibit the following order of solubility in water: primary ammonium (RNH3+)> secondary ammonium (R2NH2+) . tertiary ammonium (R3NH+). Quaternary ammonium salts usually exhibit the lowest solubility of the series.

In sterically hindered amines, as in the case of trimethylamine, the protonated form is not well-solvated. For this reason the parent amine is less basic than expected. In the case of aprotic polar solvents (like DMSO
Dimethyl sulfoxide
Dimethyl sulfoxide is an organosulfur compound with the formula 2SO. This colorless liquid is an important polar aprotic solvent that dissolves both polar and nonpolar compounds and is miscible in a wide range of organic solvents as well as water...

 and DMF
Dimethylformamide
Dimethylformamide is an organic compound with the formula 2NCH. Commonly abbreviated as DMF , this colourless liquid is miscible with water and the majority of organic liquids. DMF is a common solvent for chemical reactions...

), wherein the extent of solvation is not as high as in protic polar solvents (like water and methanol), the basicity of amines is almost solely governed by the electronic factors within the molecule.

Alkylation


The most industrially significant amines are prepared from ammonia by alkylation
Alkylation
Alkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion or a carbene . Alkylating agents are widely used in chemistry because the alkyl group is probably the most common group encountered in...

 with alcohols:
ROH + NH3 → RNH2 + H2O

These reactions require catalysts, specialized apparatus, and additional purification measures since the selectivity can be problematic. The same amines can be prepared by treatment of Haloalkanes with ammonia and amines:
RX + 2 R'NH2 → RR'NH + [RR'NH2]X

Such reactions, which are most useful for alkyl iodides and bromides, are rarely employed because the degree of alkylation is difficult to control.

Reductive routes


Via the process of hydrogenation
Hydrogenation
Hydrogenation, to treat with hydrogen, also a form of chemical reduction, is a chemical reaction between molecular hydrogen and another compound or element, usually in the presence of a catalyst. The process is commonly employed to reduce or saturate organic compounds. Hydrogenation typically...

, nitrile
Nitrile
A nitrile is any organic compound that has a -C≡N functional group. The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, one example being super glue .Inorganic compounds containing the -C≡N group are not called...

s are reduced to amines using hydrogen in the presence of a nickel catalyst. Reactions are sensitive acidic or alkaline conditions, which can cause hydrolysis of -CN group. LiAlH4 is more commonly employed for the reduction of nitriles on the laboratory scale. Similarly, LiAlH4 reduces amide
Amide
In chemistry, an amide is an organic compound that contains the functional group consisting of a carbonyl group linked to a nitrogen atom . The term refers both to a class of compounds and a functional group within those compounds. The term amide also refers to deprotonated form of ammonia or an...

s to amines. Many amines are produced from aldehydes and ketones via reductive amination
Reductive amination
Reductive amination is a form of amination that involves the conversion of a carbonyl group to an amine via an intermediate imine...

, which can either proceed catalytically or stoichiometrically.

Aniline
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...

 (C6H5NH2) and its derivatives are prepared by reduction of the nitroaromatics. In industry, hydrogen is the preferred reductant, whereas in the laboratory, tin and iron are often employed.

Specialized methods


Many laboratory methods exist for the preparation of amines, many of these methods being rather specialized.
Reaction name Substrate | Comment
Gabriel synthesis
Gabriel synthesis
The Gabriel synthesis is named for the German chemist Siegmund Gabriel. Traditionally, it is a chemical reaction that transforms primary alkyl halides into primary amines using potassium phthalimide....

organohalide reagent: potassium phthalimide
Potassium phthalimide
Potassium phthalimide is a chemical compound of formula C8H4KNO2. It is commercially available, and usually presents as fluffy, very pale yellow crystals. It is the potassium salt of phthalimide...

Staudinger reduction Azide
Azide
Azide is the anion with the formula N3−. It is the conjugate base of hydrazoic acid. N3− is a linear anion that is isoelectronic with CO2 and N2O. Per valence bond theory, azide can be described by several resonance structures, an important one being N−=N+=N−...

This reaction also takes place with a reducing agent such as lithium aluminium hydride
Lithium aluminium hydride
Lithium aluminium hydride, commonly abbreviated to LAH or known as LithAl, is an inorganic compound with the chemical formula LiAlH4. It was discovered by Finholt, Bond and Schlesinger in 1947. This compound is used as a reducing agent in organic synthesis, especially for the reduction of esters,...

.
Schmidt reaction
Schmidt reaction
The Schmidt reaction is an organic reaction involving alkyl migration over the carbon-nitrogen chemical bond in an azide with expulsion of nitrogen...

carboxylic acid
Carboxylic acid
Carboxylic acids are organic acids characterized by the presence of at least one carboxyl group. The general formula of a carboxylic acid is R-COOH, where R is some monovalent functional group...

Aza-Baylis–Hillman reaction imine
Imine
An imine is a functional group or chemical compound containing a carbon–nitrogen double bond, with the nitrogen attached to a hydrogen atom or an organic group. If this group is not a hydrogen atom, then the compound is known as a Schiff base...

Synthesis of allylic amines
Hofmann degradation
Hofmann rearrangement
The Hofmann rearrangement is the organic reaction of a primary amide to a primary amine with one fewer carbon atom.The reaction is named after its discoverer: August Wilhelm von Hofmann...

amide
Amide
In chemistry, an amide is an organic compound that contains the functional group consisting of a carbonyl group linked to a nitrogen atom . The term refers both to a class of compounds and a functional group within those compounds. The term amide also refers to deprotonated form of ammonia or an...

This reaction is valid for preparation of primary amines only. Gives good yields of primary amines uncontaminated with other amines.
Hofmann elimination
Hofmann elimination
Hofmann elimination is a process where an amine is reacted to create a tertiary amine and an alkene by treatment with excess methyl iodide followed by treatment with silver oxide, water, and heat.After the first step, a quaternary ammonium iodide salt is created...

Quaternary ammonium salt upon treatment with strong base
Amide reduction
Amide reduction
Amide reduction in chemistry is the organic reduction of amides . The main reaction product in this functional group interconversion is an amine...

amides
Nitrile reduction
Nitrile reduction
In nitrile reduction a nitrile is reduced to either an amine or an aldehyde with a suitable chemical reagent .Reagents for the conversion to amines are lithium aluminium hydride, Raney nickel / hydrogen / or diborane This organic reaction is one of several nitrogen-hydrogen bond forming...

nitrile
Nitrile
A nitrile is any organic compound that has a -C≡N functional group. The prefix cyano- is used interchangeably with the term nitrile in industrial literature. Nitriles are found in many useful compounds, one example being super glue .Inorganic compounds containing the -C≡N group are not called...

s
Reduction of nitro compounds
Reduction of nitro compounds
The chemical reactions described as reduction of nitro compounds can be facilitated by many different reagents and reaction conditions. Historically, the nitro group was one of the first functional groups to be reduced, due to the ease of nitro-group reduction....

nitro compound
Nitro compound
Nitro compounds are organic compounds that contain one or more nitro functional groups . They are often highly explosive, especially when the compound contains more than one nitro group and is impure. The nitro group is one of the most common explosophores used globally...

s
can be accomplished with elemental zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...

, tin
Tin
Tin is a chemical element with the symbol Sn and atomic number 50. It is a main group metal in group 14 of the periodic table. Tin shows chemical similarity to both neighboring group 14 elements, germanium and lead and has two possible oxidation states, +2 and the slightly more stable +4...

 or iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...

 with an acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

.
Amine alkylation
Amine alkylation
Amine alkylation is a type of organic reaction between an alkyl halide and ammonia or an amine. The reaction is called nucleophilic aliphatic substitution , and the reaction product is a higher substituted amine...

haloalkane
Haloalkane
The haloalkanes are a group of chemical compounds derived from alkanes containing one or more halogens. They are a subset of the general class of halocarbons, although the distinction is not often made. Haloalkanes are widely used commercially and, consequently, are known under many chemical and...

Delepine reaction
Delepine reaction
The Delépine reaction is the organic synthesis of primary amines by reaction of a benzyl or alkyl halides with hexamethylenetetramine followed by acid hydrolysis of the quaternary ammonium salt...

organohalide reagent hexamine
Hexamine
Hexamethylenetetramine is a heterocyclic organic compound with the formula 6N4. This white crystalline compound is highly soluble in water and polar organic solvents. It has a cage-like structure similar to adamantane. It is useful in the synthesis of other chemical compounds, e.g. plastics,...

Buchwald-Hartwig reaction
Buchwald-Hartwig reaction
The Buchwald–Hartwig reaction is a chemical reaction used in organic chemistry for the synthesis of carbon–nitrogen bonds via the palladium-catalyzed cross-coupling of amines with aryl halides. Though publications with similar focus were published as early as 1983, credit for its development is...

aryl halide specific for aryl amines
Menshutkin reaction
Menshutkin reaction
The Menshutkin reaction in organic chemistry converts a tertiary amine to a quaternary ammonium salt by reaction with an alkyl halide:The reaction has been named after its discoverer, the Russian chemist Nikolai Menshutkin, who described the procedure in 1890...

tertiary amine reaction product a quaternary ammonium cation
Quaternary ammonium cation
Quaternary ammonium cations, also known as quats, are positively charged polyatomic ions of the structure NR4+, R being an alkyl group or an aryl group. Unlike the ammonium ion and the primary, secondary, or tertiary ammonium cations, the quaternary ammonium cations are permanently charged,...

hydroamination
Hydroamination
The hydroamination reaction is the addition of an N-H bond across the C=C or C≡C bonds of an alkene or alkyne. This is a highly atom economical method of preparing substituted amines that are attractive targets for organic synthesis and the pharmaceutical industry.The hydroamination reaction is...

alkene
Alkene
In organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...

s and alkyne
Alkyne
Alkynes are hydrocarbons that have a triple bond between two carbon atoms, with the formula CnH2n-2. Alkynes are traditionally known as acetylenes, although the name acetylene also refers specifically to C2H2, known formally as ethyne using IUPAC nomenclature...

s
Hofmann-Löffler reaction
Hofmann-Löffler reaction
The Hofmann-Löffler reaction is an organic reaction in which a cyclic amine 2 is generated by thermal or photochemical decomposition of N-halogenated amine 1 in the presence of a strong acid...

haloamine

Alkylation, acylation, and sulfonation


Aside from their basicity, the dominant reactivity of amines is their nucleophilicity
Nucleophilic acyl substitution
Nucleophilic acyl substitution describes the substitution reaction involving nucleophiles and acyl compounds. Acyl compounds are carboxylic acid derivatives including esters, amides and acid halides...

. Most primary amines are good ligand
Ligand
In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The nature of metal-ligand bonding can range from...

s for metal ions to give coordination complexes. Amines are alkylated by alkyl halides. Acyl chloride
Acyl chloride
In organic chemistry, an acyl chloride is an organic compound with the functional group -CO-Cl. Their formula is usually written RCOCl, where R is a side chain. They are usually considered to be reactive derivatives of carboxylic acids. A specific example of an acyl chloride is acetyl chloride,...

s and acid anhydrides react with primary and secondary amines to form amide
Amide
In chemistry, an amide is an organic compound that contains the functional group consisting of a carbonyl group linked to a nitrogen atom . The term refers both to a class of compounds and a functional group within those compounds. The term amide also refers to deprotonated form of ammonia or an...

s (the "Schotten-Baumann reaction
Schotten-Baumann reaction
The Schotten-Baumann reaction is a method to synthesise amides from amines and acid chlorides:Sometimes the name for this reaction is also used to indicate the reaction between an acid chloride and a alcohol to form an ester...

").

Similarly, with sulfonyl chlorides, one obtains sulfonamides
Sulfonamide (chemistry)
In chemistry, the sulfonamide functional group is -S2-NH2, a sulfonyl group connected to an amine group.A sulfonamide is a compound that contains this group. The general formula is RSO2NH2, where R is some organic group. For example, "methanesulfonamide" is CH3SO2NH2...

. This transformation, known as the Hinsberg reaction
Hinsberg reaction
The Hinsberg reaction is a chemical test for the detection of amines.It is an excellent test for distinguishing primary,secondary and tertiary amines.In this test, the amine is shaken well with Hinsberg reagent in the presence of aqueous alkali . A reagent containing an aqueous sodium hydroxide...

, is a chemical test for the presence of amines.

Because amines are basic, they neutralize acid
Acid
An acid is a substance which reacts with a base. Commonly, acids can be identified as tasting sour, reacting with metals such as calcium, and bases like sodium carbonate. Aqueous acids have a pH of less than 7, where an acid of lower pH is typically stronger, and turn blue litmus paper red...

s to form the corresponding ammonium salts R3NH+. When formed from carboxylic acids and primary and secondary amines, these salts thermally dehydrate to form the corresponding amide
Amide
In chemistry, an amide is an organic compound that contains the functional group consisting of a carbonyl group linked to a nitrogen atom . The term refers both to a class of compounds and a functional group within those compounds. The term amide also refers to deprotonated form of ammonia or an...

s.

Diazotization


Amines react with nitrous acid
Nitrous acid
Nitrous acid is a weak and monobasic acid known only in solution and in the form of nitrite salts.Nitrous acid is used to make diazides from amines; this occurs by nucleophilic attack of the amine onto the nitrite, reprotonation by the surrounding solvent, and double-elimination of water...

 to give diazonium salts. The alkyl diazonium salts are of little synthetic importance because they are too unstable. The most important members are derivatives of aromatic amines such as aniline
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...

 ("phenylamine") (Ar = aryl or naphthyl):
ArNH2 + HNO2 + HX → ArN2+X- + 2 H2O


Anilines and naphthylamines form more stable diazonium salts, which can be isolated in the crystalline form. Diazonium salts undergo a variety of useful transformations involving replacement of the N2 group with anions. For example, cuprous cyanide gives the corresponding nitriles:
ArN2+ + Y- → ArY + N2


Aryldiazonium couple with electron-rich aromatic compounds such as a phenol
Phenol
Phenol, also known as carbolic acid, phenic acid, is an organic compound with the chemical formula C6H5OH. It is a white crystalline solid. The molecule consists of a phenyl , bonded to a hydroxyl group. It is produced on a large scale as a precursor to many materials and useful compounds...

 to form azo compound
Azo compound
Azo compounds are compounds bearing the functional group R-N=N-R', in which R and R' can be either aryl or alkyl. IUPAC defines azo compounds as: "Derivatives of diazene , HN=NH, wherein both hydrogens are substituted by hydrocarbyl groups, e.g. PhN=NPh azobenzene or diphenyldiazene." The more...

s. Such reactions are widely applied to the production of dyes.

Conversion to imines


Imine formation
Alkylimino-de-oxo-bisubstitution
Alkylimino-de-oxo-bisubstitution in organic chemistry is the organic reaction of carbonyl compounds with amines to imines . The reaction name is based on the IUPAC Nomenclature for Transformations...

 is an important reaction. Primary amines react with ketone
Ketone
In organic chemistry, a ketone is an organic compound with the structure RCR', where R and R' can be a variety of atoms and groups of atoms. It features a carbonyl group bonded to two other carbon atoms. Many ketones are known and many are of great importance in industry and in biology...

s and aldehyde
Aldehyde
An aldehyde is an organic compound containing a formyl group. This functional group, with the structure R-CHO, consists of a carbonyl center bonded to hydrogen and an R group....

s to form imine
Imine
An imine is a functional group or chemical compound containing a carbon–nitrogen double bond, with the nitrogen attached to a hydrogen atom or an organic group. If this group is not a hydrogen atom, then the compound is known as a Schiff base...

s. In the case of formaldehyde
Formaldehyde
Formaldehyde is an organic compound with the formula CH2O. It is the simplest aldehyde, hence its systematic name methanal.Formaldehyde is a colorless gas with a characteristic pungent odor. It is an important precursor to many other chemical compounds, especially for polymers...

 (R' = H), these products typically exist as cyclic trimer
Trimer (chemistry)
In chemistry, a trimer is a product derived from three identical precursors. Trimers are typically cyclic. Chemical compounds that often trimerise are aliphatic isocyanates and cyanic acids. Often, trimerization competes with polymerization....

s.
RNH2 + R'2C=O → R'2C=NR + H2O

Reduction of these imines gives secondary amines:
R'2C=NR + H2 → R'2CH-NHR


Similarly, secondary amines react with ketones and aldehydes to form enamine
Enamine
An enamine is an unsaturated compound derived by the reaction of an aldehyde or ketone with a secondary amine followed by loss of H2O.The word "enamine" is derived from the affix en-, used as the suffix of alkene, and the root amine. This can be compared with enol, which is a functional group...

s:
R2NH + R'(R"CH2)C=O → R"CH=C(NR2)R' + H2O

Overview


An overview of the reactions of amine is given below:
Reaction name Reaction product | Comment
Amine alkylation
Amine alkylation
Amine alkylation is a type of organic reaction between an alkyl halide and ammonia or an amine. The reaction is called nucleophilic aliphatic substitution , and the reaction product is a higher substituted amine...

amines degree of substitution increases
Schotten-Baumann reaction
Schotten-Baumann reaction
The Schotten-Baumann reaction is a method to synthesise amides from amines and acid chlorides:Sometimes the name for this reaction is also used to indicate the reaction between an acid chloride and a alcohol to form an ester...

amides Reagents: acyl chlorides, acid anhydrides
Hinsberg reaction
Hinsberg reaction
The Hinsberg reaction is a chemical test for the detection of amines.It is an excellent test for distinguishing primary,secondary and tertiary amines.In this test, the amine is shaken well with Hinsberg reagent in the presence of aqueous alkali . A reagent containing an aqueous sodium hydroxide...

sulfonamides Reagents: sulfonyl chlorides
Amine-carbonyl condensation imines
Organic oxidation nitroso
Nitroso
Nitroso refers to a functional group in organic chemistry which has the general formula RNO. Nitroso compounds are a class of organic compounds containing the nitroso functional group, R−N=O....

 compounds
Reagent: peroxymonosulfuric acid
Peroxymonosulfuric acid
Peroxymonosulfuric acid, also known as persulfuric acid, peroxysulfuric acid, or as Caro's acid, is H2SO5, a liquid at room temperature. In this acid, the S center adopts its characteristic tetrahedral geometry; the connectivity is indicated by the formula HO-O-S2-OH...

Organic oxidation diazonium salt Reagent: nitrous acid
Nitrous acid
Nitrous acid is a weak and monobasic acid known only in solution and in the form of nitrite salts.Nitrous acid is used to make diazides from amines; this occurs by nucleophilic attack of the amine onto the nitrite, reprotonation by the surrounding solvent, and double-elimination of water...

Zincke reaction
Zincke reaction
The Zincke reaction is an organic reaction in which a pyridine is transformed into a pyridinium salt by reaction with 2,4-dinitro-chlorobenzene and a primary amine, named after Theodor Zincke....

Zincke aldehyde
Zincke aldehyde
Zincke aldehydes, or 5-aminopenta-2,4-dienals, are the product of the reaction of a pyridinium salt with two equivalents of any secondary amine, followed by basic hydrolysis...

reagent pyridinium salts, with primary and secondary amines
Emde degradation
Emde degradation
The Emde degradation is a method for the reduction of a quaternary ammonium cation to a tertiary amine with sodium amalgam...

tertiary amine reduction of quaternary ammonium cation
Quaternary ammonium cation
Quaternary ammonium cations, also known as quats, are positively charged polyatomic ions of the structure NR4+, R being an alkyl group or an aryl group. Unlike the ammonium ion and the primary, secondary, or tertiary ammonium cations, the quaternary ammonium cations are permanently charged,...

s
Hofmann-Martius rearrangement
Hofmann-Martius rearrangement
The Hofmann–Martius rearrangement in organic chemistry is a rearrangement reaction converting an N-alkylated aniline to the corresponding ortho and / or para aryl-alkylated aniline...

aryl substituted anilines
Aniline
Aniline, phenylamine or aminobenzene is an organic compound with the formula C6H5NH2. Consisting of a phenyl group attached to an amino group, aniline is the prototypical aromatic amine. Being a precursor to many industrial chemicals, its main use is in the manufacture of precursors to polyurethane...

Von Braun reaction
Von Braun reaction
The Von Braun reaction is an organic reaction in which a tertiary amine reacts with cyanogen bromide to an organocyanamide. An example is the reaction of dimethyl-α-naphthylamine :...

Organocyanamide By cleavage (tertiary amines only) with cyanogen bromide
Hofmann elimination
Hofmann elimination
Hofmann elimination is a process where an amine is reacted to create a tertiary amine and an alkene by treatment with excess methyl iodide followed by treatment with silver oxide, water, and heat.After the first step, a quaternary ammonium iodide salt is created...

Alkene
Alkene
In organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...

proceedss by β-elimination of less hindered carbon
Cope reaction
Cope reaction
The Cope reaction or Cope elimination, developed by Arthur C. Cope, is an elimination reaction of an amine oxide to form an alkene and a hydroxylamine. The reaction mechanism involves an intramolcular 5-membered cyclic transition state, leading to a syn elimination product...

Alkene
Alkene
In organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...

Similar to Hofmann elimination
Hofmann elimination
Hofmann elimination is a process where an amine is reacted to create a tertiary amine and an alkene by treatment with excess methyl iodide followed by treatment with silver oxide, water, and heat.After the first step, a quaternary ammonium iodide salt is created...

carbylamine reaction
Carbylamine reaction
The Carbylamine reaction is a chemical test for detection of primary amines. In this reaction, the analyte is heated with alcoholic potassium hydroxide and chloroform...

Isonitrile (primary amines only)
Hoffmann's mustard oil test Isothiocyanate
Isothiocyanate
Isothiocyanate is the chemical group –N=C=S, formed by substituting sulfur for oxygen in the isocyanate group. Many natural isothiocyanates from plants are produced by enzymatic conversion of metabolites called glucosinolates. These natural isothiocyanates, such as allyl isothiocyanate, are also...

CS2 and HgCl2 are used. Thiocyanate smells like mustard.

Biological activity


Amines are ubiquitous in biology. The breakdown of amino acid
Amino acid
Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

s releases amines, famously in the case of decaying fish which smell of trimethylamine
Trimethylamine
Trimethylamine is an organic compound with the formula N3. This colorless, hygroscopic, and flammable tertiary amine has a strong "fishy" odor in low concentrations and an ammonia-like odor at higher concentrations...

. Many neurotransmitter
Neurotransmitter
Neurotransmitters are endogenous chemicals that transmit signals from a neuron to a target cell across a synapse. Neurotransmitters are packaged into synaptic vesicles clustered beneath the membrane on the presynaptic side of a synapse, and are released into the synaptic cleft, where they bind to...

s are amines, including epinephrine
Epinephrine
Epinephrine is a hormone and a neurotransmitter. It increases heart rate, constricts blood vessels, dilates air passages and participates in the fight-or-flight response of the sympathetic nervous system. In chemical terms, adrenaline is one of a group of monoamines called the catecholamines...

, norepinephrine
Norepinephrine
Norepinephrine is the US name for noradrenaline , a catecholamine with multiple roles including as a hormone and a neurotransmitter...

, dopamine
Dopamine
Dopamine is a catecholamine neurotransmitter present in a wide variety of animals, including both vertebrates and invertebrates. In the brain, this substituted phenethylamine functions as a neurotransmitter, activating the five known types of dopamine receptors—D1, D2, D3, D4, and D5—and their...

, serotonin
Serotonin
Serotonin or 5-hydroxytryptamine is a monoamine neurotransmitter. Biochemically derived from tryptophan, serotonin is primarily found in the gastrointestinal tract, platelets, and in the central nervous system of animals including humans...

, and histamine
Histamine
Histamine is an organic nitrogen compound involved in local immune responses as well as regulating physiological function in the gut and acting as a neurotransmitter. Histamine triggers the inflammatory response. As part of an immune response to foreign pathogens, histamine is produced by...

. Protonated amino groups (-NH3+) are the most common positively charged moieties in protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

s, specifically in the amino acid lysine
Lysine
Lysine is an α-amino acid with the chemical formula HO2CCH4NH2. It is an essential amino acid, which means that the human body cannot synthesize it. Its codons are AAA and AAG....

. The anionic polymer DNA
DNA
Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 is typically bound to various amine-rich proteins. Additionally, the charged ammonium centers on lysine form salt bridges with carboxylate groups of other amino acids in polypeptides, which influences the three-dimensional structures of proteins.

Dyes


Primary aromatic amines are used as a starting material for the manufacture of azo dyes. It reacts with nitric(III) acid to form diazonium salt, which can undergo coupling reaction to form azo compound. As azo-compounds are highly coloured, they are widely used in dyeing industries, such as:
  • Methyl orange
    Methyl orange
    Methyl orange is a pH indicator frequently used in titrations.It is often used in titrations because of its clear and distinct colour change. Because it changes colour at the pH of a mid-strength acid, it is usually used in titrations for acids...

  • Direct brown 138
  • Sunset yellow FCF
  • Ponceau
    Ponceau
    Ponceau is the generic name for a family of azo dyes:*Ponceau 2R*Ponceau 4R*Ponceau 6R*Ponceau S*Ponceau SX...


Drugs


Many drugs are designed to mimic or to interfere with the action of natural amine neurotransmitters, exemplified by the amine drugs:
  • Chlorpheniramine is an antihistamine that helps to relieve allergic disorders due to cold, hay fever, itchy skin, insect bites and stings.
  • Chlorpromazine
    Chlorpromazine
    Chlorpromazine is a typical antipsychotic...

     is a tranquillizer that sedates without inducing sleep. It is used to relieve anxiety, excitement, restlessness or even mental disorder.
  • Ephedrine
    Ephedrine
    Ephedrine is a sympathomimetic amine commonly used as a stimulant, appetite suppressant, concentration aid, decongestant, and to treat hypotension associated with anaesthesia....

     and Phenylephrine
    Phenylephrine
    Phenylephrine is a selective α1-adrenergic receptor agonist used primarily as a decongestant, as an agent to dilate the pupil, and to increase blood pressure...

    , as amine hydrochlorides, are used as decongestants.
  • Amphetamine
    Amphetamine
    Amphetamine or amfetamine is a psychostimulant drug of the phenethylamine class which produces increased wakefulness and focus in association with decreased fatigue and appetite.Brand names of medications that contain, or metabolize into, amphetamine include Adderall, Dexedrine, Dextrostat,...

    , Methamphetamine
    Methamphetamine
    Methamphetamine is a psychostimulant of the phenethylamine and amphetamine class of psychoactive drugs...

    , and Methcathinone
    Methcathinone
    Methcathinone , is a psychoactive stimulant, sometimes used as a recreational drug and considered addictive. It is usually snorted, but can be smoked, injected, or taken orally...

     are psychostimulant amines that are listed as controlled substances by the US DEA.
  • Amitriptyline
    Amitriptyline
    Amitriptyline is a tricyclic antidepressant . It is the most widely used TCA and has at least equal efficacy against depression as the newer class of SSRIs...

    , Imipramine
    Imipramine
    Imipramine , also known as melipramine, is an antidepressant medication, a tricyclic antidepressant of the dibenzazepine group...

    , Lofepramine
    Lofepramine
    Lofepramine is a third Generation tricyclic antidepressant which was introduced in 1983 for the treatment of depressive disorders. It is partially converted to its active metabolite desipramine in vivo...

     and Clomipramine
    Clomipramine
    Clomipramine is a tricyclic antidepressant . It was developed in the 1960s by the Swiss drug manufacturer Geigy and has been in clinical use worldwide ever since.- Indications :...

     are tricyclic antidepressant
    Tricyclic antidepressant
    Tricyclic antidepressants are heterocyclic chemical compounds used primarily as antidepressants. The TCAs were first discovered in the early 1950s and were subsequently introduced later in the decade; they are named after their chemical structure, which contains three rings of atoms...

    s and tertiary amines.
  • Nortriptyline
    Nortriptyline
    Nortriptyline is a second-generation tricyclic antidepressant marketed as the hydrochloride salt under the trade names Sensoval, Aventyl, Pamelor, Norpress, Allegron, Noritren and Nortrilen. It is used in the treatment of major depression and childhood nocturnal enuresis...

    , Desipramine
    Desipramine
    Desipramine is a tricyclic antidepressant . It inhibits the reuptake of norepinephrine and to a lesser extent serotonin. It is used to treat depression, but not considered a first line treatment since the introduction of SSRI antidepressants...

    , and Amoxapine
    Amoxapine
    Amoxapine is a tetracyclic antidepressant of the dibenzoxazepine family, though it is often classified as a secondary amine tricyclic antidepressant.- Uses :...

     are tricyclic antidepressants and secondary amines. (The tricyclics are grouped by the nature of the final amine group on the side chain.)

Gas treatment


Aqueous monoethanolamine (MEA), diglycolamine (DGA), diethanolamine (DEA), diisopropanolamine (DIPA) and methyldiethanolamine (MDEA) are widely used industrially for removing carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

 (CO2) and hydrogen sulfide
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...

 (H2S) from natural gas and refinery process streams. They may also be used to remove CO2 from combustion gases / flue gases and may have potential for abatement of greenhouse gases. Related processes are known as sweetening
Amine gas treating
Amine gas treating, also known as gas sweetening and acid gas removal, refers to a group of processes that use aqueous solutions of various alkylamines to remove hydrogen sulfide and carbon dioxide from gases...

.

Safety


Low molecular weight amines are toxic, and some are easily absorbed through the skin. Many higher molecular weight amines are highly active biologically.

External links


See also



  • IUPAC nomenclature for the official naming rules for amines.
  • Biogenic amine
    Biogenic amine
    -Examples:Some prominent examples of biogenic amines include:* Histamine - a substance derived from the amino acid histidine that acts as a neurotransmitter mediating arousal and attention, as well as a pro-inflammatory signal released from mast cells in response to allergic reactions or tissue...

  • Imine
    Imine
    An imine is a functional group or chemical compound containing a carbon–nitrogen double bond, with the nitrogen attached to a hydrogen atom or an organic group. If this group is not a hydrogen atom, then the compound is known as a Schiff base...


  • Acid-base extraction
    Acid-base extraction
    Acid-base extraction is a procedure using sequential liquid–liquid extractions to purify acids and bases from mixtures based on their chemical properties....

  • Amine gas treating
    Amine gas treating
    Amine gas treating, also known as gas sweetening and acid gas removal, refers to a group of processes that use aqueous solutions of various alkylamines to remove hydrogen sulfide and carbon dioxide from gases...