Amine (organic)
An amine is an organic compound derived from ammonia (NH₃) by replacing one or more hydrogen atoms with organic substituents such as alkyl or aryl groups. Amines are classified as primary (RNH₂), secondary (R₂NH), or tertiary (R₃N) depending on the number of carbon-containing substituents attached to nitrogen. They are fundamental in biochemistry — amino acids, proteins, DNA bases, and many pharmaceutical drugs contain amine functional groups.
Classification of Amines by Substitution
| Type | General Formula | Example | Example Name | Basicity (pKa of conjugate acid) |
|---|---|---|---|---|
| Primary | RNH₂ | CH₃NH₂ | Methylamine | 10.6 |
| Secondary | R₂NH | (CH₃)₂NH | Dimethylamine | 10.7 |
| Tertiary | R₃N | (CH₃)₃N | Trimethylamine | 9.8 |
| Aromatic (primary) | ArNH₂ | C₆H₅NH₂ | Aniline | 4.6 |
| Quaternary ammonium | R₄N⁺ | (CH₃)₄N⁺ | Tetramethylammonium | N/A (always cationic) |
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Related Terms
Aldehyde
An aldehyde is an organic compound containing a carbonyl group (C=O) in which the carbon atom is bonded to at least one hydrogen atom, giving the characteristic –CHO functional group at the end of a carbon chain. Aldehydes are more reactive than ketones because the carbonyl carbon is less sterically hindered and more electrophilic. They are important industrial chemicals — formaldehyde is used in resins, acetaldehyde in vinegar production, and benzaldehyde gives almonds their characteristic scent.
Nucleophile
A nucleophile is a chemical species that donates an electron pair to an electrophile to form a new covalent bond, acting as a Lewis base. Nucleophiles are characterised by the presence of a lone pair of electrons, a negative charge, or a region of high electron density that attacks electron-deficient centres (electrophilic carbons). Strong nucleophiles drive SN2 reactions and nucleophilic addition; weaker nucleophiles favour SN1 pathways — making nucleophilicity a key parameter in predicting organic reaction outcomes.
Chirality
Chirality (from Greek "cheir", hand) is the geometric property of a molecule that makes it non-superimposable on its mirror image, analogous to left and right hands. A chiral molecule lacks any plane, axis, or centre of symmetry; the most common source is a tetrahedral carbon (chiral centre) bonded to four different substituents. Chirality is of enormous biological importance — enzymes, receptors, and drugs are chiral, so enantiomers often exhibit completely different pharmacological activities, which is why modern drug development rigorously controls stereochemistry.
From German "Amin", coined in the 19th century as a contraction of "ammonia" — itself derived from Latin "sal ammoniacus" (salt of Ammon), referring to ammonium chloride deposits near the Temple of Amun in Egypt. The "-ine" suffix denotes a nitrogen-containing compound.