24.1 Naming Amines
2 min read•may 7, 2024
Amines are organic compounds with a nitrogen atom bonded to carbon atoms. They're classified as primary, secondary, or tertiary based on the number of organic groups attached to the nitrogen. This classification impacts their properties and reactivity.
Naming amines follows specific rules. For simple amines, we add "-amine" to the parent alkane name. More complex amines use prefixes like "N-" for substituents on nitrogen. Heterocyclic amines have their own naming conventions based on ring structure.
Amine Classification and Nomenclature
Types of amines by substituents
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- Amines classified based on number of organic substituents (alkyl or aryl groups) attached to nitrogen atom
- Primary (1°) amines have one organic substituent attached to nitrogen atom
- General formula R-NH₂ (R = alkyl or ) (, )
- Secondary (2°) amines have two organic substituents attached to nitrogen atom
- General formula R₁-NH-R₂ (R₁ and R₂ = alkyl or aryl groups) (, )
- Tertiary (3°) amines have three organic substituents attached to nitrogen atom
- General formula R₁-NR₂-R₃ (R₁, R₂, and R₃ = alkyl or aryl groups) (, )
- Primary (1°) amines have one organic substituent attached to nitrogen atom
IUPAC nomenclature for amines
- Alkylamines named by adding "-amine" suffix to parent alkane name
- For primary amines, replace -e ending of alkane with -amine (ethylamine, propylamine)
- For secondary and tertiary amines, name alkyl substituents as N-alkyl groups (, )
- Arylamines named as derivatives of aniline ()
- Indicate substituents on benzene ring by position relative to amino group (, )
- Amines with multiple functional groups named according to order of precedence
- Amino group takes precedence over alkyl halides and alcohols but not carboxylic acids, esters, or nitriles
- Examples: (amino alcohol), (amino carboxylic acid)
- for naming amines prioritize the longest carbon chain containing the amino group
- : The amino group (-NH2) has higher priority than alkyl groups when determining the parent chain
Structure of heterocyclic amines
- Heterocyclic amines are cyclic compounds containing one or more nitrogen atoms as part of ring
- Common heterocyclic amines and numbering conventions:
- : five-membered ring with one nitrogen atom, numbered starting from nitrogen ()
- : six-membered ring with one nitrogen atom, numbered starting from nitrogen ()
- : saturated six-membered ring with one nitrogen atom, numbered starting from nitrogen ()
- : saturated five-membered ring with one nitrogen atom, numbered starting from nitrogen ()
- Fused heterocyclic amines named using parent heterocycle followed by fused ring system
- Example: (fused benzene and pyridine ring system)
Additional Naming Considerations
- : Some amines have widely used common names that differ from their IUPAC names (e.g., trimethylamine, putrescine)
- : When an amino group is not the principal functional group, it is named as an "amino-" prefix in the compound's name
- For complex amines, the substituents are listed alphabetically, ignoring prefixes like "di-" or "tri-"
Key Terms to Review (39)
-amine Suffix: The -amine suffix is a functional group in organic chemistry that denotes the presence of a nitrogen atom with one or more alkyl or aryl substituents. This suffix is used in the systematic naming of organic compounds containing the amine functional group.
2-aminoethanol: 2-aminoethanol, also known as ethanolamine, is an organic compound consisting of an ethanol group (CH2CH2OH) and an amino group (NH2). It is a colorless, viscous liquid with a slight ammonia-like odor and is widely used in the production of various chemicals and pharmaceuticals.
2-ethylpyrrolidine: 2-ethylpyrrolidine is a cyclic amine compound with an ethyl group attached to the second carbon of the pyrrolidine ring. It is a structural isomer of other ethylpyrrolidine compounds and is relevant in the context of naming amines.
2-methylpyrrole: 2-methylpyrrole is a heterocyclic aromatic organic compound consisting of a five-membered ring with one nitrogen atom and a methyl group attached to the 2-position of the ring. It is an important structural unit in various natural and synthetic compounds.
2,6-dimethylaniline: 2,6-dimethylaniline is an organic compound with the chemical formula C₆H₇N. It is a derivative of aniline, with two methyl groups attached to the benzene ring at the 2 and 6 positions. This structural feature makes 2,6-dimethylaniline an important compound in the context of naming amines.
3-ethylpyridine: 3-ethylpyridine is a heterocyclic organic compound consisting of a benzene ring fused with a nitrogen-containing pyridine ring. It is a derivative of pyridine with an ethyl group substituted at the 3-position of the pyridine ring. This compound is relevant in the context of the topic 24.1 Naming Amines, as it represents a specific type of amine with a nitrogen-containing heterocyclic structure.
4-aminobenzoic acid: 4-aminobenzoic acid, also known as PABA, is an organic compound that consists of a benzene ring with a carboxyl group and an amino group attached at the 4-position. It is an important precursor in the synthesis of various pharmaceuticals and is also found naturally in some foods.
4-chloroaniline: 4-chloroaniline is an organic compound with the chemical formula C6H6ClN. It is a derivative of aniline, where a chlorine atom is substituted at the 4-position on the benzene ring. This compound is an important intermediate in the synthesis of various dyes, pharmaceuticals, and other chemicals.
Alkyl Substituent: An alkyl substituent is a hydrocarbon group, derived from an alkane, that replaces one or more hydrogen atoms in a molecule. These substituents are commonly found in organic compounds and play a crucial role in determining the properties and reactivity of the molecule.
Aminobenzene: Aminobenzene, also known as aniline, is an organic compound consisting of a benzene ring with an amino group (NH2) attached. It is an important precursor in the synthesis of various dyes, pharmaceuticals, and other chemicals.
Aniline: Aniline is an aromatic organic compound with the chemical formula C6H5NH2. It is a colorless, oily liquid with a distinctive, unpleasant odor. Aniline is an important precursor in the synthesis of various dyes, pharmaceuticals, and other organic compounds, and it plays a significant role in the context of naming aromatic compounds, amines, and understanding their basicity.
Aryl Group: An aryl group is a functional group in organic chemistry that consists of an aromatic ring, typically a benzene ring, bonded to another atom or group. Aryl groups are important in the context of naming amines as they can be part of the substituent attached to the nitrogen atom.
Common Names: Common names, also known as trivial names or popular names, are informal designations used to identify chemical compounds that are more easily recognizable than their formal systematic names. These simplified names are widely used in everyday conversations and literature, providing a more accessible way to refer to various organic compounds, including aldehydes, ketones, carboxylic acids, nitriles, and amines.
Dimethylamine: Dimethylamine is a colorless, flammable gas with a fishy, ammonia-like odor. It is an organic compound with the chemical formula (CH3)2NH, consisting of two methyl groups (CH3) bonded to a central nitrogen atom.
Heterocyclic Amine: A heterocyclic amine is an organic compound containing a heterocyclic ring structure with at least one nitrogen atom within the ring. These compounds are particularly relevant in the context of 24.1 Naming Amines, as they represent a unique class of amine derivatives with distinct structural and reactivity properties.
IUPAC Rules: IUPAC rules are a standardized set of guidelines established by the International Union of Pure and Applied Chemistry (IUPAC) for the systematic naming and identification of organic compounds. These rules provide a consistent and unambiguous way to name molecules, which is essential for clear communication in the field of organic chemistry.
Methylamine: Methylamine is a simple organic compound consisting of a methyl group (CH3) bonded to an amino group (NH2). It is a primary amine that serves as an important building block in organic chemistry and has various applications in industry and research.
N-alkyl Group: An N-alkyl group is a substituent in organic chemistry where an alkyl group (such as methyl, ethyl, or propyl) is bonded to a nitrogen atom. These groups are commonly found in amine compounds and play a crucial role in their naming and properties.
N-methylaniline: N-methylaniline is an organic compound consisting of a benzene ring with an amino group (NH2) and a methyl group (CH3) attached. It is a derivative of aniline, where the hydrogen atom on the amino group has been replaced by a methyl group.
N-methylpiperidine: N-methylpiperidine is a cyclic secondary amine compound with a methyl group attached to the nitrogen atom. It is an important structural component in various organic compounds and has applications in the synthesis of pharmaceuticals and other chemical products.
N-methylpropylamine: N-methylpropylamine is an organic compound with the chemical formula CH3NH(CH2)2CH3. It is a primary amine, meaning it has a nitrogen atom with one hydrogen and two alkyl groups attached. The 'N-methyl' prefix indicates that one of the alkyl groups is a methyl (CH3) group.
N,N-dimethylaniline: N,N-dimethylaniline is an organic compound with the formula C6H5N(CH3)2. It is a derivative of aniline, where the two hydrogen atoms attached to the nitrogen atom are replaced by methyl (CH3) groups. This compound is important in the context of understanding the naming and classification of amines.
N,N-dimethylbutylamine: N,N-dimethylbutylamine is a type of amine compound with a butyl group and two methyl groups attached to the nitrogen atom. Amines are organic compounds derived from ammonia, and they play important roles in various chemical and biological processes.
Nomenclature Priority: Nomenclature priority refers to the set of rules used to determine the most important functional groups or substituents when naming organic compounds. It is a crucial concept in the systematic naming of molecules, particularly in the context of amines.
Piperidine: Piperidine is a heterocyclic organic compound consisting of a six-membered ring with five carbon atoms and one nitrogen atom. It is a common structural motif found in many natural and synthetic compounds, and its unique properties make it an important building block in organic chemistry, particularly in the context of naming amines, peptide synthesis, and automated peptide synthesis.
Primary Amine: A primary amine is a nitrogen-containing organic compound where the nitrogen atom is bonded to one alkyl or aryl group and two hydrogen atoms. These amines are important functional groups that participate in various organic reactions.
Primary amine (RNH2): A primary amine is an organic compound that contains a nitrogen atom attached to one alkyl or aryl group and two hydrogen atoms. It represents the simplest class of amines in organic chemistry.
Pyridine: Pyridine is a heterocyclic aromatic organic compound with the chemical formula C₅H₅N. It is a colorless, volatile liquid with a distinctive unpleasant odor, and it is widely used in the production of various chemicals and pharmaceuticals.
Pyrrole: Pyrrole is a heterocyclic aromatic organic compound consisting of a five-membered ring with four carbon atoms and one nitrogen atom. It is an important structural unit in many natural and synthetic compounds, including key biological molecules and pharmaceuticals.
Pyrrolidine: Pyrrolidine is a heterocyclic organic compound consisting of a five-membered ring containing four carbon atoms and one nitrogen atom. It is a key structural component in various organic reactions and compounds, particularly in the context of carbonyl condensations with enamines and the naming of amines.
Quaternary ammonium salt: A quaternary ammonium salt is an organic compound where a nitrogen atom is bonded to four alkyl or aryl groups and one anion, typically a halide. These compounds are often used as disinfectants, surfactants, and fabric softeners due to their ability to disrupt microbial cell membranes.
Quinoline: Quinoline is a heterocyclic aromatic compound consisting of a benzene ring fused to a pyridine ring. It is an important structural motif found in various natural and synthetic compounds, with applications in organic chemistry, medicinal chemistry, and materials science.
Secondary (R2NH): In organic chemistry, a secondary amine is an amine where the nitrogen atom is bonded to two alkyl or aryl groups and one hydrogen atom. It represents a class of amines that play significant roles in the synthesis of pharmaceuticals, dyes, and polymers.
Secondary Amine: A secondary amine is a type of amine functional group in organic chemistry where a nitrogen atom is bonded to two alkyl or aryl substituents. This is in contrast to primary amines, which have one substituent, and tertiary amines, which have three substituents. Secondary amines are important intermediates in the formation of imines and enamines.
Secondary amine (R2NH): A secondary amine is an organic compound where a nitrogen atom is bonded to two alkyl or aryl groups and one hydrogen atom. It is characterized by the formula R2NH, where R represents the alkyl or aryl groups.
Substituent Prefixes: Substituent prefixes are a set of standardized prefixes used in organic chemistry to denote the presence and position of substituent groups attached to a parent hydrocarbon or other organic compound. These prefixes are an essential component of the IUPAC nomenclature system, which is the standard for naming organic molecules.
Tertiary (R3N): In organic chemistry, a tertiary amine is an amine where the nitrogen atom is connected to three alkyl or aryl groups. This structure significantly affects the chemical reactivity and properties of the amine.
Tertiary Amine: A tertiary amine is a type of organic compound where a nitrogen atom is bonded to three alkyl or aryl groups. These nitrogen-containing functional groups are an important class of organic molecules with diverse applications in chemistry and biology.
Trimethylamine: Trimethylamine is a colorless, flammable gas with a strong, fishy odor. It is an organic compound that belongs to the class of amines, which are derivatives of ammonia with alkyl or aryl groups substituted for the hydrogen atoms.