organic nomenclature and structure

IUPAC Alkane, Alkene, Alkyne, Alcohol and Acid Names

Carbon Alkane; Alkene; Alkyne Alcohol Acid Carbon Alkane

1 Methane Methanol Methanoic 11 Undecane

2 Ethane; Ethene Ethanol Ethanoic 12 Dodecane

3 Propane; Propene; Propyne Propanol Propanoic 13 Tridecane

4 Butane; Butene; Butyne Butanol Butanoic 14 Tetradecane

5 Pentane; Pentene; Pentyne Pentanol Pentanoic 15 Pentadecane

6 Hexane; Hexene; Hexyne Hexanol Hexanoic 16 Hexadecane

7 Heptane; Heptene; Heptyne Heptanol Heptanoic 17 Heptadecane

8 Octane; Octene; Octyne Octanol Octanoic 18 Octadecane

9 Nonane; Nonene; Nonyne Nonanol Nonanoic 19 Nonadecane

10 Decane; Decene; Decyne Decanol Decanoic 20 IcosaneAlkane, alkene, alkyne, alcohol and acid names are given, up through molecules having 10 carbons. For hydrocarbons containing 11-20 carbons, only the alkane names are shown, but naming follows the same rules as for hydrocarbons or functional group names for molecules having fewer numbers of carbons.

Some Commonly Encountered Alkyl and Aryl Groups

Group Name Group Name

CH3 — Methyl CH3CH2 — Ethyl

CH3CH2CH2 — Propyl or n-propyl (CH3)2CH — 1-Methylethyl or isopropyl

CH3CH2CH2CH2 — Butyl or n-butyl |CH3CH2CH2CH3

1-Methylpropyl or sec-butyl

(CH3)3C — 1,1-Dimethylethyl or tert-butyl (CH3)2CHCH2 — 2-Methylpropyl or isobutyl

(CH3)3CCH2 — 2,2-Dimethylpropyl or neopentyl CH2=CH — Ethenyl or vinyl

CH2=CHCH2 — 2-Propenyl or allyl |CH2=CCH3

1-Methylvinyl or isopropenyl

|CH3C=O

Ethanoyl or acetyl (derived from a carboxylic acid)

Phenyl (C6H5 — )

Phenylmethyl or benzyl(C6H5-CH2 — )

Benzenecarbonyl or benzoyl(C6H5-CO — )

The groups shown above, are commonly encountered in organic compounds. You should be familiar with all of these groups, since compounds we encounter often contain them. Group names are systematic, but learning the rules for these group names takes some time.

Commonly Encountered Aromatic Compounds

Structure Name Structure Name

Benzene Toluene

Phenol Aniline

Benzoic acid Benzaldehyde

AnisoleMethyl phenyl ether

o-Xylene

For compounds containing more than one group attached to the benzene ring, compounds are named using the parent molecule (e.g., aniline, toluene, phenol, etc.) as the root name, and the other attached group relative to the parent. For benzene derivatives, the prefixes, ortho (o), meta (m), and para (p) are used, instead of 1,2 or 1,3 or 1,4 attachment positions, respectively. As an example, 1,2-xylene is o-xylene (shown above), 1,3-xylene is m-xylene, and 1,4-xylene is p-xylene. Likewise, 1,2-nitrotoluene is o-nitrotoluene, 1,3-nitrotoluene is m-nitrotoluene, and 1,4-nitrotoluene is p-nitrotoluene.

Alcohols

Structure Common Name IUPAC name

Ethyl alcohol Ethanol

Butyl alcohol Butanol

propylene glycol 1,2-propanediol

2-pentenyl alcohol 2-penten-1-ol

Benzyl alcohol(Phenyl methanol)

(not an aromatic alcohol)Benzenol

phenol(an aromatic alcohol)

phenolhydroxybenzene

All alcohols, aromatic and alkyl, contain the hydroxyl (—OH) group. Common names include the name alcohol and the alkyl group attached. For example, a 4-carbon straight-chain alcohol is named butyl alcohol. IUPAC names include the carbon number prefix attached to the -ol suffix (e.g., a 4-carbon alcohol begins Butan- followed by the -ol suffix to give Butanol preceeded by the lowest carbon number to position the —OH group, such as 1-butanol when the —OH is on the #1 carbon.). Multiple —OH groups are named as diols, triols, etc. Common names, if availabe simply name the alkyl or aryl group followed by alcohol.

Ethers


CH3CH2-O-CH2CH3 Diethyl ether Ethoxyethane

Ethyl phenyl ether Ethoxybenzene

Diphenyl ether Phenoxybenzene

All ethers, whether aromatic and alkyl, contain an oxygen bonded to two carbons (C—O—C). Common names include the names for each alkyl or aryl group, followed by ether (e.g., ethyl methyl ether or methyl phenyl ether). IUPAC naming uses the longest carbon chain as the root name, preceded by the attached group (e.g., methoxy, ethoxy,

Aldehydes


acetaldehyde Ethanal

Butyraldehyde Butanal

Benzaldehyde Benzene carbaldehyde

Aldehydes are carbonyl containing compounds with at least one —H attached to the carbonyl carbon. Common names include the suffix -aldehyde added onto the common name of the acid (after removal of the -ic suffix). For example, a 4-carbon aldehyde is butyraldehyde (butyric acid plus aldehyde) and a 2-carbon aldehyde is acetaldehyde (acetic acid plus aldehyde). IUPAC names include the carbon number prefix attached to the -al suffix (e.g., a 4-carbon aldehyde begins Butan- followed by the -al suffix to give Butanal. The name benzaldehyde is derived from benzoic acid and aldehyde.

Ketones


acetone (dimethyl ketone) Propanone

Ethyl methyl ketone 2-Butanone

Methyl phenyl ketone Acetophenone

Ketones are carbonyl containing compounds with two carbons attached to the carbonyl carbon. Common names include the suffix name of ketone, preceded by the names of the alkyl or aryl groups. For example, a 3-carbon ketone has the common name of dimethyl ketone or acetone, which is more commonly used (note that even the common name ends in -one, which designates a ketone). A 4-carbon ketone would be ethyl methyl ketone. IUPAC names include the carbon number prefix attached to the -one suffix (e.g., a 4-carbon ketone begins Butan- followed by the -one suffix to give Butanone (usually you need to specific which carbon the carbonyl carbon is, but for butanone, it is not necessary since only one butanone can exisit) . Aromatic ketones include the -phenone suffix, as for the acetophenone shown above.

Carboxylic Acids


Acetic acidanion: Acetate

Ethanoic acidanion: Ethanoate

Benzoic acidanion: Benzoate

Benzene carboxylic acidanion: Benzene carboxylate

Butyric acidanion: Butyrate

Butanoic acidanion: Butanoate

All organic acids have the carboxylic acid group. Acid names end in the -ic suffix. Common names are often used. IUPAC names include the appropriate prefix based for the number of carbon atoms (e.g., a 2-carbon acid begins with Ethan which is the alkane part of the molecule), followed by the -oic suffix (for organic acid). To name the anion of the acid, drop the -ic suffix (but do not drop the "o") and add the-ate suffix. For example, acetic acid becomes the acetate ion, and ethanoic acid becomes the ethanoate ion.

Esters


Ethyl acetate Ethyl ethanoate

Methyl benzoate Methyl benzoate

Isopropyl butyrate Isopropyl butanoate

Esters are combinations of acids and alcohols. To name esters, the first word in the name of the ester is the alcohol alkyl name (methyl from methyl alcohol [methanol]; isopropyl from isopropyl alcohol [2-propanol]). The second word in the name of an ester is derived from the anion of the acid (acetate from acetic acid; ethanoate from ethanoic acid). For example, an ester derived from ethanol (ethyl alcohol) and acetic acid (acetate anion) is Ethyl acetate.

Amines


CH3CH2-NH2 Aminoethane (1o amine)ethanamineethylamine

CH3CH2-NH-CH2CH3 Diethyl amine (2o amine) N-ethyl ethanamine

Aniline (aromatic amine) Aminobenzene

Amines are named either as substitutive amines, or as a functional group.

organic nomenclature and structure

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