Basic Organic Nomenclature

Alcohols

Suffix:    -ol

Prefix:    hydroxy-

Alcohols contain a R-OH functional group. The H atom attached to the O is weakly acidic and is responsible for hydrogen bonding making these compounds less volatile than the corresponding hydrocarbon. The H can be replaced by: another R' group to generate a ether (R-O-R'); or react with a carboxylic acid to produce an ester.

When a hydroxyl group is the highest priority functional group present in the molecule, it is names as an alkanol (note, the -e is dropped). The numbering scheme used will be the one that gives the hydroxyl group the lowest possible number. Other functional groups are located by this numbering scheme. When the -OH is the only functional group present the number locating it is place in front of the root name (i.e. 2-propanol). When other functional groups such as multiple bonds are present, the number locating the -OH is placed before the -ol (i.e. 4-penten-2-ol).

Examples naming simple alcohols:

Compound Name
Line Drawing
3D Model
methanol
ethanol
 propanol
2-propanol
cyclobutanol
1,2-ethanediol *

* note: the terminal -e is retained as the diol begins with a consonant.

Examples naming more complex alcohols:

Compound Name
Line Drawing
4,4-dimethyl-2-pentanol
4-penten-2-ol
 4-amino-3-isopropylhexanol
5-mercapto-2,4-cyclohexadienol*
*note: the 1 for the location of the hydroxyl group is not needed.

Alcohols as Substituents:

In more complex molecules with higher priority functional groups, the alcohol is named as a hydroxy- substituent. It is located by numbering the longest chain of carbons (according to the higher priority functional group) and locating the -OH group by this numbering scheme. Examples of these structures will be given in the subsequent pages.
 

Tutorial Quiz: Alcohols

Next Page: Ketones

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