Make sure you are familiar with the information from the lesson nomenclature of alkenes and alkynes.
When a compound contains functional groups, the name changes based on those groups and their priorities. The group with the highest priority of a compound determines the general name of the compound and any lower groups are added as a numbered prefix. Below is a priority list of functional groups for nomenclature, sorted from highest to lowest.
1 Carboxylic acids
Carboxylic acids contain a -COOH group and are denoted using the prefix carboxy- when there is a group with a higher priority available and the name will end in -oic acid when the carboxylic acid group has the highest priority. See for example methanoic acid, ethanoic acid, propanoic acid, butanoic acid etc. Carboxylic acids with two acidic groups also exist, such as ethanedioic acid, propanedioic acid, butanedioic acid, etc. Possible groups with a higher priority than carboxylic acids are beyond the scope of this course.
1.1 Peroxy acids
Peroxy acids (also known as peroxyacids or peracids) contain a -COOOH group and have the general name peroxy-x-oic acid when this group has the highest priority, otherwise the prefix hydroxyperoxycarbonyl- is used. An example is peroxyethanoic acid.
1.2 Sulfonic acids
Sulfonic acids contain a sulfonyl group with an acidic -OH and receive the name -sulfonic acid (analogous to carboxylic acids) when this group has the highest priority, otherwise the prefix sulfo- is used. An example is methanesulfonic acid.
2 Anhydrides
Anhydrides are created by condensation of two molecules of a carboxylic acid. They receive a name based on the carboxylic acid from which they are created, such as for example ethanoic anhydride.
3 Esters
Esters have a general structure of R-CO-O-R' where the R-CO-O- part determines the name of the ester (if the ester is the highest priority group) and receives the general name alkylalkanoate. See for example butyl propanoate. If the ester is a lower priority group, the name changes based on the position of the higher group relative to the ester bond. Compare for example ethanoyloxyethanoic acid to 3-methoxy-3-oxopropanoic acid. If the -oate has its own substituents, the group connected to the ester is added in front with a space (see methyl 3-oxopropanoate).
3.1 Sulfonate esters
Sulfonate esters are esters where the carbonyl group (C=O) is replaced by a sulfonyl group. They have a general name like alkyl alkanesulfonate, analogous to the esters. See for example butyl propanesulfonate.
3.2 Lactones
A cyclic carboxylic ester is also called a lactone. An example of a lactone is β-propiolactone.
4 Acid halides
The structure of acid halids is comparable to that of a carboxylic acid where the OH-group is replaced by a halide (F, Cl, Br or I). When it is the highest priority group the molecule will receive the general name alkanyl halide (for example propanoyl chloride). When there is a group present that has a higher priority the molecule's name will get a halocarbonyl- prefix, such as chlorocarbonyl-.
4.1 Sulfonyl chloride
The carbonyl group of an acid chloride can also be replaced by a sulfonyl group to create a sulfonyl chloride. The names of these molecules end with -sulfonyl chloride. See for example toluenesulfonyl chloride (more correctly named as 4-methylbenzene-1-sulfonyl chloride).
5 Amides
Amides are compounds analogous to esters, but containing a nitrogen atom. When the amide is the group with the highest priority the name of the compound will end with -amide. When there are substituents connected to the nitrogen atom they will be indicated using the format N-alkyl-. See for example N-ethyl-N-methylpropanamide. When there is a higher priority group present in the molecule, the name changes in a way analogous to esters. Compare for example 2-amino-2-oxoethyl ethanoate to ethanoylaminoethanoic acid. Sometimes the prefix carbamoyl- is used.
5.1 Sulfonamides
The carbonyl of amides can again be replaced by a sulfonyl to create a sulfonamide. In this case the name of the compound will end with -sulfonamide or it will receive the sulfonylamoyl- prefix. See for example ethanesulfonamide.
6 Nitrile
When a molecule contains a nitrile group (≡N) the name of the compound will end in -nitrile if this group has the highest priority. See for example ethanenitrile. If the nitrile group is not the highest priority it is indicated using the prefix cyano-. Note that in this last case the carbon of the nitrile group is not counted as being part of the longest chain.
7 Carbonyls
When a molecule contains a carbonyl (-C=O), but contains other groups with a higher priority the carbonyl will be indicated by adding an oxo- prefix to the compound name.
7.1 Aldehydes
When the carbonyl is at the end of the chain, the compound is considered an aldehyde and the name will end with -al. See for example ethanal.
7.2 Ketones
When the carbonyl is not at the end of the chain, the compound is considered a ketone and the name will end with -on. See for example propan-2-one.
8 Alcohols
The name of a compound that contains an OH group ends with -ol when this group has the highest priority, otherwise the name is prefixed with hydroxy-. See for example propan-2-ol.
8.1 Thiols
These compounds are analogous to alcohols, but contain a sulfur atom instead of the oxygen atom (-SH). The name of these compounds ends with -thiol or the prefix sulfanyl- is used. See for example propane-2-thiol. Older nomenclature sometimes uses the prefix mercapto-.
9 Amines
Amines contain a nitrogen atom and have a general name of alkylamine when the amine group has the highest priority, otherwise the prefix amino- is used. See for example ethylamine. Substituents of the nitrogen atom are indicated analogous to amides.
10 Never a main group
Functional groups in this list can never be the main group and are therefore always written in prefix form.
10.1 Ether
Ethers are linked to the main chain via an oxygen atom. Possible group names are methoxy-, ethoxy-, propoxy-, butoxy-, phenoxy- and more generally for more than four carbon atoms alkyloxy-. See for example 1-ethoxypentane. Ethers with two equal chains are sometimes named using the length of this chain, such as (di)ethylether (specifically ethylether is sometimes also just called "ether").
10.2 Sulfide
Sulfides are ether analogues with a sulfur atom instead of an oxygen atom. They receive a group name based on the length of the carbon chain, just like ethers: for example ethylsulfanylethane.
10.3 Sulfon
Analagous to ethers but with a sulfonyl group, see for example ethylsulfonylethane.
10.4 Sulfoxide
Analogous to a sulfongroup, but only has one oxygen atom doubly bonded. See for example ethylsulfinylethane.
10.5 Halogen
Halogen substituents (F, Cl, Br and I) are simply named and numbered, for example 1-iodopropane.
10.6 Miscellaneous
The following groups are also simply named and numbered: azido-, diazo-, nitro- and nitroso- (N3, N2, NO2 and NO).
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