Haloalkanes and haloarenes In haloalkanes and haloarenes (),
Halogen functional groups are prefixed with the bonding position and take the form of fluoro-, chloro-, bromo-, iodo-, or astato-, depending on the halogen. Multiple groups are dichloro-, trichloro-, etc., and dissimilar groups are ordered alphabetically as before. For example, (
chloroform) is trichloromethane. The anesthetic
halothane () is 2-bromo-2-chloro-1,1,1-trifluoroethane.
Alcohols Alcohols () take the suffix "
-ol" with a numerical suffix indicating the bonding position: is propan-1-ol. The suffixes , , , etc., are used for multiple groups:
Ethylene glycol is ethane-1,2-diol. If higher precedence functional groups are present (see
order of precedence, below), the prefix "hydroxy" is used with the bonding position: is 2-hydroxypropanoic acid.
Ethers Ethers () consist of an oxygen atom between the two attached carbon chains. The shorter of the two chains becomes the first part of the name with the -ane suffix changed to -oxy, and the longer alkane chain becomes the suffix of the name of the ether. Thus, is methoxymethane, and is
methoxyethane (
not ethoxymethane). If the oxygen is not attached to the end of the main alkane chain, then the whole shorter alkyl-plus-ether group is treated as a side-chain and prefixed with its bonding position on the main chain. Thus is 2-methoxypropane. Alternatively, an ether chain can be named as an alkane in which one carbon is replaced by an oxygen, a replacement denoted by the prefix "oxa". For example, could also be called 2-oxabutane, and an
epoxide could be called oxacyclopropane. This method is especially useful when both groups attached to the oxygen atom are complex.
Aldehydes Aldehydes () take the suffix "
-al". If other functional groups are present, the chain is numbered such that the aldehyde carbon is in the "1" position, unless functional groups of higher precedence are present. If a prefix form is required, "oxo-" is used (as for ketones), with the position number indicating the end of a chain: is 3-oxopropanoic acid. If the carbon in the carbonyl group cannot be included in the attached chain (for instance in the case of
cyclic aldehydes), the prefix "formyl-" or the suffix "-carbaldehyde" is used: is cyclohexanecarbaldehyde. If an aldehyde is attached to a benzene and is the main functional group, the suffix becomes benzaldehyde.
Ketones In general ketones () take the suffix "
-one" (pronounced
own, not
won) with a suffixed position number: is pentan-2-one. If a higher precedence suffix is in use, the prefix "oxo-" is used: is 3-oxohexanal.
Carboxylic acids In general, carboxylic acids () are named with the suffix
-oic acid (etymologically a
back-formation from
benzoic acid). As with aldehydes, the
carboxyl functional group must take the "1" position on the main chain and so the locant need not be stated. For example, (
lactic acid) is named 2-hydroxypropanoic acid with no "1" stated. Some traditional names for common carboxylic acids (such as
acetic acid) are in such widespread use that they are
retained in IUPAC nomenclature, though systematic names like ethanoic acid are also used. Carboxylic acids attached to a benzene ring are
structural analogs of benzoic acid () and are named as one of its derivatives. If there are multiple carboxyl groups on the same parent chain, multiplying prefixes are used:
Malonic acid, , is systematically named propanedioic acid. Alternatively, the suffix can be used in place of "oic acid", combined with a multiplying prefix if necessary –
mellitic acid is benzenehexacarboxylic acid, for example. In the latter case, the carbon atoms in the carboxyl groups do
not count as being part of the main chain, a rule that also applies to the prefix form "carboxy-".
Citric acid serves as an example: it is formally named rather than .
Carboxylates Salts of carboxylic acids are named following the usual
cation-then-
anion conventions used for
ionic compounds in both IUPAC and common nomenclature systems. The name of the carboxylate anion () is derived from that of the parent acid by replacing the "–oic acid" ending with "–oate" or "carboxylate." For example, , the sodium salt of
benzoic acid (), is called sodium benzoate. Where an acid has both a systematic and a common name (like , for example, which is known as both
acetic acid and as ethanoic acid), its salts can be named from either parent name. Thus, can be named as
potassium acetate or as potassium ethanoate. The prefix form, is "carboxylato-".
Esters Esters () are named as alkyl derivatives of carboxylic acids. The alkyl (R') group is named first. The part is then named as a separate word based on the carboxylic acid name, with the ending changed from "-oic acid" to "
-oate" or "-carboxylate" For example, is methyl pentanoate, and is ethyl 4-methylpentanoate. For esters such as
ethyl acetate (),
ethyl formate () or dimethyl phthalate that are based on common acids, IUPAC recommends use of these established names, called retained names. The "-oate" changes to "-ate." Some simple examples, named both ways, are shown in the figure above. If the alkyl group is not attached at the end of the chain, the bond position to the ester group is suffixed before "-yl": may be called butan-2-yl propanoate or butan-2-yl propionate.. The prefix form is "oxycarbonyl-" with the (R') group preceding.
Acyl groups Acyl groups are named by stripping the "-ic acid" of the corresponding carboxylic acid and replacing it with "-yl." For example, is called ethanoyl-R.
Acyl halides Simply add the name of the attached halide to the end of the acyl group. For example, is ethanoyl chloride. An alternate suffix is "-carbonyl halide" as opposed to "-oyl halide". The prefix form is "halocarbonyl-".
Acid anhydrides Acid anhydrides () have two acyl groups linked by an oxygen atom. If both acyl groups are the same, then the name of the carboxylic acid with the word acid is replaced with the word
anhydride and the IUPAC name consists of two words. If the acyl groups are different, then they are named in alphabetical order in the same way, with
anhydride replacing
acid and IUPAC name consists of three words. For example, is called
ethanoic anhydride and is called
ethanoic propanoic anhydride.
Amines Amines () are named for the attached alkane chain with the suffix "-amine" (e.g., methanamine). If necessary, the bonding position is suffixed: propan-1-amine, propan-2-amine. The prefix form is "amino-". For secondary amines (of the form ), the longest carbon chain attached to the nitrogen atom becomes the primary name of the amine; the other chain is prefixed as an alkyl group with location prefix given as an italic
N: is
N-methylethanamine. Tertiary amines () are treated similarly: is
N-ethyl-
N-methylpropanamine. Again, the substituent groups are ordered alphabetically.
Amides Amides () take the suffix "-amide", or "-carboxamide" if the carbon in the amide group cannot be included in the main chain. The prefix form is "carbamoyl-". e.g., methanamide, ethanamide. Amides that have additional substituents on the nitrogen are treated similarly to the case of amines: they are ordered alphabetically with the location prefix
N: is
N,
N-dimethylmethanamide, is
N,
N-dimethylethanamide.
Nitriles Nitriles () are named by adding the suffix "-nitrile" to the longest hydrocarbon chain (including the carbon of the cyano group). It can also be named by replacing the "-oic acid" of their corresponding carboxylic acids with "-carbonitrile." The prefix form is "cyano-." Functional class IUPAC nomenclature may also be used in the form of alkyl cyanides. For example, is called pentanenitrile or butyl cyanide.
Cyclic compounds Cycloalkanes and
aromatic compounds can be treated as the main parent chain of the compound, in which case the positions of substituents are numbered around the ring structure. For example, the three isomers of
xylene , commonly the
ortho-,
meta-, and
para- forms, are 1,2-dimethylbenzene, 1,3-dimethylbenzene, and 1,4-dimethylbenzene. The cyclic structures can also be treated as functional groups themselves, in which case they take the prefix "cyclo
alkyl-" (e.g. "cyclohexyl-") or for benzene, "phenyl-". The IUPAC nomenclature scheme becomes rapidly more elaborate for more complex cyclic structures, with notation for compounds containing conjoined rings, and many common names such as
phenol being accepted as base names for compounds derived from them. ==Order of precedence of group==