Suffixes naming carboxylic acids

Amides. For primary amides the suffix -amide is added to the systematic name of the parent acid. For example, CH3—CO—NHj is acetamide. Oxamide is retained for HjN—CO—CO—NHj. The name -carboxylic acid is replaced by -carboxamide. 

Table 21.1 lists the suffixes for naming carboxylic acid derivatives. The suffixes used... 

In the lUPAC system of naming carboxylic acids, the parent compound name is formed by dropping the alkane suffix "e and adding the suffix "oic" followed by the word "acid." Since the carboxyl group always comes at the end of the chain, it is automatically assigned the number 1, and this number is omitted from the name. For example. 

The lUPAC nomenclature is based on the longest continuous chain (alkane, alkene, or alkyne based) that contains the carboxyl carbon (the -COOH unit). As with aldehydes, the carbon of the COOH group is always at one terminus of the chain and must receive the lowest possible number (1), which is omitted from the name. The suffix for carboxylic acids is oic acid, with the word acid separated from the first part of the name. As with aldehydes and ketones, the carboxyl unit is higher in priority than an alkene or alkyne. Compound 38 is an eight-carbon acid with an alkane backbone, so it is octanoic acid (note the short notation for the carboxyl group). Substituents are numbered relative to the carbonyl carbon of the COOH unit, so 39 is 2,2-dimethyl-5-phenyloctanoic acid. In a similar manner, 40 is named 16-chloro-4-ethylheptadecanoic acid. 

As when we name carboxylic acids, the carbon atom of the amide group is counted when assessing the longest unbranched chain present, and as such is counted as the first in the chain. Thus amides are named after the longest carbon chain, followed by the suffix -amide. Figure 10.34 shows the structures of ethanamide (see also Figure 10.35 overleaf) and 2 methylpropanamide. 

In carboxyUc acids, the combination of C=0 plus an -OH on the carbon atom gives a carboxyl group, often represented -COOH. The O-H bond in the carboxyl group is weaker than the O-H bond in either C-H (as in a hydrocarbon) or O-H (as in an alcohol), so solutions compounds containing a carboxyl-group are acidic, hence the name carboxylic acid. The name of a carboxyhc acid ends in the suffix ic (or oic) and the word acid. 

In this chapter, we will be discussing the chemistry of carboxylic acids, esters, acyl halides, anhydrides, and amides. This is dominated by substitution, where one group is exchanged with another. Substitution is NOT possible for aldehydes and ketones, as you can t displace H or — they are hopeless leaving groups. First, let s review some nomenclature. The suffix for carboxylic acids is -oic acid and the carbonyl of the acid is always numbered as C-1. The acid takes precedence over most other functional groups. Some examples are shown in Figure 15.1. Notice that when we have both a ketone and an acid in the molecule, it is named as a carboxylic acid, and the ketone is described as oxo. ... 

When a carboxyl group is attached to a ring the parent ring is named (retaining the final e) and the suffix carboxylic acid is added as shown m entries 8 and 9... 

The names of amides of the type RCNH2 are derived from carboxylic acids by replacing the suffix oic acid or ic acid by amide... 

Substitutive lUPAC names for nitriles add the suffix nitrile fo fhe name of fhe parenf hydrocarbon chain fhaf includes fhe carbon of fhe cyano group Nifriles may also be named by replacing the ic acid or oic acid ending of the corresponding carboxylic acid with omtrile Alternatively they are sometimes given functional class lUPAC names as alkyl cyanides... 

The common method of naming aldehydes corresponds very closely to that of the related acids (see Carboxylic acids), in that the term aldehyde is added to the base name of the acid. For example, formaldehyde (qv) comes from formic acid, acetaldehyde (qv) from acetic acid, and butyraldehyde (qv) from butyric acid. If the compound contains more than two aldehyde groups, or is cycHc, the name is formed using carbaldehyde to indicate the functionaUty. The lUPAC system of aldehyde nomenclature drops the final e from the name of the parent acycHc hydrocarbon and adds al If two aldehyde functional groups are present, the suffix -dialis used. The prefix formjlis used with polyfunctional compounds. Examples of nomenclature types are shown in Table 1. 

Compounds containing the -C=N functional group are called nitriles and undergo some chemistry similar to that of carboxylic acids. Simple open-chain nitriles are named by adding -nitrile as a suffix to the alkane name, with the nitrile carbon numbered Cl. 

Carboxylic acids are named systematically by replacing the -e of the parent hydrocarbon by the suffix -oic acid the carbon atom of the carboxyl group is included in the count of atoms to determine the parent hydrocarbon molecule. Thus, formic acid is formally methanoic acid, and acetic acid is ethanoic acid. 

The second compound above raises an important issue how do you name the functional group when you have two functional groups in a compound One will go in the suffix of the name and the other will be a prefix in the substituent part of the name. But how do we choose which one goes as the suffix of the name There is a hierarchy that needs to be followed. The six groups shown above are listed according to their hierarchy, so a carboxylic acid takes precedence over an alcohol. A compound with both of these groups is named as a ketone and we put the term hydroxy in the substituent part of the name. 

Since carboxylic acids are amongst the earliest organic compounds to be isolated from nature, a large number of them are known by their common names. The common names end with the suffix -ic acid and have been derived from Latin or Greek names of their natural sources. For example, formic acid (HCOOH) was first obtained from red ants (Latin formica means ant), acetic acid (CH C OOH) from vinegar (Latin acetum, means vinegar), but n ic acid (CH3CH2CH2COOH) from rancid butter (Latin butyrum, means butter). 

The suffixes -oic acid, -al, -amide and -nitrile are used to name acyclic compounds having one or two characteristic groups. Locants are not necessary, as these groups must be at the end of a chain. The suffixes -carboxylic acid, -carbaldehyde, -carboxamide and -carbonitrile are used when more than two groups are attached to chains or one or more groups are attached to cycles. 

Common names replace the suffix -ic (-oic or -oxylic) and the word acid of the corresponding carboxylic acids by -aldehyde. Locations of substituents on chains are designated by Greek letters ... 

Symmetrical acid anhydrides are named by replacing the -acid suffix of the parent carboxylic acids with the word anhydride. Mixed anhydrides that consist of two different acid-derived parts are named using the names of the two individual acids with an alphabetical order. 

For salts of carboxylic acids, the -oic suffix of the acid becomes -oate with the counter ion named as a separate word ... 

A common system of naming nitriles takes the name of the corresponding carboxylic acid and changes the suffix -oic to -onitrile ... 

Another important class of organic compounds that we shall meet frequently, even in the early chapters of the text, are the carboxylic acids. These compounds are characterized by the carboxyl group, — COOH (7). As their names suggest, these compounds are acids. The most common example is acetic acid, CH3COOH (8 formally, ethanoic acid), the acid that gives vinegar its sharp taste. Another simple carboxylic acid is formic acid, HCOOH (9 formally, methanoic acid), the acid of ant venom. Note how the systematic (formal) names of the carboxylic acids are derived from the parent hydrocarbons (ethane and methane, respectively) by adding -anoic acid as a suffix to the stems eth- and meth-. 

Carboxylic adds where the R group is an alkyl group are called aliphatic acids. Tire salts of carboxylic adds are named with the suffix -ate. The -ate replaces the -ic (or -oic in lUPAC names), so that "acetic" becomes "acetate". (Acetate is sometimes abbreviated -OAc.) In IUPAC rules, the carbonyl carbon of a carboxylic acid takes priority over all groups discussed so far. 

One important reaction of carboxylic acids is their ability to act as acids. Carboxylic acids are medium-strong acids, with pKa values typically between 4 and 5. The conjugate bases of carboxylic acids are named by adding the suffix -oate to the parent name (Figure 11.47). One application of carboxylate anions is to serve as biologically inert anions for positively charged medications. 

The IUPAC rules name amides by appending the suffix -amide to the parent name of the carboxylic acid from which the amide is derived. If there are substituents on the amide nitrogen, they are given the locant N. Three examples are given in Figure 11.56. 

C The COOH group means that the molecule is a carboxylic acid and its name will use the suffix -oic acid. The presence of 4 carbon atoms means the prefix butan- will be used. An alternate name for the molecule is butyric acid. Choices A and B would be used for aldehydes (CHO group). Choices B and D would be used for 3 carbon atoms ... 

Common names for simple aldehydes are frequently encountered. These common names are derived from the common names for the related carboxylic acid (see Section 12.4) by replacing the suffix -ic acid with the suffix -aldehyde. Thus, the aldehyde related to acetic acid is acetaldehyde. If the carbonyl group of an aldehyde is attached to a ring system, the compound can be named as a hydrocarbon with the suffix -carbaldehyde. (Some sources use -carboxaldehyde.)... 

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