Nomenclature of Aldehydes If the CHO is bonded to a chain of carbons, find the longest chain containing the CHO group, and change the –e ending of the parent alkane to the suffix –al. If the CHO group is bonded to a ring, name the ring and add the suffix –carbaldehyde. Number the chain or ring to put the CHO group at C1, but omit this number from the name. Apply all the other usual rules of nomenclature. Figure 21.1

Common Names of Aldehydes Like carboxylic acids, many simple aldehydes have common names that are widely used. A common name for an aldehyde is formed by taking the common parent name and adding the suffix –aldehyde. Greek letters are used to designate the location of substituents in common names.

Nomenclature of Ketones In the IUPAC system, all ketones are identified by the suffix “one”. Find the longest continuous chain containing the carbonyl group, and change the –e ending of the parent alkane to the suffix -one. Number the carbon chain to give the carbonyl carbon the lowest number. Apply all of the usual rules of nomenclature. With cyclic ketones, numbering always begins at the carbonyl carbon, but the “1” is usually omitted from the name. The ring is then numbered clockwise or counterclockwise to give the first substituent the lower number.

Common Names of Ketones Most common names for ketones are formed by naming both alkyl groups on the carbonyl carbon, arranging them alphabetically, and adding the word “ketone”. Three widely used common names for some simple ketones do not follow this convention:

Naming Carboxylic Acids In the IUPAC system, carboxylic acids are identified by a suffix added to the parent name of the longest chain with different endings being used depending on whether the carboxy group is bonded to a chain or a ring. If the COOH is bonded to a chain, find the longest chain containing the COOH, and change the “e” ending of the parent alkane to the suffix “oic acid”. If the COOH is bonded to a ring, name the ring and add the words “carboxylic acid”. Number the carbon chain or ring to put the COOH group at C1, but omit this number from the name. Apply all the other usual rules of nomenclature.

Common Naming for Carboxylic Acids Greek letters are used to designate the location of substituents in common names. The carbon adjacent to the COOH is called the  carbon, followed by the  carbon, followed by the  carbon, the  carbon and so forth down the chain. The last carbon in the chain is sometimes called the  carbon. The  carbon in the common system is numbered C2 in the IUPAC system.

Naming Diacids and Salts Compounds containing two carboxy groups are called diacids. Diacids are named using the suffix-dioic acid. Metal salts of carboxylate anions are formed from carboxylic acids in many reactions. To name the metal salt of a carboxylate anion, put three parts together:

Naming Metal Salts of Carboxylate Anions Figure 19.2

Nomenclature—Acid Chlorides For acyclic acid chlorides: change the suffix –ic acid of the parent carboxylic acid to the suffix –yl chloride; or When the –COCl group is bonded to a ring: change the suffix –carboxylic acid to –carbonyl chloride.

Nomenclature—Anhydrides Symmetrical anhydrides are named by changing the acid ending of the carboxylic acid to the word anhydride. Mixed anhydrides, which are derived from two different carboxylic acids, are named by alphabetizing the names for both acids and replacing the word acid with the word anhydride.

Composition of Anhydrides Anhydride means without water. Removing one molecule of water from two molecules of carboxylic acid forms an anhydride.

Nomenclature—Esters

Nomenclature—Amides All 1° amides are named by replacing the -ic acid, -oic acid, or -ylic acid ending with the suffix amide.

Nomenclature—2° and 3° Amides

Nomenclature—Nitriles In contrast to the carboxylic acid derivatives, nitriles are named as alkane derivatives. Find the longest chain that contains the CN and add the word nitrile to the name of parent alkane. Number the chain to put CN at C1, but omit this number from the name. Common names of nitriles are derived from the names of the carboxylic acid having the same number of carbon atoms by replacing the –ic acid ending of the carboxylic acid with the suffix –onitrile. When the CN is named as a substituent it is called a cyano group.

Nomenclature—Nitriles CH3CH2CN is propanenitrile, not ethanenitrile.