Suffixes naming alcohols

To name alcohols by the IUPAC rules, add the suffix -ol to the name of the parent and indicate the position of the hydroxyl group with a locant number (Figure 11.20). Simple alcohols are also commonly named by naming the alkyl group and then adding alcohol. ... 

Alcohols or alkanols are named by using the suffix -anol. The general rules discussed earlier are used to name alcohols. 

For more complex amines, systematic nomenclature is employed. Such names are constructed in a manner very similar to that employed to name alcohols. The largest chain attached to the nitrogen is chosen as the root, numbered so that the carbon attached to the nitrogen has the lower number, and the suffix -amine is attached. Other groups that are attached to the nitrogen are given the prefix N-. 

When naming alcohols, the ending of the hydrocarbon is removed and the suffix -ol is used instead. For example, when a hydroxyl group attaches to an ethane molecule, CH3CH3, the resulting alcohol, CH3CH2OH, is known as ethanol. 

When naming alcohols, take the name of the parent alkane and drop the final e from the parent name. Then add the suffix -ol to the end of the parent name. For example, the first alcohol in Figure 11.8 has one carbon atom and four single bonds. It looks like methane, but it is an alcohol. The name of this compound will be methanol. The second compound has three carbon atoms and is an alcohol. This compound is called 1-propanol, the l indicating that the functional group is on the first carbon atom. The alcohol on the right is called 2-propanol. Because it differs from 1-propanol only by the location of the —OH group, it can be considered to be an isomer of 1 -propanol. 

It is sometimes convenient to name alcohols by the carbinol system. According to this system, alcohols are considered to be derived from methyl alcohol, CH3OH, by the replacement of one or more hydrogen atoms by other groups. We simply name the groups attached to the carbon bearing the —OH and then add the suffix -carbinol to include the C—OH portion . ... 

The I.U.P.A.C. rules for naming thiols are similar to those for naming alcohols, except that the full name of the alkane is retained. The suffix -thiol follows the name of the parent compound. 

Systematic nomenclature is used for more complex amines and is similar to that used in naming alcohols except that the suffix is -amine. 

It should be noted that amine is used as a suffix that has been added to the name of the alkyl group. That is, unlike the functional group name alcohol, which is a separate word, for example, methyl alcohol, or the functional group name, ether, as in methyl ether, the functional group name amine, is appended directly to that of the alkyl substituent, that is, methanamine. 

The suffix for alcohols is -0I, attached to the name of the alkane (or alkene or alkyne) from which it is derived. Thus, CH3OH is methanol CHjCHjOH is ethanol. Table 4.3 gives some names, properties, and uses of the lower alcohols. For more complex examples such as 4.15, the... 

The term acjdoin is commonly used as a class name for the symmetrical keto-alcohols RCOCH(OH)R, and the name of the individual compound Is derived by adding the suffix oin to the stem name of the acid to which the acyloin corresponds, e.g., acetoin, propionoin, butyroin, etc. 

Diols are almost always given substitutive lUPAC names As the name of the prod uct m the example indicates the substitutive nomenclature of diols is similar to that of alcohols The suffix dwl replaces ol and two locants one for each hydroxyl group are required Note that the final e of the parent alkane name is retained when the suffix begins with a consonant ( diol) but dropped when the suffix begins with a vowel ( ol)... 

Cholesterol is the central compound m any discussion of steroids Its name is a combination of the Greek words for bile (chole) and solid (stereos) preceding the characteristic alcohol suffix ol It is the most abundant steroid present m humans and the most important one as well because all other steroids arise from it An average adult has over 200 g of cholesterol it is found m almost all body tissues with relatively large amounts present m the brain and spinal cord and m gallstones Cholesterol is the chief constituent of the plaque that builds up on the walls of arteries m atherosclerosis... 

Esters are named by replacing the ending -ic acid with the suffix -ate. The alcohol portion of the ester is named by replacing the -ane ending of the parent hydrocarbon name with the suffix -yl. The alkyl radical name of an ester is separated from the carboxylate name, eg, methyl formate for HCOOCH. Amides are named by changing the ending -oic acid to -amide for either systematic or common names, eg, hexanamide and acetamide. 

Among oxygen containing groups, a higher oxidation state takes precedence over a lower one in deter-rnining the suffix of the substitutive nane. Thus, a compound that contains both an alcohol and an aldehyde function is named as an aldehyde. 

Simple alcohols are named by the IUPAC system as derivatives of the parent alkane, using the suffix -ol. 

Thiols, sometimes called mercaptcms, are sulfur analogs of alcohols. They are named by the same system used for alcohols, with the suffix -thiol used in place of -ol. The -SH group itself is referred to as a rnercapto group. 

Ketones are named by replacing the terminal -e of the corresponding alkane name with -one. The parent chain is the longest one that contains the ketone group, and the numbering begins at the end nearer the carbonyl carbon. As with alkenes (Section 6.3) and alcohols (Section 17.1), the locant is placed before the parent name in older rules but before the suffix in newer IUPAC recommendations. For example ... 

Although a polyfunctional organic molecule might contain several different functional groups, we must choose just one suffix for nomenclature purposes. It s not correct to use two suffixes. Thus, keto ester 1 must be named either as a ketone with an -one suffix or as an ester with an -oate suffix but can t be named as an -onoate. Similarly, amino alcohol 2 must be named either as an alcohol (-0/) or as an amine (-amine) but can t be named as an -olamine or -anritiol. 

The only exception to the rule requiring a single suffix is when naming compounds that have double or triple bonds. Thus, the unsaturated acid H2C=CHCH2C02H is 3-butenoic acid, and the acetylenic alcohol HC=CCH2CH2CH2OH is 5-pentyn-l-ol. 

The common name of an ester consists of two words. The first word (methyl, ethyl,...) is derived from that of the alcohol the second word (formate, acetate,...) is the name of the acid with the -ic suffix replaced by -ate. Thus ethyl formate (Table 22.4) is made from ethyl alcohol and formic 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. 

Answer There are two functional groups in this compound, so we have to decide between calling this compound an amine or calling it an alcohol. If we look at the hierarchy above, we see that an alcohol outranks an amine. Therefore, we use the suffix -ol in naming this compound. 

One of the major organizing principles in organic chemistry is the presence of special arrangements of atoms. These so-called functional groups convey particular chemical properties. For example, a substance that contains an —OH group is called an alcohol. The systematic name of an alcohol is obtained by adding the suffix -ol to the name of the alkane with the same carbon framework. Thus, CH3 OH has the carbon framework of methane and is called methanol, whereas C2 H5 OH has the carbon framework of efhane and is called ethanol. 

As you see later in this chapter in the section Uniting acids and alcohols to make esters, esters come from an alcohol and an acid. The name of an ester reflects this origin. The alcohol name appears first (as an alkyl), and the acid name comes second, with the suffix -ate replacing the -ic acid part of the acid name. Two examples of ester structures and names are in Figure 12-4. 

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