Nomenclature of ethers

Simple ethers are commonly called alkyl alkyl ethers. The name consists of a hst of the alkyl (or aryl) groups in alphabetical order followed by the name ether. For example, an unsymmetrical ether with an -butyl group and a methyl group is named -butyl methyl ether. Symmetrical ethers are named by using the prefix di- along with the name of the alkyl group. For example, an ether with two isopropyl groups is called diisopropyl ether. 

Three- through six-membered cyclic ethers have common names. Cyclic ethers with three ring atoms are called epoxides. Since these compounds can be made by oxidizing an alkene, the common name of an epoxide adds oxide to the name of the alkene. 

The four-membered ring ethers, called trimethylene oxides, are not common. The five-membered ring ether is called tetrahydrofirran (THF) because of its relationship to the aromatic compound fiiran. Similarly, tetrahydropyran (THP), a six-membered ring ether, is related to pyran, an unsaturated ether. 

In the lUPAC nomenclature system, the names for cyclic ethers with three-, four-, five-, and stx-mem-bered rings are oxirane, oxetane, oxolane, and oxane, respectively. The oxygen atom in each of these rings receives the number 1 in both common names and lUPAC nomenclature. The ring is numbered in the direction that gives the lowest number to the first substituent. 

Which of the following compoimds can exists as pairs of enantiomers  

We have been using the common nomenclature of ethers, which is sometimes called the alkyl alkyl ether system. The lUPAC system, generally used with more complicated ethers, is sometimes called the alkoxy alkane system. Common names are almost always used for simple ethers. 

14-3A Common Names (Alkyl Alkyl Ether Names) 

Cyclic ethers are our first examples of heterocyclic compounds, containing a ring in which a ring atom is an element other than carbon. This atom, called the heteroatom, is numbered I in numbering the ring atoms. Heterocyclic ethers are an especially important and useful class of ethers. 

Epoxides (Oxiranes) We have already encountered some of the chemistry of epoxides (Section 8-12). Epoxides are three-membered cyclic ethers, usually fonried by peroxyacid oxidation of the corresponding alkenes. The common name of an epoxide is formed by adding oxide to the name of the alkene that is oxidized. The following reactions show the synthesis and common names of two simple epoxides. 

Ethylene oxide has been used as a fumigant for foods, texties, and soil, and for sterilizing biomedical instruments. It readily diffuses through materials without damaging them. Its antbacterial effect k probably due to its ability to alty-late critical cellular enzymes. 

When we name ethers we note to the functional groups attached to the oxygen atom. After naming these groups in alphabetical order we add the word ether . If the groups are symmetric in the ether, the prefix, di—, is written before the name of the group. 

Ethers are named according to the alkoxy alkane (RO- — R+) form in systematic naming. The number of the carbon atom to which the alkoxy group (RO ) is attached is indicated. 

If necessary, review the suggested sections to prepare for this chapter. 

PLUS Visit www.wileyplus.com to check your understanding and for valuable practice. 

Ethers are compounds that exhibit an oxygen atom bonded to two R groups, where each R group can be an alkyl, aryl, or vinyl group. 

The ether moiety is a common structural feature of many natural compounds, for example  

An opiate analgesic to regulate the sleep cycle used to treat severe pain 

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The rules apply equally well to the nomenclature of ether-linked proanthocyanidins, e.g., compound 10 is epioritin-(4(3 3)-epioritin-4(3-ol. ... 

In the nomenclature of ethers, either the suffix -ether or the prefix alkoxy- is used. For example, diethyl ether can be called ethoxyethane, and methyl t-butyl ether can be named as 2-methyl-2-methoxypropane. 

Nomenclature of Ethers 630 14-4 Spectroscopy of Ethers 633 14-5 The Williamson Ether Synthesis 635... 

Introduction to Ethers Nomenclature of Ethers Structure and Properties of Ethers Crown Ethers Preparation of Ethers Reactions of Ethers Nomenclature of Epoxides Preparation of Epoxides Enantioselective Epoxidation Ring-Opening Reactions of Epoxides Thiols and Sulfides... 

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