ethers-1

Basic Organic Nomenclature

Ethers

1) Named as an alkyl alkyl ether:

Ethers are characterized by two alkyl groups being bonded to a central oxygen atom (i.e. R-O-R). The alkyls groups need not be the same, and may contain other function groups. Unfortunately there are several ways to name ethers. An older, but still common method for simple ethers, is to named it as an alkyl alkyl ether (note the spaces between the words). If the two alkyl groups are the same it is named as as dialkyl ether.

Examples naming simple ethers:

Compound Name	Line Drawing	3D Model
ethyl methyl ether
t-butyl propyl ether
isopropyl methyl ether
diethyl ether or ether

2) Named as an alkoxy- substituent:

The most common way of naming ethers is as an alkoxy substituent on a parent chain (or ring). This is the common method when one of the alkyl groups is a small simple group, while the other is complex containing multiple substituents or multiple bonds. In this case the smaller of the two alkyl groups is named as the alkoxy substituent, with the location indicated by the numbering scheme of the parent chain (or ring).

The alkoxy substituent is named by the root name of the chain chain, adding the -oxy suffix, i.e. methoxy, ethoxy, propoxy, ...

A few examples of naming alkoxy ethers:

Compound Name	Line Drawing
3-methoxy-1-propene
2-ethoxy-2,4-dimethylpentane
isopropoxycycloheptane
4-sec-butoxy-1-methylcyclohexene

Note: if you are naming the ether as an alkoxy substituent, it no longer has control over the numbering of the chain, all substituents are of equal priority and it is the location of the functional groups in the root or parent chain that will control the numbering first, or the first point of difference for the substituents. (i.e. see the first example above)

3) Named as an -oxa- substituent:

The final way to name ethers is an as oxa substituent. This method only applies to very complex molecules, where neither of the alkyl groups can be named as simple hydrocarbons, or to complex cyclic ethers.

The ether is named by including the oxygen atom in the length of the carbon chain (or ring). The location is identified by the position number and the -oxa- prefix. Note: the numbering of the chain follows previous rules, lowest numbers for substituents, multiple bonds, alphabetical order of substituents, etc.

A few examples of naming oxa ethers:

Compound Name	Line Drawing
7-chloro-2,3,4,8-tetramethyl-6-oxadecane
7-ethyl-4,8-dimethyl-6-oxa-2,4-nonadiene

Sulfides

Sulfides are the sulfur analog of ethers. They contain a sulfur atom bonded to two alkyl groups (i.e. R-S-R). The are named as an alkyl alkyl sulfide similar to the simple ethers.

A few examples of naming sulfides:

Compound Name	Line Drawing
ethyl methyl sulfide
dimethyl sulfide
sec-butyl propyl sulfide

Tutorial Quiz: Ethers

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