Ethers & Epoxides

(The classes of compounds, in which two carbon atoms are connected to an oxygen atom; epoxides are the 3-membered, cyclic version. )

Basic IUPAC nomenclature-Ethers (See the home page for parent root names, prefixes & suffixes.)

1) The longest continuous carbon chain will be the parent name. 

2) Name the -OR group as a substituent.

The longest chain is the ethane; the OR group is methoxy. Thus, the name becomes Methoxy-  +  ethane = Methoxyethane.

3) If there are two alkoxy groups, they are handled in the same fashion. They would be diethers.

The longest chain is still ethane, but now, there are two alkoxy substituents, and they are both methoxy groups. Numbers are used to describe the positions of the alkoxy groups. Thus, this name becomes: 1,2-Dimethoxyethane also known by its abbreviation: DME.

Common Names

All ethers will also have a common name, which is often used interchangeably with the IUPAC name. To assemble the common name, the two groups flanking the O atom are named, alphabetized and the word "ether" is added.

Some examples:

IUPAC	Ethoxyethane	1-Methoxy-1,1-dimethylethane	Methoxyethane	1-Methoxybutane
Common	Diethyl ether	Methyl-t-Butyl ether (MTBE)	Ethyl methyl ether	Butyl methyl ether

Basic nomenclature-Cyclic Ethers

Cyclic ethers have IUPAC names and the prefix ox- indicates the presence of oxygen in the ring system. Suffixes indicate the number of atoms in the ring. The first few members of this series are shown below:

IUPAC	Oxirane	Oxetane	Oxolane	Oxane
Common	ethylene oxide	none	tetrahydrofuran	tetrahydropyran

Basic nomenclature-Epoxides

1) Simple epoxides are named as derivatives of oxirane.

2) Where the epoxide is part of another ring system, it is shown by the prefix epoxy-.

3) Common names are derived from the name of the alkene from which the epoxide is formally derived; name the alkene and the term oxide is added.

 

IUPAC	Oxirane	cis-2,3-Dimethyloxirane	1,2-Epoxycyclohexane
Common	ethylene oxide	cis-2-butene oxide	cyclohexene oxide

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EXERCISE: Write the IUPAC name for each of the following structures.

STRUCTURE		NAME	STRUCTURE		NAME
1			6
2			7
3			8
4			9
5			10

 

END OF SECTION

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email questions & comments to: Dr. JA Colapret

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