Names of Alkyl Groups

Alkyl groups are named by an lUPAC procedure similar to that used to name alkanes with the longest continuous chain beginning at the branch point. For example, the lUPAC name for an isopropyl group is 1-methylethyl, and the lUPAC name for an o-butyl group is 2-methylpropyl. The point of attachment of the alkyl group is numbered carbon 1. 

Complex alkyl groups are enclosed within parentheses when used to name hydrocarbons. Thus, 4-isopropylheptane is also 4-(l-methylethyl)heptane. The methyl within parentheses shows that it modifies ethyl, not heptane. The nonsystematic names for the alkyl groups containing three and four carbon atoms are commonly used, and lUPAC rules allow for their continued use. 

Name the following compound, which is produced by the alga Spirogym. 

The longest continuous chain has 16 carbon atoms and is named as a substituted hexadecane. The chain is numbered from left to right to locate the four methyl groups at positions 2, 6, 10, and l4. The compound is 2,6,10,14-tetramethylhexadecane. 

First identify the longest continuous chain. That gives the parent, hexane. 

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TABLE D.4 Alkane Nomenclature Number of carbon atoms Formula Name of alkane Name of alkyl group... 

List the locations and names of alkyl groups in alphabetical order by their name (ignoring the di-, tri- prefixes) and end the name with the parent hydrocarbon. 

Name of alkyl group Formula Functional group X and boiling point. °C (1 atm)... 

Determine the numbered locations and names of the substituted alkyl groups. Use di-, tri-, and similar prefixes for alkyl groups represented more than once. Separate numbers by commas and groups by dashes. List the locations and names of alkyl groups in alphabetical order by their name (ignoring the di- tri- prefixes) and end the name with the parent hydrocarbon. 

Parent Alkane Structure of Parent Alkane Structure of Alkyl Group Name of Alkyl Group... 

Naming of alkyl groups. Alkyl groups are named like the alkanes they are derived from, with a -yl suffix. 

It has been suggested that the names of alkyl groups be derived from the alkane having the same carbon chain as the alkyl group. The -e ending of that alkane is replaced by -yl, and the chain is numbered from the end that gives the carbon at the point of attachment its lower number. This number immediately precedes the -yl ending and is bracketed by hyphens. 

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