Basic IUPAC Organic Nomenclature

Common names for alkyl substituents

Certain alkyl substituents are very common, and you should be able to recognise and name them quickly, these are listed below.
In each case, the structural formula of the substituent is given where the C that is attached to the rest of the molecule is in bold. A line drawing of a generic example and the molecular models of the series of alkyl bromides are also available.

Notes:

• the the prefix iso is not hyphenated.
  
• the symbol "R" is commonly used to generically represent an alkyl group, e.g. R-X
• the prefixes sec- or s- and tert- or t- are commonly used to indicate specific types of branched substituents.
• The less common prefix n- (or neo-) is occasionally used for a straight chain (e.g. n-hexane CH₃CH₂CH₂CH₂CH₂CH₃)
  

Structural formula	Name	Symbol	Generic line drawing
CH3-	methyl	Me
CH3CH2-	ethyl	Et
CH3CH2CH2-	propyl	Pr
(CH3)2CH-	isopropyl	iPr
CH3CH2CH2CH2-	butyl
CH3CHCH2CH3	sec-butyl or s-butyl
(CH3)2CHCH2-	isobutyl
(CH3)3C-	tert-butyl or t-butyl	tBu

©Dr. Ian Hunt, Department of Chemistry