Branched alkanes:

Branched alkanes are alkanes along with alkyl substituents branching off from the main chain. They are named through the following process:

Figure:  (a) identify the longest chain; (b) number the longest chain.

• Recognize the longest chain of carbon atoms. In the instance displayed in the diagram, the longest chain contains five carbon atoms and a pentane chain;
• No. the longest chain of carbons, beginning from the end nearest the branch point (Figure);
• Recognize the carbon with the branching group (number 2 in Figure);
• Recognize and name the branching group. (In this instance it is CH₃. Branching groups (or substituents) are considered to as alkyl groups (C_nH_2n+1) rather than alkanes (C_nH_2n+2). Hence, CH₃ is called methyl and not methane.)
• Name the structure through first recognizing the substituent and its position in the chain, then naming the longest chain. Note that the substituent and the main chain is one complete word, i.e. 2-methylpentane than 2-methyl pentane.