Basic Organic Nomenclature

Branched Alkanes - Multiple Different Substituents:

Substituents can have any number of carbon atoms in them, and each different group is named and located depending on the type of branch. Again, the substituents are named by using the root name for the number of carbon atoms in the chain, and adding -yl to indicate it is a substituent on the parent chain, i.e. methyl, ethyl, propyl, butyl, ...

The rule for ordering prefixes:
The order of listing the substituent prefixes is alphabetical before the addition of the multiple prefix identifiers such as di, tri, etc..

Thus the correct order is: butyl, ethyl, hexyl, methyl, pentyl, propyl ...

Example 1.)

analyzis:
root: dec        (10 carbon atoms in horizontal chain)
family: ane     (simple saturated hydrocarbon)
substituents    (numbering from right): 3-methyl, 4-ethyl, 6-propyl, 7-ethyl.
substituents    (numbering from left): 4-ethyl, 5-propyl, 7-ethyl, 8-methyl

Therefore the first numbering scheme is used as the 3-methyl as the first point of difference would be the methyl group when numbering from the right.

Putting these together, the IUPAC name for the compound is:    4,7-diethyl-3-methyl-6-propyldecane

Example 2.)
 

NOTE: The parent chain is indicated in the BOLD line. It is the longest chain of carbon atoms in the molecule.

analyzis:
root: dec        (10 carbon atoms in horizontal chain)
family: ane     (simple saturated hydrocarbon)
substituents    (numbering from right): 2-methyl, 3-ethyl, 5-methyl, 5-ethyl, 7-methyl, 7-ethyl.
substituents    (numbering from left): 4-methyl, 4-ethyl, 6-methyl, 6-ethyl, 8-ethyl, 9-methyl.

Putting these together, the IUPAC name for the compound is:    3,5,7-triethyl-2,5,7-trimethyldecane

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