Nomenclature Rules

  1. The root name is derived from the longest chain containing the highest priority functional group. When there is a choice, the chain with the most substituents is chosen.
  2. The suffix is used for the highest priority functional group, and the prefix for all others (except for alkenes and alkynes)
  3. For alkenes or alkynes in the root chain, the -ane ending is changed to -ene for alkenes and -yne for alkynes. In the event of a root chain containing an alkene and alkyne, an enyne is used.
  4. The number given for an alkene or alkyne is the carbon from which the alkene or alkyne starts.
  5. For the suffixes starting with a vowel, the -e is dropped from the end of the name. It is kept for suffixes with a vowel.
  6. Numbering the carbons in the root chain-

   

  1. If there is a suffix, give the group with the suffix (the highest priority group) the lowest number possible.
  2. If there is an alkene or alkyne, give the alkene or alkyne the lowest number possible.
  3. If there is no suffix or alkene/alkyne, number the carbons starting at the end with the closest substituent.

       1. In the event of a “tie",” number to give more substituents lower numbers 2. If there is still a “tie,” number so that the substituent that comes first alphabetically gets the lower number

  1. Numbers are separated from names with dashes and from other numbers with commas.
  2. List all substituents in alphabetical order. Latin prefixes do not count for ordering; however, “iso” does.