How to Name Any Organic Compound:

  1. Find the longest continuous carbon chain you can find – this will be the “parent chain”. How many carbons are in it? This will be the foundation for your molecule name.
  2. Determine what type of molecule you have. Look for each of the following (see chart at the bottom of this page), in order.  Add the proper ending to the molecule name, and number the parent chain to give the functional group of the highest precedence the lowest number possible.
  3. If there any double bonds between carbons: What carbon do they start at? Put those numbers in front of “ene” and use di, tri, tetra, etc. as necessary.  If there are any triple bonds between carbons: What carbon do they start at? Put those numbers in front of “yne” and use di, tri, tetra, etc. as necessary.  Remove “e” from the end of each if the very next letter is a vowel (including y)
  4. What side chains are attached to the parent chain? Figure out what the name is for that side chain (see chart at the bottom), and what number carbon it's on.  Put the prefixes in alphabetical order.  If there are multiple instances of the same chain, list the numbers from smallest to largest and precede the prefix above with di, tri, tetra, penta, etc. These prefixes do not affect the alphabetical-ization you just did.  Put this string at the front of your molecule name.

Example 1: Name this molecule.

  1. The longest chain here is 6 carbons long will use "hex".
  2. This molecule has an -OH on the end, so it's an alcohol. We end alcohols with -ol at the end. The carbon with the OH attached is Carbon Number 1. We have to use the index “1” since an -OH could be anywhere on the chain.  So far, our molecule's name is "hex      -1-ol"
  3. There is a double bond starting at Carbon 2. Since the next letter will be “o”, we remove the “e” from “ene”.  So far we have "hex-2-en-1-ol"
  4. We have a “chloro” atom on carbon 3 and a “methyl” group on carbon 5.  Chloro goes before methyl in the alphabet.  So, our final molecule name is "3-chloro-5-methylhex-2-en-1-ol"

Example 2: Name this molecule.

  1. I count an 9-carbon chain, so we will use "non".
  2. This molecule has a =O in the middle of the carbon chain (as opposed to the end) which makes it a ketone.  We have to tell people which carbon the =O is on, and it's on the second carbon from the right.  We wouldn't say it's on carbon 7 (from the left) since we want this number to be lowest.  So far, we have "non       -2-one"
  3. There are only single bond in this molecule.  We add "ane" to the prefix, but remove the "e" because the next letter ("o" from "one") is a vowel.  We now have "nonan-2-one"
  4. Now, the side chains: We have an -OH on carbon 5 (5-hydroxy), two -F's on carbons 6 and 7 (6,7-difluoro) and a -Br on carbon 8 (8-bromo).  In alphabetical order, we have bromo, fluoro and hydroxy.  So, the final molecule name is "8-bromo-6,7-difluoro-5-hydroxynonan-2-one"
Note: The "di" of "difluoro" does not change the alphabetization of the side groups.  I don't care it's difluoro, trifluoro or tetrafluoro ... when you put them in alphabetical order, you pretend it's fluoro.

Order of Precedence in Organic Molecule Naming (with endings)

List of Side Chains for Organic Molecules