Nomenclature of organic compounds

Naming organic compounds can be a bit daunting, as there are a lot of rules and the names just get longer as the molecules get more complex, even if it is something familiar to you. Do you recognise the following names?




Ascorbic acid, or vitamin C

(5α,6α)-7,8-didehydro-4,5-epoxy-17-methylmorphinan-3,6-diol diacetate


Once you get the hang of it, naming organic compounds is really very easy, and I will demonstrate with the following molecule:

This one

First thing to do is find the longest carbon chain.

Longest carbon chain has 7 carbons

Then identify what functional groups, (if any) are present:

We have one methyl group and one chloro group

Now we number the carbons on the chain, so that the largest number of substituents have the lowest number:

This way the chloro is number 2 and the methyl is number 5. If I’d numbered it the other way, the methyl would be 3 and the chloro 6.

Now we put it all together remembering that we order the substituents alphabetically, a hyphen goes between a number and a letter, a comma goes between two numbers and there shouldn’t be any spaces, (except when the functional group requires it).

So… that gives us: 2-chloro-5-methylheptane!


Here are some links to some practice questions:

The order of precedence of functional groups can be found here



Filed under Chem 1, Organic Chemistry

2 responses to “Nomenclature of organic compounds

  1. Cal Gin

    Hey Emma,
    Its cal, just wondering with the last question from quiz one, there was a cycloalkane in triangle form, I couldn’t figure out what it was?

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